A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z  

  Subjects -> ELECTRONICS (Total: 207 journals)
The end of the list has been reached or no journals were found for your choice.
Similar Journals
Journal Cover
IEEE Transactions on Power Electronics
Journal Prestige (SJR): 2.215
Citation Impact (citeScore): 9
Number of Followers: 86  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0885-8993
Published by IEEE Homepage  [228 journals]
  • IEEE Power Electronics Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • IEEE Power Electronics Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Administrative Committee

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Parallel-Connected 24-Pulse Rectifier Using Hybrid Harmonic Reduction
           Method at DC Side

    • Free pre-print version: Loading...

      Authors: Yuxin Lian;Shiyan Yang;Hongqi Ben;Wei Bai;Wei Yang;
      Pages: 12932 - 12937
      Abstract: This letter proposes a parallel-connected 24-pulse rectifier using a hybrid harmonic reduction method at the dc side. The proposed rectifier contains an unconventional interphase reactor (UIPR) with a double-tapped primary winding and secondary winding connected pulsewidth modulation converter. The proposed method is a combination of the passive and active harmonic method. From the viewpoint of total harmonic distortion (THD) of the input line current, ripple load voltage, and kilovoltampere rating of the active auxiliary circuit, the UIPR and active injecting current are optimally designed. An experimental prototype is developed to verify the theoretical analysis. The experimental THD is about 2.87%, which shows good performance of harmonic reduction.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Cybersecurity in Power Electronics Using Minimal Data – A
           Physics-Informed Spline Learning Approach

    • Free pre-print version: Loading...

      Authors: V. S. Bharath Kurukuru;Mohammed Ali Khan;Subham Sahoo;
      Pages: 12938 - 12943
      Abstract: Cyberattacks can be strategically counterfeited to replicate grid faults, thereby manipulating the protection system and leading to accidental disconnection of grid-tied converters. To prevent such setbacks, we propose a physics-informed spline learning approach-based anomaly diagnosis mechanism to distinguish between both events using minimal data for the first time in the realm of power electronics. This methodology not only provides compelling accuracy with limited data, but also reduces the training and computational resources significantly. We validate its effectiveness and accuracy under experimental conditions to conclude how data availability problem can be handled.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Continuously Adjustable Modular Bidirectional Switched-Capacitor
           DC–DC Converter

    • Free pre-print version: Loading...

      Authors: Shouheng Han;Yijie Wang;Zhenli Xie;Yueshi Guan;J. Marcos Alonso;Dianguo Xu;
      Pages: 12944 - 12948
      Abstract: This letter proposes a switched capacitor (SC)-based continuously adjustable modular bidirectional dc–dc converter. The structure of the proposed converter consists of three types of modules, series–parallel SC converter module, regulating module, and resonant SC converters module. A basic configuration of three modules working in buck operating mode is analyzed in detail. The boost mode operation is symmetrical to the buck mode. The regulation module provides all regulation capability, and the other two modules operate at fixed duty cycle and provide the main conversion ratio. A prototype of the basic configuration was built to verify the theory. The peak efficiency of the prototype is 97.15%.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Unified Viewpoint of Soft Startup and Rate Limiter for SOGI-FLL

    • Free pre-print version: Loading...

      Authors: Wenshuai Shi;Jingrong Yu;Ying Guo;
      Pages: 12949 - 12954
      Abstract: This letter demonstrates that the second-order generalized integrator-based frequency-locked loop (SOGI-FLL) with a soft startup/rate limiter essentially incorporates an adaptive feedforward relying on a priori information of transient input. When a fair parameter is tuned, the soft startup and the limiter give a similar performance. The shortcoming is that they have a deceleration blind zone, depending on the frequency constraints and SOGIs gain. If the allowed rate of change of frequency (RoCoF) is fixed, the fast response FLL can weaken this shortcoming. Specifically, if the RoCoF of low-inertia grids is considered, they could produce a severely biased estimation under the harmonics and dc offsets. The experimental results are given to validate the claims.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Multiagent Deep Reinforcement Learning-Aided Output Current Sharing
           Control for Input-Series Output-Parallel Dual Active Bridge Converter

    • Free pre-print version: Loading...

      Authors: Yu Zeng;Josep Pou;Changjiang Sun;Ali I. Maswood;Jiaxin Dong;Suvajit Mukherjee;Amit Kumar Gupta;
      Pages: 12955 - 12961
      Abstract: This letter proposes a multiagent soft actor-critic (MASAC) enabled multiagent deep reinforcement learning (MADRL) algorithm for output current sharing of the input-series output-parallel dual active bridge converter. The modular converter is partitioned into different submodules, which are treated as DRL agents of Markov games. Furthermore, all agents are executed decentralized to provide online control decisions after collaborative training. The proposed MASAC algorithm verified in a 150 V/50 V hardware prototype shows optimal dynamic performance.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Self-Decoupled and Integrated Coils for Modular Multitransmitter Wireless
           Power Transfer Systems

    • Free pre-print version: Loading...

      Authors: Prasad Jayathurathnage;Yining Liu;Jorma Kyyrä;
      Pages: 12962 - 12967
      Abstract: The use of multiple transmitters (Txs) has been an attractive solution for enabling free-positioning wireless power transfer (WPT) in a large area. One of the key challenges in such multi-Tx WPT systems is the cross-coupling between Tx coils. This letter proposes a compact self-decoupled Tx coil solution for multi-Tx WPT systems. The measured cross-coupling between Tx coils has been reduced by 95% compared with conventional coil designs. In addition, an integration method for a compensation inductor with the main Tx coil is proposed. Therefore, the coil design proposed in this letter facilitates creation of fully modular and scalable Tx coils for multi-Tx WPT systems. The proposed designs are experimentally verified in a laboratory prototype.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Modified PWM Scheme to Reduce Reverse Conduction Loss in GaN-Based
           Independently Controlled Multiple Output Flyback Converter

    • Free pre-print version: Loading...

