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IEEE Transactions on Industrial Electronics
Journal Prestige (SJR): 2.192
Citation Impact (citeScore): 9
Number of Followers: 85  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0278-0046
Published by IEEE Homepage  [228 journals]
  • IEEE Industrial Electronics Society

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      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • IEEE Industrial Electronics Society

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      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Information for Authors

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      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Modified T-Type Three-Level AC–DC Converter Based Multifunctional
           Compensator for Three-Phase AC Power System With Low-Frequency Pulsed Load
           

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      Authors: Jianxin Zhu;Hongfei Wu;Lin Li;Jiangfeng Wang;Ming Hua;Yan Xing;
      Pages: 11844 - 11855
      Abstract: In order to achieve an efficient pulsed power compensation for the ac-sourced pulsed power system, a multifunctional compensator (MFC) of modified T-type semi-two-stage converter is proposed in this article. The power decoupling capacitor is in parallel with one of the dividing capacitors of the three-level ac/dc converter, so that the voltage of decoupling capacitor is able to vary in a very wide range without increasing the voltage stress of the converter. The semi-two-stage compensator achieves better compensation performance and less decoupling capacitor than the single-stage circuit while having higher efficiency and lower converter power rating than the two-stage solution. Operating principles of the semi-two stage MFC are analyzed in detail, and a modulation strategy is presented to achieve two-path power flow between the decoupling capacitor and ac power system. In order to improve the dynamic response of the MFC during the transition between different pulse frequency loads, a power-difference feed-forward control and a dual low-pass filter control are proposed for the compensation. A prototype is built and tested to verify the effectiveness and feasibility of the proposed MFC and control methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Flexible Space Vector Modulation Scheme for Cascaded H-Bridge Multilevel
           Inverters Under Failure Conditions

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      Authors: Hongjian Lin;Mahmoud Mehrabankhomartash;Fan Yang;Maryam Saeedifard;Jiangpeng Yang;Zeliang Shu;
      Pages: 11856 - 11867
      Abstract: Space vector modulation (SVM) is a mature modulation scheme, which is widely used for voltage source inverters. In this article, a flexible online SVM scheme is proposed for a cascaded H-bridge multilevel inverter (CHMI) under short-circuit and open-circuit switch as well as cell failure conditions. The proposed scheme directly calculates all the active redundant switching states and the dwelling duty cycles of the three space vectors enclosing the reference vector for a CHMI such that balanced line-to-line voltages and currents under failure conditions are generated. Accordingly, the resultant switching sequences are determined to meet any specific requirement, e.g., even-order harmonics elimination and minimization of switching losses. Furthermore, in order to reduce voltage stress on the semiconductors under short- and open-circuit switch conditions, an equal power distribution criterion is introduced. The proposed SVM scheme is fast and independent of the number of levels. Experimental results are presented to demonstrate performance and effectiveness of the proposed scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Predictive Zero-Sequence Current Control of Multiple Paralleled Power
           Converters

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      Authors: Yu Li;Han He;Zhen Li;Zhenbin Zhang;
      Pages: 11868 - 11878
      Abstract: In this work, we develop a zero-sequence model to analyze the zero-sequence current, i.e., circulating current, in multiple paralleled power converters. On this basis, we propose and verify a novel and simple solution: predictive zero-sequence current control (PZSC$^2$) to freely mitigate the zero-sequence current. The proposed technique is implemented in a direct model predictive control framework via a synthesized voltage vector, which consists of an optimal shrunken voltage vector and a zero voltage vector. The former is selected to minimize the tracking error of the $alpha beta$-axis current, while the latter is properly selected to mitigate the circulating current. Notably, the zero voltage vector is solely determined by the zero-sequence current direction, without using other converters’ operating knowledge. This permits the proposed PZSC$^2$ to operate in a self-governing manner, fitting the spatially distributed applications. We validate the proposed solution through a lab-constructed hardware test bench. Experimental results verify its effectiveness considering both steady-state and transient performance.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Modified DPWM Method With Minimal Line Current Ripple and Zero-Sequence
           Circulating Current for Two Parallel Interleaved 2L-VSIs

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      Authors: Shiming He;Yadong Wang;Bangyin Liu;
      Pages: 11879 - 11889
      Abstract: High-performance comprehensive optimization of line current ripple, zero-sequence circulating current (ZSCC), and switching losses is a challenge for parallel interleaved inverters. This article proposes a modified discontinuous pulse width modulation (PWM) method for two parallel interleaved two-level voltage-source inverters (2L-VSIs), which are regarded as a single 3L-VSI to optimize its vector sequence. The line current ripple is the priority optimization target to guarantee the principle of the nearest three vectors is applied in each subsector. To reduce the ZSCC and switching losses, the vector combinations with smaller changing rate of ZSCC are selected, and the phase-leg carrying the highest current is clamped. The detailed design procedure of 3L-vector sequence and how to distribute to 2L-VSIs are revealed. The quantitative performance comparison between the proposed PWM method and existing ones in terms of line current ripple, ZSCC, and switching losses are made. Experimental results confirm the effectiveness of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • $x-y$ +Current+Regulation&rft.title=IEEE+Transactions+on+Industrial+Electronics&rft.issn=0278-0046&rft.date=2022&rft.volume=69&rft.spage=11890&rft.epage=11902&rft.aulast=Miazga;&rft.aufirst=Mohammad&rft.au=Mohammad+Hosein+Holakooie;Grzegorz+Iwanski;Tomasz+Miazga;">Switching-Table-Based Direct Torque Control of Six-Phase Drives With $x-y$
           Current Regulation

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      Authors: Mohammad Hosein Holakooie;Grzegorz Iwanski;Tomasz Miazga;
      Pages: 11890 - 11902
      Abstract: High harmonic contents of the stator currents due to uncontrolled $x-y$ subspace dramatically overshadow the performance of the switching-table-based direct torque control (ST-DTC) strategy for multiphase drives. The concept of ST-DTC based on virtual voltage vectors (VVs) has been frequently developed to alleviate this problem. However, VVs with fixed duty ratios are incapable of compensating inherent machine/converter asymmetries and dead time harmonics, which are mapped into the $x-y$ subspace. To solve this problem, this article develops a dynamic duty-ratio-based DTC technique for six-phase induction machine drives, where the duty ratios of the selected VVs are not constant anymore. These duty ratios are updated based on the $x-y$ voltage commands arising from the closed-loop $x-y$ current controllers over every sampling period. The attained merits over and above the conventional fixed duty-ratio-based DTC schemes include effective $x-y$ current cancellation without increase in average switching frequency and decrease in dc-link utilization. Experimental results are presented to validate the effectiveness of the proposed control technique.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Computationally Efficient Model Predictive Control With Fixed Switching
           Frequency of Five-Level ANPC Converters

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      Authors: Yong Yang;Jianyu Pan;Huiqing Wen;Xinan Zhang;Margarita Norambuena;Longya Xu;Jose Rodriguez;
      Pages: 11903 - 11914
      Abstract: This article proposes a fixed switching frequency (FSF)-based improved model predictive control (MPC) for a five-level active neutral-point clamped (5L-ANPC) converter. Compared to the conventional MPC for 5L-ANPC converter, the proposed MPC significantly reduces the computational burden while ensuring the balance of dc-link and flying capacitor voltages. The proposed MPC optimally selects the control voltage vectors to reduce common mode voltage (CMV), leading to a small CMV of the converter. Using three voltage vectors action per control cycle in MPC, FSF is achieved. Steady-state and dynamic performances of the proposed MPC have been evaluated by experiments. The results verify the feasibility and effectiveness of the proposed MPC method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Overvoltage Suppression for Modular Multilevel Converter With Switch
           Open-Circuit Fault

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      Authors: Zhen Wang;Li Peng;
      Pages: 11915 - 11925
      Abstract: To enhance reliability and exploit advantages, modular multilevel converters (MMCs) are mostly desired with uninterrupted operational capability during submodule (SM) open-circuit fault. Once an SM fault is located, the closing signal will be delivered to the corresponding bypass switch. However, due to the response delay of mechanical switches, capacitor voltage of the SM with lower switch fault will continue increasing, thus resulting in severe overvoltage and threatening the safety of MMC. In view of this, this article proposes an arm current reshaping-based method to suppress capacitor overvoltage under SM failure. During the period of overvoltage suppression, all the arm currents are reshaped to decrease capacitor charging of the faulty SM and maintain the terminal currents of MMC. Besides, since the capacitor voltage variations are also reshaped by the reshaped arm current, common-mode voltage is injected to satisfy the requirements of arm voltages. Consequently, the degree of SM overvoltage can be alleviated by over 50% without extra hardware investment. Simulation and experimental results confirm the feasibility and validity of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Mission Profile Emulation for Flexible Number of Submodules in Modular
           Multilevel Converters With Nearest Level Modulation

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      Authors: Shan Jiang;Ke Ma;Xu Cai;Georgios Konstantinou;
      Pages: 11926 - 11935
      Abstract: Mission profile emulation (MPE) for submodules (SMs) in the modular multilevel converter (MMC) is a crucial step before a full-scale system is put into field operation. Existing methods suffer from limitations of the testing accuracy due to the staircase-like arm voltages that result in distorted loading current and require large filter inductance. This is especially the case when a limited number of SMs are under test. In this article, an efficient MPE method is proposed to emulate the loading behaviors of multiple SMs in MMC. The testing circuit allows two arms of MMC with flexible SM number, operating in inverting and rectifying mode under nearest level modulation, to be tested simultaneously with reduced dc supply voltage. A common H-bridge circuit is introduced in the testing circuit, with each arm of the H-bridge circuit functioning as the voltage compensator by using feedforward control. In this way, the current distortion can be significantly suppressed, and testing accuracy can be guaranteed in a cost-efficient manner even though no large inductor is included in the testing circuit. The proposed method allows SMs under test to be loaded as in the actual back-to-back MMC system. Simulations and experimental measurements are given to validate the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A New Type of Three-Phase Asymmetric-LCL Power Filter for Grid-Tied
           Voltage Source Inverter With Step-Up Transformer

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      Authors: Weimin Wu;Yaozhong Zhang;Frede Blaabjerg;Henry Shu-Hung Chung;
      Pages: 11936 - 11945
      Abstract: Power filters have been widely used to suppress switching harmonics caused by the modulation of grid-connected inverters. In order to save the total inductance and cost and reduce the volume, different power filters were proposed for the three-phase three-wire grid-connected voltage source inverter. However, in industrial applications, due to the consideration of production cost, the difficulties caused by the deviation of actual parameters have to be addressed. In this article, we propose a new three-phase three-wire power filter with a simple structure, almost the smallest total inductance, and strong resistance to the adverse effects of parameter shifts. The parameters of the proposed filter and the design of the grid-connected system controller are introduced in detail. When studying the influence of parameter offset, a comparison between different types of notch power filters is also given. Simulation and experimental results on a 380 V/50 Hz/6 kW three-phase inverter prototype verify the performance of the proposed power filter.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Enhanced Short-Horizon Integration Actual Voltage Reconstruction Method
           Based on Inverter Nonlinear Error Inverse-Compensation

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      Authors: Naizhe Diao;Xianrui Sun;Chonghui Song;
      Pages: 11946 - 11956
      Abstract: In this article, an enhanced short-horizon integration actual voltage reconstruction method based on nonlinear error inverse-compensation (NEIC-SHIVR) is proposed for voltage source inverters. The NEIC-SHIVR method takes into account not only the influence of nonlinear errors in modulation such as dead time addition and narrow pulses elimination on voltage reconstruction but also considers the influence of nonlinear errors in PWM transfer links such as power switch delay and switch voltage drop on voltage reconstruction. First, the real-state driving signal is computed by the output driving signal and the power switch delay time. The auxiliary driving signal is reconstructed to get the auxiliary switching state according to the phase current direction. Second, referring to the auxiliary switching states and the phase-current directions, the instantaneous equivalent bus voltage within each clock pulse is computed by the dc-bus voltage and the switch voltage drop. Finally, the output voltage within each switching period is integrated by the reconstructed instantaneous equivalent bus voltage in each clock pulse. Compared with SHIVR, NEIC-SHIVR provides a more accurate reconstructed voltage. Compared with other methods, NEIC-SHIVR inherits many advantages of SHIVR. For example, it can apply to any PWM method and does not use high-cost high-frequency voltage sensors, which improves system reliability and reduces system complexity. Simulations and experiments verify the effectiveness of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A High Voltage Gain Capable MMC for Offshore Wind Farms: Frequency
           Component Analysis and Minimization of Capacitor Voltage Ripple

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      Authors: Rahul Mishra;Kamal M. Vaghasiya;Vivek Agarwal;
      Pages: 11957 - 11967
      Abstract: Modular multilevel converter (MMC) and HVdc technology together provide an indispensable solution to integrate offshore wind farms with onshore ac grid. However, the bulky size of MMC and voltage boosting transformers (VBTs) pose a big challenge to keep the footprint and cost of the onshore-platform low. With this background, a full-bridge submodule (SM) modified MMC and a suitably modified switching function are proposed, which utilize the negative SM voltage to achieve ac side voltage boosting. How much negative SM voltages are to be applied across the arms is determined by the group submodule ratio (GSR) parameter, introduced in the switching function. The acquired boosting ability not only shrinks the voltage boosting requirement of VBTs but also reduces the semiconductor switches (upto 10%) and/or the SM count (8%–30%). Analytical solutions derived for the SM capacitor sizing are also presented. The analysis is further utilized to obtain a novel circulating current injection scheme (CCIS), which utilizes phasor analysis to obtain the values of circulating current control parameters. The CCIS suppresses SM capacitor voltage ripple, especially fundamental, and reduces the capacitance requirement by 10%–15% for a wide range of GSR. Representative simulation results are showcased, and the theoretical claims are validated by hardware experiment.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • $+LC$ -Filtered+Voltage+Source+Inverters&rft.title=IEEE+Transactions+on+Industrial+Electronics&rft.issn=0278-0046&rft.date=2022&rft.volume=69&rft.spage=11968&rft.epage=11978&rft.aulast=Blaabjerg;&rft.aufirst=Changming&rft.au=Changming+Zheng;Zheng+Gong;Xiaojie+Wu;Tomislav+Dragičević;Jose+Rodriguez;Frede+Blaabjerg;">Finite-Set Quasi-Sliding Mode Predictive Control of $ LC$ -Filtered
           Voltage Source Inverters

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      Authors: Changming Zheng;Zheng Gong;Xiaojie Wu;Tomislav Dragičević;Jose Rodriguez;Frede Blaabjerg;
      Pages: 11968 - 11978
      Abstract: Three-phase voltage source inverters (VSIs) with output $ LC$ filter are preferred topologies to provide voltage and frequency support for islanded ac microgrids. This article proposes a finite-set quasi-sliding model predictive control (FS-QSMPC) scheme for $LC$-filtered VSIs to improve the output-voltage quality. By explicitly including a predictive sliding-mode function into the cost function, reduced steady-state ripple and enhanced robustness are achieved compared to typical FS-MPC. Besides, theoretical analysis of stability and robustness for FS-QSMPC is given. Analytical tuning of the weighting factor is also derived to decrease the tuning effort. Comparative simulations and experiments verify the presented approach.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A New Three-Phase Inverter Topology for Reducing the dv/dt and
           Peak-to-Peak Value of Common Mode Voltage

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      Authors: Arpan Hota;Vivek Agarwal;
      Pages: 11979 - 11986
      Abstract: Existing dc and ac bypass-assisted two-level three-φ inverter topologies can only reduce the peak-to-peak (P-to-P) common mode voltage (CMV) value by 66.6%. However, the dv/dt of CMV remains unchanged. This issue can be easily addressed by using a multilevel inverter but it increases the size, cost, and complexity of the system. As an alternative, this article proposes a novel three-phase inverter topology where one leg (out of three) of the inverter is configured to produce three-level pole voltage while the other two legs produce two-level pole voltages. This results in a unique space vector (SV) diagram with 12 SVs, whereas a 2-level inverter has only 8 SVs. A new pulsewidth modulation scheme is proposed that can utilize the SV diagram in such a way that dv/dt of CMV is reduced by 50% along with a 66.6% reduction in CMV P-to-P value in each switching cycle. Another advantage of the proposed topology is the reduced conduction losses due to fewer switches conducting at any given time. The proposed topology is compared with the existing solutions to prove its advantages. Simulation and experimental results are presented for a three-phase induction motor load to validate the various claims.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Artificial Intelligence Approach for Real-Time Tuning of Weighting
           Factors in FCS-MPC for Power Converters

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      Authors: Sergio Vazquez;Daniel Marino;Eduardo Zafra;Maria Dolores Valdés Peña;Juan J. Rodríguez-Andina;Leopoldo Garcia Franquelo;Milos Manic;
      Pages: 11987 - 11998
      Abstract: In this article a finite control set model predictive control, is used to track a current reference in a power converter connected to an $RL$ load. An artificial intelligence approach is presented for real-time determination of the weighting factor that regulates the average switching frequency, independently of the operating point. The article focuses on the design, training, and digital implementation of an artificial neural network (ANN) that can be developed in a low-cost control platform. It is presented a sampling and offline ANN training procedure, together with a low-cost hardware implementation based on integer quantization of the ANN. The abovementioned approach provides a standalone application, serving as a framework for the development of ANN applications for power-converters. The main advantage of the presented approach is that the ANN inference is executed in real time. In this way, the weighting factor is automatically updated in real-time, allowing the system to quickly adapt to any reference step changes, and consequently provide the desired behavior. Executing the setup in laboratory prototype confirmed the theoretical analysis and successful tracking of the reference frequency.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design and Implementation of 3-kW Simmer and 30-kV DC Trigger Power Supply
           System for Driving Xenon Flash Lamps in Large-Area Processes

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      Authors: Jae-Beom Ahn;Seung-Ho Song;Hong-Je Ryoo;
      Pages: 11999 - 12008
      Abstract: This article describes a 3-kW simmer and 30-kV dc trigger power supply system for driving xenon flash lamps in large-area processes. Simmer power supply is designed to output maximum of 3 kV for maintaining the lighting state of the lamp after having triggered and to supply low ripple current continuously for maintaining the ignited state. It is designed based on an LCC resonant converter and design and implementation of the high-voltage transformer and output rectifier are presented. For igniting xenon lamps, dc trigger is designed to output a maximum of 30 kV auxiliary trigger voltage. The system that both power supplies is operated by one main inverter is presented. Through the resistive-load test, it is verified that the simmer outputs 600 V, 5 A under rated-load condition and 120 V, 1 A under light-load conditions. It is also verified that the simmer outputs 3 kV and the dc trigger outputs 30 kV under the no-load condition.Finally, the simmer and dc trigger power supply system is applied to lighting various xenon lamps from single lamp (306 mm, 8Φ) to three series lamps (400 mm, 26Φ). Required output voltages for stable driving various types of xenon lamps in the lighting mode are presented.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Extended Control of the Input Angle for Matrix Converters Connected
           With the Nonunity Power Factor Loads

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      Authors: Pawel Szczepankowski;
      Pages: 12009 - 12018
      Abstract: This article proposes a novel pulsewidth modulation (PWM) modulation algorithm for multiphase conventional matrix converters, with three inputs and $k$ outputs, using the transfer function of the load angle. The proposed approach extends the range of power angle control at the input during the operation with a maximum voltage transfer ratio. The proposed concept is based on the direct analytic voltage PWM modulation with an elliptical trajectory of reference load voltages. The proposal has been verified using the circuit simulation in PSIM software, symbolic analysis using MATLAB, and finally through an experiment.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design and Evaluation of a Virtual Vector Based Modulated Model Predictive
           Control for the Indirect Matrix Converters With Improved Performance

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      Authors: Zheng Gong;Jingjie Li;Peng Dai;Dahui Su;Xiaojie Wu;
      Pages: 12019 - 12029
      Abstract: A virtual vector based modulated model predictive control (VV-M2PC) strategy is proposed for the indirect matrix converters (IMCs) in this article. Compared with the conventional M2PC, the VV-M2PC constructs and utilizes new virtual vectors to reduce the current control errors. Besides, the implementation and feasibility for the proposed strategy is discussed in detail. The comparative simulation and experimental results based on an experimental IMC prototype verify that the steady-state control performance can be improved under the VV-M2PC without affecting the dynamic-state control performance and increasing the computational burden.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Fault Tolerant Maximum Torque Per Ampere (FT-MTPA) Control for Dual
           Three-Phase Interior PMSMs Under Open-Phase Fault

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      Authors: Guodong Feng;Yuting Lu;Chunyan Lai;Beichen Ding;Narayan C. Kar;
      Pages: 12030 - 12041
      Abstract: For the dual three-phase interior permanent magnet synchronous machines (DT-IPMSMs), open-phase fault can cause current unbalance and degrade the drive performance. This article proposes a fault tolerant maximum torque per ampere (FT-MTPA) control for DT-IPMSMs, which can maximize the ratio of the average torque to the stator current and minimize the fault-induced torque ripple. In the proposed approach, optimal FT-MTPA solution is derived and theoretically proven, and current rms is considered as one design constraint to ensure the equivalent loss to the healthy condition. The proposed FT-MTPA control ensures the smooth switching between fault tolerant control and healthy control without inducing noticeable torque ripple. Compared with existing methods, the proposed approach is computation-efficient and fast in achieving the FT-MTPA control, which is critical to practical applications with fast changing loads. Moreover, this article derives the optimal solution from the faulty MTPA model with fault induced terms considered to ensure high torque. Experiments and comparisons with existing methods are conducted to evaluate the proposed approach on a laboratory DT-IPMSM.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improvement of Integrated-Induction-Based Hybrid Excitation Brushless DC
           Generator by Employing Novel Consequent-Pole Rotor

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      Authors: J. Li;K. Wang;C. Liu;
      Pages: 12042 - 12054
      Abstract: In order to achieve both the brushless excitation and flexible regulation of output voltage, the integrated-induction-based hybrid excitation brushless dc generator (II-HEBDCG) combining the main generator part with the induced excitation part is presented in this article. Moreover, the novel consequent-pole rotor featuring the pole sequence of iron-S-iron-iron-N-iron (I-S-I-I-N-I) is proposed to enhance the flux regulation capability because each coil of the main field winding (MFW) can regulate the flux of two iron poles simultaneously, where the flux paths of permanent magnet and MFW exhibit in parallel. The selection rules of pole and slot combination are summarized theoretically, and the principle of flux regulation is revealed based on the equivalent magnetic circuit, which are confirmed by finite element analysis. Then, the influences of key parameters on the performance are discussed. Furthermore, the electromagnetic performance of the proposed II-HEBDCG with the pole sequence of I-S-I-I-N-I, including the no-load flux density distribution, no-load voltage regulation, output characteristics, loss and efficiency, are comprehensively investigated and compared with that of the II-HEBDCG with conventional pole sequence of N-iron-iron-iron. It is demonstrated that the proposed II-HEBDCG obtains not only better flux (or voltage) regulation capability but also higher output power, and hence, obtains higher efficiency than the conventional one. Finally, a prototype is built and tested to verify the analyses.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Meshless Generalized Finite Difference Method to Analyze Electromagnetic
           Performance of SPM Machines With Eccentric Rotor Shape

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      Authors: Yi Wang;Jinghua Ji;Wenxiang Zhao;Donghui Cao;Zhujin Ren;
      Pages: 12055 - 12065
      Abstract: In this article, we propose an unconventional method, i.e., generalized finite difference method (GFDM), to analyze the electromagnetic performance of surface-mounted permanent magnet (SPM) machine with eccentric rotor shape. The remarkable characteristic of this method is that it is meshless. In this method, the solution region is discretized in the form of nodes, and the nodes can move with the moving structure. This is very helpful in modeling the SPM machine because there is no remeshing process during the rotation. However, mesh generation is required in the traditional finite-element analysis (FEA). First, the basic principle of the proposed GFDM is introduced. Second, the whole field domain is divided into five types of regions, viz., PMs, air gap, slot openings, slots, and stator core. Third, the differential equations satisfied by each region are discretized into algebraic equations by the GFDM. The interfaces need to be dealt with separately because of the discontinuity of the derivative of the vector potential. Then, the systems of equations are solved to analyze the electromagnetic performance of an SPM machine. Finally, this method is implemented on a 12-slot, 10-pole SPM machine. Meanwhile, the effectiveness of this method is verified by an FEA and experiment.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Computationally Efficient Finite Control Set Model Predictive Control
           for Multiphase PMSM Drives

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      Authors: Bin Yu;Wensheng Song;Kexin Yang;Yongqi Guo;Mahmoud S. R. Saeed;
      Pages: 12066 - 12076
      Abstract: Finite control set model predictive control (FCS-MPC) has been widely studied and applied in power converters and machine drives. It takes advantage of the nonlinear finite switching states of the power converters, and a discrete model is used to predict the behavior of the system. The main advantages of FCS-MPC lie in easy inclusion of nonlinear constraints, simple structure and intuitive concept. However, FCS-MPC applied in multiphase machine drives will face with the challenge of heavy computation cost. In this article, a computationally efficient FCS-MPC method is proposed for multiphase drives. The concept of virtual voltage vector is introduced to eliminate low-order harmonic currents in open-loop mode, resulting in simplified prediction model and cost function. To further simplify the enumerative optimization process, the redundant vectors are eliminated, and only five evaluations are required. By this way, the computation complexity is considerably reduced and is approximately irrespective of phase number. Thus, it can be easily generalized to multiphase drives. Moreover, the merit of simple structure is kept, which is the most important characteristic of FCS-MPC. The proposed method is compared with the existing FCS-MPC methods to illustrate its effectiveness. The experimental results have verified that the proposed method can reduce computation complexity, achieve superior steady-state and dynamic performance.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A New Space Vector Pulse Density Modulation Scheme for Two-Level Five
           Phase Induction Motor Drive

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      Authors: Monisha Menon A.;Biji Jacob;
      Pages: 12077 - 12085
      Abstract: Variable speed drives incorporating multiphase motors have started gaining attention in recent years due to their benefits over three-phase counter parts. In this article, we propose a digital control scheme based on space vector pulse density modulation for two-level five phase induction motor drive. The scheme combines principles of digital signal processing techniques, such as sigma delta modulation and vector quantization, along with space vector modulation to form computationally efficient motor drives. In this article, vector space is divided into ten nonoverlapping regions, with each region partitioned into three voronoi regions. The reference vector is vector quantized to the nearest switching vector. Absence of dwell time calculations, less memory requirements, and reduced computational complexity of the scheme along with reduced acoustic noise and electromagnetic interference in the drive are the core advantages of the scheme. The work has been experimentally implemented with 2 HP five-phase induction motor drive and the results are compared with space vector pulsewidth modulation scheme for validation purpose.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Principle and Performance of a New Brushless Doubly Fed Reluctance Machine
           With Asymmetrical Composite Modulator

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      Authors: Honghui Wen;Ming Cheng;Gan Zhang;
      Pages: 12086 - 12095
      Abstract: For the brushless doubly fed reluctance machine (BDFRM), a composite rotor featuring salient pole reluctance and short-circuited coils (SCC) is applied to efficiently improve the cross-coupling capability and magnetic field modulation effects, where the SCCs induce symmetrical multiphase current and then establish the corresponding additional magnetizing magnetomotive force to modulate the source one. This article investigates the modulation behavior and evaluates the modulation capability of the composite modulator from the perspective of the magnetic field conversion mechanism. The modulated airgap harmonic phase-shift phenomenon in space caused by the SCC modulator is first observed, resulting in the reduction on the effective magnetic field conversion factors in the BDFRM with conventional symmetrical composite rotor. The phase-shift mechanism is revealed for the first time, then an asymmetrical composite modulator configuration is proposed to eliminate the phase shift so as to enhance the rotor cross-coupling capability and improve torque performance. A BDFRM prototype with the asymmetrical composite modulator is designed and manufactured for experimentation. Theoretical predictions are verified by two-dimensional finite-element analysis together with experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Novel Radial–Axial Flux Switching Permanent Magnet Generator

