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IEEE Transactions on Industrial Electronics
Journal Prestige (SJR): 2.192
Citation Impact (citeScore): 9
Number of Followers: 86  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0278-0046
Published by IEEE Homepage  [228 journals]
  • IEEE Industrial Electronics Society Information

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      Pages: C2 - C2
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • IEEE Industrial Electronics Society Information

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      Pages: C3 - C3
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • IEEE Transactions on Industrial Electronics Information for Authors

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      Pages: C4 - C4
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Common DC-Link Capacitor Lifetime Extension in Modular DC/DC Converters
           for Electric Vehicle Fast Chargers via Variable-Angle Interleaved
           Operation

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      Authors: Abraham Marquez Alcaide;Sandro Guenter;Jose I. Leon;Giampaolo Buticchi;Samir Kouro;Leopoldo Garcia Franquelo;
      Pages: 10765 - 10774
      Abstract: The global shift toward the electrified transportation as a means of achieving decarbonized economy has led to an increase in the demand of electric vehicles. In order to enhance the transition, there is a need to develop fast and ultrafast charging substations. Hence, power converters play an inherently vital role in the mass adoption of electric vehicles. However, the reliability and active maintenance scheduling of these converters are becoming prominent issues for manufacturers and operators. As a result, optimization of the operation of an interleaved dc/dc converter present in the charging poles plays a significant role. This article proposes an alternative modulation technique for interleaved dc/dc power converters of fast chargers aiming to improve the harmonic performance of the common dc-link capacitor current. This technique leads to an extension of lifetime of the capacitor, which is one of the most critical component of the power system. Experimental results are shown in order to validate the effectiveness of the proposed method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Optimized Switching Frequency Voltage Balancing Schemes for Flying
           Capacitor Based Multilevel Converters

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      Authors: Javad Ebrahimi;Shima Shahnooshi;Suzan Eren;Hamidreza Karshenas;Alireza Bakhshai;
      Pages: 10775 - 10788
      Abstract: The redundant switching states of flying capacitor-based (FC-based) multilevel converters are used to balance the voltages of the FCs. Attempts to balance capacitor voltages have ignored the switching transitions between converter switching states. In this article, we propose a generalized voltage balancing scheme with an optimized switching frequency scheme for FC-based multilevel converters, including the classic flying capacitor multicell (FCM) converter, which needs less computation. All the switching transitions between the switching states of adjacent voltage levels are considered by the overall priority index of switching frequency. In addition, an overall priority index is utilized to balance the voltages of FCs. Using these two indexes, three criteria are developed to select the proper switching state of the converter. Using these criteria, the proposed decoupled space vector modulation scheme is implemented intuitively and simply for FC-based multilevel converters. The proposed scheme is evaluated by simulation results of a five-level FCM converter. Moreover, experimental results demonstrate the robustness of the proposed method in the static load and transient conditions.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Enhanced Low-Speed Characteristics With Constant Switching
           Torque-Controller-Based DTC Technique of Five-Phase Induction Motor Drive
           With FOPI Control

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      Authors: Venkata Subba Reddy Chagam;Swati Devabhaktuni;
      Pages: 10789 - 10799
      Abstract: The classical hysteresis controller-based DTC (C-DTC) of an induction motor is a simple control scheme with better dynamics and steady-state characteristics when compared with the flux-oriented control scheme. The major drawbacks of the C-DTC scheme are variable switching frequency and high average torque ripple under different rotor speeds. In this article, the two-level five-leg inverter-controlled five-phase induction motor drive with constant switching torque-controller-based DTC (PI-CST-DTC) scheme is introduced to improve the steady-state performance with constant switching frequency under various operating speeds. However, the proposed PI-CST-DTC exhibits slower torque and slower speed dynamics w.r.t. C-DTC, which is due to the periodic occurrence of zero vectors under transients. These slower dynamics are improved with the help of the proposed fractional-order PI (FOPI) constant switching torque-controller-based DTC (FOPI-CST-DTC) method. With the help of the hardware results, it has been verified that the proposed FOPI-CST-DTC exhibits improved low-speed steady-state and dynamic performance of the five-phase induction motor drive. The proposed CST-DTC techniques with PI and FOPI controllers are compared with C-DTC for torque ripple reduction and %THD analysis and dynamics through hardware results.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Luenberger Observer-Based Model Predictive Control for Six-Phase PMSM
           Motor With Localization Error Compensation

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      Authors: Yixiao Luo;Kai Yang;Yifei Zheng;
      Pages: 10800 - 10810
      Abstract: The reference vector strategy has been widely used in the model predictive control (MPC) to reduce the computational burden. However, the reference vector derivation as well as the predictive model are sensitive to the machine parameters. This article presents a robust MPC with Luenberger observer to compensate the localization error of the reference vector for a six-phase permanent magnet synchronous motor (PMSM) drive. First, the two-step synthesis technique is employed to increase the tracking capability in the primary subspace and reduce the harmonic currents in the secondary subspace. Then, the influence of the control set design on the robustness is investigated, and it is confirmed that the more densely the voltage vectors locate, the easier the erroneous vector selection occurs. The Luenberger observer is adopted to compensate the localization error of the reference vector caused by the machine parameter mismatch. Subsequently, the cost function is defined in the form of the voltage vector error directly, thus greatly simplifying the control structure. In this way, the steady state performance as well as the parameter robustness are enhanced significantly. Experimentations are conducted to verify the validity of the proposed method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Series–Shunt Multiport Soft Normally Open Points

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      Authors: Jianwen Zhang;Xin Feng;Jianqiao Zhou;Jiajie Zang;Jiacheng Wang;Gang Shi;Xu Cai;Yunwei Li;
      Pages: 10811 - 10821
      Abstract: Soft normally open point (SNOP) is an emerging solution for distributed networks (DNs) to address voltage violation and feeder congestion caused by the increasing integration of distributed energy resources and new types of loads. Based on power electronics, SNOPs can substitute traditional tie switches for power flow regulation, voltage adjustment, and power quality improvement, enhancing the DNs’ controllability and flexibility. Existing SNOPs found in demonstration projects and the literature are generally based on the back-to-back voltage-source converter (VSC). Because it requires more full-power-rating VSCs as the number of connected feeders increases, this solution is uneconomical in multifeeder flexible interconnection scenarios due to the high device cost and volume. Alternatively, this article proposes a series–shunt multiport SNOP (S2-MSNOP) based on a cascaded H-bridge structure and series–shunt arrangement. The proposed topology can easily extend its ports by increasing the number of submodules with small power ratings, reducing the device cost and volume. The operation principles and control strategies of the S2-MSNOP are elaborated. Verifications on both a 1-MVA simulation model and a 3.3-kVA scaled-down experimental platform prove the feasibility and effectiveness of the S2-MSNOP.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A 40-Pulse Autotransformer Rectifier Based on New Pulse Multiplication
           Circuit for Aviation Application

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      Authors: Rohollah Abdollahi;Gevork B. Gharehpetian;Amjad Anvari-Moghaddam;Frede Blaabjerg;
      Pages: 10822 - 10832
      Abstract: In this article, a new simple pulse multiplication circuit (SPMC) with low current stress is proposed, in order to upgrade a normal 20-pulse autotransformer rectifier (20PAR) to a 40PAR. The proposed SPMC comprises two tapped interphase reactors and two additional diodes with lower conduction losses. The proposed SPMC does not require a zero-sequence blocking transformer compared to conventional pulse multiplication circuits, which leads to simplicity in implementation. Simulation and experimental results show that the total harmonic distortion of the input current using 40PAR is less than 3%, which meets the DO-160G requirements for aviation applications.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Switching Network Loss Minimization Through Multivariable Modulation in a
           Multiactive Bridge Converter

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      Authors: Saikat Dey;Ayan Mallik;
      Pages: 10833 - 10847
      Abstract: This article presents a unified and generalized modeling, circuit analysis, and power flow optimization techniques for an n-port multiactive bridge (MAB) dc–dc converter comprised of n active full bridges and a multiwinding transformer. The article aims at improving the efficiency of the MAB converter for a wide load and port voltage gain range by proposing an optimal phase-duty control variable-based modulation strategy. The loss optimization technique constitutes of two stages: first, both the switching and conduction loss objective functions are equivalently formulated by relating them to the transformer winding current peaks and rmss that are synthesized by employing the proposed generalized harmonic approximation based computational model; second, a multivariable multiconstrained optimization technique is adopted in order to minimize the converter power loss for wide load-gain range. Moreover, the universal zero-voltage switching criteria for any MAB port is also derived by proposing a port-equivalent converter model. A 600 W quadruple active bridge converter proof-of-concept is designed and tested to validate the theoretical analysis, claims, thus verifying the applicability of the generic MAB loss optimization technique for any converter candidate under the MAB family. With the implementation of proposed optimal phase-duty control, the experimental results show efficiency increment up to 17% at nonunity voltage gain and 10% loading condition, when compared to the conventional phase modulation technique.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • $N$ -Parallel+Grid-Connected+Converters+for+Circulating+Current+Elimination&rft.title=IEEE+Transactions+on+Industrial+Electronics&rft.issn=0278-0046&rft.date=2023&rft.volume=70&rft.spage=10848&rft.epage=10859&rft.aulast=S.;&rft.aufirst=Durga&rft.au=Durga+Nair+S;Arun+Rahul+S.;">Inverse-Impedance-Based Centralized Predictive Current Controller for
           $N$ -Parallel Grid-Connected Converters for Circulating Current
           Elimination

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      Authors: Durga Nair S;Arun Rahul S.;
      Pages: 10848 - 10859
      Abstract: A constant switching frequency centralized predictive grid current controller is proposed for $N$-parallel grid-connected converters. The proposed work solves the circulating current problem even when converters of different power ratings are paralleled. The circulating current flow is eliminated by equalizing the converter terminal voltages of the parallel converters. A grid equivalent model of the converter is mathematically derived using Thevenin's method to achieve the objective. The converters operate at the same power factors with their currents shared, inversely w.r.t. their line inductances/impedances. The method is flexible in applying any modulation method, without contributing to low-frequency circulating currents. Hardware experiments and software simulations validated the inverse-impedance-based current sharing among the parallel converters. Experimental results show quick redistribution of the grid current among the converters under dynamic conditions, such as incoming/outgoing converter scenarios. The computational requirement with the proposed scheme is independent of the number of converters in parallel. The proposed design is easy to implement and can be deployed for $N$-parallel converter systems for grid applications, such as interlinking converters in ac/dc grids, and plug-in type electric vehicle charging stations.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Direct Predictive Voltage Control for Grid-Connected Permanent Magnet
           Synchronous Generator System

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      Authors: Yingjie He;Ying Tang;Xiaonan Gao;Haotian Xie;Fengxiang Wang;Jose Rodriguez;Ralph Kennel;
      Pages: 10860 - 10870
      Abstract: In this article, a direct predictive voltage control (DPVC) is proposed for the grid-connected permanent magnet synchronous generator system. In the proposed strategy, the dc-link voltage regulation and power regulation terms are merged into one cost function, thereby eliminating the conventional cascade control structure. The strategy selects the voltage vector that not only will generate a dc-link voltage closer to the setpoint at instant $k+2$, but will generate an active power that can further reduce that voltage error for the future instant. To cope with the mismatch between the actual and nominal parameters, the Kalman filter has been added to compensate for the steady-state error. Besides, to enhance the dynamic performance and to save the effort of parameter tuning, the weighting factor is further eliminated from the cost function by sorting the terms into two groups and independently evaluating each group in turn. To fully validate the effectiveness of the proposed strategy, the experimental test waveforms of the DPVC strategy with and without weighting factor have been presented and compared with that of the conventional PI-MPC strategy in various testing conditions.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Analysis and Optimization of Rotor Salient Pole Reluctance Considering
           Multi–Modulation Orders

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      Authors: Zhengzhou Ma;Ming Cheng;Honghui Wen;
      Pages: 10871 - 10880
      Abstract: With the aid of general airgap field modulation theory, the torque production mechanism of flux-reversal permanent magnet (FRPM) machines is revealed, and it finds that multimodulation orders of the rotor salient pole reluctance, i.e., dc modulation, first order modulation and second order modulation, have effects on FRPM machine performances, regardless of pole pair combinations. Therefore, analysis and optimization of rotor salient pole reluctance can be further improved by considering these three modulation orders, and the 12/10, 12/14, and 12/16 pole FRPM machines are taken as optimization examples together with proving their identical optimum rotor configuration. Sensitivity analysis is applied to increase the machine optimization efficiency. By comparing symmetric and asymmetric rotor configurations’ differences in contributions to machine performance considering effects of multimodulation orders, a combined optimum rotor configuration is proposed. Both finite-element analysis and experiments verify the effectiveness of theoretical analysis.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Feedback Linearization Direct Torque Control With Zero-Sequence Current
           Regulation for DC-Biased VRM Drives

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      Authors: Zimin Li;Wubin Kong;Ronghai Qu;Zixiang Yu;
      Pages: 10881 - 10890
      Abstract: A feedback linearization direct torque control (FL-DTC) scheme with the ability of regulating zero-sequence current is proposed for the dc-biased vernier reluctance machines (DC-VRMs) to improve the steady and dynamic performance of drive system. First, an accurate original nonlinear model of DC-VRM is analyzed in synchronous rotating reference frame with three variables (i.e., the electromagnetic torque, the stator flux, and zero-sequence current). The saturation of self-inductance is considered to ensure the accuracy of model under different load. The virtual 0-axis flux ψ0 is first defined in this article. Then, an FL-DTC scheme with zero-sequence current regulation is proposed to improve torque and flux ripple and dynamic response performance. The system stability is verified by the Lyapunov theory. Finally, comparative experiments to conventional PI-based SVM-DTC scheme in steady state and dynamic process are carried out. The advantages of the proposed method are verified, including high control accuracy of torque and flux, fast dynamic response to load change and speed reversal, outstanding low-speed range performance, and strong robustness to parameter uncertainties.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Comparative Study of Current Harmonics and Switching Frequency With
           Different Pulse Patterns in Duty-Cycle-Based Model Predictive Current
           Control

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      Authors: Jiayao Li;Wensheng Song;Bi Liu;Jiling Guo;Yunqiang Wu;Yunwei Li;
      Pages: 10891 - 10901
      Abstract: Model predictive current control with duty cycle optimization has been widely studied and applied in permanent magnet synchronous motor drives. However, the commonly adopted pulse arrangement of virtual voltage vectors may not be optimal, since no rigorous mathematical proof is given and too many other types of pulse arrangements exist. First, six pulse arrangement combinations of virtual vectors are defined as six patterns in this article. Then, the effects of six patterns on current distortion and switching frequency are investigated. Based on the analysis, the existing commonly adopted pattern is proved not to be the best. Instead, another optimal pattern with minimal current harmonics and the lowest switching frequency is selected to achieve better performance and lower heat loss. Finally, an experimental comparative study is implemented in this article. The results have verified that the pulse pattern selected by the proposed analytical approach can effectively reduce the current harmonics and switching frequency, compared with the commonly adopted one.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Model Reference Adaptive Compensation and Robust Controller for Magnetic
           Bearing Systems With Strong Persistent Disturbances