      Authors: Arnab Sarkar;Nachiketa Deshmukh;Sandeep Anand;
      Pages: 12968 - 12972
      Abstract: The recently proposed independently controlled multiple output flyback converter (ICMOFC) scheme improves cross-regulation by utilizing gallium nitride (GaN) switches with negative gate turn-off voltage. The highly inefficient reverse conduction (RC) of negative gate biased GaN devices leads to significant RC loss in the existing ICMOFC scheme. To mitigate this problem, this letter proposes a new pulsewidth modulation (PWM) scheme. The RC loss reduction is achieved by reducing the RC duration and RC current. The effectiveness of the proposed PWM strategy is analytically and experimentally verified using a 40-W dual output flyback converter. The results demonstrate a peak efficiency improvement of 1.26% over the existing ICMOFC scheme. Furthermore, the scheme also achieves high power density (51 W/in$^{3}$) and excellent cross-regulation (0.2%).
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Position Sensorless Control of IPMSM Using Adjustable Frequency Setting
           Square-Wave Voltage Injection

    • Free pre-print version: Loading...

      Authors: Kailiang Yu;Zheng Wang;
      Pages: 12973 - 12979
      Abstract: Position sensorless control of interior permanent magnet synchronous motors (IPMSMs) is of great importance for the sake of the cost reduction and robustness improvement. An improved position sensorless method based on adjustable high-frequency (HF) square-wave voltage injection has been proposed for the IPMSM drive under zero- and low-speed regions. The general detection method of position from positive- and negative-sequence HF current response has been developed by the simple algebraic operations of data at some adjacent sampling instants. In addition, the proposed method not only can retain the advantage of the removal of low-pass filters in current feedback but also can increase the voltage margin of inverter with adjustable frequency setting of HF signal compared with existing square-wave voltage injection methods. Comprehensive experimental results have been given to verify the proposed theoretical analysis.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Magnetizing and Leakage Inductance Integration for Split Transformers With
           Standard UI Cores

    • Free pre-print version: Loading...

      Authors: Xiaoying Chen;Guo Xu;Qiuxia Shen;Yao Sun;Mei Su;
      Pages: 12980 - 12985
      Abstract: The magnetic elements are the important parts of the dc–dc converters, which is the constriction to improve the power density of the systems. In this letter, a magnetic integration structure is proposed to integrate the magnetizing and leakage inductance for split transformer with standard UI cores, which are mass-produced. Compared with the EI/EE-core structure to achieve magnetic integration, the magnetic field is theoretically evenly distributed in a UI core, and the center leg is removed because of the flux cancelation during the derivation process of the proposed magnetic structure. In this magnetic integration structure, the magnetizing inductance and the leakage inductance can be controlled accurately by designing the numbers of printed circuit board (PCB) windings and the air gap length of the UI core. The derivation process of the proposed magnetic integration and mathematical analysis is studied. The step-by-step design process is investigated, and a design example is given. A 250 kHz, 800 W, 360/380 V LLC prototype is built to verify the feasibility of the proposed magnetic integration method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A New Magnetic Coupler With High Rotational Misalignment Tolerance for
           Unmanned Aerial Vehicles Wireless Charging

    • Free pre-print version: Loading...

      Authors: Yong Li;Wenjun Sun;Junjiang Liu;Yuhang Liu;Xiao Yang;Yanling Li;Jiefeng Hu;Zhengyou He;
      Pages: 12986 - 12991
      Abstract: In this letter, a novel magnetic coupler with high rotational misalignment tolerance is proposed for unmanned aerial vehicles (UAVs) wireless charging. The transmitting coil consists of an inner coil and an outer circular coil connected in series, which generates a horizontal magnetic field from the center to all periphery directions within the charging range. Then, to receive the flux effectively and to adapt to UAV's structure, a vertical square air-core coil is designed and attached to the landing gear. The proposed magnetic coupler can reduce significantly the magnetic fluxes penetrating through the body of the UAV, therefore mitigating electromagnetic interference with onboard devices. Simulation based on ANSYS Maxwell and experiments based on a laboratory prototype are carried out to validate the proposal. The results show that, the proposed magnetic coupler can transmit power in all 360° of rotational misalignments, and the output voltage of the wireless charging system fluctuates only 2% around the 48 V reference.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Settling-Angle-Based Stability Analysis for Multiple Current-Controlled
           Converters

    • Free pre-print version: Loading...

      Authors: Shan Jiang;Ye Zhu;Georgios Konstantinou;
      Pages: 12992 - 12997
      Abstract: This letter proposes a settling-angle-based stability criterion, as the extension of determinant-based general Nyquist criterion, to facilitate the stability analysis of nonminimum phase power systems with multiple current-controlled converters. Using only the phase information of converter impedance in the $dq$-frame, the proposed stability criterion can accurately demonstrate the system stability and identify resonance sources according to the settling angles of the overall system and its subsystems, which are validated by simulation and control hardware-in-the-loop results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Hybrid Resonant Switched-Capacitor Converter for 48–3.4 V Direct
           Conversion

    • Free pre-print version: Loading...