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      Authors: Mohammad Ali Noroozi Dehdez;Jafar Milimonfared;
      Pages: 12096 - 12106
      Abstract: In this article, a novel radial–axial (RA) flux switching permanent magnet generator (FSPMG) is introduced. In contrast to other RA flux machines, a major advantage of this generator is its implementation only by the use of conventional nonoriented electrical steel sheets, even though the flux linkage of the novel RA-FSPMG has a 3-D path. Besides that, it benefits from the flux concentration strategy and a passive rotor. A concrete foundation of the novel RA-FSPMG is provided, in which, the 3D-Flux path is described, working principles are discussed, and power-sizing equation is derived. No-load characteristics and the full-load performance of an optimized RA-FSPMG are investigated in contrast to an optimized double stator radial FSPMG and an optimized double stator axial FSPMG with similar volume, number of permanent magnets (PMs), and electrical loading. The results show the competitiveness of the novel RA-FSPMG, in particular, in the output power and the required copper mass. Furthermore, the PM demagnetization possibility and the rotor axial pull force of the optimized RA-FSPMG are investigated, in detail. All discussions are supported by the 3-D finite element analysis and experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Robust Cascaded Deadbeat Predictive Control for Dual Three-Phase
           Variable-Flux PMSM Considering Intrinsic Delay in Speed Loop

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      Authors: Kailiang Yu;Zheng Wang;Wei Hua;Ming Cheng;
      Pages: 12107 - 12118
      Abstract: In this article, a robust cascaded deadbeat predictive speed control method (PSC) is proposed with speed and disturbance observer for the dual three-phase variable-flux permanent-magnet synchronous motor (VF-PMSM) drives. Considering the intrinsic delay in speed loop, an improved predictive speed model has been derived in discrete domain. In turn, a speed observer is proposed for the cascaded PSC to mitigate the issue of this intrinsic delay. In order to improve the system robustness, the torque disturbance observer including the generalized proportional integral observer and the sliding-mode observer has been proposed for parameter variation and load torque perturbation. Furthermore, the stability analysis indicates that the margin of parameter mismatch is determined by the coefficient in the speed observer, which can be expressed as the equivalent gain in discrete domain. The performance comparison between the conventional PSC method and the proposed PSC method has been investigated for parameter robustness. The experimental results are presented to verify the improvements of the proposed PSC method for the dual three-phase VF-PMSM drives under model uncertainty and magnetization manipulation conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Model Predictive Control Strategy for Induction Motor Drive Using Lyapunov
           Stability Objective

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      Authors: Ozan Gulbudak;Mustafa Gokdag;Hasan Komurcugil;
      Pages: 12119 - 12128
      Abstract: This article presents a novel Lyapunov-based model predictive control strategy for squirrel-cage induction motor fed by a voltage source inverter. The model predictive control method has received enormous attention thanks to its rapid response to load perturbations. However, the traditional model predictive control method may suffer from instability due to the poor choice of the objective function, weighting factors, or other design parameters. In particular, the selection of the objective function may not be sufficient to ensure global stability. Since the performance of the model predictive control method highly relies on the explicit model of the system, a simple penalization term in the objective function can lead to system instability. As a result, the transient and steady-state performances are negatively affected. The objective function is reformulated as the Lyapunov energy function to deal with this ambiguous situation in this article. The control input constraints are defined in the formulated optimal control problem, and the optimal solution is explored by assessing the Lyapunov stability criterion. The proposed method ensures asymptotic stability since the control action that satisfies the Lyapunov stability condition is selected. The experimental work proves the theoretical concepts. Moreover, the proposed method does not require the weighting factors to control the multiple control goals. The experimental results demonstrate that the proposed control strategy improves the steady-state performance. The machine torque and speed are well regulated, and the quality of the stator current is improved.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Assisted Power Transfer for Voltage Balance of Bipolar DC MicroGrids Using
           Inactive Motor Drives

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      Authors: Jiadong Lu;Yihua Hu;Yuge Song;Yue Su;Jie Wang;Jinglin Liu;
      Pages: 12129 - 12139
      Abstract: A voltage balancer remains a good solution of power transfer for bipolar dc grids, which, however, would increase the costs due to its requirement for additional hardware support. In this article, an auxiliary power transfer strategy is proposed by using the inactive motor drives affiliated with the bipolar dc grid. During idle periods of the motor drive, one inverter bridge arm is connected with the bipolar dc grid at their neutral points, allowing bidirectional power transfer between the upper and lower dc-bus sources. The proposed strategy share part of the voltage balancer's power transfer burden without requiring additional hardware and affecting the normal operations of the motor drive. In addition, its effectiveness is verified by experimental results on an interior permanent magnet synchronous motor drive, showing that the power flows among the upper and lower dc-bus power supplies are controlled effectively. Also, the active control of the dc-bus voltages could be achieved by modulation of the phase currents.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Research of a Stator PM Excitation Solid Rotor Machine for Flywheel Energy
           Storage System

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      Authors: Caiyong Ye;Dezuan Yu;Kaifeng Liu;Yongzihao Dai;Cong Deng;Jiangtao Yang;Jianping Zhang;
      Pages: 12140 - 12151
      Abstract: A typical flywheel energy storage system (FESS) includes an electrical machine, a flywheel, and magnetic bearings, which are independent of each other. Therefore, the structure of FESS is complicated, which leads to the problems of high cost and low integration. This article presents a novel stator PM excitation solid rotor machine (SPE-SRM) for FESS, which integrates an electrical machine, flywheels, and a magnetic bearing. The design method of the SPE-SRM is presented specifically. First, the structure and operation principle of the SPE-SRM are illustrated. Second, the design and optimization of the flywheel-rotor are presented with considering of power, energy storage, and mechanical strength. Third, the magnetic equivalent circuit of the SPE-SRM is established to simplify the design. Besides, the armature reaction and leakage flux factor are investigated. Fourth, the performance indexes, including torque, suspension force, no-load back electromotive force (back-EMF), losses, and temperature rise are fully analyzed by the finite element analysis. Finally, a 22 kW prototype is manufactured and tested. The rationality of the concept and design is validated by experiments. The SPE-SRM has the merits of high integration, robust structure, and low cost, so it has the potential for wide application in FESS.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Predictive Firing Algorithm for Soft Starter Driven Induction Motors

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      Authors: Hauke Nannen;Heiko Zatocil;Gerd Griepentrog;
      Pages: 12152 - 12161
      Abstract: Soft starters are a well-known solution for starting induction motors in industrial applications. With a predictive algorithm approach the losses in motor and soft starter can be lowered significantly. This article presents an algorithm which can be implemented in industrial devices with a concomitant speed control option. This speed control is necessary to fit the users requirements for start-up. Besides the speed control, the characteristic behavior of the predictive algorithm is analyzed in detail. The suitability of the novel predictive closed loop approach for different representative industrial applications is proven by measurements and discussed in detail.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Energy-Based Control Technique for Monoinverter Dual Parallel PMSM With
           Different Parameters

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      Authors: Mojtaba Mansouri Boroujeni;Gholamreza Arab Markadeh;
      Pages: 12162 - 12172
      Abstract: This article declares two control strategies, named “average-model based” (AMB) and “energy-based” (EB) control methods, to control a monoinverter dual parallel surface-mounted permanent magnet synchronous motor (MIDP-PMSM) with different parameters. Up to now, it has been assumed that two parallel PMSMs have the same parameters, so the controller has been designed based on this simplifier assumption. To extend the control subject to MIDP-PMSMs with different parameters, two new methods are proposed and compared in this article. The average value of both motors’ parameters is used in the AMB control design, while in the proposed EB control method, each motor’s parameters separately contribute to designing the control laws. The proposed methods are based on the “mean-difference” technique. These methods have been compared by mathematical analysis regarding the torque per total ampere ratio, the copper losses and the dynamic response of motors’ speed. The MATLAB simulation and experimental implementation have been carried out to verify the proposed methods. The results have shown that the EB control method has better performance than the other.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Practical Approach for Estimating Bundle-Level Proximity Losses in AC
           Machines

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      Authors: Gurutz Artetxe;Borja Prieto;Damian Caballero;Ibón Elósegui;Gabriel Martinez Maza;
      Pages: 12173 - 12181
      Abstract: Losses created by skin and proximity effects can be significant in medium to high-speed ac machine designs. These have been extensively studied for form wound coil machines, but regarding randomly-placed round-wire windings, bundle-level proximity losses have been either neglected, computed via finite element (FE) simulations or estimated analytically by methods that require to know the location of each strand within the slot. This article presents a practical, yet accurate method to estimate bundle-level proximity losses in random-wound ac machines without having to specify the location of each individual conductor. The method consists on approximating the turn size and the arrangement of the conductors within the slot from the overall dimensions of the slot and the winding via simple expressions. This procedure is successfully validated via FE simulations and by constructing and experimentally testing two Interior Permanent Magnet Synchronous Machine prototypes with different winding characteristics.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Decoupling Control of Outer Rotor Coreless Bearingless Permanent Magnet
           Synchronous Motor Based on Least Squares Support Vector Machine
           Generalized Inverse Optimized by Improved Genetic Algorithm

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      Authors: Ben Xu;Huangqiu Zhu;Xin Wang;
      Pages: 12182 - 12190
      Abstract: In the decoupling control process of the outer rotor coreless bearingless permanent magnet synchronous motor using a least squares support vector machine, the kernel width σ2 and the penalty factor γ of the least squares support vector machine are difficult to tune, resulting in high kernel space complexity and low fitting accuracy. A new improved genetic algorithm is used to optimize the above parameters. First, the generalized inverse system model of the original nonlinear multiple-input multiple-output system is fitted online with the optimized least squares support vector machine, and the generalized inverse system model is connected in series with the original system to form a pseudolinear system. Then, a linear closed-loop controller is used for control. Simulations and experiments show that the robustness and wide applicability of the original system are guaranteed. The dynamic and static performances of the system are improved, verifying the effectiveness of the scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Healthy and Open Phase PMaSynRM Model Based on Virtual Reluctance Concept

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      Authors: Tomasz Dobromir Michalski;Jose Luis Romeral Martinez;Gerardo Mino-Aguilar;
      Pages: 12191 - 12200
      Abstract: The trend in the industrial power electronics electrical drives is to reach high power density and high efficiency in variable load conditions at cost-effective unwasteful designs. Currently, motors with permanent magnets (such as IPMSM and PMaSynRM) are of great interest because of compactness, low losses, and high-torque capability. The performance of a drive system can be predicted with a motor electromagnetic authentic nonlinear model. In this article, a novel, fast, and precise motor model of PMaSynRM based on virtual reluctance (VR) is proposed. It takes into account the cross saturation, winding distribution, space harmonics, slotting effect, and stepped skewing. The VRs are identified by finite element analysis (FEA) and implemented in the time-stepping simulation. The flux inversion is not required. The proposed concept is useful in the rotating field or phase quantities (for open phase simulation). The model is also discretized for SiL and HiL applications. Finally, the validation in FEA and experimental setup was performed.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Phase Model Predictive Voltage Control for Half-Centralized Open-End
           Winding Permanent-Magnet Linear Motor Traction Systems

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      Authors: Wei Wang;Yixin Jiang;Le Sun;Zheng Wang;Wei Hua;Ming Cheng;
      Pages: 12201 - 12212
      Abstract: In order to extend the speed range and reduce power electronics devices of the permanent-magnet linear motor traction system, a half-centralized open-end winding topology is studied in this article, in which two movers are supplied by three voltage-source-inverters (VSIs). All these VSIs share a common dc-bus voltage, and the zero-sequence current becomes a challenge. In order to solve cope with this challenge, two phase model predictive voltage controls (PMPVCs) are proposed. Referring to the traditional finite-control-set MPVC (FCS-MPVC), an FCS-PMPVC scheme is proposed and the optimal phase voltage group is determined by minimizing three independent phase cost functions. For FCS-PMPVC, 21 phase voltage group are evaluated while the evaluation number of the traditional FCS-MPVC is 512. In order to reduce the computation burden furthermore, a new concept phase voltage vector (PVV) is defined, and the optimal PVV is directly determined by the nearest distance principle instead of the time-consuming evaluation. The second PMPVC is named as geometrical-location PMPVC (GL-PMPVC). Both PMPVCs have same performances while the computation burden of GL-PMPVC is nearly 47% of that of FCS-PMPVC. The effectiveness of the proposed PMPVCs have been verified by experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Extended State Loop Filter With Position Error Observer for Sensorless
           IPMSM Drives

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      Authors: Zhuang Xu;Chris Gerada;
      Pages: 12213 - 12224
      Abstract: Sensorless drives of interior permanent magnet synchronous motors (IPMSMs) find a broad range of applications due to their inherent benefits. In practical electrified propulsions, the IPMSM drives are usually working in highly utilized conditions where the performance and stability could deteriorate. Without considerable compensation, this vulnerability causes the existing phase-locked loops (PLLs), estimators, or observers to lose the synchronization with the rotor position. To achieve better performance and reduce the estimation error, in a PLL-type framework for sensorless control, a position error observer (PEO) utilizing the current errors as correction terms plays the role of the phase detector. A reduced-order extended state observer (ESO) is presented to form the loop filter with a switched nonsmooth feedback structure. The outstanding property of the PEO and nonsmooth ESO is verified through experiments. The results demonstrate its strong adaptability for model uncertainties and disturbances along with the quick convergence speed and minimal oscillation.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Fault-Tolerant Model-Free Predictive Controller for Multilevel Cascaded
           H-Bridge Inverters With Faulty Cells

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      Authors: Paul Gistain Ipoum-Ngome;Rodolfo César Costa Flesch;Daniel Legrand Mon-Nzongo;Jinquan Tang;Tao Jin;Mengqi Wang;
      Pages: 12225 - 12236
      Abstract: In this article, a fault-tolerant model-free predictive controller (FT-MFPC) for cascaded H-bridge multilevel inverters (CHMLIs) is proposed. FT-MFPC is based on an association of model-free predictive controller (MFPC) and a proportional--integral (PI) like structure known as current variation controller (CVC). As in MFPC, the dynamic structure (DS) that is used for the prediction of the system output is obtained from past measurements of current variations, but CVC modifies the dynamics before they are stored for prediction. As a consequence, even if the converter operates with bypassed modules, FT-MFPC adapts its DS to represent the real dynamics of the system and enables a closed-loop response with balanced load currents in unbalanced CHMLIs. Simulation and experimental results validate the adaptability of the proposed strategy to operate a seven-level inverter under various configurations of bypassed H-bridge modules. The experimental results show that, for different postfault operations, the maximal current total harmonic distortion and imbalance factor at steady state in the worst case scenario are below 5% and 2%, respectively.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Analysis of Synergistic Stator Permanent Magnet Machine With the Synergies
           of Flux-Switching and Flux-Reversal Effects

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      Authors: Shun Cai;Hao Chen;Xin Yuan;Yun-Chong Wang;Jian-Xin Shen;Christopher H. T. Lee;
      Pages: 12237 - 12248
      Abstract: Dual permanent magnet (PM) machines have attracted numerous interests due to the high torque density and compact volume. This article investigates a synergistic PM machines with the synergies of flux switching and flux reversal effects. The flux-reversal and flux-switching PM (FSPM) flux paths circulate from two sides of the split teeth separately, which avoid the over-saturation with dual PM excitations. The preferred stator and rotor pole number is derived from a simplified analytical model and the influence of leading parameters is analyzed as design guidelines. Furthermore, the synergistic stator PM machine is optimized and compared with FSPM machines. It is revealed that the synergistic stator PM machine exhibits ∼20%, ∼10%, and ∼17% higher torque density than conventional FSPM machine, C-core FSPM machine, and E-core FSPM machine, respectively. Besides, good flux weakening capability is achieved with a larger inductance than conventional FSPM machine, and higher efficiency is obtained at both low-speed and high-speed operations. Finally, an experimental prototype is fabricated to validate the proposed concepts.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Modulated Vibration Reduction Design for Integral-Slot Interior Permanent
           Magnet Synchronous Machines

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      Authors: Yunhan Zhou;Jinghua Ji;Wenxiang Zhao;Shengdao Zhu;Huan Liu;
      Pages: 12249 - 12260
      Abstract: In this article, a targeted step skewing of rotor segments scheme is proposed to reveal the modulated vibration reduction mechanism in integral-slot interior permanent magnet synchronous machines (IPMSMs). First, the vibration characteristics of a 72-slot/12-pole integral-slot IPMSM are investigated. The dominant vibration at specific frequency band is introduced. Then, in order to analyze the main source of vibration, the magnetic field modulation effect and radial force modulation effect are investigated in detail. The results show that the high-order radial force can excite large vibration by radial force modulation effect. This kind of vibration is defined as modulated vibration. Afterwards, the optimal shift angle and number of rotor segments are determined by comparison. Finally, the conventional and proposed 72-slot/12-pole integral-slot IPMSMs are manufactured to validate the theoretical analysis. The experimental results verify that the proposed method can effectively reduce the modulated vibration of the 72-slot/12-pole integral-slot IPMSM.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Ten-Level Inverter Fed Drive Scheme with Extended Linear Modulation
           Range

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      Authors: Souradeep Pal;Mriganka Ghosh Majumder;Rakesh Resalayyan;K. Gopakumar;L. Umanand;Mariusz Malinowski;Dariusz Zielinski;
      Pages: 12261 - 12269
      Abstract: In this work, a ten-level inverter scheme is presented to extend the linear modulation range (LMR) by using a unique space vector pulsewidth modulation (SVPWM) technique, such that no lower order harmonics (such as 5th, 7th, 11th, and 13th, etc.) are present in the phase voltage as compared to six-step mode operation. The proposed scheme can increase the peak phase fundamental voltage of the inverter from 0.577 to $0.637 V_{dc}$ (maximum possible peak phase fundamental voltage of a conventional hexagonal space vector structure (SVS) voltage source inverters while operating in six-step mode), irrespective of the load power factor (p.f), where $V_{dc}$ is the dc link voltage of the inverter. The ten-level inverter structure is formed using a two-level inverter and an H-bridge (HB) in cascade from one end and a floating capacitor-based two-level inverter cascaded with an HB from the other end to drive an open-end winding induction motor (OEWIM). All the HB capacitor voltages are balanced by using space vector redundancy. The claim of balancing the capacitor voltages throughout the whole modulation range is verified experimentally in this article. Experimental results at different steady-state and transient conditions are shown to validate the proposed inverter scheme’s efficacy in increasing the LMR.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Inductance Characteristics of Flux-Switching Permanent Magnet Machine
           Based on General Air-Gap Filed Modulation Theory

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      Authors: Peixin Wang;Wei Hua;Gan Zhang;Bo Wang;Ming Cheng;
      Pages: 12270 - 12280
      Abstract: Winding inductance is a crucial parameter of machines, which plays an essential role in flux-weakening capability, reluctance torque, power factor, etc. In this article, winding inductance characteristics of flux-switching permanent magnet (FSPM) machines are investigated from the perspective of air-gap modulation magnetic field. With the aid of the general air-gap field modulation theory, the air-gap magnetic field contributed by an arbitrary energized winding of FSPM machines is modeled and analyzed. Then, an analytical expression of winding inductance is derived based on winding function and single-phase magnetic field, through which the relationship between winding inductance and single-phase magnetic field harmonics is unveiled. It is found that the direct current (dc) and 2nd harmonic components of winding inductances in FSPM machines are caused by the dc and 2nd time-harmonic components of primitive harmonics, respectively, which are essentially different from that of traditional interior permanent magnet or reluctance machines. Finally, experiments on a prototype three-phase 12/10 FSPM machine are conducted to verify the theoretical analysis.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Airgap Magnetic Field Harmonic Synergetic Optimization Approach for Power
           Factor Improvement of PM Vernier Machines

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      Authors: Liang Xu;Wenjie Wu;Wenxiang Zhao;
      Pages: 12281 - 12291
      Abstract: Permanent magnet (PM) vernier machine has excellent prospects because of its high torque density, whereas its power factor is lower than conventional PM counterpart. At present, power factor of PM vernier machine is mainly analyzed and improved from the perspective of either PM magnetic field or armature magnetic field individually. Also, synergetic effect of both PM and armature fields is rarely considered, thus limiting the power factor improvement. In this article, a synergetic optimization approach considering both PM and armature airgap harmonics simultaneously is proposed to improve the power factor of PM vernier machine. First, the power factor is analyzed from the both PM and armature airgap harmonics. Second, the proposed optimization framework is interpreted and implemented. Meanwhile, a PM vernier machine with rotor flux barriers is selected as a design example to investigate the effectiveness of the proposed optimization approach. Finally, a prototype machine is manufactured and experimented to verify the effectiveness of the proposed optimization approach.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Convergence Trajectory Optimization of Supertwisting Sliding-Mode Current
           Control for Induction Motor Drives

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      Authors: Bo Wang;Tianqing Wang;Yong Yu;Cheng Luo;Dianguo Xu;
      Pages: 12292 - 12304
      Abstract: For the induction motor (IM) current loop, the supertwisting sliding-mode control (ST-SMC) has been considered as an effective approach to achieve chattering suppression and steady-state errorless control. However, due to the system disturbance, the conventional ST-SMC suffers from control delay in the convergence trajectory, resulting in decreased antidisturbance capability. To address this problem, this article proposed a ST-SMC with convergence trajectory optimization. First, a nonlinear sliding-mode manifold is designed to achieve the ideal ST-SMC convergence trajectory. Then, a disturbance compensation term is added into the control law to eliminate the system control delay. Compared with the conventional ST-SMC, the studied method can effectively enhance the antidisturbance capability of IM current loop, leading to improved transient performance. Finally, the superiority of the investigated method is verified by the experimental results from a 3.7 kW IM test bench.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Unidirectional Voltage Vector Preselection Strategy for Optimizing Model
           Predictive Torque Control With Discrete Space Vector Modulation of IPMSM

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      Authors: Ibrahim Mohd Alsofyani;Kyo-Beum Lee;
      Pages: 12305 - 12315
      Abstract: Discrete space vector modulation (DSVM) is employed to synthesize large number of voltage vectors (VVs) to improve the steady-state performance of predictive torque control (PTC). However, enumerating all the VVs in the prediction process increases the computation load of the motor drive. To address this issue, this article proposes a unidirectional VV preselection (UVVP) method for optimizing the performance of DSVM-based PTC of ac motors. The proposed UVVP method divides both voltage space vector diagram (VSVD) and flux space trajectory into twelve 30° based sectors to reduce the impact of candidate VVs with negative effects. At each flux position, the UVVP strategy can restrict the nearest candidate VVs in the 30° based VSVD region within the circular flux trajectory. This is achieved by using the speed direction to avoid the candidate VVs, which are in the same flux sector for reverse flux rotation, hence resulting in significant flux and torque ripple reduction. The main benefit of the proposed method is its simplicity since it only requires the flux sector and speed information as well as it can generate the VV enumerations online while ensuring the reduction of computation burden.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Stacked Multilevel Inverter With Single DC Link for Open-End Winding
           Induction Motor Drive With Zero-Voltage Switching and Common-Mode Voltage
           Elimination

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      Authors: Greeshma Nadh;Arun Rahul S;
      Pages: 12316 - 12325
      Abstract: A switching-state selection scheme for a five-level stacked multilevel inverter for open-end winding motor drive is presented in this article. Using the proposed scheme, converter can be operated with a single dc supply and with zero common-mode voltage. In addition, the switching transition of high-voltage switches occurs at zero-voltage conditions. The degree of freedom provided by the redundant switching-states and voltage vectors of the inverter topology is utilized to design the modulation scheme. The proposed switching-state selection leads to inherent capacitor balancing without using any extra sensors and fundamental frequency switching of the high-voltage switches of the topology. The modulation scheme uses triangular carrier comparison and, hence, avoids the complexity of subsector identification and dwell time calculation. Half-wave symmetry in output waveforms is ensured by maintaining synchronous sampling with constant samples per fundamental cycle. The inverter topology and the effectiveness of the state selection scheme are experimentally validated on an open-end winding induction motor drive, and experimental results showing steady-state and dynamic operations are presented.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Capacitor Pre-Charge Method for Back-to-Back Seven-Level Hybrid Clamped
           Converter Without Extra Power Supply

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      Authors: Hao Tian;Mingzhe Wu;Yun Wei Li;
      Pages: 12326 - 12335
      Abstract: Multilevel converters with floating capacitors generally require precharging to build up the voltage on floating capacitors and dc-link before the normal operation. In particular, precharge is challenging for converters with overvoltage concerns under initial zero capacitor voltages. As a promising topology, seven-level hybrid clamped (7L-HC) converters also require precharge of capacitors and shall avoid high voltage stress during the precharge. Considering the high cost of deploying extra dedicated precharge circuits in a medium voltage system, the precharging method without relying on dedicated power supplies is favored. In this article, specific switching states and their corresponding selection schemes are designed to precharge floating capacitors of back-to-back 7L-HC converters. In this process, the inrush current and voltage stress can always be limited in the safe range. This method only needs series and shunt resistors typically already exist in practical converter circuits, resulting in low cost and ease of implementation. The design method of the resistances is also provided. Both simulation and experimental results validate the feasibility of this method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Deep-Investigated Analytical Modeling of a Surface Permanent Magnet
           Vernier Motor

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      Authors: Jingwei Zhu;Yuefei Zuo;Hao Chen;Jiahao Chen;Christopher H. T. Lee;
      Pages: 12336 - 12347
      Abstract: Permanent magnet Vernier motors (PMVMs) possess the advantage of high torque density for high-performance applications. However, the low power factor challenge makes it unacceptable for direct-drive applications. A lack of accurate modeling method based on the motor sizing law, i.e., air-gap flux density, linear current density, and motor geometry parameters, raises difficulties for machine designers to further conduct research on the performance metrics. This article presents a deep investigation into the analytical modeling technique for surface PMVMs (SPMVMs). It can identify an accurate approach to obtain the performance metrics, including electromagnetic torque and power factor. The modeling technique is developed based on the conformal mapping method. By using this, both radial and tangential permeability functions can be calculated to obtain the motor magnetic loading accurately, considering the leakage flux. The slotting effect on both air-gap flux density and armature-winding function is analyzed to achieve a precise formula for torque and power factor computations. The new modeling technique is applied to integral-slot SPMVMs with different slot/pole combinations, gear ratios, slot openings, and magnet thickness to evaluate the impacts of motor parameters on high-power-factor and high-torque-density designs. Finally, an SPMVM with the characteristics of high torque density and power factor is fabricated to verify the analytical model at the power rating of 0.8 kW and the speed of 500 r/min. The experimental results show that the prototype exhibits a high power factor of 0.9 and high torque density 22.5 Nm/L.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Multiobjective Model Predictive Current Control Method of Permanent Magnet
           Synchronous Traction Motors With Multiple Current Bounds in Railway
           Application

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      Authors: Shuai Lin;Xiaochun Fang;Xiaofan Wang;Zhongping Yang;Fei Lin;
      Pages: 12348 - 12357
      Abstract: For multiobjective model predictive current control (MPCC) method with penalties, the penalty weights are introduced into the cost function to determine the relative importance of control targets. However, the dimensions and value ranges of each control target are different. Thus, the penalty coefficient is difficult to determine. To avoid the difficulty of dimensionless parameter design, this article proposes a multiobjective control method called MPCC with multiple current bounds. In this article, the switching frequency and the common-mode voltage (CMV) are selected as the control target. Their control is converted into the limitation of the current ripple so that the control parameters have a clear physical meaning. On the one hand, the proposed method can realize the cooperative control of reference current tracking, switching frequency suppression, and CMV suppression. On the other hand, the key control parameters have the same dimension and strong correlation with others. Therefore, appropriate parameter design can be realized. Experimental investigations for permanent magnet synchronous motor prove the effectiveness of the control method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Transient Performance Improvement of Deadbeat Predictive Current Control
           of High-Speed Surface-Mounted PMSM Drives by Online Inductance
           Identification