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      Authors: Ximing Liu;Xin Ma;Rui Feng;Yulin Chen;Yangyang Shi;Shiqiang Zheng;
      Pages: 10902 - 10911
      Abstract: The strong gimbal persistent disturbance torque and the plant perturbations, which threaten the stability of the active magnetic bearings (AMBs) system, is a challenging topic in the research area of magnetically suspended control moment gyros (MSCMGs). This article explores a new control scheme, combined with a robust controller and an adaptive feedforward controller, to deal with the internal multiparameter perturbations of the AMB-rotor system and the external strong persistent disturbances of the moving gimbal effects. First, the moving gimbal effects consisting of the displacement/current coefficient perturbation and the moving gimbal persistent torque are analyzed and discussed. A robust controller is exploited to handle both the rotor-speed perturbation and the displacement/current coefficient perturbation. A model reference adaptive feedforward compensation controller is presented to compensate the gimbal persistent torque disturbances in an AMB-rotor system of MSCMG. Then, the stability of the proposed control scheme is verified by analysis to ensure stability. Finally, the simulations and experiments of the proposed control scheme are validated by an MSCMG prototype.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Modified Brush-Less DC Motor Having High Torque Density and Its
           Simplified Current Control Technique

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      Authors: Suman Kumar Neogi;Kishore Chatterjee;
      Pages: 10912 - 10922
      Abstract: In this article, a modified BLdc motor having a wide flat-topped back EMF waveform of around 169$^{0}$ is designed and presented. This motor when excited with an appropriate current waveform as proposed in this article provides around 13.8% improvement in torque density while ensuring that the torque ripple remains the same as that of a conventional BLdc motor drive. Further, the proposed drive can be realized by employing only three hall sensors, and the control configuration remains to be simple as that of a conventional BLdc motor drive involving two-phase conduction. The proposed motor of a 3.6 kW rating has been designed, and its various design parameters are verified on an FEM-based platform, MAGNET. A 3.6 kW motor has been fabricated and a conventional three-leg inverter is employed to drive the motor. The controller for the drive has been realized by utilizing a TMS320F28335 dsp board. The efficacy of the proposed drive is verified by performing detailed simulation and experimental studies.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Second-Order Terminal Sliding-Mode Speed Controller for Induction Motor
           Drives With Nonlinear Control Gain

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      Authors: Bo Wang;Tianqing Wang;Yong Yu;Dianguo Xu;
      Pages: 10923 - 10934
      Abstract: For the high-end industrial application of induction motors (IMs), the speed controller is expected to possess strong torque rejection capability to suppress the speed fluctuation. To accomplish this goal, this article proposes a second-order terminal sliding-mode (SO-TSM) speed controller with nonlinear control gain. First, a SO-TSM manifold is designed to introduce the convergence trajectory without speed overshoot. Second, an integral term control law is constructed to compensate external disturbance with the antiwindup mechanism. The analysis of convergence trajectory shows that the torque rejection capability of the studied method is represented by the gain value of the integral term. Thus, the studied nonlinear control gain can improve the torque rejection capability and suppress the chattering simultaneously. Finally, the experimental results from a 3.7 kW IM test bench reveal the strong torque rejection capability of the studied method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Switch Short-Circuit Fault-Tolerant Control of Five-Phase Open-Winding
           Motor Drive With a Floating Capacitor

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      Authors: Xiangwen Sun;Zicheng Liu;Dong Jiang;An Li;Pengye Wang;Ronghai Qu;
      Pages: 10935 - 10945
      Abstract: This article proposes a switch short-circuit (SC) fault-tolerant control (FTC) method for the open-winding topology with a floating capacitor (FC), where the main inverter is supplied by a dc source, and the floating inverter is merely supplied by a capacitor. The SC faults are divided into two types and analyzed in detail. For the fault of type I, the proposed reconfiguration strategy can isolate the faulty device to ensure stable operation. For the fault of type II, the control of zero-axis voltage in the topology is introduced to replace the control of the faulty bridge. Besides, the fault-tolerant power smoothing strategy is applied to suppress the low-frequency ripples of the FC voltage and input current from the dc source, which further improves the torque quality. Compared with the previous method, the proposed FTC method does not require additional hardware costs to convert the SC to an open-circuit. Meanwhile, the motor can still give out rated torque even after the fault. The performance of the proposed FTC method is verified experimentally in an open-winding five-phase induction machine system.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Sensorless Control of Wound Field Synchronous Machine Drive Using Current
           Source-Based Modular Multilevel Converter

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      Authors: Neha Aarzoo;Gautam Poddar;
      Pages: 10946 - 10956
      Abstract: This article proposes a wound field synchronous machine (WFSM) drive using a double star chopper cell (DSCC)-based modular multilevel converter (MMC) for high power medium voltage variable speed applications. A controlled current source delivers power to this DSCC-MMC. This current source is derived using the field winding of WFSM and a 12-pulse full-controlled thyristor rectifier. The 12-pulse rectifier draws power from a three-phase grid and delivers power to the field winding and the DSCC-MMC. Thus, the field current of WFSM becomes the input dc current of the DSCC-MMC, and no separate power supply is required for the field winding of WFSM. The input current to the DSCC-MMC is kept constant at all operating speeds of the WFSM for a given value of torque to keep peak–peak voltage ripple constant across the submodule capacitor of the MMC. The field current is varied proportionately with the average torque to avoid the saturation of the machine at light load torque. This variation of field current is essential for the successful operation of DSCC-MMC. The small current ripple in the field current, caused by the 12-pulse thyristor rectifier, is utilized to extract the rotor speed information for sensorless operation of vector-controlled WFSM drive. Simulation results are presented in this article to verify the proposed configuration and their control strategy at medium voltage. A hardware prototype has also been built in the laboratory to verify the same results experimentally at low voltage and low power.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Multiscenarios Parameter Optimization Method for Active Disturbance
           Rejection Control of PMSM Based on Deep Reinforcement Learning

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      Authors: Yicheng Wang;Shuhua Fang;Jianxiong Hu;Demin Huang;
      Pages: 10957 - 10968
      Abstract: In this article, a multiscenario parameter optimization method for an active disturbance rejection controller (ADRC) of a permanent magnet synchronous motor (PMSM) based on deep reinforcement learning (DRL) is proposed as MSPO-DRL. The parameter setting of the nonlinear ADRC has always been one of the difficulties affecting the optimal performance of ADRC, and there will be different optimal parameters under different control requirements. In this article, an artificial intelligence algorithm is introduced into the parameter optimization process of ADRC, and the DRL parameter optimization model that can automatically optimize and adjust the ADRC parameters in different application scenarios is constructed so that the ADRC can achieve the best control effect conveniently and the limitation of current methods has been solved. ADRC is applied to the speed loop of flux weakening control of PMSM for more electric aircraft, and the mathematical model of ADRC in this environment is built above all. The Markov decision process is integrated into ADRC. The interface module and reward function between ADRC and MSPO-DRL are designed. The concept of the ADRC control scenario is defined and integrated into the concept of the Markov decision process to improve the generalization of DRL. Then, the MSPO-DRL model is established, and the deep deterministic gradient strategy is used as the gradient descent strategy to converge the parameters optimization. After the model learning is completed, different environmental conditions are randomly selected for simulation and experiments to verify the optimization effect and generalization performance of the algorithm. Optimizations that are carried out by the heuristic algorithms are used for comparisons, and the superiority and feasibility of the proposed algorithm are verified.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Design of a Wound Rotor Brushless Doubly-Fed Machine With 1/5
           Pole-Pair Combination

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      Authors: Weidong Pan;Kexun Yu;Xi Chen;Xuefan Wang;Xianfei Xie;
      Pages: 10969 - 10980
      Abstract: The brushless doubly-fed machine (BDFM) can be used in the variable speed constant frequency field. For BDFM, the choice of the pole-pair combination and the design of the rotor are significant. The output factor of the BDFM with 1/5 pole-pair combination is higher than that of the 2/4 pole-pair counterpart. However, the rotor of the BDFM with 1/5 pole-pair combination is hard to design for its wide pole-pair ratio. This article presents a 1/5 pole-pair combination BDFM used in hydropower with a three-phase symmetrical wound rotor to solve the design challenge. First, the magnetic field modulation theory of the BDFM and the optimal output power in terms of different pole-pair combinations are introduced. Then, the slot-number phase diagram and the ampere-conductor wave method are applied to design windings of a BDFM with 1/5 pole-pair combination. Finally, the finite element (FE) models of the 1/5 and the 2/4 pole-pair combination BDFMs are established for comparison. A prototype of the 1/5 pole-pair combination is manufactured based on the proposed design scheme. Simulated and experimental results verified the feasibility of the design scheme.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • PWM Voltage-Based Modeling for PM Machines With Interturn Short Circuit
           Fault Considering the Effect of Drives

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      Authors: Ying Qin;Guang-Jin Li;Chunjiang Jia;Paul Mckeever;
      Pages: 10981 - 10991
      Abstract: This article presents a novel analytical fault model based on pulsewidth modulation (PWM) voltage rather than ideal sinewave phase voltage for permanent magnet (PM) machines with interturn short circuit fault. This model is important because PM machines are usually driven by the PWM inverter. In addition, main contributors to the accuracy of the fault model such as the cables between the inverter and the machine, the precision of the rotor position estimation, and the inverter, in particular the metal-oxide semiconductor field-effect transistors have been considered. Therefore, this developed model can fully account for the effects of PWM harmonics and accurately predicts the machine's behaviors (particularly the fault current) under fault conditions considering the effect of the drives. This has rarely been studied in the literature as most existing fault modeling methods adopt sinewave phase voltage as inputs, which cannot account for the PWM harmonics in the fault currents. However, the investigations in this article showed that the PWM harmonic component could be close to 25% of the fundamental component in the fault current, and hence cannot be neglected. The accuracy of the proposed fault model has been validated by a series of experimental tests.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Vibration Characteristics and Vibration Mitigation Analysis of End Cap PM
           Excitation Homopolar Inductor Machine

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      Authors: Caiyong Ye;Xiaodong Qi;Kaifeng Liu;Cong Deng;Haiyang Fang;Jianlin Zhou;
      Pages: 10992 - 11002
      Abstract: Vibration analysis and vibration mitigation are very important to ensure the safe and stable operation of electrical machines applied in flywheel energy storage systems. In traditional integer slot synchronous machines, it is generally believed that there is only the zeroth-mode vibration caused by odd tooth harmonics. However, the homopolar inductor machine (HIM) adopts the end cap excitation structure, which makes its air-gap magnetic field contain the dc component, odd tooth harmonics and even tooth harmonics. The force density distribution on the slotted stator is analyzed by the magnetomotive force-multiplying permeance method. The results show that there are both zeroth- and pth(pole pairs)-mode vibrations caused by tooth harmonics and dc component of the air-gap flux density. Furthermore, to reduce vibration and resonance, and to improve the electromagnetic performance of HIM, it is best to use the stator skew slot, the magnetic slot wedge and the sinusoidal rotor slot at the same time. Finally, a 54-slot/6-pole end cap permanent magnet excitation homopolar inductor machine (EPE-HIM) is tested to validate the analytical and the finite-element method (FEM) results, and the variation trend of the experimental results and FEM results is the same.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Development of High-Temperature Optocouplers for Gate Drivers Integrated
           in High-Density Power Modules

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      Authors: David Gonzalez;Pengyu Lai;Sudharsan Chinnaiyan;Salahaldein Ahmed;Binzhong Dong;Yipin Gong;H. Alan Mantooth;Shui-Qing Yu;Zhong Chen;
      Pages: 11003 - 11012
      Abstract: In this article, a high-temperature optical galvanic isolator was developed. Details on the packaging layout, LED to emitter configuration, mathematical models, and device integration in the circuit are discussed. Evaluation of other optical isolation techniques is characterized and compared. The designed package for the low-temperature cofired ceramic-based (LTCC-based) optocoupler results in a higher electrical performance showing better signal stability and current transfer ratio. The optocouplers were stressed over a range of temperatures up to 250°C. Due to the new packaging implementation, the isolators exhibit higher output at elevated temperatures. DC characterization, transient characterization, isolation voltage, and the common mode transient immunity characteristics of the isolators were performed at 25°C and up to 250°C. The optocouplers were integrated into a gate driver circuit that utilizes LTCC as a substrate to understand the integration capabilities. The double pulse test results of the gate driver show reliable and consistent switching capabilities from 25°C to 250°C. As a result, an LTCC-based gate driver circuit is achieved to be integrated into a high-density power module.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Model Predictive Control of Switched Reluctance Machines for Suppressing
           Torque and Source Current Ripples Under Bus Voltage Fluctuation

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      Authors: Lefei Ge;Jixi Zhong;Qiyuan Cheng;Zizhen Fan;Shoujun Song;Rik W. De Doncker;
      Pages: 11013 - 11021
      Abstract: This article presents a novel model predictive method for torque ripple and source current ripple suppression in switched reluctance machines (SRMs) when the bus voltage fluctuates. Based on the measured rotor position, phase current, and phase voltage, the states, including bus voltage, capacitor current, and phase flux-linkage, are calculated for the preparation of the prediction. On this basis, the machine torque and inverter current for all the possible switching states are predicted to construct the cost function. The operating state with the minimum value of cost function is considered as the optimal switch signal and applied to the control power converter, thus achieving the effect of simultaneous reduction of torque ripple and source current ripple. Experimental results show the proposed method has a significant effect on the suppression of both torque ripple and source current ripple even with bus voltage fluctuation, which verifies the effectiveness of the proposed method. The influence of the key factors, such prediction horizon, parametric variation, and weight coefficient, on the machine performance are further investigated. The proposed method is easy to be implemented in the control logic as well as robust to bus voltage fluctuations, enabling to promote the competitiveness of SRMs in electric vehicle application.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Losses and Thermal Analysis of an Integrated PCB Coreless Axial Flux PMSM
           with the Drive System

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      Authors: Jing Zhao;You Wang;Tongkai Ma;Xiangdong Liu;Jialin Li;
      Pages: 11022 - 11032
      Abstract: In this article, an integrated coreless axial-flux permanent-magnet synchronous machine (AFPMSM) system is integrated with winding and drive/control circuits on a same printed circuit board (PCB) stator. The losses and thermal problems of winding and drive/control circuits are very important for the safe operation of the integrated PCB coreless AFPMSM system. First, the losses of each part of the integrated AFPMSM system are analyzed, including stator and rotor losses, drive controller losses and mechanical losses. Then, the thermal simulation model is established to evaluate the thermal characteristics. Furtherly, the losses and thermal performances are improved by redesigning the permanent-magnet pole-arc coefficient, the shape of winding and the circuit arrangement. Finally, two integrated PCB coreless AFPMSM system prototypes before and after improvement are manufactured and tested to validate the analysis results.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Overmodulation Strategies for an Open-End Winding Induction Motor Drive
           With a Floating Capacitor Bridge