      Authors: Alessandro Dago;Mauro Leoncini;Stefano Saggini;Salvatore Levantino;Massimo Ghioni;
      Pages: 12998 - 13002
      Abstract: As the power required by modern data center processors increases, the power architecture must be adapted; for example, 48 V distribution voltage allows to reduce copper losses by a factor 16 with respect to the use of traditional 12 V power architecture. In order to generate the required processor core voltage, a two-stage approach is usually preferred, where the intermediate bus voltage is generated using an unregulated resonant dc–dc converter as, for instance, an LLC converter. Compared to LLCs, hybrid resonant switched-capacitor converters (ReSCCs) make it possible to achieve large voltage conversion ratios without the need of high turns ratio transformers. In this letter, a novel hybrid ReSCC that performs a 48–3.4 V direct conversion is presented. A prototype of the proposed converter has been implemented, capable of providing a continuous output power of 440 W with a maximum efficiency of 96.3% at 30 A load current.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Electrothermal Averaged Model of a Diode–IGBT Switch for a Fast Analysis
           of DC–DC Converters

    • Free pre-print version: Loading...

      Authors: Paweł Górecki;
      Pages: 13003 - 13013
      Abstract: In this article, an electrothermal model of a diode–insulated gate bipolar transistor switch for modeling dc–dc converters is proposed. The formulated model has the form of a subcircuit for the simulation program with integrated circuits emphasis (SPICE) program and enables computations of both electrical characteristics of the converter and junction temperatures of the semiconductor devices. The equations used in the formulated model allow modeling the operation of the converter in both continuous conduction mode and discontinuous conduction mode. The correctness of the formulated model is experimentally verified for the boost converter. Good accuracy of modeling the characteristics of the converter is obtained. A .cir file based on the formulated model for an analysis in the SPICE program is attached to the article as the active content.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Adaptation of a Solid-State Marx Modulator for Electroactive Polymer

    • Free pre-print version: Loading...

      Authors: Morgan Almanza;Thomas Martinez;Mickael Petit;Yoan Civet;Yves Perriard;Martino LoBue;
      Pages: 13014 - 13021
      Abstract: Electroactive polymers show promising characteristics, such as lightness, compactness, flexibility, and large displacements, making them a candidate for application in cardiac assist devices. This revives the need for quasi-square wave voltage supply switching between 0 and several kilovolts, that must be efficient, to limit the heat dissipation, and compact in order to be implanted. The high- access resistance, associated with compliant electrodes, represents an additional difficulty. Here, a solid-state Marx modulator is adapted to cope with electroactive polymer characteristics, taking advantage of an efficient energy transfer over a sequential multistep charge/discharge process. To ensure compactness, efficiency, as well as the needs of an implanted device, a wireless magnetic field-based communication and power transfer system has been implemented. This work demonstrates the benefit of this design through simulations and experimental validation on a cardiac assist device. At a voltage of 7 kV, an efficiency of up to 88% has been achieved over a complete charge/discharge cycle.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Fabrication of Binder-Free and High Energy Density Yarn Supercapacitor for
           Wearable Electronics

    • Free pre-print version: Loading...

      Authors: Shalu Rani;Yogesh Sharma;
      Pages: 13022 - 13029
      Abstract: Textile-based electronics systems are gaining considerable popularity nowadays and the area of wearable electronics technology is going to explode in the near future. Currently, the research on the flexible and wearable energy storage devices, to realize as power sources in wearable electronics, is on the boom. Herein, a flexible yarn-based supercapacitor (YSC) is fabricated utilizing TiO2 nanofibers and multiwalled carbon nanotube deposited on carbon yarn through the facile electrophoretic deposition technique for flexible/wearable energy storage application. The binder-free, mechanically strong, and compact deposition of the active materials on carbon yarn promotes the charge/ionic transport. The fabricated YSC device delivers a capacitance of 36.8 mF/cm at 0.1 mA/cm current rate. Moreover, the device shows 90% capacitance retention after 10 000 cycles proving excellent mechanical stability for energy storage. Furthermore, the YSC shows 95% retention after 2000 bending cycles at 0.5 mA/cm, suggesting good flexibility of the device. The YSC device shows a maximum energy density of 11.5 μWh/cm and power density of 368 μW/cm, which is better than many YSCs reported in the literature. Three YSCs are integrated into a wearable fabric and glow a red LED for more than 5 min as demonstrated in the video proving its practical application.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A General Method to Study Multiple Discontinuous Conduction Modes in
           DC–DC Converters With One Transistor and Its Application to the
           Versatile Buck–Boost Converter

    • Free pre-print version: Loading...

      Authors: Duberney Murillo-Yarce;Carlos Restrepo;Diego G. Lamar;Javier Sebastián;
      Pages: 13030 - 13046
      Abstract: The Discontinuous Conduction Mode (DCM) is usually studied in single-diode and single inductor converters, where only one DCM exists. However, multiple DCMs can appear in multi-diode and multi-inductor topologies and the methodology to identify and characterize these multiple modes is not evident. In this paper, a general method to study multiple DCMs is presented. The first step of the method consists in finding out the number $n$, which is the number of diodes conducting current passing exclusively through inductors when the transistor turns-off. For a given $n$ value, $2^{n}$ possible conduction modes are expected: 1 continuous mode and $2^{n}-1$ DCMs. The second step is to create a $n$-dimensional space called “$k$-space”. In the $k$-space, the converter operation describes a straight line when the load changes. This straight line called “converter trajectory” passes through different $n$-dimensional enclosures. Each one of these enclosures represents a different conduction mode. The third step is to determine the borders between conduction modes which are subspaces of $(n-1)$ dimensions. This method must be followed for both control strategies (i.e., open- and closed-loop control). The proposed method is applied to the ve-satile buck-boost converter. Experimental results verify the theoretical analysis for all the identified conduction modes.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Unified Modeling Approach to Tapped Inductor Converters Accounting for
           the Leakage Inductance Effects

    • Free pre-print version: Loading...