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      Authors: Shangjian Dai;Jiabin Wang;Zhigang Sun;Ellis Chong;
      Pages: 12358 - 12368
      Abstract: This article presents an analytical derivation of transient performance deterioration for high-speed surface-mounted permanent magnet synchronous machine (SPMSM) drives under parameter mismatches, with an advanced deadbeat predictive current control (DBPCC), which exhibits fast dynamics and strong robustness with disturbances rejection. All the influential factors, including permanent magnet flux linkage and inductance mismatches, inverter nonlinearity, and speeds are taken into account in the analysis. It is shown that the transient performance with the advanced DBPCC is only dependent on inductance accuracy. Large transient overshoot and cross-coupling in the dq-axis currents at high speeds arise due to inductance mismatch. Based on the understanding gained through the analysis, a novel inductance identification method is also proposed in this article, which significantly improves the transient performance of high-speed SPMSM drives. The proposed online inductance identification method does not require signal injection, is nonintrusive, and can be easily implemented. By integrating the proposed method with the advanced DBPCC, the close-to-ideal deadbeat control can be achieved for high-speed SPMSM drives even in the presence of parameter mismatch and inverter nonlinearity. Both the analysis and proposed method have been validated experimentally on a prototype high-speed (30 000 r/min) SPMSM drive under various conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Single DC-Link Multilevel 42-Sided Polygonal Voltage Space Vector
           Generation With Lower Order Harmonic Suppression Using Switched-Capacitor
           Filter

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      Authors: Rahul Dewani;K. Gopakumar;Umanand Loganathan;Leopoldo G. Franquelo;Kaushik Rajashekara;
      Pages: 12369 - 12378
      Abstract: In this work, a multilevel 42-sided polygonal space vector structure for suppression of lower order harmonics for open-end induction motor (OEIM) drive applications is proposed. The proposed power circuit topology consists of two inverters feeding an OEIM from either side. The main inverter fed with a single dc-link providing active power for motoring operation is switched at low switching frequency. The secondary inverter fed with a capacitive supply is switched at high frequency to suppress lower order harmonics upto 39th order, up to the base speed of operation allowing maximum utilization of the dc-link. The advantages of lower order harmonic suppression in motor phase voltage, for polygonal space vector structures, are combined with multilevel inverter topology. This offers various advantages like multilevel operation with low inverter switching for the main power delivery inverter and harmonic suppression throughout the modulation range. The low switching frequency primary inverter generates harmonics of the order $6*k pm 1$, where $k = 1, 2, 3,{ldots }$. The harmonics are suppressed by the capacitor-fed secondary inverter, which supplies only reactive power for suppression of lower order harmonics in motor phase voltage. Use of a single dc-link facilitates four-quadrant operation of the inverter. The proposed scheme is validated for steady-state and dynamic performance by experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Torque Ripple Suppression of Flux-Switching Permanent Magnet Machine Based
           on General Air-Gap Field Modulation Theory

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      Authors: Peixin Wang;Wei Hua;Gan Zhang;Bo Wang;Ming Cheng;
      Pages: 12379 - 12389
      Abstract: Compared with the conventional permanent magnet (PM) machines, the flux-switching permanent magnet (FSPM) machine exhibits higher torque ripple due to its special doubly salient structure and high air-gap flux density, leading to the deterioration of smooth operation. In this article, the output torque ripple suppression methods of FSPM machines from both rotor and stator sides are proposed with the aid of general air-gap field modulation theory. According to harmonic modulation mechanism, air-gap PM field can be modified by revising harmonic content of rotor and stator modulation functions and, consequently, three concepts, including cos-shaped edge rotor (CSER), cos-shaped edge stator, and double cos-shaped edge, are proposed and implemented to suppress the output torque ripple due to the cogging torque and electromagnetic torque ripple of FSPM machines. Finally, finite-element analysis and experiments are conducted to verify the proposed approaches. The results reveal that the CSER method exhibits the most effective suppression effect.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Robust MTPA Control for Novel EV-WFSMs Based on Pure SM Observer Based
           Multistep Inductance Identification Strategy

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      Authors: Yaofei Han;Chao Gong;Guozhen Chen;Zhixun Ma;Shaofeng Chen;
      Pages: 12390 - 12401
      Abstract: Wound field synchronous motors (WFSMs) without installing slip rings and brushes are drawing increasing attention in the electric vehicle (EV) propulsion systems. To ensure high control performance of the EV-WFSMs, this article proposes a robust maximum torque per ampere (MTPA) control strategy based on a series of new sliding mode (SM) inductance observers. First, after establishing the model of a WFSM based on capacitive coupling, the current control scheme is designed for the MTPA control. Second, to eliminate the impacts of the inductance uncertainties on the MTPA control, the SM mutual inductance observer, q-axis inductance observer, and d-axis inductance observer are designed, which need to be implemented one by one. Then, the Lyapunov stability criterion is used to analyze the stability conditions for the observers. Moreover, considering that the observers are achieved by using the offline inductance information provided by the suppliers, the robustness against parameter mismatch is innovatively discussed at length, and an analytical method that can avoid estimation errors is developed. The proposed inductance identification techniques and MTPA control method are verified by both simulation and experiments, which are conducted on a 580-W three-phase WFSM drive.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Active Gate Driving Technique for Series Connecting SiC MOSFETs in the
           Presence of Gate Pulse Delay Mismatch

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      Authors: Vamshi Krishna Miryala;Saravanan Dhanasekaran;P. Ganesan;Kamalesh Hatua;Subhashish Bhattacharya;
      Pages: 12402 - 12413
      Abstract: In this article, series connection of SiC MOSFETs has been attempted with the help of an active gate driving (AGD) technique. The gate currents of SiC MOSFETs are actively controlled in such a way that several devices can switch fast (within 50 ns) even in the presence of a moderate amount of gate pulse delay mismatch and jitter in the gate pulse. This enables the AGD’s to share the gate pulse signal information among each other. Such a feature can reduce the cost of the net solution by reducing the number of optical cables required for the gate pulse transmission. In addition to this, the AGD is designed in such a way that fast switching can be achieved even in the presence of moderate parasitic inductance in the layout. The proposed AGD technique is experimentally verified in a double pulse test setup with two and four switching devices in series using 32 A, 1 kV CREE SiC MOSFETs. The experimental results show turn-on and turn-off switching times of 45 and 34 ns, respectively, at 35 A load current. The AGD has also shown 47% reduction in the turn-off switching losses compared to the passive gate driving technique.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Discrete-Time Dynamic-Decoupled Current Control for LCL-Equipped
           High-Speed Permanent Magnet Synchronous Machines

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      Authors: Yu Yao;Yunkai Huang;Fei Peng;Jianning Dong;Zichong Zhu;
      Pages: 12414 - 12425
      Abstract: This article proposes a discrete-time dynamic-decoupled current controller for an LCL-equipped high-speed permanent magnet synchronous machine with only the motor currents measured. The controller is designed in the synchronous coordinate based on a complex $boldsymbol{z}$-domain transfer function. The main contribution of the proposed current controller is the robust dynamic decoupling performance to achieve better transient behavior. Moreover, an effective coefficient selection method is developed to acquire sufficient phase margin and gain margin, even with the system parameters varying $boldsymbol{pm 50%}$. Additionally, the stable region of the LCL resonance with the proposed method is discussed. Finally, the effectiveness of the proposed method is verified by driving the tested motor to 100 kr/min.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Online Inductance Identification Using PWM Current Ripple for Position
           Sensorless Drive of High-Speed Surface-Mounted Permanent Magnet
           Synchronous Machines

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      Authors: Jindong Zhang;Fei Peng;Yunkai Huang;Yu Yao;Zichong Zhu;
      Pages: 12426 - 12436
      Abstract: Back–electromotive force estimation-based rotor position estimation methods are usually adopted for high-speed surface-mounted permanent magnet synchronous machines (SPMSM) drive to deal with the limitations of position sensors in high-speed applications. Considering inductance mismatch is the main cause of the position estimation error, this article proposes a novel pulsewidth modulation (PWM) current ripple-based online inductance identification method to improve the position estimation accuracy. The proposed method utilizes the inherent PWM current ripple of the voltage source inverter for inductance identification. In addition, the transient circuit equations on the estimated $gamma delta$ frame are adopted as the identification model, and the recursive least squares method is used to obtain the estimated inductance. Compared with the traditional parameter identification methods, the proposed method does not need to inject additional signals or fix parameters. During the sensorless drive of high-speed SPMSM, the proposed method can accurately identify the inductance while not affecting the normal operation of PMSM at all, which is the main contribution of this article. With the proposed method, the estimated inductance can rapidly converge to the accurate value, and then the position estimation error will be eliminated. Finally, the effectiveness of the proposed method is verified by simulations and experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improved Model Predictive Current Control With Series Structure for PMSM
           Drives

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      Authors: Xiaoguang Zhang;Hailong Bai;Ming Cheng;
      Pages: 12437 - 12446
      Abstract: In order to improve the control performance of conventional finite-control-set model predictive control (FCS-MPC) method and keep the balance between the steady-state performance and switching frequency of the system, this article proposes an improved MPC method based on the conventional MPC method. First, the reference voltage vector of the next control instant is predicted to determine the candidate voltage vectors of the next two control instants. Then, an optimal vector selection way is proposed, in which candidate voltage vectors selected by the reference voltage vector and designed cost function structure in series. Moreover, the selection process of optimal voltage vector from the candidate voltage vectors is analyzed. Finally, the comparison experiments between the conventional FCS-MPC method and the proposed MPC method are conducted. And experimental results show the validity of the proposed control strategy.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design Consideration of AC Hybrid-Excitation Permanent-Magnet Machine With
           Axial Stator Using Simplified Reluctance Network

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      Authors: Daohan Wang;Bingdong Wang;Fangxu Zhang;Chen Peng;
      Pages: 12447 - 12457
      Abstract: In this article, we deal with design considerations of a new ac hybrid-excitation permanent-magnet machine with axial stator. Due to the presence of an axial stator, the machine features a typical three-dimensional geometric structure and field distribution. A simplified reluctance-based network is developed to capture the main design features of the machine. The analytical equations are deduced relating the main geometric dimensions to the machine design criteria: speed, power, and flux regulation capability. The influence of key machine geometric parameters, i.e., radial/axial air-gap length, stack length, and bore diameter, on output power, flux density, and flux regulation capability is investigated. It is found that there is a design tradeoff between the machine power density and flux regulation capability. The d/q-axis inductance and its ratio, which has an influence on flux weakening capability and operation performance, is examined. Finally, a 6-pole/36-slot prototype is built. Intensive experimental tests are carried out to verify the machine characteristics.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Novel Predictive Position Control With Current and Speed Limits for PMSM
           Drives Based on Weighting Factors Elimination

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      Authors: Jianhui Hu;Chun He;Yong Li;
      Pages: 12458 - 12468
      Abstract: Conventional predictive position control (PPC) method balances the position, speed and current of permanent magnet synchronous machine with different weighting factors. However, tedious tuning work of weighting factors is needed. To simplify the tuning process, a cost function that includes the system position, and current information is constructed based on deadbeat control method. A novel method based voltage boundary is proposed to limit the current and speed simultaneously, the voltage regions corresponding to current and speed constraints are analyzed and the voltage duty cycle is further modified according to the voltage regions, the complex weighting factor turning work is avoided, the current and speed limits are easy to implement with proposed method and less position error can be achieved. Finally, the proposed method is experimentally compared with a conventional finite-control-set PPC method and a direct speed model predictive control method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Polygon-Retrofitted Integrated Modular Motor Drive for Switched Reluctance
           Machines

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      Authors: Abdalla Hussein Mohamed;Hendrik Vansompel;Peter Sergeant;
      Pages: 12469 - 12479
      Abstract: Thanks to the absence of rotor windings and permanent magnets, switched reluctance motors have a small weight construction. The integration of a modular power converter in a switched reluctance motor leads to a highly compact and fault-tolerant motor drive with small weight and high power density. In this article, a polygon-retrofitted integration topology is proposed for switched reluctance motors. Both the switched reluctance motor and the power converter are cooled with one shared cooling circuit. The power converter is designed and implemented using silicon carbide technology for its low losses and small thermal resistance. The proposed integration topology is extensively studied using multiphysics modeling and experimental measurements on a fully integrated rotating setup. A highly compact and power dense drive of 3.1 kW/L is obtained.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Low-Ripple Continuous Control Set Model Predictive Torque Control for
           Switched Reluctance Machines Based on Equivalent Linear SRM Model

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      Authors: Gaoliang Fang;Jin Ye;Dianxun Xiao;Zekun Xia;Ali Emadi;
      Pages: 12480 - 12495
      Abstract: In this article, a low-ripple continuous control set (CCS) model predictive torque control (MPTC) method for switched reluctance machines (SRMs) is proposed. The inherent high nonlinearity of the SRMs makes it difficult to solve the optimization problem in the CCS MPTC algorithm analytically. To address this issue, an equivalent linear SRM model is adopted, and the cost function is also properly modified. Then, with the torque boundary values provided by executing the voltage vectors of an improved switching table, the optimization problem in the CCS MPTC method becomes simple and analytically solvable. The Lagrange multiplier method is employed to solve this optimization problem analytically and generate the optimum torque reference values for the active phases. Based on the estimated torque variation rates, the duty cycles for each phase are calculated. Extensive simulation and experimental tests are carried out in a four-phase 8/6 SRM setup. These testing results reveal that the proposed CCS MPTC method shows much lower torque ripples and current ripples in a wide speed range with a low computational burden than the existing finite control set MPTC methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Multilevel Inverter With Inherent Common Coupling Point Voltage
           Balancing of Stacked Capacitors Across a Single DC-Link for Induction
           Motor Drives

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      Authors: Tutan Debnath;Rakesh R.;Mriganka Ghosh Majumder;Mohammed Imthias;K. Gopakumar;Umanand Loganathan;Leopoldo Garcia Franquelo;
      Pages: 12496 - 12505
      Abstract: In this article, a nine-level multilevel topology is proposed by stacking of low voltage basic inverter cells and then cascading with H-bridges. The dc-link is split into four equal halves by series-connected capacitors from a common dc-link. Three common coupling points (CCPs) are formed due to the stacking of four capacitors, which are connected across the dc-link. The CCP voltage balancing is ensured by drawing or injecting zero instantaneous currents from each of these points at any instant. A six-phase symmetrical IM is used to generate equal and opposite instantaneous phase currents by applying exactly equal and opposite phase voltages for two opposite phases from the six-phase inverter. Simultaneously, the capacitor voltage balancing of H-bridge inverter cells is also achieved by proper selection of redundancies from the available pole voltage redundancies. The concept is verified with a nine-level inverter laboratory prototype, which consists of a five-level stacked inverter, and followed by two low voltage cascaded H-bridge inverters in each phase. Detailed experimental results of steady-state and transient conditions are included to validate the proposed scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Integrated Transformerless EV Charger With Symmetrical Modulation

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      Authors: Caniggia Viana;Sepehr Semsar;Mehanathan Pathmanathan;Peter W. Lehn;
      Pages: 12506 - 12516
      Abstract: This article introduces a modulation technique that nearly eliminates the common-mode (CM) leakage currents in the transformerless (nonisolated) dual-inverter single-phase charger. This improvement allows for the safe use and commercialization of the transformerless charger, making superior charger efficiency, power density, and cost possible. The CM model of the system is derived to guide the choice of the modulation scheme. Simulations are conducted to validate the CM performance predictions derived analytically. Finally, an experimental 6.6-kW charger prototype is presented to verify the CM leakage current elimination. The experimental results show not only that the proposed modulation meets the required standards regarding CM currents, but also that it does so by a wide margin, and it even outperforms the isolated system used for comparison.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Iron Loss Calculation for FSPM Machine With the PWM Inverter Supply Based
           on General Airgap Field Modulation Theory

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      Authors: Jingxia Wang;Ming Cheng;Weijie Tian;Yang Jiang;
      Pages: 12517 - 12528
      Abstract: In this article, an iron loss for the flux switching permanent magnet machine with the pulsewidth modulation (PWM) inverter supply is calculated based on the general airgap field modulation theory (GAFMT). First, the amplitudes and rotation speeds of the main space harmonics of the airgap magnetic flux density with the supply of PWM harmonics are calculated based on the GAFMT. When calculating the source magnetizing magnetomotive force based on the GAFMT, the equivalent magnetic circuit is applied to calculate the working point of the permanent magnet. Second, each spatial harmonic in the airgap magnetic field is synthesized by an equivalent current layer in the airgap and then is substituted into the 2-D finite element analysis models to calculate the iron losses. Finally, the iron losses calculated by the proposed method with different speeds, loads, and control strategies are compared with the experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design and Analysis of a Three-Speed Wound Bearingless Induction Motor

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      Authors: Zebin Yang;Qifeng Ding;Xiaodong Sun;Chengling Lu;
      Pages: 12529 - 12539
      Abstract: Aiming at the influence on the actual speed caused by the suspension winding′s rotor induced current of a squirrel-cage bearingless induction motor (SBIM), a novel three-speed wound bearingless induction motor (WBIM) is designed based on establishing the stator–rotor equivalent circuit, deriving the exciting current-suspension slip ratio equation and analyzing the magnetic field distribution with odd pole pairs and dipole pairs. The stator is embedded with a fixed four pole winding and a 2/6 pole-changing winding, while the rotor is wound with series–parallel windings connecting at a slip ratio ring. By changing the connection method of the stator coils, adjusting the three-phase voltage source, and controlling the short circuit of the rotor winding central point, it can realize that the rotor only induces the torque winding′s magnetic field under three speeds. Combining with the finite-element analysis, the induced current, air gap magnetic density, suspension force, and electromagnetic torque of the traditional SBIM and the new WBIM are quantitatively compared. Finally, an experimental platform is built for further verification. The results show that the designed three-speed WBIM can not only effectively suppress the induced current of the suspension winding and reduce its influence on the motor torque and speed, but also makes the motor has a better start-up and steady-state performance.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Novel Equivalent Circuit Model Applicable to All Operation Modes for
           Brushless Doubly Fed Induction Machines

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      Authors: Jian Ge;Wei Xu;Yi Liu;Fei Xiong;
      Pages: 12540 - 12550
      Abstract: The equivalent circuit is an indispensable tool for analyzing the steady-state characteristics of the brushless doubly fed induction machine (BDFIM). However, the most commonly used equivalent circuits are not available to analyze some special operation modes, such as the natural synchronous mode with one set of winding powered by dc current. In order to overcome the limitation, in this article, a novel equivalent circuit is proposed. At first, the electromagnetic relations within BDFIMs are described by a new approach in which the cause of working magnetic fields is refined. Then, the equivalent circuit is built by the rigorous derivation of electromagnetic relations. And a few features of BDFIMs in some typical operation modes including the natural synchronous mode are introduced in details. Finally, the validity of the equivalent circuit is made by comparison of model and experimental results based on a wound-rotor BDFIM prototype. The proposed model with clear physical concept can cover all operation modes. And both power relationship and torque components reflected in the proposed model is more detailed and clearer than those reflected in the traditional one.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Research on Magnetic Coupling Characteristic of a Double Rotor
           

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      Authors: Zixuan Xiang;Zirun Lu;Xiaoyong Zhu;Min Jiang;Deyang Fan;Li Quan;
      Pages: 12551 - 12563
      Abstract: The magnetic coupling phenomenon widely exists in the type of double rotor motor, which is difficult to be eliminated completely due to the interactions between two layers of air-gap magnetic fields in a compact geometry structure. This article studies magnetic coupling in the perspective of air-gap harmonic groups, where the novelty is to propose the concept of positive coupling harmonics and the negative one. And, a double rotor flux-switching PM machine is chosen as the research subject. Then, the article begins with the analytical investigation of the modulation principle considering magnetic coupling, where the coupling harmonic group factor is defined. According to this factor, the coupling harmonics are analyzed and selected, and the positive and negative coupling harmonic groups are further determined. Next, the influence of coupling harmonic group on the machine performance is investigated in detail, including the back-EMF, torque performances, overload capability, and so on. The results show that the raise of positive coupling harmonic group factor brings the improvement of machine performances. In addition, a prototype machine is manufactured for experimental testing. Overall, theoretical analysis, simulation and test results verify the validation of the whole investigation to a large extent.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Improved One-Cycle Control Algorithm for a Five-Phase Six-Leg Switching
           Power Amplifier in Active Magnetic Bearings

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      Authors: Chengzi Liu;Jiang Zhan;Jiawei Wang;Yan Yang;Zeyuan Liu;
      Pages: 12564 - 12574
      Abstract: To achieve levitation in active magnetic bearing (AMB) systems, levitation coils must be driven by a switch power amplifier (SPA). Therefore, SPA performance is important to stable levitation. In previous studies, five-phase six-leg (5P6L) SPA topology was proposed to reduce hardware costs. However, current tracking performance degrades due to the coupling problem of the five-phase current and freewheeling loss. Then, the rotor may deviate markedly from the balance position, affecting rotor stability. The keys to solving these problems lie in the duty cycle control of the common leg and the compensation of freewheeling loss. This article proposes an improved one-cycle control (OCC) algorithm in which the duty cycle of the common leg is optimized by finite control set model predictive control (FCS-MPC), and the freewheeling loss is compensated for by a high-precision mathematical model. In addition, the parameter uncertainty of the FCS-MPC model is analyzed, and the convergence of the optimization algorithm is investigated. Simulations and experiments show that the proposed algorithm is effective, and the high dynamic response and low steady-state error performance of SPA are achieved.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Current-Balance Mode-Based Unified Common-Mode Voltage Elimination Scheme
           for Dual Three-Phase Motor Drive System

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      Authors: Zewei Shen;Dong Jiang;Jianxiao Zou;Zicheng Liu;Cuipeng Ma;
      Pages: 12575 - 12586
      Abstract: The two-level voltage source inverter fed dual three-phase motor (DTPM) induces the high-frequency common-mode voltage (CMV) and generates the unwanted adverse effects. As one of the effective common-mode suppression methods, the conventional CMV elimination (CMVE) pulsewidth modulation (PWM) schemes are generally based on the voltage-balance mode for DTPM systems which suffer from the parameter asymmetry induced phase current imbalance. This article proposes two current-balance mode unified CMVE PWM schemes which has no restriction on the reference voltages and angle displacement between the two sets of three-phase windings. Thus, the proposed methods can be utilized in different types of DTPMs with different angle displacements between the two winding sets, and the CMVE effect can be retained both in the conditions of symmetrical and asymmetrical system parameters which is more practical than conventional CMVE schemes in real application. The function and performance of the proposal is proved by simulations and experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Equivalent Magnetic Network Modeling of Dual-Winding Outer-Rotor Vernier
           Permanent Magnet Machine Considering Pentagonal Meshing in the Air-Gap

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      Authors: Mehrage Ghods;Hamed Gorginpour;Mohammad Amin Bazrafshan;Mohammad Sedigh Toulabi;
      Pages: 12587 - 12599
      Abstract: Thedual-winding outer-rotor Vernier-permanent-magnet (VPM) generator, which possesses two-phase-windings inserted in the stator core with two slot levels of shallow and deep and saturable tooth-tips with narrow regions, has already been presented and studied for the traffic-enforcement-camera applications. The flux lines routes in this VPM generator have a complex pattern because of existing flux modulation poles, deep slots and fringing and leakage fluxes in different parts. Hence, the accurate analytical modeling of this special machine requires an advanced method. To fulfill this aim, equivalent-magnetic-network (EMN) model of the VPM generator is extracted in this article by combining reluctance-network-model and magnetic-equivalent-circuit. simpler mathematical equations and lower computational burden are advantages of the proposed EMN model in comparison with finite-element (FE) model. The method of finding the rotor position based on the region selection and considering the effect of the slot permeances and magnetic saturation under both no-load and on-load operating conditions are the other novelties highlighted. Also, especial pentagonal-shape meshes with unequal sides’ lengths and angles are proposed for the air-gap meshing, which can effectively model the complex flux routs. Test results and FE simulations are used to validate the accuracy of the developed EMN for the investigated VPM generator.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improved Analytical Analysis of Novel Integrated Variable Reluctance
           Resolver for Compact Machine Topology

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      Authors: Ronggang Ni;Yaqian Cai;Shizhuang Gu;Shuxin Nie;Xinzhen Wu;
      Pages: 12600 - 12609
      Abstract: Variable reluctance resolvers (VRRs) have been widely used for rotor position detection in harsh working conditions. However, conventional installation of VRRs inevitably occupies the axial space of machine systems, and may weaken the reliability of rotor position detection encountering shock and vibration. In this article, a novel VRR structure with inner stator is investigated, which is radially integrated inside a permanent magnet synchronous machine (PMSM) to construct compact machine topology. The hybrid machine topology is first discussed, and detailed electromagnetic design is carried out. Improved analytical analysis on air gap flux density distribution and inductance evaluation of the integrated VRR is derived based on modified winding function approach, and testified by finite element analysis. A prototype is manufactured from an existing 2.2 kW PMSM, and experiments are conducted to validate the effectiveness of proposed machine topology.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design of High-Power Ultra-High-Speed Rotor for Portable Mechanical
           Antenna Drives

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      Authors: Md Khurshedul Islam;Seungdeog Choi;Yang-Ki Hong;Sangshin Kwak;
      Pages: 12610 - 12620
      Abstract: This article presents the design of high-power ultra-high-speed (HP-UHS) rotors of permanent magnet machines for a mechanical-based ultra-very low frequency (ULF-VLF) antenna (AMEBA) application. The conventional communication system in an RF-denied environment (e.g., underground and under seawater facilities) is power demanding with very low efficiency and low power density. Thus, a portable communication system was not available until recently. Such a critical limitation could be overcome by utilizing an HP-UHS motor as a mechanical communication transmitter. This is a first attempt to the best of the authors’ knowledge. However, the unprecedentedly high-speed and HP AMEBA exhibits new design challenges, including the critical mechanical resonance of the rotor, coupled with wireless communication bandwidth (ULF-VLF). It limits the highest possible efficiency and power density of portable AMEBA systems while achieving a required design safety margin (DSM). In this article, such critical constraints of HP-UHS rotors are analytically derived and integrated into a design model. This new design model will effectively couple the electromagnetic, thermal, structural, and rotordynamic analyses for the successful AMEBA rotor design. In the optimization, the Kriging method is adopted to create the efficient approximation model of the design nonlinearities. Multiple objectives and Pareto-front analysis are used to obtain an efficient rotor design with high DSM. The proposed approach is applied to design a 2-kW 500 000 r/min rotor considering AMEBA requirements. The effectiveness of the rotor for the AMEBA application has been validated through 3-D finite-element analysis and experimental testing.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Novel Position Speed Integrated Sliding Mode Variable Structure
           Controller for Position Control of PMSM

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      Authors: Bo Tang;Wenqi Lu;Bo Yan;Kaiyuan Lu;Jianchao Feng;Liang Guo;
      Pages: 12621 - 12631
      Abstract: Improving the positioning response is one of the key goals for permanent magnet synchronous motor position servo systems. The sliding mode variable structure controller (SMVSC) is an effective method due to the advantages of strong robustness, fast response, and easy practical implementation. However, the existing SMVSCs have difficulties in optimizing the position tracking response speed and chattering performance at the same time. This article proposes an improved position speed integrated SMVSC (ISMVSC) with a new variable exponential reaching law based on position error and a saturation function, and a speed-limiting method using speed error and trajectory planning. The general design principle is given and various tests are carried out to verify the effectiveness of the proposed method. The experimental results show that compared with traditional methods, the ISMVSC can improve the positioning response speed and reduce chattering problems at the same time; it also exhibits a stronger transient speed-limiting ability. All these advantages make the proposed controller a superior method to achieve high-response positioning control of the servo system that performs point-to-point motion.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Variable Switching Frequency Scheme Minimizing Inductor Saturation Margin
           for Totem-Pole Rectifier Based on Frequency-Domain Ripple Analysis