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      Authors: Albino Amerise;Michele Mengoni;Luca Vancini;Gabriele Rizzoli;Luca Zarri;Angelo Tani;
      Pages: 11033 - 11043
      Abstract: This article considers a three-phase induction motor with open-end windings fed by a primary bridge connected to the main power source and a floating bridge. The floating bridge supplies the motor with the required reactive power, while the primary inverter only exchanges active power with the main power source. This greatly extends the speed range over which the drive can operate at rated power. To further utilize the input power source, the primary inverter can work in the overmodulation region, and the floating bridge, acting as a harmonic compensator, improves the quality of the current flowing through the motor phases. Also, the article includes some considerations on the sizing of the floating capacitor. Three different overmodulation techniques are evaluated and compared in terms of peak torque/power and efficiency. The highest performance is obtained when the main inverter generates a six-step voltage waveform, which increases motor power by almost 20% and ensures a broader speed range at maximum efficiency.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Enhanced Position Estimation Based on Frequency Adaptive Generalized Comb
           Filter for Interior Permanent Magnet Synchronous Motor Drives

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      Authors: Xuan Wu;Chao Wang;Mingcheng Lyu;Wu Liao;Xu Yu;Ting Wu;Shoudao Huang;Hesong Cui;
      Pages: 11044 - 11054
      Abstract: Accurate rotor position estimation is critical to ensure the high-performance operation of position sensorless interior permanent magnet synchronous motor (IPMSM) drives. However, the back electromotive force (BEMF) estimated by the model-based observers is usually nonideal, which may further degrade the position estimation accuracy. In this article, a frequency-adaptive generalized comb filter (FAGCF) with a quadrature phase-locked loop (PLL) is adopted to suppress the rotor position estimation errors by filtering out the dominant distortions in the BEMF, including the (6k±1)th harmonics caused by inverter nonlinearity and flux spatial harmonics, as well as the dc offset from the inaccurate current measurements. This proposed filter is constructed by multiple digital delay blocks and therefore has the advantage of easy implementation with less online parameters tuning effort. Meanwhile, a linearized model is derived for PLL parameter design, with which the stability of the FAGCF-PLL position estimation system can also be analyzed theoretically. The effectiveness of the proposed sensorless control strategy has been validated with the experimental results on a 1.5-kW IPMSM drive.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • High-Order Sliding-Mode Observer With Adaptive Gain for Sensorless
           Induction Motor Drives in the Wide-Speed Range

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      Authors: Tianqing Wang;Bo Wang;Yong Yu;Dianguo Xu;
      Pages: 11055 - 11066
      Abstract: For speed-sensorless induction motor (IM) drives, the high-order sliding-mode observer (SMO) can improve the robustness of speed estimation. However, it is difficult for the existing high-order SMOs to ensure finite-time convergence, resulting in performance degradation or even instability in the wide-speed range. To address this problem, a high-order SMO with adaptive gain is proposed based on the motor operation speed. First, a high-order sliding-mode surface is designed to achieve finite-time convergence of the rotor flux estimation in the reference model. Then, an adaptive gain is proposed to guarantee the stability of the high-order SMO in the wide-speed range. Second, an improved discretization method is introduced to ensure the stability and reduce the discretization error in the adaptive model. On this basis, the rotor speed is further obtained by the model reference adaptive system. Compared with the existing SMOs, the investigated method can achieve finite-time convergence and guarantee the estimation stability in the wide-speed range, including field-weakening range. Finally, the experimental results from a 3.7 kW IM test bench reveal the effectiveness of the investigated strategy.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Space Vector Modulation Strategy for PMSMs Operating at Low
           Switching-to-Fundamental Frequency Ratio

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      Authors: Javier Riedemann;Z. Q. Zhu;David A. Stone;Martin P. Foster;Jim Greenough;Keisuke Takemoto;Dusan Ivanovic;Bob Bateman;
      Pages: 11067 - 11077
      Abstract: A novel space vector modulation (SVM) strategy for a permanent magnet synchronous machine drive, operating at low switching-to-fundamental frequency ratio, is presented in this article. The proposed strategy is based on applying more than two active vectors in a switching period, aiming to consider the expected rotation and possible movement from one sector to another of the voltage reference vector within that period. The method is simple as the calculation of the duty cycles is still based on the expressions for a conventional SVM. Current distortion and efficiency calculations are also provided, comparing the proposed SVM with conventional SVM and six-step modulation. The results show that the proposed method generates a current distortion similar to the conventional SVM at high frequency ratios but much lower at low frequency ratios. Moreover, comparing with six-step modulation, the current distortion generated by the proposed SVM is always lower, independent of the frequency ratio. On the other hand, the efficiency of the inverter obtained with the proposed SVM is higher than the one obtained with conventional SVM. The effectiveness of the proposed strategy is validated via simulations and experiments.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Improved Sensorless Operation of Double Inverter Fed Wound Rotor Induction
           Machine With Seamless Mode Transitions

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      Authors: Vishnu Vardhan Reddy;Neha Aarzoo;Gautam Poddar;Shambhu Sau;
      Pages: 11078 - 11086
      Abstract: The performance of a sensorless induction motor drive depends on the accuracy in estimating the flux position from the supply voltage and machine parameters. Accurate estimation of flux position at low speed operation is difficult due to the low supply frequency. In a double inverter fed induction motor drive (IMD), the low speed operation can be obtained by maintaining the relative frequency between stator and rotor supply voltage without reducing the individual supply frequency to a very low value. In this article, a novel frequency profile for the stator and rotor supplies of a doubly fed induction motor (DFIM) drive is proposed, in which the minimum supply frequency of any side inverter is around 0.5 p.u. for the whole speed range of operation. With this proposed scheme, the zero speed operation of the drive is obtained by maintaining both the stator and rotor supply frequencies as 1.0 p.u. To achieve this, the DFIM is required to be operated as a squirrel cage induction motor for certain speed range. The control scheme for both the stator and rotor side inverters along with seamless mode transitions are also presented. In this DFIM drive, the required motor power is only 50% of the rated load power and the total volt–ampere (VA) rating of the two inverters is same as that of a conventional squirrel cage IMD. Experimental studies are carried out on a 45 kW wound rotor induction machine to validate the control scheme with the proposed frequency profile and results are presented.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Single-Phase Short-Circuit Fault Tolerant Control for Five-Phase Permanent
           Magnet Machines With Copper Loss Reduction

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      Authors: Huanran Wang;Chunyang Gu;Shuo Wang;Weiduo Zhao;Shun Bai;Giampaolo Buticchi;Chris Gerada;He Zhang;
      Pages: 11087 - 11097
      Abstract: Five-phase machines represent a widely adopted choice for fault-tolerant applications due to their extra degrees of freedom. This article deals with the single-phase short-circuit fault tolerant control using original transformation matrix for five-phase permanent-magnet machines. The proposed method first follows the fundamental phase current injection (FCI) method based on the calculated SC current. Moreover, third-order harmonic phase current injection (THCI) method is presented to reduce copper loss. The computational method of derating factor is also adopted for industrial applications. The fault tolerance and dynamic performance are also verified by the experimental results. A reduction of copper loss in THCI method by about 15% is achieved, compared with general and FCI methods.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Control of Cascaded/Brushless Doubly-Fed Induction Motors With
           Real-Time Torque Optimization

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      Authors: Md Abid Hossain;Marc Bodson;
      Pages: 11098 - 11108
      Abstract: Brushless doubly-fed induction machines offer a potential alternative to regular doubly-fed induction generators for wind turbines, due to higher reliability and lower maintenance costs. As motors and generators, the brushless machines could also be part of new technological solutions for hybrid-electric propulsion, including aircraft propulsion. The main advantage is that most of the power would be transferred from generators to motors without electronic conversion. The article proposes a new speed control algorithm that maximizes the available torque within the limits of the control winding currents and ensures anti-windup protection. The maximum torque and the control variables are obtained through simple analytical computations. The derivations of the article are based on a complex-variable representation that simplifies the mathematical model and the control algorithm. Compact formulas specify the controller parameters as functions of the machine parameters and the desired closed-loop behavior. The results are tested on a laboratory testbed using a cascaded doubly-fed induction motor and demonstrate fast responses reaching torque limits that are computed in real time by the algorithm. While control is achieved through the converter interfaced with the control windings, the data shows that most of the active and reactive power is exchanged directly through the power windings. Similar results are obtained in simulations of a larger brushless doubly-fed induction motor.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A New Hybrid Concentrated-Winding Concept With Improved Power Factor for
           Permanent Magnet Vernier Machine

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      Authors: Shuangchun Xie;Shun Cai;Yuefei Zuo;Libing Cao;Jingwei Zhu;An Li;Yuming Yan;Christopher H. T. Lee;
      Pages: 11109 - 11120
      Abstract: This article investigates a high power-factor permanent magnet vernier machine (PMVM) equipped with low-coupling hybrid concentrated-winding (CW). The proposed hybrid-CW, carrying both star- and delta-winding sets, exhibits a good filtering property to both sub- and super-order harmonics. Through the meticulous design of the short coil pitch, the ratio of inductance to magnet flux linkage is decreased, leading to a great improvement in power factor. The proposed low-coupling winding design contributes to further power factor improvement by reducing the inductance while retaining the magnet flux linkage. It is revealed that the mutual coupling between different coils of a single phase and that between different windings of three phases is suppressed significantly in the hybrid-CW, thus leading to a high power factor and potentially high fault tolerance. Finite element results show that the proposed hybrid-CW PMVM exhibits a significantly improved power factor up to 0.96 from 0.83 and 0.75, as compared with two counterpart PMVMs with open-slot and split-tooth structures, respectively. Benefiting from the magnetic gearing effect, the proposed PMVM has a promising active torque density of 40 N⋅m/L. Taking the end-winding volume into consideration, the proposed PMVM exhibits an actual torque density of 21.98 N⋅m/L, which is 22.52% and 52.43% higher than the investigated open-slot and split-tooth counterpart PMVMs. Finally, a prototype is fabricated and tested to validate the high-power-factor and high-torque-density features of the proposed hybrid-CW PMVM.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Single-Drive SiC-JFET-SCM for Solid State Circuit Breaker in MVDC
           Distribution Networks

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      Authors: Wei Wang;Zhikang Shuai;Hong Duan;Z. John Shen;
      Pages: 11121 - 11131
      Abstract: Solid-state circuit breaker (SSCB) has the advantages of fast response, strong controllability, and no arc cutting in dc fault clearance, but it also has the problem of cascaded voltage unbalance in the medium voltage direct current distribution networks. First, this article proposes a single-drive topology of silicon carbide junction field-effect transistor super cascade module (SiC-JFET-SCM). Then, the turn-off process of the SiC-JFET-SCM is analyzed in detail by establishing the mathematical models. It is found that the resistance-capacitance circuits (RC) networks can affect the action process of SiC-JFET-SCM, leading to the difference in off-time between traditional analysis and actual work. Finally, based on that, the critical parameters are calculated to provide a theoretical basis for the device selection. A 3.3 kV/63A SSCB based on SiC-JFET-SCM is designed, which can identify faults precisely, and achieve a better dynamic and static voltage balance. Experimental results verify the effectiveness of the designed SSCB under different fault conditions.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Single-to-Three-Phase 12-Switch AC–DC–AC Converter

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      Authors: André Elias Lucena da Costa;Nustenil Segundo de Moraes Lima Marinus;Cursino Brandão Jacobina;Nady Rocha;
      Pages: 11132 - 11141
      Abstract: This article proposes a new single-to-three-phase converter composed by two three-leg converters. The proposed converter is an alternative to cope with the single-phase-to-three-phase asymmetry, since it guarantees a reduction in the input current by the rectifier circuit. The reduced component count is another advantage of proposed converter compared with the other solutions presented in the literature. Therefore, the proposed configuration is a good alternative to solve the problem found in remote (or rural) applications, where only a single-phase grid is available and there is a demand to supply three-phase loads. The overall control strategy for providing dc-link voltage control, grid current control, and pulsewidth modulation generation are presented. Experimental results are presented as well, in different scenarios.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Design of a Strong Robust Wireless Power Transfer System With Wide-Range
           Output Regulation Based on Dual-Band Architecture

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      Authors: Zhan Sun;Yijie Wang;Jinwu Sun;Yueshi Guan;Dianguo Xu;
      Pages: 11142 - 11152
      Abstract: With the continuous development of wireless power transfer (WPT) equipment in the direction of miniaturization, how to adapt the traditional sensitive Class E system to high-voltage, high-power and wide-range adjustable output occasions has become a crucial research issue. Here, compared with the other two, the difficulty of improving the system robustness under the large power fluctuation and achieving the system's wide-range output voltage regulation is much greatly. Aiming at the above difficulties, a novel dual-band system architecture based on power synthesis is proposed, the power variation of the megahertz WPT subsystem is actively compressed by the kilohertz WPT subsystem with strong robustness and the high-frequency subsystem only needs to bear relatively low power fluctuations, thereby reducing the difficulty of system design and ensuring the efficient operation. Meanwhile, compared with the traditional system, the buck circuit only needs to perform partial power regulation to achieve the wide range of voltage output. To verify the feasibility of the proposed architecture, a 200 W experimental prototype was built, with a maximum efficiency of 89%.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Multimode Wide Output Range High-Voltage Power Supply for Magnetrons

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      Authors: Yang Liu;Zhixing He;Renjie Hou;Liheng Lin;Hongyu Dong;Feng Wang;Wanglin Fang;An Luo;
      Pages: 11153 - 11162
      Abstract: High voltage electric field power supply with a wide output voltage range is widely used in microwave generating, X-ray, ion implantation, and other fields. However, the existing high-voltage power supplies cannot meet the demand of wide voltage regulation range for high-voltage high-power magnetrons. In this article, a multimode high-voltage dc–dc converter with a wide output voltage range is proposed, which is composed of two input series connected full-bridge inverters, six inductor–inductor–capacitor resonant networks, and two types of voltage multipliers. The proposed high-voltage power supply owns six operation modes and five available output voltage ranges by modifying the inverter's driving scheme. Thus, the proposed converter can reduce the variation range of the resonant network's gain when regulating the output voltage widely. In this article, a detailed comparative analysis is presented of the operating principle of the proposed topology and its six operation modes. Moreover, the expression of its output voltage gain is shown with the control strategy. Finally, a 7.5 kW 3.5–10 kV output prototype is built to verify. The results convincingly demonstrate the applicability of the proposed converter offering high efficiency over a wide range of output power.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Decoupling Control of Double-Side Frequency Tuning for
           LCC/S WPT System