      Authors: Jia Yao;Kewei Li;Kaisheng Zheng;Alexander Abramovitz;
      Pages: 13047 - 13059
      Abstract: This article suggests a unified modeling approach to the analysis of tapped-inductor converters. The leakage inductance, inherent to coupled magnetic structures, and the associated snubber circuit effects were considered and incorporated into the suggested model. The proposed nonideal tapped inductor switcher model is formulated as an equivalent subgraph that can help to model most, if not all, converter topologies that comprise a two-winding tapped inductor. Both the continuous current mode and the discontinuous current mode were modeled. To validate the proposed approach, analysis of a Flyback converter with an RC snubber is presented. Theoretical prediction of the steady-state and small-signal behavior of the converters were confirmed by simulation and experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • High-Definition High-Bandwidth DC/AC Power Conversion Through Binary
           Asymmetric Cascaded H-Bridges

    • Free pre-print version: Loading...

      Authors: Zhongxi Li;Stefan M. Goetz;
      Pages: 13060 - 13069
      Abstract: It is known that cascaded H-bridges with heterogenous module voltages can, in theory, generate exponentially-refined output voltage levels and achieve high output resolutions from only one power source. However, several critical considerations have yet to be thoroughly studied, namely the controllability of module voltages under any load conditions, and how to schedule the switching states optimally. We present a scheduling algorithm and topological modifications for binary asymmetric cascaded H-bridges (ACHBs) to achieve complete sensorless operation under any load conditions while using only one power source. The scheduling algorithm cancels the energy intake of floating modules per time frame, while low-power auxiliary dc/dc circuits, which naturally emerge from the bridge structure, can correct any voltage drift without the need for voltage sensors. Rigorous analyses reveal an inherent performance tradeoff between reference-tracing accuracy and floating module voltage controllability for ACHBs in general, for which the proposed algorithm always achieves the Pareto front. The proposed ACHB and the algorithm are tested on an experimental setup with six modules and 65 output levels (i.e., effectively six bits).
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Dual-Frequency Bands Grid Impedance Emulator for Stability Test of
           Grid-Connected Converters

    • Free pre-print version: Loading...

      Authors: Jiashi Wang;Ke Ma;Weiyu Tang;Xu Cai;Luhai Zheng;Xinqiang Li;Aiguo Wang;
      Pages: 13070 - 13080
      Abstract: The grid-connected converters are becoming a fundamental building block in the modern power grid, and the stability of grid-connected converters, especially when they are connected to weak grid, has drawn increasing attention. In order to test the interaction with various grid impedances and validate the stability behaviors, more accurate and advanced emulation of grid impedance is becoming an emerging need. However, the existing approaches are still difficult to flexibly shape the grid impedance under medium-to-high frequency range. In this article, a novel configuration for programable impedance emulation of power grid is proposed. The proposed grid emulator is composed of two power electronics converters with special control functions, i.e., the impedance forming converter (IFC) and power supporting converter (PSC). The IFC is designed with a higher switching frequency to virtually emulate different grid impedances under medium-to-high frequency band. On the other hand, the PSC is designed with a lower switching frequency to generate/absorb the power of the converter under test. Besides, a Norton-circuit-based virtual impedance control strategy is introduced to eliminate the derivation term in the control structure of virtual impedance. Finally, the performance of the proposed emulator is verified by various simulations and experimental prototype.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Current-Limited Suboptimal Sliding Mode Control for Voltage-Regulated
           Synchronous Buck Converters

    • Free pre-print version: Loading...

      Authors: Rafael Ramos;Víctor Repecho;Domingo Biel;
      Pages: 13081 - 13090
      Abstract: This article proposes a new sliding mode control based on a nonlinear switching surface that provides a suboptimal current-limited start-up response in step-down converters. The main idea behind the design consists in combining different switching surfaces. The first one forces the system trajectories to track a constant current path until the output voltage error is small. A nonsingular terminal switching surface then drives the trajectories to the vicinity of the steady-state operating point. Finally, a first-order switching surface regulates the steady state providing very good rates of load and line regulation. The article presents the design guidelines of the suboptimal sliding mode control and the experimental evaluation that confirms the effectiveness of the proposal.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Grid-Forming Vector Current Control

    • Free pre-print version: Loading...

      Authors: Mario Schweizer;Stefan Almér;Sami Pettersson;Arvid Merkert;Vivien Bergemann;Lennart Harnefors;
      Pages: 13091 - 13106
      Abstract: In this article, a novel point of view on grid-forming control with current controlled power electronic converters is presented. A control concept based on the emulation of the combined effect of a virtual synchronous condenser and a parallel-connected virtual current source is proposed. It combines the positive effects of virtual synchronous generator control, such as the provision of inertia, voltage support, the possibility of islanded operation, and good control performance in weak grids, with the benefits of vector current control, such as fast current limitation, improved synchronization properties, and fast setpoint tracking. The proposed control concept is simply a modification of standard vector current control. Therefore, it can be implemented easily on all control platforms with minor software changes. The control method is verified with analytical models, time-domain simulations, and experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Zero-Additional-Hardware Power Line Communication for DC–DC
           Converters

    • Free pre-print version: Loading...

      Authors: Renke Han;Daniel J. Rogers;
      Pages: 13107 - 13118
      Abstract: A power line communication (PLC) solution to provide a data link between two or more dc–dc power converters is proposed. The approach does not require additional analog circuitry or high-sample-rate analog-to-digital converters to be added on top of the original system. A modulation and signal injection method for the transmitter, and a sampling and demodulation strategy for the receiver are developed. The PLC frequency band is placed between the control loop cutoff frequency and the power electronics circuit cutoff frequency, in a region that we identify as the “intermediate frequency band”. The transmitter modulates the converter voltage or current output by injecting perturbations into the control loop at the input to the PWM unit. To tolerate unsynchronized transmitter and receiver clocks, a virtual zero-crossing location algorithm is combined with long/short pulse identification to achieve demodulation at the receiver. The solution is verified experimentally and achieves reliable bidirectional PLC communication at 2 kb/s with an 8 kHz receiver sampling frequency.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Dynamic ZVS-Guaranteed and Seamless-Mode-Transition Modulation Scheme
           for the DAB Converter That Maximizes the ZVS Range and Lowers the Inductor
           RMS Current

    • Free pre-print version: Loading...