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      Authors: Jinshui Zhang;Yan Zhang;Jinjun Liu;Yuan Gao;Xiaoyang Gao;
      Pages: 12632 - 12640
      Abstract: Powdered iron core (PIC) inductors demand a considerable design margin to avoid magnetic saturation, limiting the converters’ power density. This article formulates a frequency-domain method to assess the saturation’s influence on the current ripple, and proposes an optimal variable switching frequency scheme to offset the harmonics growth. A Totem-Pole rectifier prototype is built to estimate this scheme. Its harmonics distortion is reduced by 0.69% without causing instability or extra power loss. Thus, deeper saturation is allowed for PIC inductors and the saturation margin is narrowed, shrinking inductor’s volume by 2/3 to reach a higher power density.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Reliability Improvement of Voltage Regulator Modules by a Virtual Series
           Voltage Source

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      Authors: Zhaoyang Zhao;Dao Zhou;Huai Wang;Pooya Davari;Frede Blaabjerg;
      Pages: 12641 - 12652
      Abstract: Output voltage deviation is a key performance index of voltage regulator modules (VRMs) with consecutive load transients. Usually, a large-capacity filter capacitor bank is used in VRMs to reduce the voltage deviation and stabilize the output voltage during transients. However, capacitors are one of the most vulnerable links in power electronic converters. For reliability reasons, it is essential to reduce the capacitance requirement while guaranteeing the transient performances of VRMs. Focusing on this, many efforts have been made to optimize the design of VRMs, where the transient auxiliary circuit-based scheme is a popular one. Unfortunately, there exists a large number of additional components in the existing auxiliary circuits. Considering this issue, in this article, we present a virtual series voltage source (VSVS) based auxiliary circuit scheme, which has minimum component counts. By using a controlled coupled inductor as the VSVS, the proposed scheme enables VRMs to have a relatively small transient voltage overshoot and without needing large bulk capacitance. Moreover, considering different control schemes with the same designing aim, the number and the electrothermal stress of critical components (e.g., capacitors) of VRMs are different; it is difficult to compare directly their advantages and disadvantages. Regarding this issue, this article investigates the converter-level reliability of VRMs with different control schemes. Taking a 12–3.3 V VRM as a case study, the reliability benchmarking results illustrate that the proposed scheme can significantly improve the reliability of VRMs.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Novel RDD Pulse Shaping Method for High-Power High-Voltage Pulse Current
           Power Supply in DBD Application

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      Authors: Shanshan Jin;Jindong Chen;Zhibin Li;Chunhui Zhang;Yajun Zhao;Zhi Fang;
      Pages: 12653 - 12664
      Abstract: High-voltage pulse power supplies are key power input devices for the study and application of discharge plasma. A high-voltage pulse current power supply (HV-PCPS) with an energy storage pulse transformer based on flyback topology can output microsecond pulsewidths with high-power, ultrahigh voltage, and high reliability, which are suitable for most dielectric barrier discharge (DBD) plasma applications. However, during the process of DBD driven by an HV-PCPS based on an energy storage pulse transformer, the output pulse voltage waveform quality is poor, making it not suitable for stable discharge long-term operation. This article aims to solve the aforementioned problem and proposes a novel resistor–diode–diode (RDD) shaping method. Not only can this novel method solve the problem of poor quality of the output pulse power from the HV-PCPS, guaranteeing stable discharge for various DBD electrodes, it can also limit the maximum output voltage amplitude. This prevents overvoltage breakdown when the output terminal is in an open state or a light load state because the HV-PCPS is acting as a current source. This article also analyzes the effectiveness of an RDD branch when solving the problem in theory, and gives a detailed parameter design method. Finally, a 30-kV HV-PCPS prototype is built to verify the effectiveness of the proposed RDD pulse shaping method. The average pulse power output of the whole prototype is greatly improved, and it can achieve an average pulse power output of 1 kW. Furthermore, the electrode loads of different DBD reactors can be driven by this technology.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Optimal Driving and Loading Scheme for Multiple-Receiver Inductive Power
           Transfer

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      Authors: Rong He;Peng Zhao;Guangdong Ning;Kang Yue;Yu Liu;Minfan Fu;
      Pages: 12665 - 12675
      Abstract: An inductive power transfer system is able to charge multiple receivers (RXs) through a single transmitter. In order to develop suitable control methods, this article explores and compares the influence of driving current and loading resistance on the efficiency and power distribution. It starts from a simple system with equal coupling and then extends the discussion to a general one. With proper simplification, an optimization problem is defined to derive several important factors, including the optimal driving current, optimal loading resistance, and the corresponding optimized efficiency under various application constraints. In the final experiments, the dynamic tuning of driving current is able to maximize the system efficiency to 92.1% for a general three-RX system. In another customized system with equal coupling, the maximum error between the achieved efficiency and the real maximum efficiency is 0.4% through the calculation-based current control.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Interleaved Buck-Type Rectifier With Pseudo-DC-Link Capacitors for
           Automatic Current Balancing

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      Authors: Kerui Li;Siew-Chong Tan;Shu Yuen Ron Hui;
      Pages: 12676 - 12687
      Abstract: This article presents an interleaved buck-type rectifier with pseudo-dc-link capacitors featuring automatic current balancing, soft-switching operation, efficient ac-dc conversion, and tight output regulation. The ac-input-current-synchronized modulation scheme that hybridizes for cycle-by-cycle phase-shift and duty ratio adjustment is adopted for zero-voltage switching (ZVS) operation and output regulation. In addition, the pseudo-dc-link capacitors facilitate the convergence and current balancing between output inductors. Mathematical models are provided to quantitatively describe the mechanism of current balancing, steady-state performance, and dynamic response. A lab prototype is built, and the experimental results are provided to verify the features.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • High Power ZVZCS Phase Shift Full Bridge DC–DC Converter With High
           Current Reset Ability and No Extra Electrical Stress

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      Authors: Yong Shi;Langlang Feng;Qifan Li;Jiayu Kang;
      Pages: 12688 - 12697
      Abstract: Zero-voltage zero-current switching (ZVZCS) phase-shift full-bridge (PSFB) dc–dc converters are candidate converters for high-power switching mode power supply because of their low cost and high efficiency. However, these converters still have some definite weaknesses, e.g., resetting obstacles of high-value currents, extra electrical stress on the power devices. Hence, customers seldom adopt these topologies in high-power applications. This article proposes a new ZVZCS PSFB dc–dc converter to solve the above problems. A clamping circuit with two mosfets, two diodes, and a resetting transformer ensures ZCS of the lagging-leg switches over a wide load range, and no extra electrical stress arises on the primary or secondary components. The clamping circuit has a high current reset ability and can break through the power limitation of conventional ZVZCS PSFB dc–dc converters. The volume of the resetting transformer is small because of the low voltage-second product, and the added mosfets cause low power loss because of the wide soft-switching load range and low on-resistance. The experimental results from a 12-kW prototype prove the rightness and advantages of the proposed converter.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A PWM Plus Phase-Shift Control for Four-Switch Buck-Boost Converter to
           Achieve ZVS in Full Input Voltage and Load Range

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      Authors: Jie Fang;Xinbo Ruan;Xinze Huang;Renxi Dong;Xiaojian Wu;Jianyu Lan;
      Pages: 12698 - 12709
      Abstract: Four-switch buck-boost (FSBB) converter features positive output voltage and low voltage stress of power switches. In this article, a pulsewidth modulation plus phase-shift control scheme is proposed to achieve zero-voltage-switching for all the power switches in full input voltage and load range and minimize the inductor current ripple and root mean square (RMS) value. The implementation of the proposed control scheme is given. A prototype of a 500-W FSBB converter is built and tested in the lab, and the experimental results verify the effectiveness of the proposed control scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Mutual-Inductance-Dynamic-Predicted Constant Current Control of LCC-P
           Compensation Network for Drone Wireless In-Flight Charging

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      Authors: Yu Gu;Jiang Wang;Zhenyan Liang;Zhen Zhang;
      Pages: 12710 - 12719
      Abstract: In this article, we propose a mutual-inductance-dynamic-predicted constant current (CC) control to realize the secondary-feedback-free output current adjustment for drone wireless in-flight charging systems. In practical systems, the challenge is to keep a CC output for drones under the continuous fluctuations of mutual inductance, the variation of desired charging current, and the carrying weight limits of drones, which has been nearly unexplored in previous studies on wireless power transfer systems. Accordingly, this article proposes a novel mutual-inductance prediction scheme combined with optimized phase shift control to maintain the desired CC charging output, which can be implemented at the transmitting side to address the impact of the above-mentioned challenges. In the article, simulated and experimental results are both given to verify the feasibility of the proposed control scheme, wherein the prediction accuracy is above 92.5%, the CC control accuracy is within 5%, and the average response time is less than 320 ms. It shows that the proposed dynamic-predicted CC control scheme has improved real-time capability and enhanced robustness, which is an ideal technical means for drone wireless in-flight charging.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Family of Nonisolated Fully Soft Switched Bidirectional Converters With
           Single Switch Auxiliary Circuit

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      Authors: Mohsen Packnezhad;Hosein Farzanehfard;
      Pages: 12720 - 12727
      Abstract: In this article, a family of nonisolated zero voltage switching (ZVS) bidirectional dc–dc converters (BDCs) with simple auxiliary circuit and continuous current at low voltage side source ($V_L$) is proposed. The auxiliary circuit is only composed of a single switch, a capacitor, and a small inductor which is applied to all proposed nonisolated BDCs to provide soft switching condition for all semiconductor elements. Thus, in terms of components count, the presented converters are superior to other counterpart BDCs. In addition, the continuous current at $V_L$ is maintained, while the main and auxiliary switches in both operating modes are turned on and off at ZVS. Moreover, all diodes turn off at zero current switching which mitigate the reverse recovery problem. Hence, a suitable overall efficiency is achieved in all proposed BDCs. The proposed bidirectional buck/boost converter is analyzed for both step-up and step-down operating modes in details and a 100 W converter prototype is implemented to verify the main converter features and the theoretical analysis.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Low Voltage Stress PFC Rectifier Based on Nonoverlapping Strategy Using
           Resonant Switched-Capacitor Converter

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      Authors: Zhangyong Chen;Yubo Han;Yunfeng Wu;Zhengdong Lu;Xiangyu Liu;
      Pages: 12728 - 12738
      Abstract: In order to break limited step-down ratio range and poor regulation capacity in the conventional resonant switched-capacitor converters for rectifier application, a single-stage ac/dc rectifier based on the dual-resonance switched-capacitor converter is proposed in this article. Through utilizing a dual-resonant structure and nonoverlapping strategy to realize wide continuous voltage gain of the proposed converter, high power factor (PF) and low total harmonic distortion (THD) based on the narrow dead zone are guaranteed by operating at high step-down conversion ratio in this converter topology. Moreover, the voltage gain is concentrated between resonant frequency and double resonant frequency to achieve a narrow switching frequency range for rectifier application. Furthermore, operating at flat voltage stress curves to obtain low voltage stress character. Comprehensive mode analysis, input PF and THD, and stress analysis are given, and analysis results indicate that the proposed power factor correction converter can work with soft turn on and zero-current turn off; high efficiency is realized. Finally, an experimental prototype with 85–130 Vac input and 47 Vdc/44 W output is built and tested for verifying the operation modes and PFC performance, and the comparison between different rectifiers and the proposed one is provided.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Current-Mode DC–DC Buck Converter With Accurate Current Limit Using
           Multiplex PWM Comparator

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      Authors: Xinquan Lai;Jingxiang Zhao;Bingyuan Wang;
      Pages: 12739 - 12749
      Abstract: In a conventional current-mode dc–dc buck converter, two sensed inductor current signals are processed in three separate comparators to regulate the converter under various load conditions. These independent sensing currents and comparators not only consume large quiescent current and silicon areas but also cannot guarantee the accuracy of the current limit threshold. This article proposes a current-mode dc–dc buck converter with an accurate current limit using a multiplex pulsewidth modulation (PWM) comparator. Through a multiplex PWM comparator, only one sensing current and one comparator are required to process the inductor current information and complete the regulation of the converter under various load conditions. The response speed of overcurrent protection is also increased without consuming more power and silicon area. Moreover, by generating the zero temperature coefficient (ZTC) sensing current and adding ZTC reference current with slope compensation information, the accuracy of the current limit threshold is greatly improved under various temperatures in a wide input voltage range. The proposed buck converter with a multiplex PWM comparator was fabricated using a standard 1P3M 0.18 μm BCD (BiCMOS/DMOS) process and the experimental results show that the proposed scheme functions properly in the 5-A load range, and the current limit threshold also varies only 8.1% in the temperature range from −40 to 125 °C with the input voltage up to 60 V.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Single-Stage PFC Charge-Pump Bridgeless Converters for LED Driver
           Applications

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      Authors: Zito Palhano da Fonseca;Claudinor Bitencourt Nascimento;Alceu André Badin;
      Pages: 12750 - 12761
      Abstract: This article presents the analysis and design of a single-stage charge-pump (CP) bridgeless converter for light-emitting diode (LED) applications. The proposed topology is based on a boost bridgeless converter operating in a discontinuous conduction mode, which is associated with the CP concept. The proposed electronic lighting system employs a reduced component count, and the CP concept is used to reduce the LED current ripple. A high power factor is demonstrated to be an inherent property of the proposed topology, and no input current control is necessary. The operating principle of the proposed converter, which includes two operating modes in a steady state, is presented and analyzed. We also present a prototype operating with a switching frequency of 75 kHz, an input voltage range of 90–160 VRMS, and an output power of 60 W with a power factor of 0.989, the total harmonic distortion of 14.15%, and the efficiency of up to 95.4%. Additionally, all individual harmonic magnitudes of the input current meet the IEC 61000-3-2 class-C standard limits.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Improved Pulse Density Modulation Control for Secondary Side Controlled
           Wireless Power Transfer System Using LCC-S Compensation

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      Authors: Veli Yenil;Sevilay Cetin;
      Pages: 12762 - 12772
      Abstract: In this article, an improved pulse density modulation (PDM) control for secondary side controlled wireless power transfer (WPT) system is proposed. The LCC-S network is selected for the compensation of the reactive power in the system. In the secondary side, an active rectifier with improved PDM control is used to regulate the output voltage. The output voltage regulation is achieved by changing the pulse density of the rectifier switches. By using the proposed PDM pattern, the input pulse sequence of the active rectifier can be distributed more homogenously compared to the conventional PDM control. Therefore, the output current ripple of the primary side inverter and the output voltage ripple of the active rectifier are reduced. The light load efficiency is also improved compared to conventional PDM control. The soft switching conditions are achieved for inverter and active rectifier switches. The experimental prototype with 150 mm air gap is built to validate the performance of the proposed system. The overall efficiency of the system with the proposed PDM is improved by 1.7% and 9.9% compared to the conventional irregular and regular PDM control, respectively. The output voltage ripple of the active rectifier and the output current ripple of the primary inverter are also reduced at light load conditions with the proposed PDM.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Short-Circuit Characteristics and High-Current Induced Oscillations in a
           1200-V/80-mΩ Normally-Off SiC/GaN Cascode Device

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      Authors: Gang Lyu;Jiahui Sun;Yuru Wang;Kevin J. Chen;
      Pages: 12773 - 12783
      Abstract: A normally-off SiC-JFET/GaN-HEMT cascode device is recently proposed, featuring a cascode configuration that incorporates a high-voltage (HV, e.g., 1200 V) silicon-carbide (SiC) junction field effect transistor (JFET) delivering the HV blocking capability and a low-voltage (LV) enhanced-mode (E-mode) gallium-nitride (GaN) high electron mobility transistor (HEMT) providing the normally-off gate control. This all-wide-bandgap device exhibits superior thermal stability and high switching speed compared to its counterparts, e.g., the SiC/Si cascode device. In this article, we study short-circuit (SC) characteristics of a 1200-V/80-mΩ SiC/GaN cascode device by considering the interactions between the SiC and GaN devices. The single-event SC withstand time (SCWT) of the demonstrated SiC/GaN cascode device is tested to be ∼3 μs under a dc-bus voltage (Vdc) of 600 V when the turn-on gate voltage (VG-on) is set to 5 V. The SC failure occurs due to the formation of hot spots induced by thermal-runaway leakage currents inside the SiC JFET. The SCWT of the cascode device could be improved by applying a moderate VG-on (e.g., SCWT = ∼6.5 μs at VG-on = 3.5 V under v dc = 600 V) without affecting the on-state resistance ( r on). However, it is identified that current oscillations tend to be triggered during the SC period when VG-on is too low (e.g., lower than 3 V). The oscillation behavior is attributed to the en-rgy stored in the interconnection parts between the SiC and GaN devices. The harmful oscillations could be suppressed by applying higher VG-on, which drives the SiC JFET into low-transconductance mode by modulating the drain-to-source voltage (VDS-G) of the LV GaN HEMT.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Beta-Quasi-Z-Source (β-qZS) DC–DC Converter Without Duty Cycle
           Constraint for Wide Input Voltage Applications

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      Authors: Emmanuel S. Oluwasogo;Honnyong Cha;Tien-The Nguyen;
      Pages: 12784 - 12794
      Abstract: A novel beta-quasi-Z-source (β-qZS) converter is proposed for an isolated dc–dc converter with the buck (step-down) and boost (step-up) functions. The β-qZS isolated dc–dc converter addresses the common challenges such as components stresses, reliability, suppression of switch voltage overshoot, size, and power derating in the existing impedance source-based isolated dc–dc converter applications. In addition, the proposed topology dealt with operating duty cycle constraint and loss of duty cycle phenomenon in the Z/qZS galvanically isolated dc–dc converters. This article describes the configuration and provides the principle of operation for the proposed β-qZS converter topology. A laboratory prototype is developed, and the experimental results satisfy the theoretical analysis.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Multi-Segment Compensation Method for Improving Power Density of
           Long-Distance IPT System

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      Authors: Jianwei Mai;Yijie Wang;Xianrui Zeng;Yousu Yao;Kang Wu;Dianguo Xu;
      Pages: 12795 - 12806
      Abstract: Inductive power transmission has been applied in industries, such as electric vehicles, consumer electronics and biomedical fields. However, there is a long-term key problem in this field that has not been solved. This is the adverse effect of the parasitic capacitance of the coil, which will cause the change of the coil inductance, the reduction of the quality factor and the reduction of efficiency. Especially in the field of long-distance wireless power transmission. The existing technologies all adopt the scheme of sacrificing volume in exchange for the quality factor of the coil. As a result, the volume of the system is very large, and the quality factor of the coil is still not high enough because the influence of parasitic capacitance has not been completely eliminated. Here, we found the solution. Connect compensation capacitors in series to the coil sections to short-circuit the parasitic capacitance and reduce its loss. The designed system has a diameter of 502 mm and a thickness of 22 mm, which can transmit 115.2 W of power within a distance of two meters with an efficiency of 29%.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Large-Area Free-Positioning Wireless Power Transfer to Movable Receivers

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      Authors: Shamsul Arefeen Al Mahmud;Ishtiaque Panhwar;Prasad Jayathurathnage;
      Pages: 12807 - 12816
      Abstract: This article introduces a method for efficient and robust free-positioning wireless power transfer (WPT) in a large area, which can be applied to many use cases, including wireless charging of industrial robots, drones, and electric scooters. In these large areas of WPT applications, multiple transmitters (Txs) are placed in a pad-like area, and the Tx coils are optimally excited to enable robust and efficient power transfer to movable receivers within the charging area. The proposed configuration enables almost continuous magnetic flux path from a set of Tx coil(s) to another set of Tx coil(s) through the receiver coil ferrite core. Therefore, efficient power transfer is ensured throughout the whole Tx coverage area. The article introduces a novel method to detect the position and orientation of the receiver only from the Tx-side measurements. The proposed solution is experimentally verified in a laboratory prototype, and the experimental results show dc-to-dc efficiency of 91% with only 1% variation in most of the Rx positions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A 13-, 11-, and 9-Level Boosted Operation of a Single-Source Asymmetrical
           Inverter With Hybrid PWM Scheme

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      Authors: Mohammad Ali;Mohd Tariq;Adil Sarwar;Basem Alamri;
      Pages: 12817 - 12828
      Abstract: This article explores a single-source UXE-type asymmetrical multilevel inverter for its operation on 13-, 11-, and 9-levels with boosted output voltage. The 13- and 11-level operations require a single voltage sensor to maintain the auxiliary dc link at $V_{text{dc}}/2$ and produce 1.5 and 1.25 boosting using redundant states and exhibit lower capacitor inrush currents. For the 9-level operation, the topology exhibits self-balancing of the dc-link at $V_{text{dc}}$ and a boosting of 2. With a conventional pulsewidth modulation (PWM) for the 13-level operation, the inverter can drive a predominantly inductive load of 0.35 lagging at unity modulation index. For the 11-level operation, the levels cease to maintain beyond the modulation of 0.95. Thus, a hybrid PWM is proposed to fully utilize the redundant states for the charging of the switched-capacitors and enhance the inverter active load capability in the 13-level mode by 21% at unity modulation index ($m_a$) and address a 0.8 power factor load at the $m_a$ of 0.9. For the 11-level operation, the levels are maintained at any $m_a$ with the hybrid PWM. The operation of the inverter is also verified for nonlinear load. Further, the 9-level operation with twice boosting and self-balancing is presented. The results are verified on MATLAB/Simulink and validated experimentally.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Analysis, Design, and Optimization of the IPT System With LC Filter
           Rectifier Featuring High Efficiency

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      Authors: Jianwei Mai;Xilai Sun;Yijie Wang;Peng Gu;Xianrui Zeng;Kang Wu;Yousu Yao;Dianguo Xu;
      Pages: 12829 - 12841
      Abstract: Passive diode bridge rectifier with LC filter is widely used in wireless power transfer (WPT) system due to its simple structure and uncontrolled characteristics. However, as the load resistance decreases, its input phase angle will also decrease rapidly until it shows obvious capacitive. Therefore, a novel rectifier topology with an input-series inductor (hereafter called ISIR) is proposed in this article to solve this problem. What is more, the ISIR can avoid the duty cycle loss and improve the dc–dc efficiency. First, the mechanism of ISIR is analyzed in detail combined with the operating status of topology. Then, the inductance and compensation parameters are determined based on theoretical calculation and simulation results. Finally, a prototype with a maximum load of 7 Ω is built to validate the feasibility and effectiveness of ISIR, and 88% efficiency is achieved under this condition. Compared with the traditional method, it has increased by 1.05%. The maximum efficiency of WPT system is as high as 91.14% with the proposed ISIR.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Self-Driven Synchronous Rectification ZCS PWM Two-Switch Forward
           Converter With Minimum Number of Components

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      Authors: Hamid Bahrami;Hesamodin Allahyari;Ehsan Adib;
      Pages: 12842 - 12850
      Abstract: A new soft-switching dual-switch forward converter with self-driven synchronous rectifier is presented in this article. The proposed converter operates under discontinuous conduction mode; therefore, compared with the two-switch forward (TSF) converter, one diode along with one inductor is removed from the output side. The leakage inductance of the transformer is employed to transfer the power from the input side to the output side. To provide the zero-current switching (ZCS) condition for all semiconductor devices in both on and off instants, a delay time between the off-command signals of main switches along with a capacitor is used as auxiliary circuit, which eliminates the required additional switch for soft switching. Moreover, the auxiliary circuit in addition to provide soft-switching condition, resets the transformer core, resonantly. Compared with the TSF converter with the help of the new auxiliary circuit, two reset diodes at the input side can be removed. The proposed converter is controlled with duty cycle using the pulsewidth modulation. Also, a winding is added at the output side of transformer to drive the MOSFET of synchronous rectification. Thus, a ZCS TSF converter with the minimum number of components is proposed. The operating modes of the proposed converter along with the design approach and the stress analysis are completely considered. To verify the theoretical results, a prototype is implemented and the theoretical results are compared with the experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A New Power Converter for Current Source Converter-Based Wind Energy
           System

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      Authors: Ling Xing;Qiang Wei;Yunwei Li;
      Pages: 12851 - 12858
      Abstract: The current source converter (CSC) based conversion system is a good candidate for next-generation series-connected wind energy conversion systems. In this article, a new power converter is proposed for the CSC-based series-connected wind system. In addition, three versions of the proposed converter are developed. Compared with the existing CSC-based converters, the proposed one provides a practical solution for the series-connected wind system, achieves superior current harmonic performance, and features inherent power balancing, simple control, and high scalability, in addition to keeping all the advantages of the existing CSCs. The operation principle of the proposed converter is discussed, and its performance is verified by the simulation and lab-scaled experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Ultrahigh Step-Up Multiport DC–DC Converter With Common Grounded Input
           Ports and Continuous Input Current

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      Authors: Sajad Rostami;Vahid Abbasi;Nazilasadat Talebi;
      Pages: 12859 - 12873
      Abstract: This article presents a multiport dc–dc converter (MPC) with four ports suitable for renewable energy applications. The converter is composed of two boost converters and a switched capacitor. The converter includes a bidirectional buck–boost converter to charge/discharge an energy storage. In the design procedure of the converter, existence of a common ground between the load and input ports, high voltage gain and continuous current of the ports are introduced, which make the converter appropriate for more applications. The converter boosts voltage with high gain in all of its operation modes. In addition, it operates in unbalanced conditions such as different powers and voltage levels of the input sources. According to the used switching strategy, controlling input power of the sources and output voltage is possible. Furthermore, the converter switches between charging and discharging modes automatically. To validate the feasibility and effectiveness of the proposed MPC, a prototype with 250 W nominal power is prepared. The converter boosts 20–400 V in all of the experimented modes.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Low-Pass Virtual Filter for Output Power Smoothing of Wind Energy
           Conversion Systems

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      Authors: Kai Liao;Dingwen Lu;Min Wang;Jianwei Yang;
      Pages: 12874 - 12885
      Abstract: As theincrease of wind power penetration, the fluctuations of wind power results in serious power system frequency turbulences. This article proposes a low-pass virtual filter (VF) for wind energy conversion systems (WECSs) to smoothen output power. First, a linearized model is established for a WECS. Then, a low-pass VF is derived for the active power control loop in WECS to modulate the kinetic energy stored in rotating mass for output smoothing. The principle is to modify the traditional wind power controller to emulate a physical energy storage system controlled as a low-pass filter to smooth the wind power output. The proposed low-pass VF does not need the physical deployment of energy storage system but still can filter the high-frequency fluctuations in the output wind power. Furthermore, in order to ensure operation stability of the wind turbine (WT), a stability-constrained coefficient is determined according to the proposed stability criteria to ensure the stability of WTs. Simulation and experiment results verify the effectiveness of the proposed VF in WECS for output wind power fluctuation reduction and the stability-constrained coefficient for stability ensuring.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Soft-Switching High Step-Up DC–DC Converter Based on Switched-Capacitor
           and Autotransformer Voltage Multiplier Cell for PV Systems

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      Authors: Márcio Rodrigo Santos de Carvalho;Eduardo Augusto Oliveira Barbosa;Fabricio Bradaschia;Leonardo Rodrigues Limongi;Marcelo Cabral Cavalcanti;
      Pages: 12886 - 12897
      Abstract: This article introduces a nonisolated, high step-up voltage multiplier cell (VMC)-based dc–dc converter for applications such as module-integrated converter and power optimizers. The VMC combines switched capacitor with autotransformer techniques and active clamp circuit. The autotransformer tertiary winding is employed to increase voltage gain without operating the main switch under extreme duty cycle condition, to reduce the current through the main switch before it turns offand to ensure its zero-voltage switching (ZVS) operation on a wide operation range. The auxiliary switch in the clamp circuit provides ZVS for the main switch and vice-versa. Thus, both switches are turned on with zero voltage and there is no switching loss. Hence, high switching frequency is used to reduce the passive components’ volume and weight. Besides, the low dc-bias and bidirectional magnetizing current allows a smaller magnetizing inductance in the autotransformer to further minimizing the dimensions of the magnetic core. The leakage inductances are used to provide zero-current switching condition for the diodes, eliminating their reverse-recovery losses. The operation principle, steady-state analysis, and design guidelines are depicted and validated through experimental results obtained from a 350-W prototype of the proposed converter. Efficiency of 96.5% at full load is also reported.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Power Optimization Distribution Method for Fuel Cell System Cluster
           Comprehensively Considering System Economy