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      Authors: Ping'an Tan;Bin Song;Wang Lei;Han Yin;Bo Zhang;
      Pages: 11163 - 11173
      Abstract: The parameter fluctuations will lead to the frequency detuning problem of the wireless power transfer (WPT) system, thus affecting the transmission efficiency and output stability. The traditional primary-side frequency tuning method cannot realize the full compensation of the secondary-side resonance parameters, and the double-side frequency tuning method with data communication still exists a coupling problem. Therefore, in this article, we propose a decoupling control of double-side frequency tuning for LCC/S WPT system, which has the advantages of avoiding information exchange and circuit simplicity. First, based on the circuit model, the influence mechanism of frequency detuning on the transmission efficiency and voltage gain is deeply studied. On this basis, a zero phase angle control method based on the optimal efficiency tracking and a two-step perturb and observe method with maximum current search are proposed to adjust the primary and secondary resonance parameters, respectively. Finally, a 200 W experimental prototype was built to verify the effectiveness of the proposed frequency tuning strategy. It is strong robustness to the parameter fluctuations, and double sides can well maintain the resonance state, which can improve the transmission efficiency and stability of the LCC/S WPT system.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Analysis and Experimentation of a Novel Modulation Technique for a
           Dual-Output WPT Inverter

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      Authors: Manuele Bertoluzzo;Giuseppe Buja;Hemant Kumar Dashora;
      Pages: 11174 - 11184
      Abstract: Dynamic wireless power transfer systems require to supply many transmitting coils deployed under the road surface and arranged along the so-called track. This layout entails the use of a large number of inverters or of devices that switch the power to the proper coils. This article presents a technique that uses a single three-phase inverter to supply two coils with voltages having different and independently adjustable amplitudes of their first harmonic component. Differently from the well-known phase shift technique, the amplitude and the phase of the voltages are not correlated. Moreover, the presented technique has the ability of inherently reducing the phase difference between the two output currents when the supplied loads are partially reactive. This feature enhances the power transfer capability of the inverter when both the track coils are coupled with the same pickup. After presenting this technique, this article analyzes the functioning of the dual-output inverter in different load conditions recognizing the boundaries of four different modes of operation. For each of them the analytical expression of the amplitude and phase of the generated voltages are given. The theoretical findings are validated by experiments performed on a prototypal setup that implements the presented modulation technique.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Multiloop Control With Two Duty-Ratio Feedforward Current Loops via
           Sensing Series-Capacitor Current for Voltage Doubler PFC Converter

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      Authors: Hung-Chi Chen;Yin-Chun Lan;
      Pages: 11185 - 11193
      Abstract: In this article, the voltage doubler PFC converter with two boost inductors and one series-capacitor is studied. Only when both symmetrical duty ratios are larger than 0.5, the conventional multiloop control with one inner current loop and one voltage loop can be directly applied to the voltage doubler PFC converter due to its topology asymmetry. To remove this duty-ratio limit, the multiloop control with two duty-ratio feedforward current loops is proposed where the series-capacitor current is sensed to reconstruct two inductor currents. It follows that the number of sensor in the proposed control is three equal to the number of sensor in the conventional multiloop control. The proposed method is implemented in a field programmable gate array chip. The provided simulation and experimental results validate the effectiveness.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Comparison of Low Pulse-Repetitive-Frequency Pulsed Power Supplies With
           Extremely Small Storage Capacitor

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      Authors: Ye Xu;Xinbo Ruan;Xinze Huang;
      Pages: 11194 - 11204
      Abstract: In active phased array radar, the T/R modules are powered by a low-voltage pulsed power supply (PPS). When the pulse repetitive frequency (PRF) is quite low, bulky storage capacitor or input LC filter is often used in the PPS, resulting in a low power density. The two-stage PPS and the active capacitor converter (ACC) based PPS can greatly reduce the storage capacitor by intentionally increasing its voltage ripple. In this article, the two kinds of PPSs with extremely small storage capacitor are compared in terms of the configuration, operating principle, main components and efficiency, and it is shown that the ACC-based PPS is more superior for low PRF than the two-stage PPS.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Hybrid-Level Modulation Scheme for Dual-Bridge Series-Resonant Converter

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      Authors: Yihan Gao;Lu Zhou;Qiang Ding;Xiangwei Shen;Minghan Dong;Xin Zhang;Hao Ma;
      Pages: 11205 - 11215
      Abstract: This article proposes a hybrid-level modulation (HLM) scheme to achieve full load range zero voltage switching over various voltage gains for dual-bridge series-resonant converter. According to the load conditions, HLM includes two parts. At heavy load, a variable-frequency symmetrical level modulation (VFSLM) scheme is offered to ensure the complete commutation of the bridge legs with soft-switching operation. In addition, the optimal root mean square of the inductor current can be achieved, which further benefits the transfer efficiency. At light load, the switching frequency demanded by VFSLM is much higher than the resonant frequency. So, a dual asymmetric level modulation (DALM) scheme is proposed to prevent devices from hard-switching operation within a moderate range of changes in frequency. Furthermore, the method of identifying control variables with DALM is analyzed for overall efficiency optimization. The developed approach is validated on a 6.6-kW on-board-charger whose output voltage varies from 220 to 470 V.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Net Power Enhancement of PEMFC System Based on Dual Loop Multivariable
           Coordinated Management

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      Authors: Liangzhen Yin;Qi Li;Elena Breaz;Weirong Chen;Fei Gao;
      Pages: 11216 - 11230
      Abstract: A dual loop multivariable coordinated management (DLMCM) is proposed in this article dealing with the existed nonlinearity and strong coupling between operating parameters such as stack temperature and oxygen excess ratio, to achieve net power enhancement of proton exchange membrane fuel cell (PEMFC) system. The proposed optimization method includes: 1) outer net power optimization loop and 2) inner data-driven multivariable control loop. In solving the outer net power optimization, the experimental data based net power smooth surface model and the security constraints are proposed for maximum net power regulator design. Regarding inner data-driven multivariable control loop, first, pseudopartial derivative linearization (PPDL) is proposed for online modeling and estimation of the multi-input and multi-output system. Then, PPDL-based discrete adaptive integral terminal sliding mode control is proposed to achieve maximum net power trajectory tracking. Experimental tests carried out on 5-kW PEMFC system show that the proposed DLMCM has better tracking ability, and internal disturbance rejection compared with sliding mode control. Moreover, the comparative study with manual guided control, temperature control, and air flow control testifies the effectiveness of proposed DLMCM for net power enhancement with a low level of parasitic power consumption ratio.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • An Input-Series Output-Series Noninverting Buck–Boost Converter for 1500
           V DC Bus With Wide Input and Output Voltage Ranges

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      Authors: Dongkwan Yoon;Younghoon Cho;Sunho Bae;Jaeho Lee;
      Pages: 11231 - 11241
      Abstract: This article proposes the input-series output-series noninverting buck–boost converter (ISOSNIBBC) with wide input and output voltage ranges. The proposed ISOSNIBBC is composed of noninverting buck–boost converters in series and a coupled inductor. Compared to traditional series-connected converters, the proposed converter has advantages of simple structure, intuitive voltage gain, high reliability, and easy modularization using industry standard power modules. Small signal models and operating modes of the proposed converter are suggested and analyzed. After that, the voltage and the current controllers are qualitatively designed using the derived models. To validate the proposed converter and controllers, the 8-kW converter prototype for 1500 V dc bus system has been built and tested. Both the simulation and the experimental results verify the operating mode analyses, the small signal models, and the designed controllers. The experimental results confirm that the proposed converter has various power processing capabilities required in 1500 V dc applications.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Health Diagnosis for Lithium-Ion Battery by Combining Partial Incremental
           Capacity and Deep Belief Network During Insufficient Discharge Profile

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      Authors: Yujie Wang;Kaiquan Li;Pei Peng;Zonghai Chen;
      Pages: 11242 - 11250
      Abstract: Accurate state of health estimation of lithium-ion batteries provides scientific basis for secure operation and stepwise utilization in on-board powertrain. However, the variable discharge depths inevitably reduce the elasticity and precision of the estimation method in prevalent partial discharge situations. In this work, multiple candidate health indicators are extracted from the peaks and valleys of the partial incremental capacity curves and screened first. Specifically, the fine-tuning process of deep belief network based on particle swarm optimization are elaborated and synthetic comparison in terms of error and time consumption with three classical deep networks is performed. To better accommodate practical scenarios, three datasets of the LiFePO$_{4}$ cells under different discharge depths are applied to verify the proposed framework. The experimental results indicated that the presented framework is feasible and the prediction error can be minimized to less 2%.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Combined Control Strategy for Proportional Current Sharing in DC Microgrid
           Clusters

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      Authors: Panbao Wang;Mohamed Zaery;Di Zhao;Wei Wang;Dianguo Xu;
      Pages: 11251 - 11261
      Abstract: The integration of adjacent dc microgrids (MGs) results in the formation of a dc MG cluster which can increase the system power supply capacity. This article proposes a control strategy for dc MG clusters which combines communication-free control and distributed fixed-time control to simultaneously achieve current sharing and voltage regulation with excellent transient characteristics. Firstly, a communication-free control, which presents greater flexibility than the distributed control, is used in the dc MG layer. Subsequently, the distributed fixed-time control is used in the dc MG cluster layer to balance the output current of each MG. The optimal control parameters are obtained by using the zero-pole distribution diagram and establishing a small-signal model of the dc MGs; the stability of the proposed control strategy is also verified. Different scenarios are considered to validate the plug-and-play capability and controller performance by using a dc MG experimental prototype. Real-time hardware-in-the-loop verification containing three MGs is conducted using two RT-boxes to prove the scalability of the proposed cluster control.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • PV Grid-Connected Inverter With DC Voltage Regulation in CCM and VCM
           Operation to Reduce Switching Losses

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      Authors: Chinna Karasala;Rakesh Rao Lekkala;Hareesh Myneni;Siva Kumar Ganjikunta;
      Pages: 11262 - 11275
      Abstract: In this article, a photovoltaic (PV) grid-connected inverter (GCI) is employed for multifunctional control [i.e., real power flow control from PV panels, mitigation of current, and voltage-related power quality (PQ) problems], and the GCI input reference dc voltage is formulated as a function of GCI output currents for loss reduction during low currents through inverter switches. In the latest literature, the PV GCI is used for mitigating current-related PQ problems, and it is also used for mitigating minor voltage-related PQ problems (voltage sag, voltage swell, and voltage imbalance). During voltage sag conditions, GCI output current is high enough to maintain rated voltage at the point of common coupling, and in this case, the reference dc voltage requirement is high. However, during rated grid voltage condition, low power generation from PV, and minimum load condition, keeping maximum dc voltage at the input of the GCI leads to heavy burden on GCI switches. In the proposed method, in order to reduce losses in the GCI, the input dc voltage of the GCI is reduced during low GCI output current. The proposed method is validated with a MATLAB simulation and a hardware experiment by comparing data existing in literature with the proposed method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Modified VOC Using Three Symmetrical Components for Grid-Supporting
           Operation During Unbalanced Grid Voltages and Grid-Forming Operation in
           Hybrid Single-Phase/Three-Phase Microgrid

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      Authors: Ritwik Ghosh;Narsa Reddy Tummuru;Bharat Singh Rajpurohit;
      Pages: 11276 - 11286
      Abstract: Virtual oscillator (VO) control is the most advanced time-domain-based control strategy for grid-supporting and grid-forming inverters. VO Controllers (VOCs) provide better dynamic performance than droop controllers and virtual synchronous machine controllers. However, the existing VOCs can only provide synchronization with the positive-sequence voltages of a connected electrical network. As a result, the existing VOCs cannot operate in an electrical network with unbalanced voltages. This article has introduced the Instantaneous Symmetrical component-based VOC (S-VOC), which can provide continuous synchronization simultaneously with the positive-, negative-, and zero-sequence voltages of a connected electrical network. The proposed S-VOC enables two very important and relevant functionalities for grid-supporting and grid-forming inverters. The functionalities are the grid-supporting operation in the presence of unbalanced grid voltages and the accurate load-sharing in grid-forming mode when single-phase and three-phase sources are integrated into the same hybrid microgrid architecture. At the same time, the proposed S-VOC preserves the superior dynamic performance of the existing VOC. Furthermore, the proposed S-VOC can replace the existing VOC without any extra sensor. The systematic design procedure and mathematical analysis of the proposed S-VOC are presented in this article. Simulation studies and hardware experiments are conducted for validation.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • An Improved Photovoltaic Power Reserve Control With Rapid Real-Time
           Available Power Estimation and Drift Avoidance

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      Authors: Yinxiao Zhu;Huiqing Wen;Qinglei Bu;Xue Wang;Yihua Hu;Guipeng Chen;
      Pages: 11287 - 11298
      Abstract: The main challenges in designing the power reserve control (PRC) lie in the rapid estimation of the maximum available power ($P_mathrm{avi}$) in real time and effective drift avoidance under the condition of fast-changing irradiation. Conventional PRC strategies utilize direct measurement or curve-fitting-based estimation to determine the $P_mathrm{avi}$, which shows obvious limitations, such as extra hardware, implementation complexity, and slow estimation speed. Meanwhile, the drifted reserved power ($Delta P$) may deteriorate the dynamic response performance, bring high dc-link overvoltage risk, and affect the system operation stability due to the voltage-step-$Delta P$ regulation mechanism in conventional PRC methods. To address these issues, an improved PRC strategy with a fast $Delta P$ transient mechanism is proposed with the rapid estimation of $P_mathrm{avi}$ through just one pair of photovoltaic (PV) voltage and current sampling. Thus, the proposed algorithm is cost-effective, easy to implement, and compatible with existing PV systems since no additional hardware components are required. Moreover, the proposed PRC breaks through the inherent limitation of the voltage-step-$Delta P$ mechanism, which can ensure the $Delta P$ drift mitigation even under fast-changing weather conditions. Main experimental comparisons with other advanced PRC strategies were conducted to verify the advantages of -he proposed algorithm in terms of rapid real-time available power estimation and drift avoidance.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Efficiency Optimized Power-Sharing Algorithm for Modular Battery Energy
           Storage Systems

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      Authors: Bortecene Yildirim;Mohammed Ali Elgendy;Andrew N. Smith;Volker Pickert;
      Pages: 11299 - 11309
      Abstract: Modular battery energy storage systems (MBESSs) enable the use of lower-rated voltage converters and battery modules, and simpler battery management systems. They also improve the system's reliability and allow flexible power sharing among different modules. This article proposes a power-sharing algorithm that maximizes the energy conversion efficiency of this battery energy storage system, considering state of charge (SoC) balancing and battery lifespan. Real-time optimum power sharing is undertaken based on a simple lookup table, whose data were generated via offline genetic algorithm optimization considering the converter's efficiency map. To demonstrate the effectiveness of the proposed algorithm, a six-module prototype system was constructed, each comprising a half-bridge converter and a 10 Ah, 12.8 V, LiFePo4 battery. System testing occurred at different battery power levels in both charging and discharging modes, using the proposed efficiency-optimized power-sharing and the conventional SoC-based power-sharing methods. The results obtained show that the proposed power-sharing control significantly improves the light load efficiency compared to the conventional and equal power-sharing methods. At high loads, the proposed method gives a higher efficiency than the SoC-based method and an equivalent efficiency to the equal power-sharing method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Constant-Coupling-Effect-Based PLL for Synchronization Stability
           Enhancement of Grid-Connected Converter Under Weak Grids