      Authors: Linxiao Gong;Xinyu Jin;Junzhong Xu;Zifeng Deng;Houji Li;Thiago Batista Soeiro;Yong Wang;
      Pages: 13119 - 13134
      Abstract: The dual active bridge (DAB) converter operating with a relatively high switching frequency is well suited for deriving a high-power density electric vehicle (EV) charger. In this case, safeguarding the realization of zero voltage switching (ZVS) for a wide operating range becomes crucial to ensure a good performance in terms of efficiency and control reliability. Unfortunately, most modulation schemes available today in the literature require a detrimental compromise in the achievable ZVS range, particularly the ones working mainly toward the minimization of the current stress. Due to the fact a public EV charger will work with multiple vehicles having quite different charging profiles, i.e., with wide operational voltage and currents ratings, the ZVS operation may be prone to fail to undermine the whole cycle charging efficiency. To relieve the issues, this article proposes a new modulation scheme for the DAB converter featuring a maximized ZVS range and a quasi-optimal inductor rms current. Herein, the concept of dynamic settings of the required modulator's ZVS-current is utilized and a straightforward implementation with seamless circuit mode transition is achieved. With the above characteristics, the dynamic and static losses of the component circuits can be reduced together. By adopting the dynamic ZVS-current settings strategy, the turning-on currents of the DAB switches are adjusted in real-time guaranteeing the ZVS operation under various operating conditions. With the seamless transition, the inductor current can be smoothly regulated to ensure system stability. The proposed modulation scheme is introduced, analyzed, validated, and benchmarked in a 4.5 kW/100 kHz SiC-based DAB prototype, whose peak efficiency can reach 96.3% when operated at partial load.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • High-Gain Nonlinear Active Disturbance Rejection Control Strategy for
           Traction Permanent Magnet Motor Drives

    • Free pre-print version: Loading...

      Authors: Yin Bai;Guoqiang Zhang;Qiwei Wang;Dawei Ding;Binxing Li;Gaolin Wang;Dianguo Xu;
      Pages: 13135 - 13146
      Abstract: In order to improve the performance of the traction permanent magnet motor drives without weight transducer for direct-drive elevator applications during starting operation, this article proposes a novel control method based on the high-gain nonlinear active disturbance rejection control (HNLADRC) strategy. First, the limitation of linear and nonlinear error decay function of active disturbance rejection control (ADRC) method is analyzed, which is not suitable for the complex situation at starting operation of the traction motor. A high-gain nonlinear error decay function based ADRC method is proposed, which can achieve better performance in the starting operation of the traction motor. Both the high-gain extended state observer (HNLESO) and the high-gain nonlinear error feedback law (HNLEFL) are constructed by the high-gain error decay function to improve the compensation accuracy of the starting torque and the dynamics of the speed loop. By analyzing the error decay performance of the HNLESO and the HNLEFL, it is proved that the HNLADRC method has a faster error decay rate. Experimental results show that the proposed method can obtain a shorter rollback distance and faster response capability.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Novel Random Square-Wave Voltage Injection Method Based on Markov Chain
           for IPMSM Sensorless Control

    • Free pre-print version: Loading...

      Authors: Zebin Yang;Kang Wang;Xiaodong Sun;
      Pages: 13147 - 13157
      Abstract: The square-wave voltage signal injection into the estimated d-axis is an effective and novel sensorless control scheme for interior permanent magnet synchronous motor at zero speed and low speed. However, the notable acoustic and electromagnetic noises induced by the conventional fixed-frequency signal injection are very harsh and shrill to hear, which limits the practical application. Aiming at reducing unnecessary acoustic noise, a novel random voltage injection method based on the Markov chain (MC) is proposed in this article. Two high-frequency square-wave voltages with different types of frequencies and amplitudes are randomly injected into the estimated d-axis by MC rules, and this way has spread spectrum characteristics, which can effectively reduce the unnecessary noise. In addition, a new signal demodulation compensation method considering the digital delay effect in high-frequency signals is proposed, which effectively reduces the position and velocity estimation errors. Then, the power spectra density of the induced high-frequency currents under the fixed frequency injection method and the proposed MC method are compared and analyzed. The high performance of the proposed MC method has been validated by the experiment drive platform and compared with the traditional fixed frequency under different control conditions.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Quadratic Regression Model-Based Indirect Model Predictive Control of AC
           Drives

    • Free pre-print version: Loading...

      Authors: Kristóf Bándy;Péter Stumpf;
      Pages: 13158 - 13177
      Abstract: Model predictive control is a promising technique for electric drives as it enables optimization for multiple parameters and offers reliable operation with nonlinear systems. In this article, a novel approach is presented that aims to harness the advantages of both finite and continuous set model predictive methods in converter-fed ac drive control. The proposed method requires the calculation of only seven predicted states. These states are then assigned cost function values. Using a quadratic regression model, the cost function is mapped to the entire modulation region. After solving a constrained optimization problem on this cost function mapping, the optimal voltage vector is obtained, which is then applied via pulsewidth modulation. The presented method can also be applied to multilevel converter structures without the need to calculate predictions for additional voltage vectors. Therefore, the proposed method does not increase in complexity with the utilized converter topology. Furthermore, the method offers a fixed switching frequency operation and an exact noniterative solution to the optimization problem due to the formulation of the regression model. As a case study, simulation and experimental results verify the operation of the predictive torque control for permanent magnet synchronous machines with the proposed method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Carrier-Based Discontinuous PWM Scheme With Optimal PWM Sequences for a
           Five-Level Flying Capacitor Rectifier

    • Free pre-print version: Loading...