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      Authors: Tianhong Wang;Qi Li;Yibin Qiu;Weirong Chen;Elena Breaz;Alexandre Ravey;Fei Gao;
      Pages: 12898 - 12911
      Abstract: In high-power applications, the use of fuel cell system cluster (FCSC) is increasingly valued. However, most of the existing strategies emphasis in optimizing a certain control objective (e.g., efficiency or consumption), but do not fully consider the impact of other factors such as stack degradation. To address this research gap, this article proposes a power allocation method related to the system economy, which considers multiple factors that affect the operating cost of FCSC. The efficiency and hydrogen consumption are analyzed, and two high-order polynomials are used to represent these two curves. Besides, considering that the fuel cell (FC) output characteristics are variable, an online identification algorithm is adopted to update the system parameters in real-time. Moreover, in the formulated cost function, stack degradation is also considered. What is more, to ensure that the FCs can operate in the high efficiency range as much as possible, we also add constraints to limit the FCs output power. The effectiveness of the proposed method has been verified on a hardware-in-the-loop simulation platform. Compared with the equal distribution strategy, the proposed method can effectively ameliorate the economy of the system. Furthermore, the proposed method has been experimentally validated and its real-time operation ability has been highlighted on an actual FCSC.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Adaptive Fault Ride-Through Scheme for Grid-Forming Inverters Under
           Asymmetrical Grid Faults

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      Authors: Zilin Li;Ka Wing Chan;Jiefeng Hu;Siu Wing Or;
      Pages: 12912 - 12923
      Abstract: Three-phase four-wire grid-forming (GFM) inverters are promising to interface distributed energy resources into low-voltage networks. However, these inverters are prone to overcurrent under grid faults. Physically increasing the inverter current capacity is not cost-effective to cope with complicated fault conditions. In this article, an adaptive fault ride-through (FRT) scheme based on instantaneous saturators and virtual negative- and zero-sequence resistances is proposed. It features not only overcurrent limitation by modifying voltage references, but also seamless transition between normal and grid fault conditions. The proposed FRT scheme is first analyzed from different aspects, including the virtual sequence resistances, grid short-circuit ratio, fault types, and fault levels. The virtual sequence resistances are then designed to be adaptive to ensure high voltage quality at the healthy phase. The proposed FRT scheme is verified by MATLAB/Simulink simulations under asymmetrical faults. A laboratory platform with a grid-connected 3kW GFM inverter is further constructed to demonstrate its effectiveness (a video of the experimental results under three asymmetrical faults is attached).
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Nonunit Distance Protection Algorithm for Multiterminal MMC-HVdc Systems
           Using DC Capacitor Resonance Frequency

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      Authors: Vinícius A. Lacerda;Renato M. Monaro;Rafael Peña-Alzola;David Campos-Gaona;Denis V. Coury;
      Pages: 12924 - 12933
      Abstract: High-voltage dc (HVdc) transmission has been largely used to interconnect asynchronous systems and integrate renewable energy resources into electrical grids. However, the high short-circuit currents and low-tolerance of power electronics equipment impose new challenges for these systems’ protection. To address these challenges, a new distance protection algorithm for HVdc grids with modular multilevel converters (MMCs) is proposed in this article. The proposed algorithm identifies the faulty line/cable using the resonance frequency of a dc capacitor installed in each terminal. The technique was tested in a four-terminal HVdc grid with five cables and ten circuit breakers. The algorithm was highly selective for faults in the lines and provided fast identification, in less than 1 ms, without communication amongst terminals. The algorithm was tested in hardware under high-noise conditions and provided reliable results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Novel Multisource DC-DC Converter for All-Electric Hybrid Energy Systems

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      Authors: Immanuel N. Jiya;Ahmed Salem;Huynh Van Khang;Nand Kishor;Rade Ciric;
      Pages: 12934 - 12945
      Abstract: In this article, a novel nonisolated multiple input dc-dc converter (MIC) is proposed for all-electric hybrid energy storage systems. The proposed MIC is capable of bidirectional operation in noninverting buck–boost configuration and can accommodate the simultaneous energy transfer from multiple sources of different voltage levels to the dc bus. As compared to counterparts, the proposed MIC utilizes a smaller number of inductors and requires only one bidirectional switch to integrate any extra energy storage. Within the framework, a novel voltage transformation, operation modes, and control method are presented in detail. The performance and key features of operation with varying voltage levels and duty cycles of the proposed MIC are numerically verified through a high-fidelity hardware-in-the-loop platform and experimentally validated on an in-house test rig.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Adaptive DC-Link Voltage Control of a Multifunctional SPV
           Grid-Connected VSI for Switching Loss Reduction

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      Authors: Chinna Karasala;Siva Kumar Ganjikunta;
      Pages: 12946 - 12956
      Abstract: In the proposed method in this article, to minimize the burden on the switches of the multifunctional grid-connected voltage-source inverter (MFGCVSI), the voltages of dc-link split capacitors are adjusted according to power injection from the MFGCVSI. The MFGCVSI is used to control the active power injection from solar photovoltaic (SPV) power generation to the main grid and loads, load reactive power compensation, harmonic mitigation, and main grid current total harmonic distortion within 5$%$. In such a case, the voltages of split capacitors depend on the rated power injection from the MFGCVSI. The power generated from the SPV system and the loads that are connected at the point of common coupling vary with respect to time. It is observed that the selection of rated dc-link voltages during low power injection from the MFGCVSI leads to additional switching stress and higher switching losses. Therefore, to reduce the burden on inverter switches and switching losses, the reference dc voltage is reduced under low power injection from the MFGCVSI. A model predictive controller with a multiconstraint technique is used in the proposed method for balancing the dc-link capacitor voltages and average switching frequency reduction. The proposed method is validated through simulation and hardware setup.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Self-Operating Flyback Converter for Boosting Ultra-Low Voltage of
           Thermoelectric Power Generator for IoT Applications

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      Authors: Soumyabrata Patra;S. K. Sahu;Prakash Gidomal Abichandani;K. N. Meshram;Shovit Bhattacharya;K. P. Muthe;Deep Prakash;Ajay Singh;
      Pages: 12957 - 12966
      Abstract: This article presents a novel self-operating flyback converter to boost the ultra-low voltage produced by thermoelectric power generator (TEG). The proposed converter uses dual transformer, one for low-voltage startup and other to extract power from TEG. The use of separate transformer provides high-voltage transfer ratio, reduces high series resistance loss, and brings down the input impedance of circuit. The copper wire wounds ferrite toroid core transformer provides very low series resistance and negligible core loss, which improves the circuit efficiency. This boost converter operates with an input voltage range of 22–300 mV and provides maximum output power of 0.073 – 147 ${rm{mW}}$ correspondingly. The peak efficiency of 68% with output power of 1.32 ${rm{mW}}$ (voltage ∼1.83 V) is achieved at an input voltage of 50 mV. For regulated output voltage, a feedback loop is used to keep output voltage constant during sudden voltage rise of TEG. The proposed circuit uses discrete components, ferrite toroid core, and PCB, which has lower cost than available energy harvester module, which uses energy harvesting ICs, discrete components, and tiny transformer. The lower startup voltage, higher output power, and voltage with high conversion efficiency of this boost converter maximize the applications potential of the TEG as a portable power source for Internet of Things (IoT) devices.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Modeling and Suppression of Circulating Currents Among Parallel
           Single-Phase Three-Level Grid-Tied Inverters

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      Authors: Chenghui Zhang;Zhizhen Wang;Xiangyang Xing;Xiaoyan Li;Xi Liu;
      Pages: 12967 - 12979
      Abstract: T-type three-level inverters have attracted extensive attention for their utility in many applications, especially photovoltaic power generation. For these inverters, parallel operation offers superior performance in capacity, reliability, and scalability. However, the introduced circulating current (CC) may cause overcurrent in line, which seriously threatens the safety and stability of the system. The mechanism of CC lacks detailed analysis in single-phase modular inverters. Thus, an accurate mathematical model is established and a CC suppression method is proposed in this article for parallel-operated single-phase T-type three-level inverters. First, the characteristics of port degradation are analyzed, and an improved equivalent circuit is introduced based on the findings. Then, according to the improved equivalent circuit, a detailed mathematical model is established. Using this model, excitation sources of CC are analyzed and divided into three parts. After that, a CC suppression method involving carrier-based pulsewidth modulation with offset voltage injection is proposed, and a deadbeat controller is designed to calculate the offset voltage. Moreover, the proposed method can balance the neutral-point voltage across dc-link capacitors as well. Simulation and experimental results validate the theoretical analysis and effectiveness of the proposed scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Adaptive Control Framework for Dynamically Reconfigurable Battery
           Systems Based on Deep Reinforcement Learning

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      Authors: Feng Yang;Fei Gao;Baochang Liu;Song Ci;
      Pages: 12980 - 12987
      Abstract: This article presents an adaptive control framework for dynamically reconfigurable battery (DRB) systems based on the deep reinforcement learning method. The proposed adaptive control framework relies on deep Q-network to learn the DRB system operations. By utilizing its model-free nature, the proposed framework can significantly reduce the complexity of building experiences or expert models for DRB systems as well as improve battery operating time by ensuring cell balancing. Extensive simulation and experimental study has been carried out with data gathered from a real-world DRB testbed, and the results show the effectiveness and efficiency of the proposed control framework.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Approach to Inertial Compensation of HVdc Offshore Wind Farms by MMC With
           Ultracapacitor Energy Storage Integration

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      Authors: Wu Zeng;Rui Li;Lei Huang;Chang Liu;Xu Cai;
      Pages: 12988 - 12998
      Abstract: Recent studies have shown that the grid connection of offshore wind farms through modular multilevel converter–high voltage direct current (MMC-HVdc) transmission system has brought low inertia issue. It is an urgent requirement for offshore wind farms to compensate for the inertia. After analysis and evaluation in this article, it is found that integrating an ultracapacitor energy storage system (UESS) into an MMC has an advantage comprehensively considering cost, size, and dynamic. Based on the evaluation, this article proposes an approach to inertial compensation of HVdc offshore wind farms by MMC-UESS integration. An ultracapacitor is selected as an energy storage element (ESE) for its high power density since the inertial response is a short-term response and it is hoped that added ESE does not significantly increase the size of an MMC submodule. Batteries with high energy density but low power density are not suitable for such applications. The optimal operating voltage of a UESS and the control scheme between MMC loops and inertial emulation are proposed in this article. Experimental results from real-time simulation and a downscaled prototype are presented to verify the effectiveness of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Vector Analysis Based Multiobjective-Modulated Model Predictive Control
           for Four-Switching-State Multilevel Converters

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      Authors: Sai Tang;Jun Wang;Daming Wang;Chao Zhang;Xin Yin;Zhikang Shuai;Zheng John Shen;
      Pages: 12999 - 13010
      Abstract: The article proposes a new vector analysis based model predictive control (VAMPC) method for multilevel converters with four different switch configurations. It is based on track of an error vector using fundamental state vectors, and can achieve deadbeat control of four switching states multilevel converters with multiple control objectives. Compared with conventional finite control set model predictive control (FCS-MPC) method, VAMPC can achieve excellent spectrum characteristics in the case of a slight increase in computational burden. The VAMPC method is experimentally validated on a 100-kHz GaN-based three-level flying capacitor (FC) converter. Compared with the FCS-MPC, VAMPC leads to significant reduction in steady-state control errors. For example, the inductor current total harmonic distortion of the FC converter is now reduced by more than 60%.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Three-Phase Flying Capacitor Clamped Current Source Converter With Active
           Capacitor Voltage and CMV Control

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      Authors: Li Ding;Yuzhuo Li;Yun Wei Li;
      Pages: 13011 - 13021
      Abstract: AC-type flying capacitor (FC) concept has been proposed for current source converter (CSC) topologies recently, which offers unique merits over the traditional CSCs, such as lower dv/dt with improved dc-link voltage quality as well as flexible common-mode voltage (CMV) control. To cope with the main-stream three-phase industrial applications, in this article, the three-phase flying-capacitor-clamped CSC is introduced and extensively investigated for the first time. A novel space vector modulation is proposed, featuring a modular design process, active FC voltage control, and CMV suppression. The detailed commutation principles and the capacitor clamping voltage influence under different switching states are comprehensively addressed. Then, the redundant switching states are optimized to fulfill the multiple targets simultaneously. Simulation and experimental results are performed to demonstrate the superior dc-link power quality and CMV performance compared with the traditional three-phase CSC topology.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Unbalanced Active Power Distribution of Cascaded Multilevel
           Converter-Based Battery Energy Storage Systems

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      Authors: Gaowen Liang;Glen G. Farivar;Salvador Ceballos;Hossein Dehghani Tafti;Josep Pou;Christopher D. Townsend;Georgios Konstantinou;
      Pages: 13022 - 13032
      Abstract: In a battery energy storage system (BESS) based on the cascaded H-bridge (CHB) converter or modular multilevel converter (MMC), the active power distribution among the submodules (SMs) can be highly unbalanced, especially when batteries with different power ratings are used. Meanwhile, there are certain limits for the unbalanced power distribution among the SMs. It is a challenge to determine whether the active power distribution is viable for cascaded multilevel converters with unequal capacitor voltages because the complexity grows exponentially as the number of SMs increases. This article proposes a generalized analytic solution to this problem, which reduces the complexity significantly and is readily applicable to converters with large number of SMs. The validity of this method is proved theoretically and verified with simulation and experimental results on both the MMC and CHB converter.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Direct Power Control of Three-Phase Electric Springs

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      Authors: Qingsong Wang;Zhengyong Ding;Ming Cheng;Fujin Deng;Giuseppe Buja;
      Pages: 13033 - 13044
      Abstract: Three-phase electric spring (TPES) was originally proposed to solve three-phase imbalance issues in power systems. So far, several attempts have been reported on proposing power control methods for it. However, existing solutions on TPES either depend on circuit parameters or have relatively slow dynamic responses. In this article, a novel power control strategy that incorporates the advantages of direct power control (DPC) is proposed to solve the above issues. It might be the first attempt to propose a simple power control strategy with rapid dynamic response and independent with circuit parameters for TPES. Besides, the relationship between power operating range and circuit parameters is well analyzed, which provides a way for parameter optimization. To restrain the resonance phenomenon caused by the TPES topology, the passive and active damping methods are compared, revealing that power quality of the control objective can be greatly improved with the active damping. Finally, the proposed DPC with both damping methods is validated by simulations and experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Distributed Dynamic Event-Triggered Control for Accurate Active and
           Harmonic Power Sharing in Modular On-Line UPS Systems

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      Authors: Jinghang Lu;Mehdi Savaghebi;Bingfu Zhang;Xiaochao Hou;Yao Sun;Josep M. Guerrero;
      Pages: 13045 - 13055
      Abstract: Due to the mismatched line resistance in the modular online uninterruptible power supply (UPS) systems, accurate active power and harmonic power sharing is an arduous work. To tackle this issue, this article proposes a distributed dynamic event-triggered control for the power sharing to accurately compensate the effect of mismatch among the line resistances. Benefiting from the proposed control strategy, the UPS modules adaptively regulate the virtual resistance at the fundamental and harmonic frequencies, and hence, the accurate active power and harmonic power sharing are achieved. In addition, the suggested technique allows the UPS modules to exchange information at only the event-triggered times, which greatly reduces the number of communication among the neighboring units. Furthermore, the system's stability is analyzed using a Lyapunov function. Finally, experimental case studies are provided to evaluate the performance of the proposed control strategy, showing its effectiveness in achieving the accurate power sharing, and plug-and-play capability.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Voltage-Fed Isolated Matrix-Type AC/DC Converter for Wind Energy
           Conversion System

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      Authors: Yang Xu;Zheng Wang;Zhixiang Zou;Giampaolo Buticchi;Marco Liserre;
      Pages: 13056 - 13068
      Abstract: In this article, a voltage-fed isolated matrix-type ac/dc converter (VF-MC) is proposed for wind energy conversion system (WECS). Instead of the line-frequency transformer, the high-frequency transformer (HFT) is used for isolation between the generator and the grid. The direct matrix converter (MC) is employed to connect the wind power generator and the HFT, and the intermediate dc capacitors are saved in the ac/ac conversion. Moreover, the proposed VF-MC can work without use of filter capacitors on generator side, and enable more compact size. The dedicated space-vector-modulation scheme and commutation method are proposed for safe operation of the MC. The voltage spikes due to the leakage inductance of HFT are thus reduced and the additional snubber circuit is avoided in the proposed system. A 1-kW laboratory prototype of the proposed VF-MC-based WECS is built to verify the effectiveness of the system experimentally.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Synchronization Stability Analysis of Grid-Forming Inverter: A Black Box
           Methodology

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      Authors: Yang Qi;Han Deng;Jingyang Fang;Yi Tang;
      Pages: 13069 - 13078
      Abstract: Driven by the demands of carbon footprint reduction, the conventional fossil-based generators are gradually being replaced by grid-forming inverter. One crucial aspect of grid-forming inverter is synchronization stability, which is not only related to the inverter power-frequency (P-f) dynamic but also influenced by power grid characteristics as well as grid impedances. From the perspective of a local inverter, it is difficult to know the detailed information. As a result, severe oscillations and even the loss of synchronization may occur and pose a great threat to the power grid. To overcome this problem, a black-box approach is presented in this article. Initially, a frequency-domain identification approach is proposed to acquire the power grid characteristic by the inverter itself. Based on the measurement results, the P-f dynamic of grid-forming inverter is explicitly reshaped to ensure the synchronization stability. The proposed methodology does not require any prior power system knowledge or the trivial modeling process. Finally, the effectiveness of the proposed method is verified by hardware experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • New Discontinuous Space Vector Modulation Strategies for Impedance-Source
           Inverter With Superior Thermal and Harmonic Performance

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      Authors: Ping Liu;Jie Xu;Meidi Sun;Jing Yuan;Frede Blaabjerg;
      Pages: 13079 - 13089
      Abstract: Impedance-source inverters provide a promising single-stage power conversion with boost-buck capabilities and inverter legs short-circuit immunity. To achieve superior thermal and output harmonic performance, two novel discontinuous modulation strategies for the three-phase quasi-Z source inverter, called the maximum-boost discontinuous space vector modulation (SVM) and the simple-boost discontinuous SVM respectively, are proposed in this article. By properly arranging the shoot-through states and clamping a certain switch to the positive or negative dc-link rail during one-third of the fundamental period, reduced thermal stresses and superior total harmonic distortion performance can be achieved. The proposed modulation strategies are analyzed and compared to the conventional ones in terms of current stresses, power losses, thermal stresses, and output harmonics. Finally, simulations and experimental tests are carried out to validate the performance of the proposed modulation strategies and verify the presented analysis.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Simplified Historical-Information-Based SOC Prediction Method for
           Supercapacitors

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      Authors: Houlian Wang;Gongbo Zhou;Jing Xu;Zhiqiang Liu;Xiaodong Yan;Julie A McCann;
      Pages: 13090 - 13098
      Abstract: Range anxiety has become an important issue for the application of electric vehicles. Drivers need information on whether they can reach their destinations and what the remaining capacity would be before starting a trip. In order to satisfy the needs and save computing resources for computing-intense applications in vehicles, in this article we propose a simplified historical-information-based state of charge (SOC) prediction (SHSP) algorithm. First, definitions of SOC, historical average power, and equivalent current are given. Based on these definitions, Rint-based models of supercapacitors, under constant power and constant current loading, are established respectively. Then, a relationship between the historical average power and the predicted SOC is derived with the help of the equivalent current as a “bridge.” The experimental results demonstrate that the 35-step-forward SOC prediction error of the driving-behavior-based SOC prediction (SHSP) is close to the driving-behavior-based SOC prediction method (DBSP) and lower than the long-Short-term-memory-based SOC prediction method (LSTM). Importantly, the time of running SHSP code is less than that of running DBSP code and much less than that of running LSTM code.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Novel Cross-Coupling Position Command Shaping Controller Using H ∞ in
           Multiaxis Motion Systems

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      Authors: Nien-Tsu Hu;Li-Yeh Chen;Chin-Sheng Chen;
      Pages: 13099 - 13110
      Abstract: A new structure of cross-coupling position command shaping controller using ${H_infty }$ control scheme for the precise tracking in the multiaxial motion control is proposed in this article, together with its stability analysis.This new structure has the advantage that the controller has a simpler design process and robuster performance than the conventional ones. The proposed controller is evaluated and compared experimentally with an uncoupled controlled and conventional system. The experimental results show that the new structure remarkably reduces contour error. In addition, this new controller can be implemented easily on a majority of motion systems in use today via reprogramming the reference position command subroutine.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Reconstructing External Force on the Circumferential Body of Continuum
           Robot With Embedded Proprioceptive Sensors

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      Authors: Qingxiang Zhao;Jiewen Lai;Henry K. Chu;
      Pages: 13111 - 13120
      Abstract: The compliance of continuum robot poses difficulty in designing the controller, as the robot does not have position encoder and could be subject to uncertain external force (UEF). The former can be resolved through external sensors, while the latter issue still needs further investigation. This article presents a novel robot design that embeds eGaIn sensors into the soft material, and the elongation in the robot chamber can lead to different changes in resistance values. The sensors act as a proprioceptive mechanism to sense the presence of the UEF. To locate the UEF, the robot surface is divided into multiple regions, and the column and row positions with the force can be solved using Hidden Markov Model and regularization algorithm. Through the virtual work principle, the force magnitude can be also evaluated. Experimental results confirm that, with possible four columns and five rows, the accuracy of finding the actual column and row positions are, respectively, $ 97%$ and $ 98.5%$. The mean error in evaluating the tip position and the force magnitude is about $ text{4};text{mm}$ and $ text{0.23};text{N}$. This article offers a new approach to obtain the information of the UEF, allowing continuum robots to work in a constrained environment.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Context-Free Method for Robust Grasp Detection: Learning to Overcome
           Contextual Bias

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      Authors: Yuanhao Li;Panfeng Huang;Zhiqiang Ma;Lu Chen;
      Pages: 13121 - 13130
      Abstract: The vision-based grasp detection method is an important technique used to research the grasping task of robots. Unfortunately, the performances of these research methods in practice are worse than the state-of-the-art accuracy on public datasets, because shifts in data distribution owing to real-world conditions are common in the real world and neural network-based methods are sensitive to small data changes. These disturbances mainly change the image texture, causing the performance of grasp detection methods to decline sharply. However, the evaluation metric of existing models does not reflect the actual robustness of the method. Therefore, we propose a new solution. First, referring to the existing research on image classification methods, we propose a benchmark to verify the realistic robustness of the grasp detection model. Second, to improve the robustness of the model, we randomly transfer texture knowledge from other images to provide variable texture information for network training. This forces the model to rely more on the contour features of the object than on the texture when making decisions; we call this approach “context-free.” We verify the effectiveness of our method for robustness enhancement in various grasp tasks and test the proposed method in a real robot grasping scene.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Novel Informative Autonomous Exploration Strategy With Uniform Sampling
           for Quadrotors

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      Authors: Xuetao Zhang;Yubin Chu;Yisha Liu;Xuebo Zhang;Yan Zhuang;
      Pages: 13131 - 13140
      Abstract: In this article, a novel informative autonomous exploration strategy with uniform sampling is proposed to efficiently reduce the unknown volume of 3-D environments and provide an accurate truncated-signed-distance-function-based reconstruction for quadrotors. Different from existing methods, the proposed method locally samples candidate viewpoints uniformly and achieves a global coverage efficiently by backtracking history nodes when there is no unmapped space near the quadrotor. Specifically, by sampling viewpoints with a fixed radius and assigning priority, the best one is selected to which a collision-free path will be planned. Then, a history list is designed to store the executed nodes, which is backtracked to find the unmapped space, resulting in a complete exploration of the environment. In addition, a hierarchical information gain is proposed to balance the space exploration efficiency and reconstruction accuracy by considering the uncertainty of the surface and volume of the unknown space. Comparative experiments in simulation show that the proposed method outperforms the sampling-based state-of-the-art method in terms of both the exploration time and reconstruction accuracy. Moreover, the effectiveness of the proposed approach is further evaluated in a real-world experiment.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Adaptive Compensation for Infinite Number of Actuator Faults and
           Time-Varying Delay of a Flexible Manipulator System

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      Authors: Yonghao Ma;Xiuyu He;Shuang Zhang;Yongbin Sun;Qiang Fu;
      Pages: 13141 - 13150
      Abstract: This article addresses a novel adaptive compensation strategy for a flexible manipulator in the presence of unmodeled system dynamics and an infinite number of time-varying actuator faults. Differing from the existing results, the unmodeled system dynamics are represented by a nonlinear time-varying delay function, which is tackled with the aid of neural network technique and Lyapunov–Krasovskii function. By introducing the projection technique and a piecewise Lyapunov function, a fault-tolerant control method is proposed, the uniformly ultimate boundedness of the closed-loop system is ensured, and the number of actuator faults is allowed to be infinite. Simulation and physical experiment results show that the manipulator can track the desired angle and the vibration can be suppressed effectively under the proposed scheme for the system with uncertainties and actuator faults.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Robust Multipoint-Sets Registration for Free-Form Surface Based on
           Probability

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      Authors: Weixing Peng;Yaonan Wang;Hui Zhang;Yurong Chen;Haotian Wu;Jiawen Zhao;
      Pages: 13151 - 13161
      Abstract: Free-form surface reconstruction using point clouds is a common issue in manufacturing. In this article, a robust joint registration approach for multiview point clouds is proposed to address the problems brought by coarse initialization, outliers, and noise. The basic idea is that minimizing the L2 distance between probability distributions of integrated and standard models, such that a robust initialization is provided for fine registration to avoid local minima. The fine registration is formulated as a joint closet point problem, which is implicitly constrained by closed-loop consistency. In addition, a Lie algebra solution is derived to enforce rigid transformations. The robust initialization is judged by the simulated annealing algorithm. Finally, a probabilistic distance is defined and a maximum likelihood estimation of multiview transformations is designed to resist noise. The experiment on simulated and real data illustrate better robustness of our method to initial errors, outliers, and noise.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Cooperative Manipulation of Deformable Objects by
           Single-Leader–Dual-Follower Teleoperation

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      Authors: Darong Huang;Bin Li;Yanan Li;Chenguang Yang;
      Pages: 13162 - 13170
      Abstract: This article proposes a method for single-leader–dual-follower teleoperation, where one robot (direct-follower robot, DFR) is directly teleoperated and the other robot (assisting-follower robot, AFR) can autonomously cooperate with the DFR to hold and move a deformable object, with the contact force regulated to a desired value. Since the AFR does not know its partner’s movement, first, it achieves position alignment with the DFR by using the contact force. Second, we develop an adaptive movement estimation algorithm according to the Lyapunov theory, such that DFR’s position is estimated in the presence of dynamic uncertainties. Finally, we adopt the impedance control to generate a reference trajectory for the AFR to track, in order to maintain the desired contact force. Several simulations are conducted on a platform with two three-degrees-of-freedom robots. Experiments are performed with a dual-arm robot (Baxter), results of which demonstrate the feasibility and effectiveness of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Real-Time Robotic Multigrasp Detection Using Anchor-Free Fully
           Convolutional Grasp Detector