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      Authors: Xianfu Lin;Ruoxue Yu;Jingrong Yu;He Wen;
      Pages: 11310 - 11323
      Abstract: The phase-locked loop (PLL)-caused couplings on the grid-connected converter (GCC) are strengthened by increasing its bandwidth and then incur synchronization instability. This article proposes a constant-coupling-effect-based PLL (CCE–PLL) to resolve the aforementioned issues. Initially, the feature of the PLL-caused couplings on GCC is explored. It exhibits that the couplings are varied along with the PLL bandwidth hence jeopardizing the system's stability. Subsequently, the CCE–PLL with a constant and low coupling regardless of its bandwidth on the GCC is proposed. It illustrates that the CCE–PLL bandwidth does not influence the GCC's impedance response, bringing the GCC and CCE–PLL can be designed separately. Last, the experiments confirm that using CCE–PLL, the system has high robustness against grid impedance variation, and the GCC is capable of injecting/absorbing 1.0 per unit active power in a very weak grid. Moreover, the system attains good anti-interference ability and transient performance under system disturbances thanks to the permission usage of the high CCE–PLL bandwidth.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Novel Simplified Finite Control Set Repeat Model Predictive Control for
           Grid-Connected Inverters

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      Authors: Bingtao Zhang;Weimin Wu;Yong Yang;Ning Gao;Jianming Chen;Eftichios G. Koutroulis;Henry Shu-Hung Chung;Marco Liserre;Frede Blaabjerg;
      Pages: 11324 - 11333
      Abstract: Due to fast dynamic response, multiconstraint control capability, and strong robustness, the finite control set model predictive control (FCS-MPC) algorithm has been extensively studied. However, the traditional FCS-MPC algorithm has a heavy computational burden because of the need to traverse all possible voltage vectors. In order to reduce the candidate vectors, a new simplified finite control set repeat model predictive control algorithm (FCS-RMPC) is proposed in this article. In the proposed algorithm, the optimal vectors at the same position in consecutive fundamental frequency periods are regarded as the same or adjacent. Based on this, the proposed algorithm takes the historical data of the optimal voltage vector into consideration for the selection of the optimal vector during the next time steps. Based on the proposed FCS-RMPC algorithm, the computational burden of the system can be significantly reduced. The experimental platform of a three-phase two-level grid-connected inverter with the LCL filter is established to validate the feasibility and effectiveness of the proposed control strategy.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Fault Current Limiter Self-Adapting Activation Strategy for Flexible
           HVDC System Based on Fault Severity Assessment

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      Authors: Nengqiao Wei;Niancheng Zhou;Jianquan Liao;Qianggang Wang;
      Pages: 11334 - 11345
      Abstract: In the flexible HVdc system, fault current limiters (FCLs) need to be configured to reduce the rising rate of fault current. However, the FCL configured according to the bipolar near-end metallic short-circuit faults may cause the fault current to be unnecessarily oversuppressed and consume equipment life. This article develops a method to activate FCLs of the flexible HVdc system adaptively to follow changes in fault severity. Based on analyzing the relationship between the fault current and the transition resistance at the initial moment of the fault, a method to predict the fault condition based on the single-ended instantaneous information is proposed, which realizes the fault severity assessment. Considering mutual coupling of FCLs action sequences, a fast action sequence generate (FASG) method of FCLs based on fault current limiting contribution is proposed, which realizes the coordination between multiterminal FCLs without communication. An FCL self-adapting activation strategy (SAAS) for flexible HVdc systems based on fault severity assessment and FASG is constructed. This strategy matches the severity of the fault by adjusting the FCL action sequence, improving the current limiting effect of severe faults and the life of FCLs. The accuracy of the SAAS is validated on a scaled-down two-terminal system in the laboratory and the simulation.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Robustness Enhancement of Coping With Dual Factors for Grid-Connected
           Inverter in Weak Grid Based on Synthesis-Admittance- Phasor Scheme

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      Authors: Tianzhi Fang;Huili Zhang;Hao Wu;Yu Zhang;
      Pages: 11346 - 11356
      Abstract: For the grid-connected inverter, phase-locked loop is generally adopted to obtain the voltage phase information in order to make the grid current be synchronized with the grid voltage. In the meantime, the grid-voltage-feedforward scheme is usually employed to improve the grid current quality. However, both of these two factors may cause negative impacts on the stability in weak grid. In this article, we focus on the LCL-type grid-connected inverter and aim to investigate the reasons for instability and optimize. In view of the existence of dual unstable factors, a synthesis-admittance-phasor scheme is proposed to analyze the influence mechanism of multiple admittances. And considering the attenuation effect of the bandpass link, the design goal of the bandpass link is determined according to the phase margin requirements, and the design process is further given. The results show that the grid-connected inverter with the optimally designed bandpass link can still work stably even against the wide grid-impedance variation.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Synchronverters With Fast Current Loops

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      Authors: Zeev Kustanovich;Shivprasad Shivratri;Hang Yin;Florian Reissner;George Weiss;
      Pages: 11357 - 11367
      Abstract: Virtual synchronous machines (VSMs) are inverters that behave toward the power-grid-like synchronous generators. Hence, they can be used as grid-forming inverters, and they can support the grid with inertia, droops, fault ride-through, and more. Synchronverters are a much studied type of VSMs. In this article, we present several improvements and innovations to the synchronverter control algorithm. We offer a complete design procedure for this algorithm. One change is meant to mitigate the fact that earlier designs are very sensitive to grid voltage measurement errors and processing delay, which may cause harmonic distortion and fluctuating amplitude of the grid-side currents. We propose to include a fast current controller as the internal control loop of the inverter. The design of this current controller involves delicate issues of compensating the delays and eliminating the dc components of the currents. The new design also enables a natural way for distortionless current limitation. We present a smooth start-up procedure. Our simulations and experiments show that the current controller leads to a dramatic reduction of the sensitivity of the VSM to measurement errors, processing delay, and grid voltage imbalance
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Unified Real-Time Simulation Method for DC/DC Conversion Systems
           Consisting of Cascaded Dual-Port Submodules

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      Authors: Zirun Li;Jin Xu;Pan Wu;Guojie Li;Keyou Wang;Yiming Yang;Jie Du;
      Pages: 11368 - 11378
      Abstract: The dc/dc conversion systems are constructed from multiple cascaded dual-port submodules in series and/or parallel at both the input port and output port. The complexity of the series-parallel structures brings great challenges to real-time simulation. This article proposes a unified real-time simulation method of series-parallel dc/dc conversion systems, which unifies the input-series-output-series, input-series-output-parallel, input-parallel-output-parallel, and input-parallel-output-series structures. First, based on the nodal analysis method, the dual-port equivalent model of each submodule in the series-parallel dc/dc conversion system is obtained. Second, by cascading each submodule, the unified form of the system's dual-port equivalent model of the series-parallel dc/dc conversion system is constructed. For the series connection, the port is equivalent to Thevenin's equivalent circuit. For the parallel connection, the port is equivalent to Norton's equivalent circuit. The real-time simulation model of a specific series-parallel dc/dc conversion system can be obtained by combining the input/output port equivalent circuits. Besides, the high-frequency waveforms of the internal circuit can also be obtained through parallel calculation steps. The real-time simulation of the proposed unified model is carried out with a 250-ns time step on a Xilinx K-7 series field-programmable gate array, which verifies the accuracy and simulation efficiency of the unified model.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Model-Free Predictive Control of Power Converters with Multifrequency
           Extended State Observers

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      Authors: Oluleke Babayomi;Zhenbin Zhang;
      Pages: 11379 - 11389
      Abstract: The performance of model-free predictive control (MFPC), which is based on the ultralocal model, is highly dependent on the effectiveness of the extended-state observer (ESO). The standard linear ESO has a high-gain which enhances disturbance rejection attributes. Nevertheless, this ESO has two main limitations: 1) it amplifies high-frequency measurement noises, and 2) it deteriorates disturbance rejection performance when the noise immunity is improved. Therefore, this article introduces a new technique to improve both the disturbance rejection and noise suppression of ESO without increasing the bandwidth: the multifrequency-based ESO (MF-ESO). Two novel ESO structures that operate on the MF-ESO principle are analyzed: 1) parallel and 2) cascade ESOs. Extensive frequency domain analyses unravel the comparative capabilities of the MF-ESO structures for improved disturbance rejection and/or high-frequency noise suppression. A novel adaptive gain is proposed to improve CESO's dynamic performance. The superior features of the proposed MF-ESO are experimentally validated by the MFPC of a grid-connected power converter.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • PF-MRAC-Based Elimination of Sensors in Solar-Powered PMSM Drive-Based
           Water Pumping System

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      Authors: Bhim Singh;Mohd. Kashif;
      Pages: 11390 - 11400
      Abstract: The water pumping system powered by solar photovoltaic (PV) array and driven by permanent magnet synchronous motor demands a current-sensor to operate PV array at its maximum power and an encoder to implement field-oriented control of motor. Reduction in reliability and increment in system cost are the two major drawbacks that demand their elimination. Even the application of system for locations with high ambient temperature is limited as these sensors are temperature sensitive. In this work, power-factor-based model-reference adaptive-control (PF-MRAC) to remove encoder as well as current sensor is presented. Even stator winding resistance and rotor flux linkage are estimated by PF-MRAC. Thus, presented MRAC is independent of parameter uncertainty contrary to conventional MRAC. Besides, developed PF-MRAC does not contain integral and derivative operators, and hence, it is free from saturation and noise problems. The estimated speed is used for the estimation of PV power, which is then used for extracting maximum power from PV array, thereby removing current sensor. Besides, an additional converter is not required for realization of presented maximum power point tracking method. The developed PF-MRAC is realized on dSPACE Microlab box platform, and test results are acquired for various operating scenarios on laboratory prototype.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Voltage Balancing of Series-Connected SiC mosfets With Adaptive-Impedance
           Self-Powered Gate Drivers

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      Authors: Rui Wang;Asger Bjørn Jørgensen;Wentao Liu;Hongbo Zhao;Zhixing Yan;Stig Munk-Nielsen;
      Pages: 11401 - 11411
      Abstract: Passive clamping snubbers for voltage balancing (VB) series-connected power devices exhibit strong applicability and high robustness; moreover, they are particularly suitable for the emerging fast-switching silicon-carbide (SiC) metal-oxide-semiconductor field-effect transistors (mosfets). However, the compromise still exists as a better VB performance comes at a penalty of a larger loss of snubber. Consequently, in this article, novel adaptive-impedance “snubbers” are proposed for series-connected SiC mosfets on the basis of converter-based self-powered gate driver design, and a better tradeoff is achieved between loss and VB both in static and dynamic states. Further, the proposed passive VB strategy could be combined with an active delay control strategy by introducing an extra closed-loop controller. Benefiting from a more accurately established small-signal system model, the closed-loop numerical parameters are easier to design. As a result, well-balanced voltage distribution is realized during the continuously switching process of series-connected SiC mosfets. To verify the effectiveness, a comprehensive analysis is first provided as guidance, followed by the corresponding detailed hardware and software design. Finally, the experiments are conducted by using two SiC mosfets, which show excellent VB performance at a 110 kV/μs switching speed.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Decentralized Control for a Multiactive Bridge Converter

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      Authors: Yang Qi;Xiong Liu;Weilin Li;Zhongzheng Zhou;Wenjie Liu;Kaushik Rajashekara;
      Pages: 11412 - 11421
      Abstract: Multiactive bridge (MAB) converter has played an important role in the power conversion of renewable-based smart grids, electrical vehicles, and more/all electrical aircraft. However, the increase in MAB submodules greatly complicates the control architecture. In this regard, the conventional centralized control strategies, which highly rely on the central controller, are limited by the computation burden and flexibility. To overcome this problem, this article proposes a decentralized control for MAB converters. The MAB submodules switching frequencies are adaptively regulated based on local information. Through this effort, flexible electrical power routing can be realized without the need for communications. The proposed control strategy not only relieves the computation burden of MAB control system, but also improves its modularity, flexibility, and expandability. Finally, hardware experimental results of a typical MAB converter are presented for verification.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Learning for Depth Control of a Robotic Penguin: A Data-Driven Model
           Predictive Control Approach

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      Authors: Jie Pan;Pengfei Zhang;Jian Wang;Mingxin Liu;Junzhi Yu;
      Pages: 11422 - 11432
      Abstract: For bionic underwater robots, it is a great challenge for depth control due to model uncertainty and strong nonlinearity. To this end, we propose a data-driven model predictive control (MPC) approach using reinforcement learning (RL) for robotic penguin depth control. First, by imitating the underwater mode of the biological penguin, a robotic prototype with a tendon-driven head, two-degrees-of-freedom wings, and a tendon-driven tail was designed. Then, a data-driven MPC framework is proposed considering the structure and motion properties of the robotic penguin. Especially, a data-based learning environment is constructed using a motion capture system, computational fluid dynamics, and a backpropagation neural network. Meanwhile, to maximize the benefits of the controller while ensuring safety and stability, a data-driven MPC using the RL scheme is applied to approximate the optimal policy. Combined with an appropriate reward design and periodic training, the closed-loop controller performance is significantly improved, and the validity of the proposed framework is finally tested by extensive simulations and experiments. Notably, this work will provide valuable insights into the learning-based motion control of bionic underwater robots.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Distributed Formation Control for a Multirobotic Fish System With
           Model-Based Event-Triggered Communication Mechanism

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      Authors: Shijie Dai;Zhengxing Wu;Pengfei Zhang;Min Tan;Junzhi Yu;
      Pages: 11433 - 11442
      Abstract: This article confronts the formation control problem for a multirobotic fish system with event-triggered communication mechanism. A 3-D distributed formation control framework is proposed to drive the robotic fish agents to an anticipated configuration aligning with a moving target. In particular, a consensus-based formation control law is intended to realize the two-stage formation control process. Taking the energy-constrained occasions into consideration, the communication structure and event-triggered protocols are initially tailored. Meanwhile, the Lyapunov function is employed and the globally asymptotic stability of the proposed method is fully demonstrated. Afterwards, making use of the local measurements of triggering times, the unscented Kalman filter is introduced and a novel model-based event-triggered mechanism is put forward to further mitigate otiose communication consumption. Finally, adequate simulations and experiments are carried out to verify the effectiveness and robustness of the proposed scheme. Thereby, the proposed formation control frame offers great potential for future practical marine operations of the underwater multiagent systems.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Adaptive Switching Control Based on Dynamic Zero-Moment Point for
           Versatile Hip Exoskeleton Under Hybrid Locomotion