      Authors: Peng Zhang;Xuezhi Wu;Jing Wang;Wenzheng Xu;Jingdou Liu;Jingjing Qi;Anna Yang;
      Pages: 13178 - 13191
      Abstract: Five-level flying capacitor (5L-FC) rectifier is advantageous in unidirectional power applications due to its less power devices, higher power density, better reliability, etc. To further improve the efficiency, discontinuous PWM (DPWM) methods are preferred. This article investigates a carrier-based implementation of DPWM for the 5L-FC rectifier to reduce the switching losses. Since there is always a pair of redundant switching modes that have opposite effects on the neutral point (NP) in each region of the space-vector diagram, the NP voltage regulation can be easily realized by selecting suitable clamping modes in each control period, even with unbalanced dc loads. The generated PWM sequences based on the phase disposition PWM are also optimally redistributed to realize minimal switching loss with FC voltage balancing in two consecutive carrier periods. In addition, the permissible range of unbalanced dc loads is theoretically deduced. Finally, simulations and experiments are conducted to verify the performance of the proposed carrier-based DPWM scheme.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Fully Self-Powered Inductor-Less Electromagnetic Vibration Energy
           Harvesting System Using Auxiliary Coils for Hysteresis Current MPPT
           Control

    • Free pre-print version: Loading...

      Authors: Hongfei Xiao;Han Peng;Xianchao Liu;Hanyi Sun;
      Pages: 13192 - 13204
      Abstract: Utilizing coil inductor of electromagnetic vibration energy harvester (EVEH) to form single stage ac–dc boost converter can make the self-powered milli-power system more compact. However, large output current harmonics of EVEH significantly degraded the output power in such system. This article proposes a new approach of adopting hysteresis current control to realize maximum power point tracking (MPPT) and reduce current harmonics in inductor-less converter by using auxiliary coils. The output characteristics and correlations between multiple coils are firstly studied to verify the feasibility of using auxiliary coil to represent the output of main coil. The optimal winding strategy for main coil and auxiliary coils is revealed for no degradation on maximum output power of main coil. Based upon these, a completely self-powered multicoil EVEH system is designed with auxiliary coils as reference for MPPT controller and as auxiliary power supply in cold-start. Experiments show that the designed prototype can obtain 9.54 mW output power at acceleration of 3 m/s2, with the overall efficiency of 77.6%. To charge a 10 mF supercapacitor from zero to 5 V, an average output power of 7.27 mW can be obtained with an average charging efficiency of 62.4%. In addition, the start-up method adopting auxiliary coil allows the system to cold-start when the output voltage is lower as 0.5 V. The proposed approach has been demonstrated to achieve high overall efficiency in milli-power self-powered EVEH system and also has significant advantages in cost and volume compared with using external devices to obtain reference.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Passivation of Grid-Following VSCs: A Comparison Between Active Damping
           and Multi-Sampled PWM

    • Free pre-print version: Loading...

      Authors: Ivan Z. Petric;Paolo Mattavelli;Simone Buso;
      Pages: 13205 - 13216
      Abstract: This article compares different strategies used to enhance the stability properties of grid-following voltage-source converters (VSCs). Because of digital delays, VSC admittance exhibits a nonpassive zone, which introduces negative damping and may destabilize the grid-connected operation. It is shown that typically used active damping (AD) strategies only bring positive impact up to a certain frequency, while deteriorating admittance properties around and above the Nyquist frequency. Multi-sampled pulsewidth modulation (MS-PWM) greatly extends the passive admittance region, using only a single-loop current controller. Experimental admittance measurements are performed on a single-phase VSC, up to twice the switching frequency. Subsequently, different grid-connected scenarios are tested to show that MS-PWM retains stable operation, where AD methods cause instability. This article also offers analytic modeling and experimental measurements of noise propagation for compared strategies. It is shown that derivative-based AD is not highly sensitive; however, MS-PWM offers additional noise suppression.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Unified Design Approach of Optimal Transient Single-Phase-Shift
           Modulation for Nonresonant Dual-Active-Bridge Converter With Complete
           Transient DC-Offset Elimination

    • Free pre-print version: Loading...

      Authors: Chuan Sun;Xingyue Jiang;Junwei Liu;Lingling Cao;Yongheng Yang;K. H. Loo;
      Pages: 13217 - 13237
      Abstract: The dynamics of nonresonant dual-active-bridge converter (DABC) are simultaneously affected by the transient modulation strategy and controller design. In general, inappropriate transient modulation strategies can lead to nonzero transient dc offsets in the inductor current and transformer’s magnetizing current, thus introducing excessive trajectory tracking error and time delays between the pulsewidth modulation generator and controller. Consequently, truly optimal transient responses cannot be achieved solely through a high-performance controller, unless the modulation-induced transient dc offsets can be completely eliminated. This article presents a comprehensive review of the optimized transient phase-shift modulation (OTPSM) strategies for single-phase-shift modulated DABC, and derives a novel optimal modulation method referred to as symmetric single-sided OTPSM (SS-OTPSM), which is based on a unified theoretical framework of OTPSM and an additional condition enabling a full elimination of all undesired transient dc offsets. The proposed SS-OTPSM can be easily and cost-effectively implemented in a cycle-by-cycle manner, and inherently compatible with fast controllers. Additionally, in order to more accurately match DABC’s power transfer model under SS-OTPSM, an enhanced model predictive controller (EMPC) is proposed. By a combined use of SS-OTPSM and EMPC, ultrafast and completely dc-offset-free dynamics can be achieved without measuring the inductor current. The effectiveness of the proposed schemes is verified by closed-loop simulation and experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Direct Torque Control With Phase Commutation Optimization for
           Single-Winding Bearingless Switched Reluctance Motor

    • Free pre-print version: Loading...