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      Authors: Yongxiang Wu;Fuhai Zhang;Yili Fu;
      Pages: 13171 - 13181
      Abstract: Robotic grasping is essential for intelligent manufacturing. This article presents a novel anchor-free grasp detector based on fully convolutional network for detecting multiple valid grasps from RGB-D images in real time. Grasp detection is formulated as a closest horizontal or vertical rectangle regression task and a grasp angle classification task. By directing predicting grasps at feature points, our method eliminates the predefined anchors that commonly used in prior methods, and thus anchor-related hyperparameters and complex computations are avoided. For suppressing ambiguous and low-quality training samples, a new sample assignment strategy that combines center-sampling and regression weights is proposed. Our method achieves a state-of-the-art accuracy of 99.4% on Cornell and 96.2% on Jacquard dataset, and real-time speed of 104 frames per second, with approximately 2× fewer parameters and 8× less training time compared to previous one-stage detector. Moreover, an efficient multiscale feature fusion module is integrated to improve the performance of multigrasp detection by 25%. In real-world robotic grasping of novel objects, our method achieves a grasp success rate of 91.3% for single object and 83.3% for multiple objects with only 26 ms used for the whole planning. The results demonstrate that our method is robust for potential industrial applications.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Real-Time Perception-Limited Motion Planning Using Sampling-Based MPC

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      Authors: Hanchen Lu;Qun Zong;Shupeng Lai;Bailing Tian;Lihua Xie;
      Pages: 13182 - 13191
      Abstract: Motion planning with visual perception is a hot topic for autonomous flight of micro aerial vehicles (MAVs). However, many existing works fail to be implemented in realistic scenarios in real time due to practical constraints, such as the limited field of view (FOV) of the onboard camera and the limited computational capability. Compared to the existing methods, the proposed approach solves the optimization of motion and perception at the same time. A sampling-based model-predictive control framework is explored as a local planner to generate trajectories, which are dynamically feasible and collision-free with limited perception. The sampling-based local planning framework is extended to two independent scenarios for MAVs: 1) planning safe trajectories with limited FOV constraint and 2) planning trajectories with effective perception of the point of interest. The effectiveness of the proposed method is demonstrated through both simulation and real-flight experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Position Tracking Control of Fully-Actuated Underwater Vehicles With
           Constrained Attitude and Velocities

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      Authors: Shiming He;Liwei Kou;Yanjun Li;Ji Xiang;
      Pages: 13192 - 13202
      Abstract: This article presents a redundant control strategy of fully-actuated underwater vehicles. The proposed strategy offers vehicles more control flexibility for addressing the position tracking problem under the attitudes and velocities constraints. In kinematics, position tracking is formulated as a convex optimization problem, where the velocity constraints are considered as a feasible region and the attitudes are bounded via a barrier function. Then, a conservative boundary is determined in the context of stability analysis of the dynamic controller with a disturbance observer and an auxiliary system so that kinematic variables lie in the constraints even with the velocity tracking error. Also, it is proven that the position tracking error can converge to a neighborhood about zero, which can be made arbitrarily small. The simulations and experimental results through multiple scenarios have illustrated the efficiency of the proposed strategy.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Motion Saliency-Based Collision Avoidance for Mobile Robots in Dynamic
           Environments

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      Authors: Binghua Guo;Nan Guo;Zhisong Cen;
      Pages: 13203 - 13212
      Abstract: Obstacle avoidance is a sizable challenge for robots working in a multiple dynamic obstacle environment. Conventional obstacle avoidance methods often require complex calculations to process all dynamic obstacles detected in the scene. Avoiding dangerous moving objects in time is often difficult when obstacles are many. In this article, we propose a robot obstacle avoidance method based on motion saliency for dynamic environments. First, we use segmented dynamic objects to calculate the saliency of dynamic objects and segment dangerous dynamic objects. Then, we use the B-spline curve to predict the movement of dangerous dynamic objects and combine it with the nonlinear model predictive control method to avoid dangerous obstacles in the dynamic environment of the robot. Considering the motion behavior of different dynamic objects, our obstacle avoidance strategy is to generate obstacle-free paths by adjusting the speed of the robot or connecting the centers of the rolling variable-size circles. Finally, we conduct a series of experiments to verify the effectiveness of our method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Geometric Adaptive Robust Hierarchical Control for Quadrotors With
           Aerodynamic Damping and Complete Inertia Compensation

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      Authors: Weisheng Liang;Zheng Chen;Bin Yao;
      Pages: 13213 - 13224
      Abstract: In this article, the geometric adaptive robust hierarchical control strategy is proposed for underactuated quadrotor, in which the negative effects of nonlinearities, uncertainties, and coupling are thoroughly considered and effectively attenuated. For handling nonlinearities, geometric control is adopted, i.e., the attitude error is directly defined on tangent space of rotation group, thus better attitude tracking performance can be achieved. To deal with uncertainties, a comprehensive dynamic model is established with compound damping terms representing the main aerodynamic effects and all inertia parameters including mass, inertia tensor, and center of gravity. Then, integrated direct/indirect adaptive robust control is developed with adaptive compensation of aerodynamic damping and complete inertia, which is beneficial to improve tracking performance. As for the coupling, hierarchical control architecture is utilized to relax the strong coupling between attitude and translational subsystems. Moreover, the stability of the overall closed-loop hierarchical system, together with transient performance and final tracking accuracy, has been rigorously analyzed without time-scale separation assumption. Finally, comparative experiments demonstrate the better performance of the proposed method in terms of tracking accuracy and robustness.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Model-Based Actor−Critic Learning of Robotic Impedance Control in
           Complex Interactive Environment

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      Authors: Xingwei Zhao;Shibo Han;Bo Tao;Zhouping Yin;Han Ding;
      Pages: 13225 - 13235
      Abstract: In complex robot applications, such as human−robot interaction and robot machining, robots should interact with an unknown environment. To learn the interactive skill, a model-based actor−critic learning algorithm and a safety-learning strategy are proposed in this article to find the optimal impedance control, in which the learning process is safe and fully automatic and does not know the system parameter. In the learning algorithm, a critic is defined as a quadratic form of the system states and the external force. A modified deterministic policy gradient algorithm is presented to improve the learning efficiency. The proposed approach utilizes a model-based constraint and a highly efficient learning algorithm. In the safety-learning strategy, the robot is trained under a constant force, and the learned impedance control can transfer to different interaction situations by choosing the suitable impedance index. The effectiveness of the learning algorithm and the performance of the learned impedance control are validated in a UR5 robot. The robot can perform human−robot interaction and robot machining tasks after the training process with 100 s training time.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Locally Weighted Learning Robot Control With Improved Parameter
           Convergence

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      Authors: Kai Guo;Yu Liu;Bin Xu;Yapeng Xu;Yongping Pan;
      Pages: 13236 - 13244
      Abstract: An adaptive robot control approach that can achieve an accurate approximation of the complex robot dynamics without knowledge unlearning in the case of multiple sequential tasks is proposed in this article. A locally weighted learning (LWL) model with automatic structure growth according to the size of the learning domain is introduced to approximate unknown robot dynamics, and a composite learning technique with regressor extension is applied to improve parameter convergence. The LWL ensures that learning in one area of the learning domain does not cause unlearning in another area, and the composite learning theoretically guarantees the identification performance of the LWL model. By the exploitation of both stored data in memory and instantaneous data, parameter convergence in the LWL model is achieved under a more achievable interval-excitation condition than the stringent persistent-excitation condition. This further enhances the trajectory tracking performance for multiple sequential tasks, which is generally not achievable by existing approximation-based adaptive robot control approaches. Experimental studies have verified the superiority of the proposed approach over prevalent approaches.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design and Robust Control of a Precise Torque Controllable Steering Module
           for Steer-by-Wire Systems

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      Authors: Dasol Cheon;Kanghyun Nam;Sehoon Oh;
      Pages: 13245 - 13254
      Abstract: Steer-by-wire (SBW) system has been introduced to reduce the number of parts in a vehicle by eliminating the mechanical link between the steering wheel and the road wheel. Even though intensive research has been conducted on the SBW system, the performance of the actuator system that provides the desired steering feel still needs improvement. Therefore, this article presents a compact size torque controllable steering wheel module for the SBW system, where the actuator that provides the steering feel to the driver is modularized with the gear mechanism and the spring. The steering torque sensing mechanism is compactly integrated by placing the spring inside the gear mechanism. Thanks to the advantage in the torque measurement and control ability by the spring mechanism, high gear-ratio transmission can be employed in the proposed module, which can also address the low inherent mechanical impedance problem that may cause fail-safety issues in the SBW system. To enhance the impedance rendering performance of the proposed module, an internal model compensator which is composed of inertia and friction compensation is applied. The kinematics, statics, and dynamics of the proposed module are theoretically analyzed, and a model-based control algorithm is proposed based on this analysis result. Finally, the increase in the inherent impedance and the torque control performance of the proposed module are verified through experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Study on AC Copper Losses in an Air-Cored Axial Flux Permanent Magnet
           Electrical Machine With Flat Wires

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      Authors: Tianzheng Xiao;Jian Li;Kai Yang;Junquan Lai;Yang Lu;
      Pages: 13255 - 13264
      Abstract: In this article, we propose the calculation method of ac copper losses of air-cored axial flux permanent magnet (AFPM) electrical machine with flat wires fed by pulsewidth modulation (PWM) inverters. The ac copper loss due to armature currents in air-cored electrical machines is significant when these machines are driven by PWM inverters. Besides, the exposure of windings to the inhomogeneous alternating rotor magnetic field causes ac copper loss. Analytical formulas are efficient tools to evaluate these losses but few pieces of literature have reported the derivation in such machines. To address this issue, the formulas of aforementioned ac copper losses are derived based on Maxwell's equations and Poynting theorem. As for end windings, the ac copper loss caused by armature current is calculated analytically, while the rotor-induced ac copper loss is calculated by aid of static three-dimensional finite-element analysis (FEA). The interaction of load current and rotor-induced eddy current is also studied. A 12-slot-16-pole air-cored AFPM machine is analyzed with the proposed method, and the analysis is validated by time-transient FEA simulations and prototype experiments. The influence of modulation ratio on ac copper loss due to armature current of the AFPM machine is also discussed.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Robust Precision Position Tracking of Planar Motors Using Min-Max Model
           Predictive Control

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      Authors: Su-Dan Huang;Kai-Yu Peng;Guang-Zhong Cao;Chao Wu;Junqi Xu;Jiangbiao He;
      Pages: 13265 - 13276
      Abstract: In this article, a min-max model predictive control (MPC) method of planar motors is proposed for the first time to achieve robust precision position tracking, which has a low computational burden and strong capability to deal with the problems of stability, robustness, optimization, and input constraints. A state-space model with a homogeneous state equation is built to describe the dynamics of the time-varying reference trajectory. Combining the state-space model of the reference trajectory and that of the planar motor, an augmented state-space model is established to obtain an error state formulation. Then, using the error state formulation, a min-max optimal control problem subject to the constraints on bounded uncertainty, stability, and control input is developed. Moreover, applying the theory of asymptotically stable invariant ellipsoids and employing the nested invariant ellipsoids, the explicitly linear state-feedback control laws are obtained using a linear-matrix-inequalities based offline control algorithm. Finally, the min-max MPC is applied to a planar motor system developed in the laboratory for an experimentally comparative study. The results demonstrate the effectiveness of the proposed min-max MPC of planar motor for robust precision position tracking applications.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improved Analytical Modeling of an Axial Flux Double-Sided Eddy-Current
           Brake With Slotted Conductor Disk

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      Authors: Yinxi Jin;Baoquan Kou;Liyi Li;
      Pages: 13277 - 13286
      Abstract: Due to the enhanced air gap flux density and eddy currents in the favorable path, eddy current brakes with slotted conductors have attracted more attention in recent years. However, due to the increased difficulty in analytical modeling, there is currently no suitable analytical model available for the optimization design of eddy current brakes with slotted conductor. To solve this problem, an improved analytical model is provided based on the subdomain model and the least squares method in this article. The proposed analytical model considers slotted conductor disk, magnetic saturation of primary core and actual path of eddy currents in the conductor disk. The accuracy of the proposed analytical model is verified by finite-element method (FEM) and experimental measurement. The results show that the improved analytical model has good accuracy in the entire speed range. As the analytical model takes less computational time than three-dimensional FEM, it can be used as an effective tool for the optimization design.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Deep Residual Recurrent Neural Network Model-Augmented Attention With
           Physical Characteristics: Application to Turntable Servo System

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      Authors: Cheng Xie;Songlin Chen;Fengyu Guo;Xiaokun Liu;
      Pages: 13287 - 13295
      Abstract: Turntable servo systems are affected by working status changing in actual work, thus, bringing some uncertain factors. Having models that have accurate predictive capabilities can be valuable for control and decision-making purposes. This article proposes a deep residual recurrent neural network (DRRNN) model-augmented attention with physical characteristics, which is used to build an accurate speed prediction model for a turntable servo system. Integrating the known physical features into the design of the residual network model can increase the interpretability of the overall model. Meanwhile, the recurrent neural network-augmented attention model is used to represent the unknown nonlinear characteristics. The addition of the attention mechanism can effectively improve the accuracy of the nonlinear model. Finally, this article proposes an iterative identification method based on the linear and nonlinear model error with alternative compensation. Through alternating error compensation, the linear model’s accuracy can be continuously improved, then the overall and the nonlinear part of the model can be established accurately by retraining the whole model. Experimental results show that the DRRNN model designed in this article can predict the rotational speed in single-step or multistep well. Compared with the traditional mechanism modeling method, the modeling accuracy can be greatly improved.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • High Precision Hybrid Reluctance Actuator With Integrated Orientation
           Independent Zero Power Gravity Compensation

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      Authors: Gerhard Stadler;Ernst Csencsics;Shingo Ito;Georg Schitter;
      Pages: 13296 - 13304
      Abstract: This article presents a novel method for enabling energy-efficient and orientation-independent gravity compensation in active vibration isolation systems by taking advantage of the inherent negative stiffness of a hybrid reluctance actuator (HRA). Counteracting the gravitational force acting on the mover of an HRA with the position dependent force of the actuator’s integrated permanent magnet, the gravitational force can be compensated without the need for an additional actuation. An HRA-system with two translational degrees of freedom (DOF) is developed, comprising a permanent magnet for generating a constant biasing flux for both system axes and two actuator coils per axis for actively controlling the position of the mover. The system prototype has an actuation range of $pm$0.7 mm in both DOF, while enabling energy efficient gravity compensation of payloads up to 500 g by an additional current feedback control loop. Experiments demonstrate that the current consumption for compensation of a 500 g payload is reduced from 1.58 A to 10 mA, which corresponds to a reduction of the power consumption by a factor of 25 000.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A High Thrust Density Voice Coil Actuator With a New Structure of Double
           Magnetic Circuits for CubeSat Deployers

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      Authors: Yong Zhao;Honghao Yue;Fei Yang;Jianguo Zhu;
      Pages: 13305 - 13315
      Abstract: The deployer uses a voice coil actuator (VCA) to control precisely the separation velocity of CubeSats with different masses. This article proposes a novel VCA with a new structure of double magnetic circuits featuring high thrust density. Unlike the conventional design, the new design achieves high thrust density by using a new structure of double magnetic circuits to concentrate the magnetic flux in the airgap and alleviate the magnetic saturation in the yoke. An improved equivalent magnetic circuit is developed to reveal the performance improvement of the novel VCA. The electromagnetic characteristics of the new VCA are investigated and compared with the conventional counterparts by finite element analysis and experimental tests. One VCA deployer prototype has been fabricated and testedexperimentally to validate the thrust density and separation characteristics.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Predictive Algorithm for Control of Common Mode Voltage and Switching
           Frequency in Direct Matrix Converter Fed System

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      Authors: Sohaib Qazi;Tabish N. Mir;Abdul H. Bhat;Bhim Singh;
      Pages: 13316 - 13325
      Abstract: Multiobjective model predictive control (Mo-MPC), owing to its simplicity and adaptability to comply with diverse constraints, has gained popularity in the control of direct matrix converters (DMCs). However, the MPC strategy makes the converter operate at an uncontrolled and variable switching frequency, which may inhibit high power density applications due to increased power losses. This article proposes a method for controlling the switching frequency of the converter and simultaneously regulating the common mode voltage in the DMC fed system while maintaining sinusoidal load and source currents at near unity input power factor. Furthermore, in order to streamline the control while simultaneously dealing with these objectives, a suitable normalization technique is implemented for scaling the errors in each objective. This method is validated through simulation and experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Safety Flight Control for a Quadrotor UAV Using Differential Flatness and
           Dual-Loop Observers

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      Authors: Xiang Yu;Xiaobin Zhou;Kexin Guo;Jindou Jia;Lei Guo;Youmin Zhang;
      Pages: 13326 - 13336
      Abstract: Focusing on a quadrotor unmanned aerial vehicle (UAV), the presence of unintended actuator faults and external disturbances increases the risk of a crash. Although plenty of efforts have been devoted, how to integrate capability analysis into safety control design is still an open issue. This article presents the design of a safety control system for quadrotor UAVs. Firstly, a system capability analysis method based on a differential flatness algorithm is developed, so that the derivatives (i.e., velocity, jerk, and snap) of flight trajectory can be formulated as flat variables. A tradeoff between system capability and permissible flight maneuverability is made to avoid actuator saturation. Secondly, dual-loop nonlinear disturbance observers are exploited to identify the actuator faults and disturbances, which can thereby be handled by a cascade control scheme. Moreover, the trajectory is regenerated online at the expense of degraded flight maneuverability or even emergency landing, in view of the remaining actuator control authority. When comparing to the existing methods, the gap among safety control, trajectory generation, and system capability analysis is bridged to ameliorate practical flight safety. Finally, flight tests are carried out to demonstrate the unique merits of the proposed system.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An Integrated Scheme for Coefficient Estimation of Tire–Road Friction
           With Mass Parameter Mismatch Under Complex Driving Scenarios

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      Authors: Yan Wang;Chen Lv;Yongjun Yan;Pai Peng;Faan Wang;Liwei Xu;Guodong Yin;
      Pages: 13337 - 13347
      Abstract: The accurate knowledge of tire–road friction coefficient (TRFC) contributes to the optimization of driver maneuvers for further improving the safety of intelligent vehicles. The performance of the existing estimation methods would decline when a vehicle performs complex driving maneuvers. In addition, the mass parameter mismatch also deteriorates the estimation accuracy of TRFC. To address these problems, in this article, an integrated scheme for TRFC estimation is proposed by combining a strong tracking unscented Kalman filter and an interactive multiple model unscented Kalman filter. Real-time experiments are implemented on a mass-produced vehicle to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed approach has better estimation accuracy than the existing ones under various driving scenarios.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Synthesis of a Calibration-Free Visual Feedback Controller for an Inverted
           Pendulum Using a Fisheye Lens

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      Authors: Kazuyoshi Hatada;Masayuki Sato;Kentaro Hirata;Yoichiro Masui;
      Pages: 13348 - 13358
      Abstract: This article considers the synthesis of feedback controllers for a class in which strong robust stability is required against sensing errors. The motivation dealing with this class arises from the stabilization problem of a cart-driven inverted pendulum by visual feedback control using a fisheye lens. While fisheye lenses guarantee a wide-angle of view, a large image distortion at off-center area is inevitable. Therefore this study first derives a geometric measurement model of a pendulum angle using a general fisheye lens model. A new design method for robust controllers for our problem is then proposed. Finally, a robust feedback controller that allows lens distortion is designed. The effectiveness of the controller based on the proposed model and the proposed design method is verified through numerical simulations and experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design-Oriented Study of the Orthogonal Vector-Based Linear Kalman Filter:
           Enhancements and Applications

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      Authors: Wen Xu;Chun Huang;Saeed Golestan;
      Pages: 13359 - 13372
      Abstract: This article focuses on the orthogonal vector-based linear Kalman filter (LKF) and provides a systematic design guideline. To optimize the steady-state performance, a parameter tuning algorithm and a decoupling method are proposed. In this way, one can tune the Kalman gains individually and reduce the coupling between harmonic models. A stability analysis is also conducted in this part, which helps to properly design the steady state of the LKF. To optimize the dynamic performance and take the maximum benefit out of the adaptive mechanism of the LKF, a dynamic tracking algorithm is proposed in this article. Compared with the conventional filtering/synchronization methods, the proposed LKF can achieve a relatively fast dynamic response, small overshoot/peak errors, and good filtering capability. These advantages are verified by experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Safety Control for Quadrotor UAV Against Ground Effect and Blade Damage

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      Authors: Kexin Guo;Wenyu Zhang;Yukai Zhu;Jindou Jia;Xiang Yu;Youmin Zhang;
      Pages: 13373 - 13383
      Abstract: This article proposes a safety control scheme for quadrotor unmanned aerial vehicle (UAV) to counteract ground effect and blade damage. The impacts of ground effect and blade damage are quantitatively analyzed in the established model. The proposed safety control scheme consists of position and attitude loops. Specifically, a proportional and derivative controller is designed as a baseline control with acceleration feedforward in the position loop. A disturbance observer (DO) using the measured Euler angles is exploited to estimate the lumped disturbance forces. The developed DO can effectively mitigate the estimation deviation caused by the angle tracking error. Subsequently, differential flatness theory is used to obtain the Euler angle references and the derivatives. In the attitude loop, sliding mode control and fixed-time sliding mode observer (SMO) are integrated to deal with ground effect and blade damage promptly. To demonstrate the effectiveness of the proposed safety control scheme, flight experiments are carried out, where the quadrotor UAV flies close to the rugged ground in the presence of blade damage.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Wiener Variable Step Size With Variance Smoothening Based Adaptive Neurons
           Technique for Utility Integrated PV-DSTATCOM System

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      Authors: Sandeep Kumar Sahoo;Shailendra Kumar;Bhim Singh;
      Pages: 13384 - 13393
      Abstract: In this article, the Wiener variable step size with variance smoothening (WVSSV) technique is introduced for the utility supportive solar photovoltaic (PV) system. This system performs the function of power factor correction, compensation of nonactive component, and reduction of total harmonics distortion (THD) from the utility grid. The dc–ac converter is used in between the PV array and the common connection point and it is controlled through the WVSSV technique to produce the switching signals. The WVSSV technique presents impressive robustness and good adaptation in highly adverse nonlinear load conditions by estimating the clean and harmonic less fundamental component. The presented technique has a good convergence rate even at the starting of adapting and the step size is adjusted to eliminate the variety of noise and harmonics of nonlinear loads. The efficacy of the WVSSV control technique is presented through simulated and test results and depicts the improved steady-state as well as dynamic performances of the PV system. The THDs of grid parameters are found under the IEEE-519 standard in different working conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Variable Voltage Control of a Hybrid Energy Storage System for Firm
           Frequency Response in the U.K.

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      Authors: Jianwei Li;Fang Yao;Qingqing Yang;Zhongbao Wei;Hongwen He;
      Pages: 13394 - 13404
      Abstract: The National Grid in the U.K. proposed the firm frequency response (FFR) documents on recent developments regarding tendering options for active balancing mechanism units, specifically for batteries. However, frequent bipolar converting and instantaneous high power demand challenge battery lifetime and operation cost in the FFR. Combining a battery with a supercapacitor (SC) has several advantages, but the system cost may rise. Targeting the FFR service, this article presents a new variable voltage control within a semiactive battery SC hybrid scheme. In the proposed hybrid energy storage system, the dc bus voltage is controllable to improve the SC use ratio while reducing the converter's cost. A power management strategy integrating fuzzy logic with dynamic filtering method is proposed benefiting in broadening the filtering flexibility while reducing battery degradation. In addition, both the long-term simulations and scaled-down experiments are implemented to verify the proposed topology with the control strategy and power management by quantitative comparisons of battery degradations and SC use ratios.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Decoupling Synchronous Control Method of Two Motors for Large Optical
           Telescope

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      Authors: Xin Li;Wenlin Zhou;Dan Jia;Junzhang Qian;Jun Luo;Ping Jiang;Wenli Ma;
      Pages: 13405 - 13416
      Abstract: Aiming at the problem of two motors system of a large optical telescope, a feedforward friction compensated linear active disturbance rejection control (FFLADRC) algorithm is proposed in this article. The algorithm consists of a friction compensated linear active disturbance rejection control (FLADRC) and two nonlinear tracking differentiators (NTDs). The FLADRC realizes the control of the two motors system by decoupling and compensates the friction. The NTDs are used to generate reference position, velocity, and acceleration signals. First, a mathematical model of the two motors system is established. Second, the FFLADRC algorithm is derived using the idea of decoupling. Third, the parameters tuning method of the FFLADRC is given. Fourth, the stability and synchronization mechanisms of the algorithm are analyzed. Finally, the experiments are carried out on a large optical telescope. In the experiments, single motor control, master–slave control, cross-coupling control, and FFLADRC are compared. The results show that FFLADRC has the minimum synchronization error and tracking error, which verifies the effectiveness of the proposed algorithm.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Low Frequency Current Ripple Suppression for Two-Stage Single-Phase
           Inverter Based on Impedance Editing

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      Authors: Hongyan Zhou;Liangzong He;Zhile Lin;
      Pages: 13417 - 13427
      Abstract: The instantaneous output power of the two-stage single-phase inverter pulsates at double-line frequency, generating a large amount of second harmonic current (SHC) in the front-end dc-dc converter and input dc source. The SHC is harmful to the system performance. To address the issue, a control strategy based on port-impedance editing, where inductor current feedforward (ICFF) and bus voltage feedforward paths are employed, is proposed to reduce the low frequency ripple in the article. Due to only bandpass filter employed in each feedforward path, the proposed control scheme is relatively easy to be implemented. Under the control strategy, the dc-bus port-impedance of dc-dc converter is increased rapidly at double-line frequency, while staying low impedance for other frequencies. What is more, different ICFF paths are taken into insight to obtain optimized path. Meanwhile, the small signal model of front-end dc-dc converter is established and the design principle of key parameters is provided for the derived control strategy. Furthermore, the dynamic response with bandwidth limitation is also discussed in this article. Finally, a two-stage single-phase inverter prototype was fabricated and tested. The experimental results verify the performance of the proposed strategy with SHC reduction.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Learning Control for Motion Coordination in Wafer Scanners: Toward Gain
           Adaptation

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      Authors: Fazhi Song;Yang Liu;Dong Shen;Li Li;Jiubin Tan;
      Pages: 13428 - 13438
      Abstract: Accurate pattern transfer in wafer scanners necessitates the wafer stage and the reticle stage executing a coordinated motion with the synchronization error in terms of nanometers. In an attempt to cope with this challenging issue, a cross-coupling iterative learning control (ILC) with two inputs and two outputs is proposed and then decomposed into two ILC with the same convergence condition, a master–slave ILC for the reticle stage and an independent ILC for the wafer stage. To handle the inevitable stochastic disturbance, which inhibits the achievable ILC performance, an adaptive gain is involved in the proposed method for the sake of accelerated convergence as well as enhanced robustness. It remains constant or is decreased adaptively along the iteration axis, depending on the proportion that the stochastic term accounts for in the error signal. Moreover, a phase leader is chosen as the learning filter and tuned along with the initial learning gain by a frequency-domain approach. Experimental comparisons with existing close yet distinctive approaches highlight the effectiveness and superiority of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Distributed Virtual Inertia Implementation of Multiple Electric Springs
           Based on Model Predictive Control in DC Microgrids

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      Authors: Hanqing Yang;Tieshan Li;Yue Long;C. L. Philip Chen;Yang Xiao;
      Pages: 13439 - 13450
      Abstract: Smartload with series-connected dc electric spring (ES) and noncritical load (NCL) structure can compensate for load voltage and improve the power quality. In this article, a distributed virtual inertial control framework based on model predictive control is proposed for low inertia in the dc microgrid. First, the current prediction model of the ES bidirectional full-bridge dc/dc converter is presented. Based on the virtual inertia control, model predictive control is used to optimize virtual capacitance during the operation. When the system suffers from disturbance, virtual capacitance increases to slow down the change of the dc bus voltage. When disturbance happens, the system can be stabilized quickly by reducing the virtual capacitance. Then, the consensus algorithm based on distributed control is established after defining the NCL voltage deviation rate, which can achieve the balance of NCL voltage deviations, and effectively avoid the more significant voltage deviation in one of NCLs. Furthermore, the small-signal model of the proposed control method is developed, and the influence of the proposed controller on the small-signal stability is described by employing the eigenvalue analysis method. Finally, based on the RT-Lab hardware-in-the-loop simulation system, comparisons and analysis are made to verify the effectiveness of the proposed control method under power step conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design and Analysis of Demand-Customized Selective Wireless Power Transfer
           System