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      Authors: Yinan Miao;Xingjian Wang;Shaoping Wang;Rufei Li;
      Pages: 11443 - 11452
      Abstract: In this article, an adaptive switching controller based on the dynamic zero-moment point for versatile hip exoskeleton is proposed. The linear finite hysteretic state machine is designed to recognize hybrid motion phases. The torque planning strategy based on dynamic zero-moment point is deployed to obtain assistant torque adaptively under different locomotion. Experiments are carried out to verify the performance of the controller, confirming the stability and accuracy of the motion phase recognition, which also demonstrates excellent kinematic performance. The net metabolic rate can be reduced by 6.93% while wearing the versatile hip exoskeleton walking. The integrated surface electromyography can be reduced by 54.8% while wearing the exoskeleton lifting objects. Compared with existing research, the performance of the proposed controller has significant advantages. The proposed controller is capable of multiple types of locomotion, including flat walking, stair climbing, and lifting heavy objects with low complexity and energy consumption.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • PGO-LIOM: Tightly Coupled LiDAR-Inertial Odometry and Mapping via Parallel
           and Gradient-Free Optimization

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      Authors: Hongming Shen;Qun Zong;Bailing Tian;Xuewei Zhang;Hanchen Lu;
      Pages: 11453 - 11463
      Abstract: Real-time localization and mapping for micro aerial vehicles (MAV) is a challenging problem, due to the limitation of the onboard computational power. In this article, a tightly coupled light detection and ranging (LiDAR)-inertial odometry is developed, which achieves high accuracy, real-time trajectories estimation for MAV utilizing only onboard sensors and a low-power onboard computer. The key idea of the proposed method is to integrate the IMU measurements, correct LiDAR matching measurements, LiDAR matching outliers into one nonlinear and noncontinuous objective function, and formulate the localization and mapping problem as a stochastic optimization problem. To deal with the nonlinear and noncontinuous objective function, a gradient-free optimization method is proposed to solve the stochastic optimization problem with a single parallel iteration. The novel constructed objective function and gradient-free optimization algorithm enable the proposed LiDAR-inertial odometry to achieve high accuracy and low time consumption. The effectiveness of the proposed method is demonstrated through various scenarios, including public datasets and real-world flight experiments.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Soft Variable Stiffness Hand With an Integrated Actuating–Cooling
           System

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      Authors: Junfeng Li;Jiahao Li;Zuqi Wu;YongAn Huang;
      Pages: 11464 - 11473
      Abstract: In this article, a new soft finger is presented to achieve a fast variable stiffness mechanism using polycaprolactone based on an integrated actuating–cooling system. First, the variable stiffness finger demonstrates a dramatic 15-fold stiffness variation from 10.2 × 104 to 0.67 × 104 N·mm2 when the temperature is changed in a range from 20 °C to 60 °C. The cycle time of the variable stiffness based on the integrated actuating–cooling hydraulic system is approximately 505 s, which is much shorter than that of 3870 s based on the pneumatic method. Second, due to the varied weight of water in the chamber, Cosserat rod theory is used to model the bending shape of the soft finger instead of the constant curvature model. A feasible method to control the position and stiffness simultaneously based on the Cosserat model is presented. Finally, a three-fingered soft hand is fabricated based on the variable stiffness and self-locking method, which can hold objects up to 3560 g successfully, which is more than 5.2 times its own weight of 680 g.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Unified Human–Robot–Environment Interaction Control in Contact-Rich
           Collaborative Manipulation Tasks via Model-Based Reinforcement Learning

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      Authors: Xing Liu;Yu Liu;Zhengxiong Liu;Panfeng Huang;
      Pages: 11474 - 11482
      Abstract: Many safety-critical or performance-demanding systems are human-in-the-loop, i.e., the robot interacts with human being and environment, in which human-in-the-loop control becomes a key research topic. In this article, a unified optimal interaction control in joint space is presented for multipoint human–robot–environment interaction (HREI) problems, which are very common in human–robot collaborative manipulation tasks. Specifically, model-based reinforcement learning method is leveraged for obtaining optimal interaction control. For multipoint human–robot–environment interaction, the interaction forces exerted on each link are isolated and estimated via the backward generalized momentum observer method. In human–robot–environment interaction problems, the environmental as well as the human arm's dynamics parameters are usually unknown, stochastic, and time-varying. To obviate the dependence on these parameters, the Gaussian mixture modeling / Gaussian mixture regression (GMM/GMR) method is employed to learn the unknown external dynamics. It is noteworthy the interaction forces are considered as system states, the time derivatives of which are computed based on the GMM/GMR learning results via chain-rule. Then, the iterative linear quadratic Gaussian with learned external dynamics (ILQG-LED) method is utilized to realize optimal multipoint HREI control. The validity of the proposed method is verified through experimental studies.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Integrated Disturbance Observer-Based Robust Force Control

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      Authors: Kangwagye Samuel;Kevin Haninger;Roberto Oboe;Sehoon Oh;
      Pages: 11483 - 11494
      Abstract: For robotic tasks that involve combined transmitting and contact force control, achieving the high-performance motion control while ensuring stable environment contact is difficult. Among the factors that affect the quality of this force control, in this article, we may account vibrations due to misalignment in the mechanical components, actuator inaccuracies, nonlinear effects of friction, and backlash. All the above mentioned factors can be collectively considered as force disturbances. Toward high-performance motion control and contact stability, a novel integrated disturbance observer (DOB) (IDOB) is proposed. The IDOB uses force sensor measurements with position measurements and a plant model to isolate and robustly suppress the effects of force disturbances within the plant without compromising contact stability. This is applied here to a force control system to demonstrate the enhanced force control performance in free space and in contact. The passivity, robust stability, and disturbance rejection of the proposed IDOB are compared with those of existing force controllers, with and without force-based DOBs. Finally, actual experiments are conducted in free space and contact under various interaction conditions, showing that the IDOB improves transmitting force control and disturbance suppression performances. Moreover, peak collision force is reduced while maintaining contact stability with stiff environments.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Conditional-Extreme-Point Based Fault-Tolerant Predictive Control of
           Five-Phase PMSM With Low Switching Frequency

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      Authors: Huanan Wang;Wenxiang Zhao;Tao Tao;Mei Kang;Yuanfang Qian;
      Pages: 11495 - 11506
      Abstract: The virtual voltage vector based fault-tolerant control has been widely concerned, but suffering from the increased switching frequency and the reduced bus voltage utilization at the faulty operation. Also, the harmonic space is uncontrollable. This article proposes a conditional-extreme-point based fault-tolerant model predictive control for a five-phase permanent magnet synchronous motor. The conditional extreme point is used to predict the optimal reference voltage vector. First, to suppress the harmonics, dual control sets are established without the sacrifice of bus voltage utilization. Then, the unconditional extreme point and y-axis voltage are predicted to select the appropriate control set, and two adjacent vectors are preselected for generating the optimal reference voltage vector. Subsequently, the conditional extreme point of the cost function is calculated to obtain the optimal reference voltage vector. Due to the unemployment of the null vector, the switching frequency is greatly reduced. Finally, the experimental results are presented to verify the proposed control scheme.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Modeling of Current-Driven End-Effect Force Ripple in Air-Cored Linear
           Synchronous Motor With Multiple Modular Stators

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      Authors: Jae Hyun Kim;Sang Won Jung;Yoon Sik Kwon;Sangmin Lee;Jun Young Yoon;
      Pages: 11507 - 11515
      Abstract: This article presents a segmented layer model (SLM) for the air-cored linear permanent-magnet synchronous motors (LPMSMs) with multiple modular stators. In the LPMSM with modular stators, the significant current-driven ripples (CDRs) are observed as the permanent magnet mover moves across the stator modules, due to the magnetic end effects. Such CDRs become more severe as the current excitation level increases. In order to correctly model the overall motor forces in the LPMSM, the analytic motor model needs to be able to capture the magnetic end effects from both the stator and mover, and also include the current-driven effects. The SLM method presented in this article divides the analytical region into several segmented layers to be able to accurately capture both the geometric-saliency- and current-driven force ripples by using layers with different fundamental spatial frequencies. The fidelity of the proposed SLM is validated both by the finite element method (FEM) and the experiments. The SLM achieves an accuracy of more than 97% and 87% compared to the FEM and experimental results, respectively, while reducing the computation time by two orders of magnitude as compared to the FEM.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Dynamic Phasor-Based Stochastic Transient Simulation Method for MTDC
           Distribution System

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      Authors: Pengwei Chen;Peipei Zhao;Liang Lu;Xinbo Ruan;Chao Luo;
      Pages: 11516 - 11526
      Abstract: To investigate the impact of uncertain variability on multiterminal dc distribution systems and provide an efficient simulation tool, this article develops a stochastic transient simulation method based on dynamic phasor (DP). Starting from the lumped elements, the dynamic phasor models of the elements with parameter migration are established first, as well as the corresponding dynamic companion circuits used in digital simulation. By introducing the switching function and low-frequency approximation, the DP-based companion circuit of the voltage source converter is formulated, and the revised nodal voltage equations that can be solved in the framework of Electromagnetic Transients Program are also derived. Then, combined with the discussion on the ill condition of the nodal admittance matrix, the main process of DP-based stochastic transient simulation and the hybrid simulation scheme integrating electromagnetic transient (EMT) simulation are further proposed. Through the comparison with the full EMT simulation and physical experiments, the effectiveness of the DP-based dynamic companion circuits is validated, as well as the efficiency of the proposed simulation method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Quadrature Sinusoidal Signals Correction of Magnetic Encoders via Radial
           Basis Function Neural Network and Adaptive Loop Shaping

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      Authors: Siyi Yu;Weike Liu;Xiaofeng Yang;Feng Shu;
      Pages: 11527 - 11534
      Abstract: Magnetic encoders are widely used in industrial motion control, due to their low-cost, simple structures, and low environmental requirements. However, the obtained quadrature sinusoidal signals suffer from various disturbances, which affects the accuracy of the magnetic encoders. The current methods which combine the neural network with phase-locked loop (PLL) typically require the knowledge of harmonic orders in advance and use a proportional-integral controller as loop filter of the PLL. In this article, we propose a new method, in which a radial basis function neural network (RBFNN)-based PLL is combined with adaptive loop shaping. In this method, with the incorporation of RBFNN into PLL, the disturbances could be readily eliminated, thus avoiding additional parameter identification. Furthermore, the adaptive loop shaping served to redesign the PLL's loop filter, aiming to strengthen the high-frequency noise attenuation capability. The method has been validated both theoretically and experimentally, confirming that it is an effective method to improve the accuracy of the magnetic encoders.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Ground Experiment of Safe Proximity Control for Complex-Shaped Spacecraft

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      Authors: Rong Chen;Zhijun Chen;Yuzhu Bai;Yong Zhao;Wen Yao;Yi Wang;
      Pages: 11535 - 11543
      Abstract: The safe proximity to spacecraft is a prerequisite for most on-orbit service missions. However, performing proximity operations on orbit is dangerous and high cost. Therefore, preverification of the proximity control algorithm through ground experiments can determine the reliability and promote the success of actual on-orbit missions. This article constructs an air floating experiment system and a guidance algorithm for the safe proximity to a complex-shaped tumbling spacecraft. The proposed control algorithm consists of two parts: 1) one part is an improved Gaussian mixture model, with which a novel artificial potential function is designed to accurately describe the complex shape of the target and provide three-dimensional collision avoidance constraints and 2) the other part is to use the fixed time control method to ensure that the service spacecraft can reach the desired position within a fixed time. The numerical simulation and experiments are implemented to verify the effectiveness of the proposed algorithm.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • LSTM-MPC: A Deep Learning Based Predictive Control Method for Multimode
           Process Control

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      Authors: Keke Huang;Ke Wei;Fanbiao Li;Chunhua Yang;Weihua Gui;
      Pages: 11544 - 11554
      Abstract: Modern industrial processes often operate under different modes, which brings challenges to model predictive control (MPC). Recently, most MPC related methods would establish prediction models independently for different modes, which results in their control effect highly relying on switching strategies. Inspired by the powerful representation capabilities of deep learning, this article proposed a deep learning based MPC method. Specifically, the LSTM network is applied to predict behaviors of controlled system, which can automatically match different operation modes without switching strategy. Then combined with MPC framework, an adaptive gradient descent method is introduced to handle optimization problem and its constraints. In addition, stability and feasibility analysis have been conducted from the aspect of theory to ensure practical application of the proposed method. Experiments on a numerical simulation process and an industrial process platform show the strength and reliability of the proposed method, which reduces the overshoot by about 10$%$ compared to common learning-based MPC methods and improves the control accuracy effectively.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Current Ripple Mitigation Strategy of Modular Multilevel DC/DC Converter
           for Battery Energy Storage System

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      Authors: Tianmu Chen;Guohong Zeng;Long Jing;Sirui Wang;Weige Zhang;
      Pages: 11555 - 11565
      Abstract: For modular multilevel dc/dc converter (MDC) with conventional modulation strategies, the inductor current ripple will increase if dc/dc units’ input voltages and/or output references are unbalanced. In this article, a current ripple mitigation strategy is proposed for MDC battery energy storage system, which is based on harmonic model for ripple analysis using the Fourier series. By varying the duties and phase-shifted angles simultaneously, multiple current harmonics are eliminated. Moreover, in order to freely adjust batteries’ current under the condition of duties is calculated by ripple suppressing method in every modulation process, the control period is divided into several intervals and variables in each interval are separate. Through constraining every unit's average duty of all intervals, battery current is dominated under distribution scheme while achieving the goal of ripple mitigation. Experimental result on a four-unit MDC is presented to verify the feasibility and effectivity of the proposed modulation method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Synchronous Vibration Force Suppression of Magnetically Suspended CMG
           Based on Modified Double SOGI-FLL

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      Authors: Peiling Cui;Yanbin Li;Jinlei Li;Liang Du;Yang Wu;
      Pages: 11566 - 11575
      Abstract: The mass imbalance of the rotor will produce the synchronous vibration force that is transmitted to the magnetically suspended control moment gyroscope (MSCMG) through the magnetic levitation stator, which affects the imaging performance of the satellite. The suppression of the synchronous vibration force needs the speed signal. In order to solve the synchronous vibration force of the MSCMG when the speed measurement sensor fails, this article proposed an modified double second-order generalized integral frequency-locked loop (SOGI-FLL) method, which uses the frequency of the disturbance signal generated through the mass imbalance of the rotor to adaptively estimate the rotor speed and suppress the synchronous vibration force generated by the active magnetic bearing system. The phase compensation is introduced to ensure the stability of the system in full frequency band. The electromagnetic force is directly used as the input signal of the control algorithm to achieve zero magnetic force control. Simulation and experiment are carried out, and the results are given to prove that the algorithm proposed in this article can accurately estimate the rotation speed and achieve the vibration force suppression in the full rotation speed range. It is of great significance for the high-precision control of the active magnetic bearing (AMB) rotor system.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Error-Bounded Tracking of Maglev Planar Motor Based on Robust Model
           Predictive Control