      Authors: Tao Zhu;Xin Cao;Qiang Yu;Zhiquan Deng;Zhenyang Hao;
      Pages: 13238 - 13249
      Abstract: Compared with the traditional control method, the direct torque control and direct force control method significantly reduces the torque ripple and the root-mean-square current of the phase winding in the single-winding bearingless switched reluctance motor. However, due to the unreasonable selection of voltage vectors and full cycle control, this method has some problems, such as too many control objects, excessive switching times, and low torque–ampere ratio. This article proposes an improved method for the abovementioned problems. First, the turn-on angle and conduction region of each phase winding are chosen as the control targets, and the operation principle is introduced accordingly. Second, according to the difference of the torque generated by the neighboring phases, the output torque can be distributed more properly to obtain the higher torque–ampere ratio in the commutation region. Finally, the sectors divided in the electrical space are reorganized and the corresponding voltage vectors are optimized. Experimental results show that the proposed method can secure lower torque ripples, fewer switching times, and copper loss. In addition, the torque–ampere ratio is improved as well.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Improved Position Sensorless Drive Method for IPMSM Based on Fully
           Discretized Model and Inductance Identification Utilizing Current Ripple

    • Free pre-print version: Loading...

      Authors: Jindong Zhang;Fei Peng;Yunkai Huang;Yu Yao;Zichong Zhu;
      Pages: 13250 - 13263
      Abstract: This article proposes an improved position sensorless drive method for interior permanent magnet synchronous machines (IPMSM) in medium- and high-speed regions, which relies on the fully discretized extended back-electromotive force (EEMF) model and online inductance identification. First, the fully discretized EEMF model is developed for constructing position observers, which overcomes the accuracy deterioration of the conventional Euler-discretized model with the speed increasing. And then, an online inductance identification method for IPMSM, which utilizes the inherent pulsewidth modulation (PWM) current ripple of the voltage source inverter (VSI), is proposed to improve the position estimation accuracy. Compared with the traditional parameter identification method, the proposed method does not require the additional signal injection, therefore, the undesirable torque fluctuation and additional voltage occupancy due to signal injection are avoided. Benefiting from the fully discretized EEMF model and the estimated inductances, the improved rotor position estimation of IPMSM can be achieved. Finally, the proposed method is verified by simulations and experiments.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Lifetime Performance Analysis of Imbalanced EV Battery Packs and
           Small-Signal Cell Modeling for Improved Active Balancing Control

    • Free pre-print version: Loading...

      Authors: Zhe Gong;Aseer Chowdhury;Olivier Trescases;
      Pages: 13264 - 13276
      Abstract: Conventional battery balancing techniques target fast voltage or state-of-charge convergence while improving circuit-level metrics such as power density, efficiency, and component count. System-level metrics, including prolonged pack cycle life, reduced degradation rate, and increased energy capacity, are often overlooked. In this work, the lifetime discharge energy of imbalanced battery packs is quantified and compared using Monte-Carlo-style battery lifetime transient simulations with experimentally captured drive cycles. Computations were carried out across $>$20 000 core-hours on the Niagara supercomputer at the SciNet HPC Consortium. Imbalance was introduced by sampling the cell capacity and impedance values from normal distributions with up to $sigma$=5% capacity/impedance variation at the beginning-of-life. Conventional balancing techniques are found to have little lifetime energy benefit over no balancing. A linearized equivalent circuit model (L-ECM) technique is introduced for small-signal analysis of battery packs with arbitrary capacity and impedance imbalance. An L-ECM-based balancing control is found to have a lifetime discharge energy improvement of up to 53.2% in the worst-case pack lifetime energy over no balancing. The L-ECM balancing control is demonstrated experimentally to provide 9.2% increased single-cycle discharge energy compared to no balancing in a Tesla Model S battery module.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Realization of Signal-Injection Sensorless Control of SMPMSM With
           Saturation-Induced Saliency by Modification of Current Trajectory

    • Free pre-print version: Loading...

      Authors: Yoon-Ro Lee;Yong-Cheol Kwon;Seung-Ki Sul;
      Pages: 13277 - 13287
      Abstract: This article discusses the feasibility of signal-injec- tion sensorless control (SISC) in low saliency surface-mounted permanent-magnet synchronous motors (SMPMSMs). At first, dynamic inductances of a target SMPMSM according to rotor position and dq-axes currents are measured from an experiment. The current response induced by the injected voltage is theoretically calculated based on the inductances. The induced current signal in every operable point on dq current plane is evaluated with a newly defined index variable. An optimal current trajectory for the SISC is proposed after the evaluation. By adopting optimal trajectory control instead of maximum torque per ampere control, the performance of the SISC in the SMPMSM can be conspicuously improved at the cost of slightly increased electrical loss. The proposed method is verified with experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Selective Periodic Disturbance Elimination Using Extended Harmonic State
           Observer for Smooth Speed Control in PMSM Drives

    • Free pre-print version: Loading...