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      Authors: Xiaoyang Tian;Kwok Tong Chau;Zhichao Hua;Wei Han;
      Pages: 13451 - 13461
      Abstract: A demand-customized selective wireless power transfer system is proposed in this article. Multiple receivers can be recognized based on their positions and the magnetic field in the powering area can be controlled and regulated accordingly. For authorized receivers, the system can simultaneously deliver power to meet different output requirements for different electrical appliances, while for unauthorized ones, they can be shut down independently for energy security, even when they are also in the powering area. Compared to the traditional calculation models for multi-input multi-output systems, the proposed current control algorithm uses a piecewise optimization procedure to simplify the iteration and improve control flexibility. Hybrid-frequency pacing is adopted as the control strategy to further reduce the output fluctuation and raise the system efficiency. An experimental prototype with a 3 × 3 transmitter matrix is established. The system can successfully power two receivers with the same sizes for four different power requirement scenarios, which validates the selectivity and the controllability of the proposed system.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Dual-Path Mixed-Domain Residual Threshold Networks for Bearing Fault
           Diagnosis

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      Authors: Yongyi Chen;Dan Zhang;Hui Zhang;Qing-Guo Wang;
      Pages: 13462 - 13472
      Abstract: Intelligent bearing fault diagnosis based on deep learning is one of the hotspots in mechanical equipment monitoring applications. However, traditional deep learning-based methods have a weak antinoise ability and poor generalization performance in a noisy environment. This article presents a new simple and effective deep attention mechanism network, namely, dual-path mixed-domain residual threshold network (DP-MRTN), which aims to improve the accuracy of the rolling bearing fault diagnosis in a noisy environment. The DP-MRTN combines the channel attention mechanism, spatial attention mechanism, and residual structure. The soft threshold function is used as the nonlinear transformation layer, and the dilated convolution is introduced to establish a dual-path neural network so as to select the important features in the signal without resorting to any signal denoising algorithm. The performance of the DP-MRTN is validated against those state-of-the-art results on the real three-phase asynchronous motor experiment platform in Zhejiang University of Technology. We have achieved 99.97$%$ ($ pm 0.09%$) accuracy on Gaussian white noise, 99.87$%$ ($ pm 0.12%$) accuracy on Laplacian noise, and 99.98$%$ ($ pm 0.02%$) accuracy on real noise. The results show that the proposed method can significantly improve the accuracy of fault diagnosis in a noisy environment compared with the traditional deep learning method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Saturated Adaptive-Law-Based Backstepping and Its Applications to a
           Quadrotor Hover

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      Authors: Xiaolong Zheng;Xuebo Yang;He Zhao;Yuhong Chen;
      Pages: 13473 - 13482
      Abstract: This article presents a saturated adaptive-law-based backstepping control method for a class of uncertain nonlinear systems with external dynamic disturbances. In this approach, a novel adaptive backstepping control method with a new command filter is primarily proposed to design the feedback controllers. In order to address the system unknown nonlinearities caused by external dynamic disturbances, a method named “saturated adaptive law approach” is used to estimate the system unknown nonlinearities online. Meanwhile, a filter called “dual command filter” is applied to estimate the derivative of certain signal such that the saturated adaptive law approach can be well implemented. With the help of Lyapunov stability criteria, it is proved that the target signal can be tracked by the output of the system with small error. Finally, our control method is applied to a quadrotor hover system, and two sets of comparison experiments are given to show the effectiveness of the proposed control method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Dual-Loop Robust Control Scheme With Performance Separation: Theory and
           Experimental Validation

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      Authors: Tianyi He;Xiang Chen;Guoming G. Zhu;
      Pages: 13483 - 13493
      Abstract: A dual-loop robust control scheme and its property of performance separation are presented in this article. The dual-loop control scheme consists of two degrees of freedom for nominal and robust performances, with the nominal controller being any stabilizing controller in the observer-based state-feedback form and robust controller being a standard $H_{infty }$ controller. When there is model error and/or disturbance, the robust controller is activated to compensate the nominal controller; otherwise, the dual-loop control returns to a single-loop nominal controller. We also show that the nominal and robust performances of the dual-loop control are independent of one another. As a result, the nominal and robust controllers can be designed separately offline, and then, online coordinated in the dual-loop control. Furthermore, the state-space realization and controller implementation are also provided. Finally, a two-wheeled robot with varying slip effect is considered as an illustrative example. Both simulation and experimental results show that the dual-loop control outperforms the classical robust control methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Frequency-Varying Suppression of Vibration for Active Magnetic Bearing
           Using Improved Resonant Controller

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      Authors: Rundong Yang;Zhiquan Deng;Cong Peng;Kexiang Li;
      Pages: 13494 - 13503
      Abstract: This article presents an improved resonant controller for the magnetic suspension centrifugal compressor. Compared to the conventional method using shifted phase compensation, the proposed method uses a lead–lag block aiming at promising the system stability by its phase–frequency characteristic. This characteristic can realize no parameter switching during the whole working range. The stability conditions of the proposed method are analyzed in this article, and a parameter design method is given for such an approach. In addition, the rotating speed can be used as a part of the loop gain so that the ability of suppression can be enhanced at high-frequency working range. Finally, the simulation and experimental results reveal that the proposed method guarantees the system stability at low-frequency range and shows great suppression performance at full working range.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Predefined-Time Secondary Control for DC Microgrid

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      Authors: Yu Zhang;Yan-Wu Wang;Jiang-Wen Xiao;Xiao-Kang Liu;
      Pages: 13504 - 13513
      Abstract: DC microgrid as a microscale power system has drawn growing attention for its various applications, which calls for good power quality, proper power sharing, and fast response property. However, the existing researches are not yet able to achieve the purpose in a predefined time. In this article, a new predefined-time secondary controller is proposed for DC microgrid to realize the objectives of both voltage regulation and current sharing among DGs within a predefined time. The controller is designed by employing a sign function and a $K^1$ function and by defining a new composite error, which does not need to sample the voltage of DC bus or the current of neighbors, but only the local current and voltage. The upper bound of the convergence time of both the voltage and current in the DC microgrid is just related to one parameter which can be predefined and is independent of initial error. The effectiveness of the proposed controller is verified by multiple simulations and experiments built on MATLAB/Simulink and a hardware-in-the-loop experimental platform. The conducted simulations and experiments include several typical scenarios together with a comparison, which illustrate the advantages of the proposed controller such as fast convergence rate and small overshoot.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Nonsmooth Observer-Based Sensorless Speed Control for Permanent Magnet
           Synchronous Motor

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      Authors: Wenwu Zhu;Shihua Li;Haibo Du;Xinghuo Yu;
      Pages: 13514 - 13523
      Abstract: The sensorless speed regulation problem for a surface-mount permanent magnet synchronous motor system is studied in this article. First, a new nonsmooth observer scheme is proposed to estimate the rotor position, speed, and lumped disturbance of the system. Based on the estimated information, a composite speed controller is then designed, in which the nonsmooth control technique is employed in the feedback design, and the estimated value of disturbance is used in the feedforward compensation. By Lyapunov theory, rigorous analysis guarantees the stability of the closed-loop system and shows that the proposed method can enhance the disturbance rejection property of the system. Finally, simulation tests and experiment results are given to verify the effectiveness of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Automobile Instrument Detection Using Prior Information and Fuzzy Sets

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      Authors: Jiawei Zhang;Yu Liu;Jinyong Yu;Xianqiang Yang;Xinghu Yu;Juan J. Rodríguez-Andina;Huijun Gao;
      Pages: 13524 - 13534
      Abstract: Since there are many kinds of automobile instruments and the industrial environment is usually complex, automatic instrument detection during automobile production test becomes a challenging task. This article presents an automobile pointer instrument detection method based on prior information and fuzzy sets. The proposed method consists of two frameworks built around a pointer meter prior information model (PMPIM). The first one targets PMPIM construction to obtain the required prior information. With this purpose, a pointer-free template is obtained from a template generation algorithm and pointer positions are mapped into an energy function for optimization, using an energy function-based pointer positioning algorithm. The energy function is defined based on the distance between the crisp and fuzzy sets. The second framework targets PMPIM utilization to detect pointer meters during production test. A fuzzy-based image enhancement method is proposed to enhance test images and the template simultaneously. A prior information and energy function-based pointer positioning algorithm is also proposed to locate pointers in test images. Finally, the indicator value (the value the pointer points to) is calculated according to the positions of the pointer and scale marks. Experimental results show that the proposed method achieves better generalization and robustness than existing state-of-the-art methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • In Situ Magnetic Field Reconstruction and Torque
           Estimation for PMECCs

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      Authors: Weiqi Luo;Wei Liu;Xikang Cheng;Yang Zhang;Zhenyuan Jia;
      Pages: 13535 - 13543
      Abstract: Permanent magnet eddy current couplings (PMECCs) are widely used in industry to transmit torque through their interior magnetic field. It is important to measure the interior magnetic field of a PMECC, which helps ensure its excellent performance and prevent possible accidents. However, the distribution of magnetic fields is difficult to reconstruct in situ by traditional measuring or modeling approaches. This article proposes a method to continuously reconstruct the distribution of interior magnetic fields and estimate the relative parameters in a short time with a limited number of Hall sensors. A model of field-associated reconstruction (FAR) is proposed to reconstruct the distribution of interior magnetic fields using historical data and sensor positions as constraints. The slip and output torque can be estimated based on the FAR without the need to use additional speed–torque sensors. The experimental results verify the performance of the proposed method. The results show that the model performed well in the reconstruction of axial and tangential components and relatively well near the geometric boundary in the reconstruction of radial components. The relative errors in the speed and torque estimations are approximately 4% and 6%, respectively. The limitations and corresponding reasons are also discussed.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Impact of Static Air-Gap Eccentricity on Thermal Responses of Stator
           Winding Insulation in Synchronous Generators

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      Authors: Yu-Ling He;Kai Sun;Yu Wu;Hai-Sen Zhao;Xiao-Long Wang;Chris Gerada;David Gerada;
      Pages: 13544 - 13554
      Abstract: In this article, we present a comprehensive analysis on the thermal response characteristics of the stator winding insulation under static air-gap eccentricity (SAGE) conditions in synchronous generators. Different from previous studies, this article not only takes into account the interactions of both the core-loss-caused heat and the copper-loss-caused heat but also investigates the thermal degrading distribution regularities due to SAGE. The whole work is based on the qualitatively theoretical analysis, the finite-element analysis, and the experimental validation on a nonsalient synchronous generator. The study shows that SAGE will significantly make the temperature rise, resulting in uneven temperature distribution and intensifying the thermal responses, such as the thermal deformations, stresses, and strains, of the insulation. The nose part and the joint between the line winding and the end winding on the smaller air-gap side are the two most dangerous positions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Online Sensitive Turn-to-Turn Fault Detection in Power Transformers

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      Authors: Seyed-Alireza Ahmadi;Majid Sanaye-Pasand;Moein Abedini;Mohammad Hamed Samimi;
      Pages: 13555 - 13564
      Abstract: Power transformers are of the most critical and expensive equipment in the power system industry. Meanwhile, they are exposed to a variety of faulty and abnormal operating conditions. Therefore, to prevent extension of these events they are protected by different protective schemes. Among the various types of the transformer faults, detecting turn-to-turn faults is the most challenging one for the protection systems. Industrial experiences and standard documents reveal that the existing protection systems include severe shortcomings, and still more efforts are required to offer a reliable method for detecting such faults. To this end, this article puts forward the proposal of a novel turn-to-turn fault detection method to satisfy the basic protection requirements of dependability, security, and speed. This method properly detects the low-level turn-to-turn faults while is stable during system transients and external faults. Performance of the proposed method is evaluated through various experimental and simulation studies. The obtained results verify superior operation of the proposed method under different faults and conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Sparse Representation Convolutional Autoencoder for Feature Learning of
           Vibration Signals and its Applications in Machinery Fault Diagnosis

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      Authors: Mengqi Miao;Yuanhang Sun;Jianbo Yu;
      Pages: 13565 - 13575
      Abstract: Vibration signals are widely utilized in many fields, which can reflect machine health state. Those typical deep learning techniques cannot learn impulsive features from vibration signals due to interference of strong background noise. Supervised learning greatly rely on vast labeled data, which limits the implementation of deep learning in industry applications. Hence, in this article, a new deep neural network (DNN), sparse representation convolutional autoencoder (SRCAE), is proposed to extract impulsive components of vibration signals for machinery fault diagnosis in an unsupervised manner. A sparse representation (SR) block is proposed to extract impulsive components of vibration signals and transform the time-domain signal to a sparse domain by sparse mapping of a convolutional graph. The SR block is inserted into a deep network to remove noise and learn impulsive features for machinery fault diagnosis. Furthermore, an unsupervised selective feature transmission mechanism is proposed to improve training efficiency and realize feature filtering simultaneously. Finally, the effectiveness of SRCAE is verified on rotary machine fault diagnosis experiments. The testing results show that SRCAE has good noise filtering and impulsive components extraction performance. The recognition accuracy of SRCAE reached 97.16% based on the fivefold cross validation, which demonstrates the outperformance of SRCAE in comparison with state-of-the-art DNNs.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Fault Diagnosis for Power Converter in SRM Drives Based on Current
           Prediction

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      Authors: Hao Chen;Chenghui Fang;Guorui Guan;Nejila Parspour;
      Pages: 13576 - 13585
      Abstract: This article proposes an online diagnosis scheme for transistor faults of asymmetric half-bridge converter (AHBC) in switched reluctance motor (SRM) drives. In order to extract more information from the phase current to identify faults, based on the conventional current measurement method, two novel current measurement methods are presented by reconstructing current sensors. According to the novel current measurement methods, a current prediction method is raised. The phase current at the kth sampling time is available so that the estimated current can be calculated. The fault can be detected and located by analyzing the given and actual switching states, which are deduced by comparing the measured and estimated currents. Compared with existing methods, the proposed scheme can be applied to diagnosis of multiple faults in n-phase AHBC, which can operate at various control strategies and chopping modes. With a single current sensor in each phase, the scheme will not increase the cost and complexity of the SRM drive. Furthermore, the scheme does not require complicated computation, making it easy to implement online. The experimental results confirm the effectiveness and flexibility of the proposed scheme.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Novel Online Monitoring Scheme for Underground Power Cable Insulation
           Based on Common-Mode Leakage Current Measurement

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      Authors: Yang Wu;Pinjia Zhang;
      Pages: 13586 - 13596
      Abstract: Insulation aging of underground power cables may lead to severe fault and system outages. Condition monitoring of cable insulation is essential to maintain power system reliability. However, most existing insulation monitoring methods can only work in offline mode and cannot describe cable aging severity quantitatively. In this article, a novel online monitoring scheme for underground power cable insulation based on common-mode (CM) leakage current measurement is proposed. An online neutral-point voltage injection approach is proposed, and CM leakage current distribution model for both the cables with and without metal sheath under the injected voltage is derived. The insulation capacitance can therefore be monitored online without disturbance to the system operation. Simulations and experiments are conducted to prove the effectiveness of the proposed method. With the aid of a designed CM leakage current sensor, CM leakage current smaller than 5 mA can be detected and the accurate evaluation of aging severity is achieved. The key feature of the proposed method lies in its nonintrusiveness and online fashion: the normal operation of the system will not be interrupted, and accurate quantitative monitoring of cable insulation can be achieved online.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Wavelet Package Energy Transmissibility Function and Its Application to
           Wind Turbine Blade Fault Detection

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      Authors: Xuefei Wang;Zepeng Liu;Long Zhang;William P. Heath;
      Pages: 13597 - 13606
      Abstract: To harvest wind energy from nature, wind turbines are increasingly installed globally, and the blades are the most essential components within the turbine system. The blades usually suffer from time-varying nonstationary wind loads, and the load information is normally unknown or difficult to collect. This poses significant challenges to the blade assessment and damage detection. Transmissibility function (TF) methods have the potential to address this challenge as they do not require loading information. In this article, a novel wavelet package energy TF (WPETF) method is proposed to increase the high-frequency resolution while maintaining its low sensitivity to noise, and it is further used for wind turbine blade fault detection. Compared with the existing Fourier TF method, the proposed method is immune to the external loading impacts, does not require excitation knowledge, and is robust to noise. Compared with the existing wavelet energy TF method, the novel one uses wavelet package decomposition instead of wavelet decomposition to further increase the high-frequency resolution, which provides richer damage-induced information. The effectiveness of the WPETF method for wind turbine blade condition assessment is first verified numerically, and then on three industrial-scale wind turbine blades with both naturally (uncontrolled) and artificially introduced (controlled) damage. Its advantages over a number of existing methods are also demonstrated.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Investigation on the Influencing Factors of Arcing Time for Secondary Arcs

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      Authors: Hongshun Liu;Ziyue Zhang;Tian Xia;Jingjing Yang;Qingquan Li;Dongxin He;Yifan Wang;
      Pages: 13607 - 13615
      Abstract: When the single-phase grounding fault is removed due to interruptions in circuit breakers, a secondary arc emerges and continues to burn, which weakens the continuity and stability of electrical power supplies. Therefore, analyses of the influencing factors of the arcing time are necessary to find suppression technologies for secondary arcs. Scatter plots of the arcing time as a function of the relevant parameters for each experiment are plotted to determine the distribution rule for the scattered points. In addition, the correlation coefficients between the arcing time and the relevant parameters are calculated through statistical correlation algorithm processing. Finally, multivariate fitting is performed between the arcing time and the relevant parameters, and a function is obtained from the fitting for testing. The results show that the arc length and secondary current are significantly positively correlated with the arcing time, while the maximum recovery voltage is significantly negatively correlated. However, the arc area and diameter have little correlation with the arcing time. The proposed method not only provides theoretical support and suppression measures for secondary arcs but can also be applied as an effective means to improve the continuity and security of electrical power supplies.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • An On-Line Calibration Method for TSEP-Based Junction Temperature
           Estimation

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      Authors: Yingzhou Peng;Qian Wang;Haoran Wang;Huai Wang;
      Pages: 13616 - 13624
      Abstract: Temperature sensitive electrical parameters (TSEP) provide an indirect and noninvasive method for on-line junction temperature estimation of power semiconductor devices. It is known that the fundamental of TSEP-based methods is to calibrate the relationship between TSEP and junction temperature in advance. However, the calibration methods in the literature need to open the module, require pretesting, or record the operating data of a converter in the entire power rating range, which are inconvenient in field applications. This article proposes an on-line and noninvasive calibration method by measuring the data at three operating states that are already existed in the regular converter operation. It is achieved by measuring the accessible heatsink/case temperature and TSEP during converter regular operation. The concept, implementation, and error analysis of the proposed method are presented in this article. Experimental verification is given to prove the effectiveness, accuracy, and convenience of the proposed method.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Acquisition of FDS for Oil-Immersed Insulation at Transformer Hotspot
           Region Based on Multiconstraint NSGA Model

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      Authors: Xianhao Fan;Jiefeng Liu;Hui Hwang Goh;Yiyi Zhang;Chaohai Zhang;Saifur Rahman;
      Pages: 13625 - 13635
      Abstract: The evaluation of the state of transformer oil-immersed insulation based on the traditional methods becomes unreliable due to the nonuniform aging effect. To address this issue, a novel model for accessing the aging information of transformer oil-immersed insulation at the hotspot is proposed. In this article, frequency-domain spectroscopy (FDS) is selected as the carrier for characterizing the aging states of oil-immersed insulation. The multiobjective function for reversing the FDS of the hotspot is constructed based on the dielectric response equivalent circuit. Then, the nondominated sorting genetic algorithm with the multiconstraint scheme is proposed to solve the multiobjective function, by which the FDS data of the transformer hotspot region are acquired. The verification results indicate that the average standard deviation between the computed FDS of the hotspot region and the measured data is less than 0.26. The contribution of this article is in the exploration of the proposed model as a potential tool to extract the FDS data of the hotspot region. This will promote a more reliable aging evaluation of the transformer oil-immersed paper insulation at the hotspot.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Fast Anomaly Diagnosis Approach Based on Modified CNN and Multisensor
           Data Fusion

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      Authors: Wenfeng Gong;Yuanzhe Wang;Meiling Zhang;Ehsan Mihankhah;Hui Chen;Danwei Wang;
      Pages: 13636 - 13646
      Abstract: In this article, a modified convolutional neural network (CNN) algorithm, namely 1D-GAPCNN-SVM, is proposed to address the early anomaly diagnosis problem. Considering the fact that traditional 2D-CNN based approaches contain too many model parameters and are not suitable for fast diagnosis applications using multisensor 1-D time-series measurements, 1D-CNN is introduced to deal with this problem. To reduce the number of parameters, a 1-D global average pooling layer is designed to substitute the fully connected layer with two or three layers. In order to further improve the diagnosis accuracy, a nonlinear multiclass support vector machine (SVM) is adopted to replace the traditional Softmax classifier as the final discriminator. Raw multisensor 1-D time-series data are directly fed into the diagnosis model, then the diagnosis result can be automatically generated. Two experiments, which are rolling bearing and GPS anomaly detection, have been conducted to demonstrate the effectiveness and the superior performance of the proposed method compared to the conventional SVM, K-nearest neighbor, deep neural network (DNN), and traditional 2D-CNN.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Development of Nottingham Arc Model for DC Series Arc Modeling in
           Photovoltaic Panels

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      Authors: Masoud Jalil;Haidar Samet;Teymoor Ghanbari;Mohsen Tajdinian;
      Pages: 13647 - 13655
      Abstract: DC series arc faults are known as a great threat to photovoltaic (PV) systems. Due to component aging and the high level of dc voltage, the occurrence of dc series arc fault is a serious concern in PV generation units. This article deals with driving effective dc series arc models from the original Nottingham arc model using the recorded practical data in a PV system. The original Nottingham arc model has three constant parameters and suffers significant inaccuracy for modeling the series arc faults. To avoid the inaccuracy in the modeling, at first, a Nottingham model is developed that is relevant to voltage and current of the fault with three parameters including one constant model order for exponents of the current and two time-series coefficients. Also, to further improvement in the model's accuracy, a two-fold Nottingham model is proposed that is relevant to voltage and current of the fault with five parameters including two constant model orders for exponents of the current and three time-series coefficients. Finally, a full-time-variant Nottingham model is proposed that mathematically contains three time-series parameters including one time-variant model order of the current exponent. In the full-time-variant Nottingham model, the optimal parameters corresponding to each sliding window of data are utilized. In all the proposed models, the arc coefficients are estimated using a new formulation using the least-squares error technique. Verifying the effectiveness of the proposed models through actual data, the accuracy of the proposed models is compared with the original Nottingham model.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Multiple Activation Functions and Data Augmentation-Based Lightweight
           Network for In Situ Tool Condition Monitoring

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      Authors: Zhichao You;Hongli Gao;Shichao Li;Liang Guo;Yuekai Liu;Jingbo Li;
      Pages: 13656 - 13664
      Abstract: Intelligent manufacturing raises higher requirements for tool condition monitoring (TCM) in terms of accuracy, robustness, and adaptability. At present, direct methods based on image processing and deep learning have made breakthroughs in TCM. However, some issues, such as image quality, model parameters, and dataset scale in the abovementioned methods, restrict industrial applications of TCM. Regarding the abovementioned issue, the purpose of this article is to propose a lightweight network model based on multiple activation functions to promote the intelligent industrial application of TCM. First, the image quality mechanism caused by complex working conditions is analyzed in industrial environments. Correspondingly, data augmentation is adopted to solve the problem of data scale under the premise of ensuring data quality and richness. Then, the adaptive activation function and the hard version of swish are introduced at the front and second half of the network to avoid information loss and reduce the activation function cost. Finally, a lightweight network based on cloud-edge collaboration for TCM is constructed. The model is iteratively optimized in the cloud and inferenced on the edge embedded device. The accuracy and adaptability of the proposed network are verified by accelerating milling cutter life under multiple working conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Detection of Permanent Magnet Damage of PMSM Drive Based on Direct
           Analysis of the Stator Phase Currents Using Convolutional Neural Network

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      Authors: Maciej Skowron;Teresa Orlowska-Kowalska;Czeslaw T. Kowalski;
      Pages: 13665 - 13675
      Abstract: Permanent magnet synchronous motors (PMSMs) due to their numerous advantages, such as simple and compact design, easy production and high power-to-weight ratio, high power factor in the range of constant torque, low inertia, and more precise control compared to other electric motors, are increasingly used in various applications, such as electric vehicles, wind power, home, and industrial appliances. However, PMSMs, such as other electrical machines, may subject to various types of damage during the operation. Due to their use in devices of a critical nature (e.g., transport applications), the detection of these damages at their initial stage constitutes an extremely important issue. In this article, we investigate the possibility of the permanent magnets (PMs) faults detection of PMSM using a convolutional neural network (CNN) based on the raw stator current data. The article aims to show the possibility of detecting the PM demagnetization using the information obtained directly from the measured current signal as well as indicate the influence of simultaneous incipient interturn short circuits and the operating condition of the drive on the accuracy of the developed diagnostic system. The results of the experimental research carried out on a specially designed PMSM show the impressive capability of the developed CNN-based diagnostic system to precisely detect the initial phase of PMs damage.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Unveiling Interpretable Key Performance Indicators in Hypoxic Response: A
           System Identification Approach

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      Authors: Jing Chen;Rong Xiao;Lei Wang;Lingling Zhu;Dawei Shi;
      Pages: 13676 - 13685
      Abstract: Advances in wireless networks and wearable electronic devices have enabled the monitoring of massive physiological data for disease diagnosis. In this article, we aim to explore the hypoxic response dynamics through the use of system identification based on physiological data monitored by wearable devices. A third-order autoregressive moving average with exogenous inputs model is developed to describe the dominant system dynamics, based on which an interpretable index called “sum of distance” (SoD) is proposed from a systems and control perspective for AMS risk evaluation. The effectiveness of SoD is evaluated on the basis of physiological data from a proof-of-the-concept study. Statistically, significant relationships of DSI with ground truth AMS metrics (including, Lake Louise score, deep sleep duration, and deep sleep ratio) are observed. To accelerate the evaluation algorithm design, a simulator is designed. A model parameter selection method based on the three-sigma rule is proposed to generate an in silico population, and a total disturbance sequence is determined for disturbance simulation. The created data has the same trend as the real measurements. The proposed method and experimental results indicate the feasibility of improving the AMS risk evaluation performance by understanding and learning the hypoxic response mechanism.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Water Cut Measurement of Horizontal Oil–Water Flow Using
           Trielectrode Capacitance Sensor

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      Authors: Weihang Kong;He Li;Lei Li;Guanglong Xing;
      Pages: 13686 - 13695
      Abstract: From the actual development and testing requirements of horizontal wells in domestic oilfields, according to the problems that the common sensors have relatively low resolution during the water cut measurement for the oil–water flow in the horizontal wells with medium and low production, a trielectrode capacitance sensor (TECS) is designed and a water cut measurement system based on TECS is developed for different conditions of horizontal oil–water flow. Specifically, the electrostatic field distribution of the annular measurement region is investigated under different conditions of horizontal stratified flow. Then, its equivalent capacitance on the electrodes is analyzed. Based on the simulated results, the effects of structural parameters on sensitivity distribution are analyzed, including the electrode length, the radius of the flow channel, and the thickness of the insulation, determining its optimal structure. Moreover, the static and dynamic experiments, as well as the field testing, validate the designed TECS, indicating that the TECS enables measuring the water cut of horizontal oil–water flow, especially under low flow rate and oil–water stratified conditions. The developed TECS could realize the water cut measurement with a wide flow rate range (3–60 m$^3$/d) and the full water cut range (0%–100%) for the horizontal oil–water flow.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Selectively Powering Multiple Small-Size Devices Spaced at Diffraction
           Limited Distance With Point-Focused Electromagnetic Waves