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      Authors: Kaiyang Zhang;Fengqiu Xu;Xianze Xu;
      Pages: 11576 - 11586
      Abstract: This article presents a robust model predictive control (MPC) scheme for error-bounded tracking of the magnetically levitated (maglev) planar motor. The motivation lies in bringing the machining error within the desired tolerance zone. An augmented system containing the dynamics of measured position, estimated state, and estimated disturbances is used as the prediction model of MPC, such that the obtained optimal control signals can remove the positioning errors in steady state caused by the disturbances. Based on the augmented system, reference dynamics and constraints, a robust control invariant (RCI) set is derived using an iterative procedure, which can be terminated in finite steps. The RCI set is explicitly incorporated into the MPC formulation for error-bounded tracking. The proposed method is successfully implemented on the maglev positioning system, and systematic experiments are given to illustrate that tracking errors are bounded in the defined region.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Parameter Selection and Performance Analysis of Linear Disturbance
           Observer Based Control for a Class of Nonlinear Uncertain Systems

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      Authors: Sen Chen;Zhixiang Chen;Zhi-Liang Zhao;
      Pages: 11587 - 11597
      Abstract: The article presents a principle of selecting the parameters in linear disturbance observer based control (LDOBC). Via designing the numerator of Q-filter based on the presented principle, a class of optimal parameterized LDOBCs are proposed, which is featured with stronger robustness to uncertainties. Based on a new realization of proposed LDOBC and Lyapunov method, this article rigorously investigates the closed-loop transient performance under a wide class of nonlinear uncertainties described in time domain. Moreover, the relationship between the control parameters and the bounds of tracking and estimating errors is explicitly shown, which illuminates the highly consistent closed-loop performance of the presented LDOBC.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A High-Bandwidth Current Estimator With Self Tunning for Digital Buck
           Controller

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      Authors: Limin Yu;Shen Xu;Chenxi Yang;Yugeng Wu;Longxing Shi;Weifeng Sun;
      Pages: 11598 - 11607
      Abstract: In order to solve the low-cost problem of high-speed current sampling in digital buck controllers, a current estimation method based on the direct current resistance current detection principle is proposed in this article. The inductor current including direct current (DC) and alternating current (AC) is obtained by performing high-frequency digital filtering on the voltage across the inductor (VL). Quantitative analysis of various factors affecting the accuracy of current estimation is carried out. For improving the estimated current accuracy, the multi-phase interleaved clock sampling technique and the algorithm of the average duty cycle in the filter cycle are proposed to improve the VL accuracy in each filter cycle. Meanwhile, considering the completeness of the current estimation algorithm, a calibration mechanism with a known current sink to adjust filter parameters online is adopted for the change of the inductance (L) and its equivalent impedance (RL) due to process and aging. The proposed algorithm is verified in a buck prototyping board. Experimental results are presented to show that the proposed method is effective in both fixed frequency and variable frequency control modes. The DC and ac accuracy of estimated current reach 5% and 2%, respectively. The estimated inductor current delay is within 100 ns.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Suppressing Coupled Axial–Torsional Vibration of Drill-String System
           Considering Regenerative Cutting Induced Delay and Actuator Saturation

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      Authors: Chengda Lu;Zhaoqing He;Luefeng Chen;Quanxin Li;Min Wu;
      Pages: 11608 - 11617
      Abstract: This article is concerned with suppression of coupled axial–torsional vibration of drill-string system, taking into account the state-dependent delay inherited from regenerative cutting of drill-bit on rock and actuator saturation of drill-rig. Note that, in practice, the measurement and saturated control input could only be applied at the surface side of drill-string, while a nonlinearity of time-delay is introduced due to the bit-rock interaction at the downhole side. The main contribution of this article lies in three points. First, to capture the rich dynamics of drill-string, a multi-degree-of-freedom lumped parameter model of two differential equations is established for the axial and torsional motions of drill-string. A bit-rock interaction model for coupled cutting-frictional contact process is employed, resulting in a constraint on current and delayed states of drill-bit. Second, combining the drill-string and bit-rock interaction models, the dimensionless dynamic of coupled axial–torsional vibration of drill-string is described by a state-space equation of time-delay system with saturation nonlinearity. Third, using a second-order Bessel-Legendre integral inequality and a reciprocally convex inequality, delay-dependent sufficient conditions are provided to design a proper dynamic output-feedback controller with an antiwindup compensator for vibration suppression, using surface measurement and control only. The effectiveness of the approach is demonstrated through a case study of real data and an experiment based on a laboratory drill-rig.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Memristive Autapse-Coupled Neuron Model With External Electromagnetic
           Radiation Effects

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      Authors: Sen Zhang;Chunbiao Li;Jiahao Zheng;Xiaoping Wang;Zhigang Zeng;Guanrong Chen;
      Pages: 11618 - 11627
      Abstract: Thanks to their distinct synaptic plasticity and memory effects, memristors not only can mimic biological neuronal synapses but also can describe the influence of external electromagnetic radiation. This article proposes a novel memristive autapse-coupled neuron model (MACNM) using a locally active memristor as an autapse and simultaneously introducing a flux-controlled piecewise-nonlinear memristor to describe the external electromagnetic radiation. Theoretical analysis and numerical simulation results show that the MACNM is able to generate multiple numbers of grid multiscroll hidden attractors. Moreover, it can exhibit rich and complex hidden firing dynamics, including periodic spiking/bursting firing, chaotic spiking/bursting firing, as well as firing patterns transition. In particular, hidden firing multistability of five coexisting homogeneous chaotic bursting firing patterns with different offsets along the boosting route is discovered, giving raise to the interesting phenomenon of hidden homogeneous multistability. Finally, a circuit is designed to verify the physical feasibility of the abundant electrical activities in the proposed MACNM.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Privacy-Preserving Distributed Iterative Localization for Wireless Sensor
           Networks

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      Authors: Lei Shi;Wei Xing Zheng;Qingchen Liu;Yang Liu;Jinliang Shao;
      Pages: 11628 - 11638
      Abstract: Effectively determining the accurate locations of sensor nodes while preserving data privacy is an interesting and challenging problem in the research of wireless sensor networks. On the basis of the well-performing distributed iterative localization framework in wireless sensor networks, this article proposes a dual privacy-preserving scheme based on node-intermittent updates and noises injection. A comprehensive analysis of the localization algorithm in terms of convergence and privacy-preserving performance is presented. It is theoretically demonstrated that the localization algorithm can achieve global accurate localization without leaking the privacy information of sensor nodes. At last, the performance of the privacy-preserving localization algorithm is verified by building an experimental platform containing six robots.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Braking Sensor and Actuator Fault Diagnosis With Combined Model-Based and
           Data-Driven Pressure Estimation Methods

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      Authors: Yicai Liu;Zhentao Chen;Lingtao Wei;Xiangyu Wang;Liang Li;
      Pages: 11639 - 11648
      Abstract: The braking system is significant for intelligent vehicles, which influences vehicle safety directly. However, under harsh working conditions, the inevitable health degradation and even failure of the braking system may cause severe safety issues. This article proposes a novel braking actuator and sensor fault diagnosis scheme with combined model-based and data-driven pressure estimation methods. The model-based wheel cylinder pressure (WCP) estimator is established first based on the mathematical model of the hydraulic control unit (HCU) from the perspective of cause. The data-driven WCP estimator is then proposed based on the vehicle dynamics multivariate time series (MTS) model with the gated recurrent unit from the perspective of effect. However, acquiring a large dataset is a practical challenge for real vehicle tests, so a novel data augmentation method called shifting is presented to enhance the model generalization ability. Next, fault detection, isolation, and identification are realized by comparing the threshold and the cumulative sum (CUSUM) of the residuals generated by the combined WCP estimation methods. The validation results show that the proposed data-driven method outperforms the traditional multilayer perceptron (MLP), long short-term memory (LSTM), and transformer regarding accuracy and generalization. Vehicle tests simulating sensor and actuator faults validate the proposed fault diagnosis scheme.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Self-Training Reinforced Adversarial Adaptation for Machine Fault
           Diagnosis

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      Authors: Jinyang Jiao;Hao Li;Jing Lin;
      Pages: 11649 - 11658
      Abstract: To alleviate the predicament of data annotating and the need for collecting data from identical distribution, unsupervised domain adaptation technologies have been widely deployed in the field of machine fault diagnosis. Nevertheless, most of them focus only on domain alignment and fail to make full use of the unlabeled target data. Given this, a novel self-training reinforced adversarial adaptation (SRAA) diagnosis method is developed in this article. In SRAA, an adversarial adaptation mechanism based on a bi-classifier disparity measure is introduced to implicitly align two domains. Meanwhile, a bi-classifier-oriented self-training algorithm is further proposed to fully mine the connotation information of unlabeled target data and reinforce model performance, in which an adaptive sample selection strategy and soft cross-entropy loss are included to guide high-confidence self-training. Empirical evidence from extensive experiments demonstrates the efficacy of SRAA, and comprehensive comparisons against the existing approaches show the superiority of our method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A New Data-Driven Diagnosis Method for Mixed Eccentricity in External
           Rotor Permanent Magnet Motors

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      Authors: Shengsen Zhou;Conggan Ma;Yanyan Wang;Dafang Wang;Yu-Ling He;Feifei Bu;Ming Wang;
      Pages: 11659 - 11669
      Abstract: In this article, a new data-driven diagnosis method is proposed for mixed eccentricity (ME) in the external rotor permanent magnet motors (ERPMMs). Differently from the previous articles, the proposed method has the advantages of large sample size, high sample diversity, high efficiency, and strong generalization ability. First, the improved parametric analytical model (AM) of back electromotive force (EMF) of the ERPMMs is established. Then, the characteristics of the back EMF are analyzed. Accordingly, its amplitudes of fundamental waves and sideband harmonics are selected as the ME indexes. Afterwards, by using the proposed parametric AM, a database of ME signals is established efficiently, which contains tens of thousands of labeled samples. Furthermore, based on the back propagation neural network, a high-precision diagnosis model for ME in the ERPMM is established. Interference faults, such as unbalanced stator windings and uneven magnetization are also discussed. Finally, an experimental prototype for simulating the ME is manufactured and the effectiveness of the proposed method is verified. The maximum absolute diagnostic error is less than 4.0%. It provides a new idea for multiparameter diagnosis for ME.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Assessment of Tool Wear With Insufficient and Unbalanced Data Using
           Improved Conditional Generative Adversarial Net and High-Quality
           Optimization Algorithm

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      Authors: Tianyu Liu;Bojian Chen;Weiguo Huang;Lisa Jackson;Lei Mao;Qingbo He;Qiang Wu;
      Pages: 11670 - 11680
      Abstract: The reliability of manufacturing tooling is key for intelligent manufacturing process, which requires accurately online identification of abnormal tool condition. However, in practical applications, insufficient and unbalanced data bring great difficulty for reliable tool wear assessment. In this study, a combined improved conditional generative adversarial net with high-quality optimization algorithm (CGAN-HQOA) is proposed to generate tool data having higher similarity with real data. Assessment of tool wear condition utilizing this newly generated data within convolutional neural network is shown with increased accuracy. The generated data can maintain sample diversity while minimizing deviation from real sample characteristics with CGAN-HQOA. The effectiveness is investigated using unbalanced data under various scenarios, where the quality of generated data from the proposed model is compared to those from commonly used data generation algorithms, such as generative adversarial nets. Moreover, the robustness of the proposed method is investigated by using different cutting tools. Results demonstrate that with the proposed model, better quality data can be generated, and more accurate tool wear condition can be assessed using generated data. The findings will be beneficial in practical applications where only limited test data are available, whereas accurate and online tool wear can be evaluated with proposed method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Novel Approach to Partial Discharge Detection Under Repetitive Unipolar
           Impulsive Voltage

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      Authors: Haihua Wang;Guochun Xiao;Laili Wang;Yunqing Pei;Feifei Yan;Qingshou Yang;
      Pages: 11681 - 11691
      Abstract: Partial discharge (PD) detection is an important method to verify the reliability of the insulation structure of high-voltage power electronics devices. Although there are many research works on PD detection inside power modules, they mainly focus on traditional electrical detection methods and 50-Hz working conditions, which do not meet the repetitive unipolar impulsive voltage conditions of power modules, and traditional methods cannot solve the electromagnetic interference (EMI) problem under working conditions. This article proposes a novel approach to PD detection in power modules. This approach designs an optic fiber sensing system based on optic theory, and conducts the detailed mathematical theoretical deduction. In addition, a partial discharge inception voltage (PDIV) signal processing method based on PD acoustic signal is proposed. Finally, the proposed approach is applied to a power module. The PD signal and PDIV are successfully captured without EMI interference and new insulation problems.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Comprehensive Analysis of Principal Slot Harmonics as Reliable Indicators
           for Early Detection of Interturn Faults in Induction Motors of Deep-Well
           Submersible Pumps

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      Authors: Jorge Bonet-Jara;Joan Pons-Llinares;Konstantinos N. Gyftakis;
      Pages: 11692 - 11702
      Abstract: Early detection of interturn faults is one of the most important issues in electrical machines, as the fault severity evolves very fast to a catastrophic failure due to the high thermal stress. However, as this article shows, in submersible induction motors for deep-well pumps, it evolves slower. These motors are highly water-cooled, which significantly reduces the thermal stress caused by the fault, increasing the possibility of early detection. Among fault detection methods, only those based on line current/voltage measurements can be used, as motors are at great depths. This article investigates the principal slot harmonics as reliable indicators for early detection of interturn faults in this application. To this end, a comprehensive analysis is conducted using finite-element analysis where the behavior of these harmonics is studied under different fault severities, both alone and coexisting with other asymmetries, such as unbalanced voltages, eccentricity, or rotor faults. The findings are used to develop a reliable diagnostic scheme based on the monitoring of the most fault-sensitive harmonics along with the voltage and current unbalance indexes. Finally, the scheme is applied, for the first time, in the context of continuous monitoring of a 230-HP induction motor showing its efficacy.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Multilevel Adaptive Near-Lossless Compression in Edge Collaborative
           Wireless Sensor Networks for Mechanical Vibration Monitoring

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      Authors: Chunhua Zhao;Baoping Tang;Lei Deng;Yi Huang;Qikang Li;
      Pages: 11703 - 11713
      Abstract: To address the difficulties of severe lack of storage and computational resources and high delay of transmitting massive vibration data in wireless sensor networks (WSN) for mechanical vibration monitoring (MVM), this article proposes a novel multilevel adaptive near-lossless compression in edge collaborative WSN multilevel adaptive near-lossless compression (MANLC) for MVM, which could effectively solve the above problems. On the one hand, the sparse pattern of mechanical fault signals is analyzed. An MANLC method is proposed to characterize mechanical fault feature information with high accuracy in low storage space, and the proposed method is implemented on the self-developed acquisition node (AN), which effectively improves the storage space and transmission efficiency. On the other hand, the edge computing (EC) technique is integrated into WSN, and data reconstruction and high-precision feature detection are efficiently implemented on the self-developed EC node, which effectively reduces the storage and computing pressure of the data center server. The comprehensive experiments demonstrate that high-precision data reconstruction and feature detection could be achieved in the proposed approach from measurements that occupy a little storage space of the AN. The computational power and transmission efficiency of WSN are significantly improved, which provides a potential solution for practical engineering applications.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Online Monitoring of Cable Insulation Degradation for Inverter-Fed Machine
           System Using PWM Switching Oscillations

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      Authors: Dawei Xiang;Sitian Zhu;Hao Li;Pengju Gao;Yan Zheng;
      Pages: 11714 - 11724
      Abstract: Online cable condition monitoring is a reliability enhancement technique for inverter-fed machine systems, which requires high sensitivity with quantitative assessment capability to detect the incipient insulation degradation as early as possible. This article presents a noncontact cable condition monitoring method by utilizing the inverter's self-excited high-frequency (HF) pulsewidth modulation switching oscillations. As an HF resonance, the switching oscillation is sensitive to the small change of degrading cable insulation capacitance. First, the characteristic mode, i.e., the HF differential-mode, is selected for sensitive cable condition monitoring from the multimodal switching oscillation in an inverter-fed machine system. Then, an online condition monitoring scheme is proposed, including the framework, the noncontact HF oscillation current sensor, and the indicator(s) of cable insulation condition estimated from the amplitude-frequency features of the characteristic oscillation mode. Finally, experimental work was carried out on a 20-m cable-connected 3-kW inverter-fed machine test rig and the results demonstrate the good sensitivity and robustness of the method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Abnormal Data Detection Based on Adaptive Sliding Window and Weighted
           Multiscale Local Outlier Factor for Machinery Health Monitoring

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      Authors: Qinglin Xie;Gongquan Tao;Chenxi Xie;Zefeng Wen;
      Pages: 11725 - 11734
      Abstract: Identifying abnormal data to improve data quality is of great importance for machinery health monitoring (MHM). Existing abnormal data detection methods generally depend on appropriate parameter settings and prior knowledge of data distribution, which result in relatively low adaptability to MHM data. To obtain more reliable MHM results, this article proposed a novel method to detect abnormal data. First, the concept of adaptive sliding window (ASW) is defined and the advantages of ASW in avoiding data leakage and data redundancy are derived. The ASW can optimally divide the overall data into several segments. Next, statistical factors in time- and frequency-domain are extracted from these segments to generate corresponding research objects. Then, an improved weighted multiscale local outlier factor (WMLOF) algorithm is proposed herein to evaluate the data anomaly degree of each object. The WMLOF has the ability to assess and fuse the local outlier factor characteristics at multiple scales, and eventually yields a more comprehensive WMLOF value to evaluate the anomaly degree of the MHM data. Finally, the effectiveness and superiority of the ASW and WMLOF are validated by a synthetic simulation of a faulty rolling bearing and two engineering projects pertaining to a railway vehicle gearbox, and bench test data. Comparative analysis shows that the proposed abnormal data detection method based on the ASW and WMLOF strategies outperforms five reported algorithms in outlier detection.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Dynamic Watermarking for Cybersecurity of Autonomous Vehicles

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      Authors: Lantian Shangguan;Kenny Chour;Woo Hyun Ko;Jaewon Kim;Gopal Krishna Kamath;Bharadwaj Satchidanandan;Swaminathan Gopalswamy;P. R. Kumar;
      Pages: 11735 - 11743
      Abstract: Autonomous vehicles (AVs) are rapidly proliferating. However, their future adoption is dependent on guarantees of their safety and security. Studies have shown that AVs are vulnerable to malicious cyberattacks with potentially lethal consequences. It is, therefore, imperative to deploy defensive techniques to enhance their cybersecurity. The method of dynamic watermarking (DW) has been proposed as an active technique for cyber-physical systems to detect cyberattacks. In this study, DW is implemented on an actual AV. It is shown that the DW technique is effective for timely detection of different types of attacks on the yaw rate measurement under autonomous operation, and thereby, allows recourse to measures such as stopping or pulling off to the side to prevent collisions.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Nitrogen Oxides Concentration Estimation of Diesel Engines Based on a
           Sparse Nonstationary Trigonometric Gaussian Process Regression With
           Maximizing the Composite Likelihood

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      Authors: Haojie Huang;Xin Peng;Wei Du;Steven X. Ding;Weimin Zhong;
      Pages: 11744 - 11753
      Abstract: Gaussian process regression (GPR) has been a popular Bayesian method for nonlinear fitting. It has the advantage of predictive capability, uncertainty measurement, and interpretable structure. However, the original GPR has a heavy complexity, which limits its effectiveness on Big Data problems. Though plenty of sparse GPR methods were proposed to deal with it, they usually result in reducing the prediction accuracy. In this article, a novel sparse GPR with a newly defined objective function is proposed to obtain the hyperparameters in a different manner compared to traditional maximizing-likelihood. Experimental results on a real diesel engine dataset and several public datasets verify that the proposed method can have a better performance on the prediction.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Diagnosis and Location of Cable Defects Based on Digital Reconstruction of
           Impedance Spectrum Under Pseudotrapezoidal PFM Excitation

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      Authors: Ji Liu;Shouming Wang;Haiyue Zhang;Mingze Zhang;Wei Sun;
      Pages: 11754 - 11763
      Abstract: Because the output voltage of the existing high-frequency instrument for the defect detection of long-scale transmission cable is too low, it is necessary to output both high-frequency and high-voltage excitation. A diagnosis and location method of cable defects based on pseudotrapezoidal pulse frequency modulation excitation and impedance spectrum digital reconstruction is proposed. A high-capacity pseudotrapezoidal excitation system based on SiC high-speed inverter is designed to measure the impedance spectrum up to the highest frequency of 7 MHz. Through digital reconstruction, the impedance spectrum with different cable defects can be obtained by the bandwidth extension within the range of 100 kHz–63 MHz. Compared with traditional low-voltage sinusoidal excitation, the location results using the proposed time-space conversion function have a more minor interval oscillation and a faster convergence speed. The accuracy of defect location is improved by 80%, which verifies the effectiveness and accuracy of the proposed method.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Machinery Health Prognostics With Multimodel Fusion Degradation Modeling

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      Authors: Naipeng Li;Yaguo Lei;Xiaofei Liu;Tao Yan;Pengcheng Xu;
      Pages: 11764 - 11773
      Abstract: Degradation modeling aims to formulate the health state degradation process of machinery. Commonly used degradation models pay more attention to describing the global increasing or decreasing trend without considering the local fluctuation in the degradation process. To deal with the above-mentioned issue, this article proposes a multimodel fusion degradation modeling method. The basic idea is to fuse multiple models to describe various degradation trends of machinery involving the global trend as well as the local fluctuation. A generalized statistical degradation modeling framework is constructed, wherein the degradation process is formulated by fusing multiple models with various degradation trends. The failure event is reinterpreted under the condition of state observations fluctuating around the failure threshold. The probability density functions of the time when the state observation exceeds and drops below the failure threshold are derived, respectively. An iterative matching pursuit algorithm is developed to select the optimal models adaptively. A numerical illustration and an experimental study are conducted to verify the proposed method. The results demonstrate its superiority in health prognostics compared with two benchmark methods in cases where the degradation process has dominant local fluctuation.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Data Augmentation Considering Distribution Discrepancy for Fault Diagnosis
           of Drilling Process With Limited Samples

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      Authors: Aoxue Yang;Chengda Lu;Wanke Yu;Jie Hu;Yosuke Nakanishi;Min Wu;
      Pages: 11774 - 11783
      Abstract: The fault diagnosis during drilling is necessary to prevent the accidents develop to more serious status. Data-driven diagnosis methods have great advantages in nonlinear industrial process, however, the problem of limited samples restricts its further application. This article proposes a data augmentation method based on synthetic data generation and updating for drilling fault diagnosis with limited samples. First, the generator is trained with generative adversarial nets (GAN), and the GAN is improved by the design of parameter selection module, and loss function in generative model. Then, sufficient samples are obtained, and a balanced dataset is constructed for modeling. Meanwhile, by considering the distribution discrepancy, the self-organizing incremental neural network-based synthetic data updating is realized to track the changes of data distribution when the data drift appears. Finally, the actual data acquired from two wells are employed for the method validation. The experimental results illustrate that the proposed method is helpful for improving the performance of diagnosis model with limited samples, and the negative impact to diagnosis model due to the distribution discrepancy also can be overcome.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • An Encoder-Based Relative Attitude Observation Method for Self-Calibration
           in Dual-Axis RINS

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      Authors: Zeyang Wen;Gongliu Yang;Qingzhong Cai;Tianyu Chen;
      Pages: 11784 - 11794
      Abstract: This article investigates an encoder-based relative attitude observation method for self-calibration in a dual-axis rotational inertial navigation system (RINS). First, the calibration error of the gyroscope parameters caused by the velocity and position observations in systematic calibration is analyzed. Second, a relative attitude observation method utilizing photoelectric encoders for gyroscope parameter estimation is proposed. We apply the proposed method in our designed dual-axis RINS to verify its effectiveness in this article. Experimental results show that the calibration accuracy of the gyroscope can be improved to 0.0005$^ circ text{/h}$ in bias, and 0.98 ppm in scale factor using the proposed method. The proposed self-calibration method can be utilized as a high-accuracy self-calibration method in the dual-axis RINS when the vehicle is in static condition.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • A Unified Initial Alignment Method of SINS Based on FGO

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      Authors: Hanwen Zhou;Xiufen Ye;
      Pages: 11795 - 11803
      Abstract: The initial alignment provides an accurate attitude for strapdown inertial navigation system (SINS). By further estimating the IMU's bias and misalignment angle, the recursive Bayesian filter is accurate. However, the prior heading error has significant influence on the convergence speed and accuracy. In addition, the accuracy will be limited by its iteration at a single time-step. Coarse alignment method optimization-based alignment uses maximum likelihood estimation (MLE) to find the optimal attitude quickly. However, few methods consider the IMU bias and misalignment angle, which will reduce the attitude accuracy. In this article, a unified method based on factor graph optimization (FGO) and inertial base frame (IBF) is proposed. The attitude is estimated by MLE, IMU bias, and misalignment angle are estimated by MAP estimation. The state of all time steps is optimized together to further improve the accuracy. Physical experiments on the rotation MEMS SINS show that the heading accuracy of this method is improved in limited alignment time.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Heterogeneous Integration of Monolithic LED-PD With Circuitry for
           Intensity Stabilization

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      Authors: X. Ma;H. Lyu;Y. F. Cheung;H. W. Choi;
      Pages: 11804 - 11809
      Abstract: The monolithic integration of a photodiode (PD) to a light-emitting diode (LED) enables the on-chip monitoring of light output intensity from the emitter. The light output intensity from the LED, which would fluctuate and degrade over time, can be stabilized with the aid of a driver circuit that reads the photocurrent from the on-chip PD as a feedback signal. Previous demonstration of such systems, implemented with feedback driver circuits built with microcontroller boards or analog circuit assembled on printed circuit boards, showed that the intensity can be stabilized to within 0.03%, albeit with dimensions disproportionate to the LED-PD chip itself. A simplified circuit consisting of a transimpedance amplifier, proportional-integral controller, and a low-dropout regulator is heterogeneously integrated with the LED-PD as a system-in-package, making use of bare dies for the majority of components. Using this approach, the entire system is shrunk to a dimension of 4 mm × 5 mm, which is comparable to the size of the LED-PD chip. The reduced footprint facilitate practical applications of the LED-PD devices for intensity-stabilized lighting or displays. The stability is further improved to 0.01% on average over 1-h periods based on the on-chip PD photocurrent, while the power efficiency is improved to over 70%.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Hybrid Method for Reducing the Residual Field in the Magnetic Shielding
           Room

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      Authors: Yanbin Li;Jiye Zhao;Xikai Liu;Tong Wen;Shiqiang Zheng;Peiling Cui;
      Pages: 11810 - 11818
      Abstract: This study proposes a hybrid method for improving the magnetic shielding performance of a magnetic shielding room (MSR) with few permalloy layers. In this method, two types of compensating coils are combined, one placed outside the MSR and the other placed inside. The coupling effect between the outside coil and the permalloy layer is used to adjust the residual field distribution characteristics of the MSR, and the inside coil is used to compensate for the adjusted residual field. This method has been verified with an MSR with two permalloy layers and an inner space of 1.3 × 1.3 × 2.2 m. According to the result, the residual field was reduced to less than 2.5 nT in a cube with a 0.4-m side length, which is seven times lower than that without compensation, and the inner space utilization rate was also improved by two times compared with existing MSRs with a comparable space size. The proposed method is of great significance in the development of magnetic shielding technology.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • ES-net: An Integration Model Based on Encoder–Decoder and Siamese Time
           Series Difference Network for Grade Monitoring of Zinc Tailings and
           Concentrate

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      Authors: Hu Zhang;Zhaohui Tang;Yongfang Xie;Zeyang Yin;Weihua Gui;
      Pages: 11819 - 11830
      Abstract: In froth flotation, the tailings grade and concentrate grade are the two key performance indexes. At present, the monitoring models of these two key grades mostly use the froth image or video from a flotation cell. However, flotation cells are closely related and coupled seriously. It is difficult to use a froth image or video from a flotation cell to represent the concentrate or tailings grade. Therefore, an encoder–decoder and Siamese time series network (ES-net) is proposed. First, an encoder–decoder (ED) model is designed to predict target grade (i.e., the zinc tailings or concentrate grade) by the video feature sequence of the first rougher and the measured target grade sequence. Meanwhile, a Siamese time series and difference network (STS-D net) is constructed to predict the target grade by the video feature sequences of target flotation cell (i.e., the last scavenger or cleaner) at current and previous moments and the previously measured target grade. After that, a multitask learning strategy is proposed to integrate the ED model and STS-D net. Experiments show that the proposed ES-net can effectively integrate multiple froth visual features from different flotation cells and obtain more accurate concentrate and tailings grades than the existing models.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
  • Improved Sliding DFT Filter With Fractional and Integer Frequency
           Bin-Index

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      Authors: Tushar Tyagi;
      Pages: 11831 - 11836
      Abstract: This article presents a modified and improved filter structure based on the sliding DFT by changing the comb filter coefficient to positive and changing the comb filter delay from $N$ to $N/2$. The proposed filter structure is able to track the input signal within half a cycle as compared to the conventional sliding DFT filter, which takes one complete cycle. The improved filter can be tuned to both the fractional as well as integer bin indices without having any impact on the computational complexity. The present work experimentally verifies the practical feasibility of the proposed filter by implementing it in a field programmable gate array.
      PubDate: Nov. 2023
      Issue No: Vol. 70, No. 11 (2023)
       
 
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