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      Authors: Zi-Han Cheng;Tao Li;Lin Hu;Xin Ma;Feng Liang;Deshuang Zhao;Bing-Zhong Wang;
      Pages: 13696 - 13705
      Abstract: The issue of accurately distinguishing and selectively powering multiple closely spaced devices is challenging but vital for wireless power transfer (WPT). In this article, a continuous-wave time-reversal selective radiative wireless power transfer (CWTR-SRWPT) method based on a multipoint focusing idea is proposed. With the proposed method, we realize a selective radiative WPT prototype system, which can arbitrarily select multiple devices spaced at a diffraction limited distance and power them simultaneously. The accurate positioning and high-precision spatial selection of the closely spaced energy-dissipated devices are achieved by the multipoint focusing field (MPFF) without any auxiliary positioning equipment. The MPFF is produced by a set of weight-optimized single-point focusing fields that are generated by the fundamental time-reversal technique. Theoretical analysis and full-wave simulations to the performances of the CWTR-SRWPT system are presented. The experimental demonstrations of selectively powering multiple LEDs are also conducted. The results indicate that the proposed method exhibits exciting performances of high-precision selectivity, accurate positioning, and satisfactory over-the-air efficiency. It demonstrates potential applications in selectively powering the wireless sensors distributed densely in future intelligent factories.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Sequential Dynamic Aperture Focusing Strategy for Transmissive Ultrasonic
           Phase Array Tomography

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      Authors: Hao Liu;Feng Dong;Zhanpeng Li;Zhixing Zhang;Chao Tan;
      Pages: 13706 - 13715
      Abstract: Industrial ultrasonic tomography (UT) possesses unique benefits in nonintrusive detection of cross-sectional medium and has received broad attention in decades. Aiming at the complex bubble imaging, the conventional independent-transducer-based UT has low spatial resolution due to wide projection path and low projection number. Based on ultrasound phase array (UPA) transducers, this article proposes a sequential dynamic aperture focusing strategy for transmissive ultrasonic phase array tomography (UPAT). The emitting aperture focuses the ultrasound beam on a close distance to generate a high intensity and wide-angle acoustic field that covers multiple receivers in single excitation and further induces high amount of multiangle narrow projections, through which the measurement speed and imaging performance are substantially improved. Beyond numerical analysis on image accuracy and noise robustness, an experimental UPAT system with independent T/R channels is developed to evaluate the proposed method, where the improvement on imaging accuracy and speed are testified through qualitatively and quantitatively comparison with the state-of-art UT and the beam scanning UPAT techniques. The UPAT-focus strategy is proved to be advanced and feasible in imaging complex medium distribution.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improving the Performance of Just-In-Time Learning-Based Soft Sensor
           Through Data Augmentation

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      Authors: Xiaoyu Jiang;Zhiqiang Ge;
      Pages: 13716 - 13726
      Abstract: Just-in-time learning (JITL) is a widely used method for online soft sensing. The limitation of available data and the increase of sample dimensions will make the historical dataset sparse, seriously impair the reliability and usability of JITL applications in the industry. To this end, data augmentation technology (DA) is introduced into the JITL framework for the first time to improve the performance of JITL-based soft sensors. In this article, a novel causality-informed variational autoencoder (CIVAE) is developed to generate virtual samples to augment the historical dataset. Based on this, a complete framework of data augmentation just-in-time learning (DA-JITL) is formulated offline and online and implemented with two different strategies. Finally, a numeral example and an actual industrial example are applied to verify the effectiveness of the proposed method. Besides, the effect of virtual data on JITL and the influence of virtual data volume, virtual data ratio and other factors are carefully discussed on the proposed method. In the industrial case, two indicators (rmse and R2) of the proposed method have been improved by an average of 25% and 17%, respectively, compared to the traditional JITL approach.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Design of an Effective Antenna for Partial Discharge Detection in
           Insulation Systems of Inverter-fed Motors

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      Authors: Peng Wang;Shijin Ma;Shakeel Akram;Pengfei Meng;Jerome Castellon;Zongze Li;Gian Carlo Montanari;
      Pages: 13727 - 13735
      Abstract: Partial discharge (PD) measurements under repetitive impulse voltages are critical for the qualification of inverter-fed motor insulation systems. Severe electromagnetic interference due to high frequency switching from power electronic devices can cause the traditional PD detection techniques of sinusoidal voltage unfeasible. This article presents the design of an Archimedes spiral antenna that can work effectively for PD detection under fast rise time repetitive impulse voltages. The antenna structure is optimized by a media superstrate with a high dielectric constant over the radiant surface. Through the optimized design, both the gains of the antenna in the 0.5–1.5 GHz frequency range and the signal-to-noise ratio for PD detection are increased substantially. Modeling and experimental results prove that the gain of the antenna can reach 2.5 dB in the frequency range of 500–900 MHz and become higher than 7.0 dB in the frequency range of 900–2.0 GHz, with a voltage standing–wave ratio smaller than 1.4. This seems to be a significant achievement for PD detection under fast rise time impulse voltages.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Error Compensation for Low-Density Circular Gratings Based on Linear
           Image-Type Angular Displacement Measurements

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      Authors: Hai Yu;Qiuhua Wan;Changhai Zhao;Qingyang Han;Zhiya Mu;
      Pages: 13736 - 13743
      Abstract: The image-type angular displacement measurement method based on linear image recognition has garnered attention because of its higher frequency response, strong fault tolerance, and high robustness. In the small-size image angular displacement measuring device, due to the limited pixel size, the circular grating cannot place more lines when realizing single-channel absolute coding recognition on a small diameter grating disk. This leads to larger errors in angular displacement measurement when the line density of the grating disk is low. To improve the measurement accuracy of small-scale displacement, the present work aimed to reduce this error by studying the error compensation method involving low-density grating disks. First, the mechanism of linear image-type angular displacement measurements is described, and a measurement algorithm based on linear scan images is proposed. Second, the measurement error model for low-density grating disks is established according to the proposed measurement algorithm. Third, a simplified error compensation algorithm based on a harmonic model is developed. Finally, simulations and experiments are performed to verify the performance of the proposed algorithm. Simulation results show that the developed harmonic compensation algorithm can effectively reduce the error caused by the low-density circular grating. When the proposed error compensation algorithm is applied to a grating disk with a 62 mm diameter and 2N lines, the measurement accuracy is improved from 8.14” to 4.78”. The proposed error compensation algorithm can significantly improve the accuracy of linear image-type angular displacement measurements involving low-density grating disks, and the results presented herein laid a foundation for improving the accuracy and engineering applicability of angular displacement measurement technology.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Highly Linear and Flexible FPGA-Based Time-to-Digital Converter

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      Authors: Yuanyuan Hua;Danial Chitnis;
      Pages: 13744 - 13753
      Abstract: Time-to-digital converters (TDCs) are major components for the measurements of time intervals. Recent developments in field-programmable gate array (FPGA) have enabled the opportunity to implement high-performance TDCs, which were only possible using dedicated hardware. In order to eliminate empty histogram bins and achieve a higher level of linearity, FPGA-based TDCs typically apply compensation methods either using multiple delay lines consuming more resources or postprocessing, leading to a permanent loss of temporal information. In this article, we propose a novel TDC with a single delay line and without compensation to realize a highly linear TDC by encoding the states of the delay lines instead of the thermometer code used in the conventional TDCs. The experimental results show our states-based approach achieves an improved differential nonlinearity of [$-$0.998, $-$1.533] for time resolution of 5.00 ps, [$-$0.44, 0.49] for 10.04 ps, [$-$0.16, 0.19] for 21.65 ps, [$-$0.10, 0.11] for 43.87 ps, [$-$0.06, 0.07] for 64.12 ps, and [$-$0.07, 0.05] for 87.73 ps, whilst no empty bins have been observed. To the best of authors’ knowledge, the achieved raw linearity together with the zero empty bins and a simple delay line structure exceeds previously reported of the FPGA-based TDCs.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Comprehensive Analysis on a New Type VR-Resolver With Toroidal Windings
           Under Healthy and Eccentric Cases

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      Authors: Peyman Naderi;Reza Ghandehari;
      Pages: 13754 - 13762
      Abstract: A novel analysis for a new type of variable reluctance resolvers (VR-Resolvers) with toroidal windings based on the magnetic equivalent circuit (MEC) method is presented in this work. Different cases including various windings configurations as well as different rotor structures are considered in order to investigate the performance of the resolver precisely. The position error of both healthy and eccentric resolvers are studied by a flexible MEC model. The effect of the eccentricity fault on the resolvers with different specifications is also evaluated to analyze the manufacturing tolerance due to the eccentric rotor for several cases. It is notable that the presented MEC provides the opportunity to adjust accuracy and model several structures in both healthy and faulty conditions by just a single model. Finally, the MEC results are confirmed by finite element method and experimental results to show the effectiveness of the proposed model. In general, development of a new VR-Resolver and analyzing its performance under different windings configurations and rotor structures by proposing a modified MEC approach are the paper novelties.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Monocular Vision-Based Calibration Method for the Axial and Transverse
           Sensitivities of Low-Frequency Triaxial Vibration Sensors With the
           Elliptical Orbit Excitation

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      Authors: Ming Yang;Zhihua Liu;Chenguang Cai;Ying Wang;Jing Yang;Junjie Yang;
      Pages: 13763 - 13772
      Abstract: The low-frequency triaxial vibration sensors have been gradually applied in many engineering fields of vibration monitoring because they can measure the multidirection vibrations simultaneously. The accurate axial and transverse sensitivities, determined by the calibration method, are the prerequisite for ensuring their measurement accuracy. Currently, the laser interferometry (LI) which is based on a single component or a tricomponent linear shaker is usually applied to calibrate these sensitivities. However, the former has to require the multiple reinstallations of the sensor and the latter cannot avoid the motion coupling caused by the shaker, these inevitably increase the calibration uncertainty. In this article, we investigate a monocular vision (MV)-based two-component shaker calibration method, which determines the axial sensitivity based on the time-spatial synchronization and transverse sensitivity at the elliptical orbit excitation. The MV method is used to measure this excitation, and a plane sensitivity model is presented to describe these sensitivities. This investigated method can simultaneously reduce the uncertainties caused by the reinstallations and motion coupling to improve the calibration accuracy. Experimental results compared with the LI and Earth's gravitation method demonstrate that the investigated method obtains the satisfactory accuracies both in axial sensitivity magnitude and phase as well as transverse sensitivity magnitude and direction calibration.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Presentation of a Novel Variable Reluctance Tubular Resolver

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      Authors: Fateme Zare;Ali Keyvannia;Zahra Nasiri-Gheidari;
      Pages: 13773 - 13780
      Abstract: Encoders and resolvers are the most common position sensors in controlling electrical machines. However, due to their ability to work under harsh conditions, resolvers are more preferred. In linear position detection, the transversal edge effects and the longitudinal end-effects adversely affect the accuracy of conventional linear resolvers. On the contrary, due to the cylindrical symmetry of tubular machines, they are not subject to the edge effects. With this idea, this article presents a novel linear VR resolver with a tubular structure to achieve higher accuracy than the existing linear resolvers. A magnetic equivalent circuit model is then developed to prove the correct performance of the proposed resolver. It is discussed that the proposed resolver is tolerant of mechanical eccentricities. Different configurations are studied, and finite-element analysis is conducted to analyze the resolver's outputs considering longitudinal end-effects and under mechanical eccentricities. The results show the proposed configuration has a robust performance under eccentricities while its accuracy sharply deteriorates due to the longitudinal end effect. Therefore, an effective method is proposed for compensating the longitudinal end effect. Finally, the compensated resolver is experimentally built and tested to verify the success of the developed sensor.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Study on the Practical Application of Surface Acoustic Wave Yarn Tension
           Sensor

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      Authors: Yong Ding;Wenke Lu;Yihong Zhang;Yang Feng;Yi Zhou;
      Pages: 13781 - 13790
      Abstract: Nowadays, the commonly used yarn tension sensors cannot meet the requirement well in the textile manufacturing process. So surface acoustic wave (SAW) yarn tension sensor is a good selection to adapt to today's textile manufacturing and improve the production efficiency. First, two key problems of SAW yarn tension sensor in practical application are proposed in this article, one is the construction of the sensor measurement system, the other is the temperature compensation. Then, the integrated design of measurement circuit and measurement structure is implemented and introduced in this article, which improves the accuracy, reliability, and sensitivity of SAW yarn tension sensor. Finally, binary regression analysis method and least squares support vector machine (LSSVM) algorithm optimized by particle swarm optimization (PSO-LSSVM) method are applied to the temperature compensation of SAW yarn tension sensor, which both achieve satisfactory compensation effect. By comparison, PSO-LSSVM method is more convenient and flexible, and still has a large space for improvement. Through those research contents, it can be concluded that the design and implementation of the measurement system lay a foundation for the practical application of SAW yarn tension sensor, the research of temperature compensation is of great significance to the wide application of the sensor.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Trampoline-Shaped Micro Electric-Field Sensor for AC/DC High
           Electric Field Measurement

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      Authors: Zhifei Han;Fen Xue;Jun Hu;Jinliang He;
      Pages: 13791 - 13798
      Abstract: The measurement of high electric field is widely used in applications such as power grid, electrical equipment, space launch, petroleum industry, and meteorological monitoring. Traditional electric field measurement methods, such as field mills, are bulky and cause electric field distortion. In this article, we presented a trampoline-shaped microelectric field sensor (E-sensor) based on microelectromechanical system (MEMS). The micro E-sensor uses the effect of electrostatic induction, which generates force that drives the vibration of a piezoresistive film and converts the electric field into a differential voltage signal. The presented E-sensor can measure both ac and dc high electric fields with relatively high resolution and wide range. Through experimental measurement, the device exhibits an ac resolution of 172 V/m/Hz1/2 and a linear measurable electric field range of 312 V/m to over 700 kV/m. The presented E-sensor has good performance with mm-level size and low cost, which could be mass produced for broad applications.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • IGCT Gate Unit for Zero-Voltage-Switching Resonant DC Transformer
           Applications

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      Authors: Jakub Kucka;Drazen Dujic;
      Pages: 13799 - 13807
      Abstract: Recently, integrated gate-commutated thyristors (IGCTs) have shown a great potential for the soft-switching dc transformer applications based on LLC resonant converter. The zero-voltage switching that is present in this converter topology enables an operation of IGCTs without clamping circuit and with significantly higher switching frequencies, while maintaining the exceptionally low conduction losses. The high voltage and current ratings of the IGCTs make them a preferred choice for an efficient bulk power transmission. This article shows how gate units for IGCTs can be optimized for this soft-switching application. It presents a simplification of the driving topology and the design process for high switching frequencies. This results in low power consumption and a very small size of the gate unit. The prototype of the gate unit is built and experimentally validated in a 2.5 kV 0.75 kA resonant operation of the IGCT.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Advanced Fractional-Order Lithium-Ion Capacitor Model With Time-Domain
           Parameter Identification Method

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      Authors: Shuang Song;Xiong Zhang;Yabin An;Yanwei Ma;
      Pages: 13808 - 13817
      Abstract: Lithium-ion capacitor (LIC) is a viable candidate with good commercial prospects in renewable energy, hybrid electric vehicles, and smart grids. It is the convenient route of application development to build the equivalent circuit model of the device in the simulation software. In this article, two advanced fractional-order models of LICs with parameters related to physical properties are proposed to describe the variation of voltage curve in the time domain. The structure of the models is determined based on the reaction process in the frequency domain. The two models differ in their diffusion part in which the fractional differential is introduced into the porous electrode theory in two ways to express the surface inhomogeneity of the porous electrode. The physical significance of the constant phase element (CPE) is particularly analyzed, and it is found that CPE has the ability to describe charge redistribution features. A parameter identification method is presented to solve the parameter estimation difficulties of models with CPE in the time domain. The applicability of the models is verified under constant and dynamic current conditions.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Tailored Hidden Markov Model: A Tailored Hidden Markov Model Optimized for
           Cellular-Based Map Matching

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      Authors: Renhai Chen;Shimin Yuan;Chenlin Ma;Huihui Zhao;Zhiyong Feng;
      Pages: 13818 - 13827
      Abstract: Although the GPS-based positioning is ubiquitous for its high precision, the high power consumption brought by the high sampling frequency and the poor GPS signal penetration limits its availability in locating low-power mobile devices (especially mobile phones). As a promising complement, the cellular-based positioning has attracted great attention since it consumes much less power as well as its higher availability. However, the sparsity of cellular-based data (due to lower sampling rate) and large localization errors make the measurement accuracy becomes the main challenge of the cellular-based positioning. hidden Markov model can well solve the problem of positioning error of GPS data, but it is less accurate when applied to map matching of cellular-base data. Therefore, to improve accuracy, in this article, we propose a novel algorithm called the tailored hidden Markov model (THMM) that is optimized for the cellular-based data. Specifically, the geometric, the topological, and the probabilistic characteristics have been considered and fully exploited in the THMM design. Our proposed schemes are evaluated using real-world motor vehicle movement trajectories collected in Tianjin and the experimental results are encouraging compared with the state-of-the-art algorithms.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Local Measurement-Based Phase Sequence Exchange Emergency Control
           Approach

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      Authors: Yifan Li;Hui Li;Shaofeng Huang;Jingwen Li;Haifeng Wu;
      Pages: 13828 - 13837
      Abstract: Phase sequence exchange (PSE) is a recently developed emergency control technology in which power electronic devices are used to switch the three-phase sequence, thereby reducing the power angle of the generator by 120° and preventing the system from losing stability. This article proposes the installation of the PSE device in the fragile cut-set line of the power grid, and to use the local measurement information for control. This method can restore the stability of the system when the power grid oscillates, thereby avoiding the collapse of the island power grid after splitting due to oscillation. First, an improved real-time power angle calculation method is proposed. When a system loses synchronization and the power angle of a line reaches the threshold, the PSE device on the same cut-set line acts simultaneously to prevent the system from falling out-of-step and “splitting” from the cut set. A PSE prototype is used for experimental verification on the real-time digital simulator platform. The results demonstrate that the proposed power angle calculation method greatly reduces the error, and the proposed PSE control method can achieve online monitoring and real-time control, which achieves better control effects than conventional methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Aggressive Quadrotor Flight Using Curiosity-Driven Reinforcement Learning

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      Authors: Qiyu Sun;Jinbao Fang;Wei Xing Zheng;Yang Tang;
      Pages: 13838 - 13848
      Abstract: The ability to perform aggressive movements,which are called aggressive flights, is important for quadrotors during navigation. However, aggressive quadrotor flights are still a great challenge to practical applications. The existing solutions to aggressive flights heavily rely on a predefined trajectory, which is a time-consuming preprocessing step. To avoid such path planning, we propose a curiosity-driven reinforcement learning method for aggressive flight missions and a similarity-based curiosity module is introduced to speed up the training procedure. A branch structure exploration strategy is also applied to guarantee the robustness of the policy and to ensure the policy trained in simulations can be performed in real-world experiments directly. The experimental results in simulations demonstrate that our reinforcement learning algorithm performs well in aggressive flight tasks, speeds up the convergence process and improves the robustness of the policy. Besides, our algorithm shows a satisfactory simulated to real transferability and performs well in real-world experiments.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Model Predictive Control Based Type-3 Fuzzy Estimator for Voltage
           Stabilization of DC Power Converters

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      Authors: Meysam Gheisarnejad;Ardashir Mohammadzadeh;Mohammad-Hassan Khooban;
      Pages: 13849 - 13858
      Abstract: The stability of power electronic devices is prone to instability when supplying constant power loads (CPL) due to their negative impedance specifications. This necessitates an efficient control methodology to overcome the destabilization issue and regulate the response of the output voltage. In particular, this article proposes a novel interval type-III fuzzy neural network-based model predictive control (IT3FNNMPC) to mitigate the destructive effects of CPL in dc/dc boost converters implemented in the microgrid (MG) and power system distribution. In a typical MGs configuration, the IT3FNNMPC controller is formulated and designed in a constraint control problem to achieve a fast-transient response of system voltage. The feasibility and applicability of the designed IT3FNNMPC controller have been validated by hardware-in-the-loop real-time simulations.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Safe and Energy-Saving Vehicle-Following Driving Decision-Making Framework
           of Autonomous Vehicles

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      Authors: Ying Zhang;Tao You;Jinchao Chen;Chenglie Du;Zhaoyang Ai;Xiaobo Qu;
      Pages: 13859 - 13871
      Abstract: The safety and energy efficiency of autonomous vehicles in the vehicle-following driving scenario is seriously affected by the decision-making framework. This article proposes a safe and energy-saving decision-making framework for autonomous vehicles to avoid the potential rear-end collision and improve the energy efficiency in vehicle-following driving scenario. To realize this framework, the vehicle longitudinal dynamics model is first presented, and the autonomous vehicle's requirements from the safety and energy efficiency perspectives are comprehensively analyzed in the vehicle-following driving scenario. Then, a two-stage decision-making framework is designed. The first stage determines the safety region in the powertrain control domain, and the second stage determines the optimal energy efficiency in the safety region. Based on the two-stage decision-making framework, the perspective of “safety first” principle can be enforced by simultaneously considering the driving safety and energy efficiency. Finally, the experiment is conducted to demonstrate the advantages of the proposed method by comparing it with two other state-of-art methods.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Artificial Intelligence-Based Power-Temperature Inclusive Digital
           Predistortion

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      Authors: Ahmadreza Motaqi;Mohamed Helaoui;Noureddine Boulejfen;Wenhua Chen;Fadhel M. Ghannouchi;
      Pages: 13872 - 13880
      Abstract: This article investigates the effects of the average power variation and the ambient temperature on the behavioral modeling and predistortion of high-power amplifiers concurrently. The measurement results showed that in addition to the average power variation, the behavior of a high-power PA is a function of ambient temperature as well. This article proposes a novel smart digital predistortion (DPD) model that considers both average power variation and temperature (PTI-DPD). The PTI-DPD is implemented using artificial intelligence-based model and it benefits from sets of data formats containing the signal, its delayed versions, average power variation, and ambient temperature. The developed architecture provides an uninterrupted linearization across the ambient temperature and average power variation span without need for a continues feedback path or multiple models. A series of measurements have been conducted to study the PTI-DPD performance across the temperature and average power range. According to the results, the PTI-DPD achieves an average of −48.5 dBc adjacent channel power ratio across the average power and temperature span.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Event-Triggered Adaptive Parameter Control for the Combined Cooling,
           Heating, and Power System

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      Authors: Yang Liu;Jun Zhao;Wei Wang;
      Pages: 13881 - 13890
      Abstract: An industrial integrated energy system gathers a variety of production capacity and energy-related units, which also involves the production, transformation, and consumption of cold, heat, power, gas, etc. The combined cooling, heating, and power (CCHP) system built upon the cascade utilization of energy plays a significant role in improving the utilization rate of multiple energy resources. In this article, a controlled hierarchical relevance vector machine is modeled for identifying the scheduling event in the by-product gas system of a steel industry, which can effectively overcome the disturbance triggered by the changing of operational modes (OMs). Considering the multiple time scales (MTSs) property and the changing of seasons and load conditions of the CCHP, a unified modeling approach is proposed to describe MTSs and multiple OMs of the CCHP by using fuzzy singular perturbation here. Furthermore, an extended $Q$-learning approach by incorporating a hierarchical interval type-2 fuzzy system is designed for dynamically choosing the optimal controller’s parameter for the proposed unified model along with the changing of OMs. The performance of the proposed method can be experimentally validated by a series of industrial application cases to highlight the necessity of modeling and self-adaptive parameter of the controller.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Improvement for MIMO Systems by Increasing Antenna Isolation and Shaping
           Radiation Pattern Using Hybrid Network

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      Authors: Min Li;Yujie Zhang;Fan Jiang;Di Wu;Kwan Lawrence Yeung;Lijun Jiang;Ross Murch;
      Pages: 13891 - 13901
      Abstract: In this article, a novel method is proposed to design a hybrid network (HN) to increase isolation and shape radiation patterns for multiple-input multiple-output (MIMO) antenna systems. The HN is a combination of a decoupling feeding network and a defected ground network, which are populated by several surface-mounted reactive components whose reactances are determined by the N-ary optimization algorithm. Two decoupling examples are presented to validate the design methodology and elaborate on the design procedure. Measurement results show that the HN helps to realize impedance matching with reflection coefficients below –10 dB, isolation improvement from –5.4/–8.9 dB to below –20 dB, and low envelope correlation coefficient below 0.06 for MIMO antennas with the element separation of 0.16λ0/0.24λ0. Moreover, in both examples, the decoupling case with omnidirectional radiation patterns achieves a better throughput performance, compared with another decoupling case with directional radiation. In comparison to prior decoupling networks only focusing on isolation enhancement, the proposed HN achieves high isolation and desired radiation patterns simultaneously with a very accurate design methodology.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Artificial Neural Network-Based Pole-Tracking Method for Online
           Stabilization Control of Grid-Tied VSC

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      Authors: Chen Zhang;Nenad Mijatovic;Xu Cai;Tomislav Dragičević;
      Pages: 13902 - 13909
      Abstract: To cope with the weak grid stability issue of grid-tied voltage source converters (VSCs), this article proposes an artificial neural network (ANN) based approach for online stabilization control of the grid-tied VSC with the pole-tracking feature. First, an ANN is adopted to establish the mapping between the control parameters and the closed-loop poles of the grid-VSC system, serving as a computationally light model surrogate that is favorable for real-time control applications. Then, an online parameter search algorithm enabling simultaneous tuning of multiple controllers and parameters is developed, by which the system's poles under a new grid condition can be pulled to the reference ones, i.e., achieving the pole-tracking-based stabilization control of this article. Finally, the efficacy of the proposed method along with its stabilization effect is verified by MATLAB simulations and experimental results.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • A Quasi-Resonant Extended State Observer-Based Predictive Current Control
           Strategy for Three-Phase PWM Rectifier

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      Authors: Xiaowei Yang;Haitao Hu;Hai Hu;Yunjiang Liu;Zhengyou He;
      Pages: 13910 - 13917
      Abstract: In this letter, a quasi-resonant extended state observer-based predictive current control (QRESO-based PCC) strategy is proposed for three-phase pulse width modulation (PWM) rectifier. Specifically, the QRESO is utilized to estimate the predictive value of system total disturbance and grid current at time instant k+1 in the stationary αβ frame, and the required control input at time instant k+1 is then calculated based on the principle of deadbeat predictive control. The proposed control scheme can achieve robust control against to the electrical parameter variation, accommodate the measurement noise, and also assure the satisfactory steady-state and dynamic performance for the PWM rectifier. Besides, the stability analysis of QRESO and the whole current close-loop control system with the consideration of QRESO in the discrete-time domain are presented. Finally, several hardware-in-the-loop test results of the proposed control strategy are provided and compared with the model free predictive current control based on linear extended state observer and the generalized integrator-extended state observer-based PCC strategy, which validate the effectiveness and superiority of proposed QRESO-based PCC strategy.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
  • Single-Loop Control for Single-Phase Dual-Boost Grid-Tied Inverter With
           Half Cycle Modulation and Feedforward Virtual-Vectors MPC

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      Authors: Bin Liu;Deqiang He;Guojin Li;Hui Liu;Liulin Yang;Yanming Chen;
      Pages: 13918 - 13924
      Abstract: In this letter, a simplified single current loop control scheme for single-phase dual-boost inverter has been developed, combining half cycle modulation and virtual-vector (VV) based model predictive control (MPC). As the control reference can be slipped and allocated into two side boost, only a unified grid current reference is relied on in this proposed control method. Furthermore, with the concept of feedforward control, the global optimal solution space in MPC can be compressed, taking the duty ratio as boundary for the precompacted solution space. Thereby, the improved MPC can select the optimal VV in a smaller and closer subspace. Consequently, much finer control effect can be obtained. Experimental tests are provided to validate the proposed solution and its merits.
      PubDate: Dec. 2022
      Issue No: Vol. 69, No. 12 (2022)
       
 
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