      Authors: Mingjin Hu;Wei Hua;Zuo Wang;Shihua Li;Peixin Wang;Yuchen Wang;
      Pages: 13288 - 13298
      Abstract: The elimination of periodic torque disturbance in permanent magnet synchronous machine (PMSM) drives is a multifrequency control task, and adding resonant parts to the controller has an impact on the robustness of the system. This article aims to address the torque-ripple reduction in PMSM drives for smooth speed control, where an extended harmonic state observer (EHSO) is designed for estimation and attenuation of the selective periodic disturbance. The defects of applying the conventional bandwidth-parameterization method to the harmonic disturbance observer are explored. To improve the disturbance-rejection capability and the relative stability, a pole-placement strategy is proposed and analyzed through sensitivity function, which can preserve the comparable dynamic performance as the conventional extended state observer at the low-frequency range. The proposed EHSO also features easy parameter tuning and a modular structure for multiple harmonic disturbance rejection. Finally, the proposed method is evaluated on a laboratory PMSM platform.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Novel Sensitivity Analysis to Moment of Inertia and Load Variations for
           PMSM Drives

    • Free pre-print version: Loading...

      Authors: Tomasz Tarczewski;Rafal Szczepanski;Krystian Erwinski;Xiaosong Hu;Lech M. Grzesiak;
      Pages: 13299 - 13309
      Abstract: A high-performance electrical drive with a permanent magnet synchronous motor (PMSM) should ensure superior dynamic properties, reasonable load torque compensation, and robustness against parameter variations. The performance investigation related to the dynamic properties is usually made using the step response indicators and integral performance indexes. The robustness evaluation is more complex than performance analysis since there are no simple tools for this purpose, especially if it is done experimentally to consider nonlinearities and unmodeled dynamics of the plant. In this article, sensitivity functions suitable for investigating the closed-loop control systems in the time and the frequency domain are proposed, explained, and experimentally verified. Three control schemes designed for the speed control of PMSM are analyzed: a cascade control structure, robust two-degrees-of freedom speed controller, and a cascade-free constrained state feedback controller. Studies are conducted for experimental responses of the drive in the time and the frequency domain to investigate the sensitivity of the PMSM drive against the moment of inertia and load variations. Analysis of nonlinearities influence on the developed sensitivity functions is also presented.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Sub Line-Frequency Stability Analysis of Single-Phase Constant Power Loads
           Using Envelope Impedance

    • Free pre-print version: Loading...

      Authors: Manuel Gutierrez;Erik K. Saathoff;Eric Ponce;Steven B. Leeb;
      Pages: 13310 - 13318
      Abstract: Regulated constant power loads present an incremental negative input impedance that can destabilize the interconnected system. With ac, power-factor corrected (PFC) constant power loads, instabilities can arise from a dynamic instability between the source and load impedance. The dynamics involving a rectifying interface are nonlinear and evade classical impedance and stability analysis. Several efforts have been made to understand and characterize the important dynamic interaction between ac PFC converters and ac sources. This article unravels this work to present a useful model for an ac PFC converter and a tunable controller that can stabilize source–load interactions. Specifically, an envelope impedance technique is developed for analyzing ac source and PFC load. This article also demonstrates an instability arising from incompatible source and load envelope impedance in hardware, and a variable bandwidth constant power load that can correct the instability.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Impact of Gate Resistance on Improving the Dynamic Overcurrent Stress of
           the Si/SiC Hybrid Switch

    • Free pre-print version: Loading...

      Authors: Xiaofeng Jiang;Huaping Jiang;Xiaohan Zhong;Hua Mao;Zebing Wu;Lei Tang;Haoyu Chen;Jinpeng Cheng;Li Ran;
      Pages: 13319 - 13331
      Abstract: A silicon/silicon carbide (Si/SiC) hybrid switch (HyS), comprised of a high-current Si insulated gate bipolar transistor and a low-current SiC metal oxide semiconductor field effect transistors, gains attention because it offers lower on-state loss under both light and heavy loads. However, the dynamic overcurrent stress experienced by the HyS under the heavy load has to be coped with to avoid reliability degradation and the maximum current rating limitation. This article comprehensively studies how gate resistances regulate the dynamic behavior of the HyS under the heavy load condition. Experiments and analyses are conducted for both turn-on and turn-off processes. It is found that the gate resistance is important for not only the dv/dt control but also the overcurrent suppression. Moreover, the lower switching loss can be achieved by adjusting gate resistances when the HyS operates at a heavy load, compared with the gate timing control. A guideline is developed for the design of the gate resistances. This study offers an insight into the role of gate resistances in switching performances of the HyS and an alternative way of coping with the dynamic overstress stress.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Noninvasive and Accurate Measuring Method of the MMC and HVDC Circuit
           Breaker Action Moment Based on Transient E-Field Pulse

    • Free pre-print version: Loading...

      Authors: Xu Kong;Yan-zhao Xie;Wen-qi Xing;Zhen-dong Sun;Shao-yin He;Li Liu;Peng Qiu;Xiao-jun Ni;Kun Zhang;
      Pages: 13332 - 13342
      Abstract: This article introduces the measurement and analysis of the transient electric field (E-field) derived from the switching operation of the modular multilevel converter (MMC) and the high voltage direct current (HVdc) circuit breaker (CB) in a 200 kV converter station constructed in the Zhoushan Islands, China. It is revealed that the switching transient E-field in the converter station is a quasi-static field. Although the switching E-field pulse is a kind of electromagnetic interference to the secondary electronic circuit of the converter station, it can be used to accurately monitor the action moment of the MMC and the CB. The action moment of the MMC and the CB can be measured with an error of less than 0.005 ms based on the steep pulse front of the switching E-field pulse. This result, which is far more accurate compared to the measurement using the voltage recording system that comes with the converter station. This is of significance to the relay protection of the HVdc transmission system whose fault rapidly develops. Additionally, this method has the advantage of being noninvasive, flexible, and low cost. It has potential application value in the condition monitoring of the MMC and the HVdc CB.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Design of an Indirectly Coupled Filter Building Block for Modular
           Interleaved AC–DC Converters

    • Free pre-print version: Loading...

      Authors: Ripun Phukan;David Nam;Sungjae Ohn;Gopal Mondal;Sebastian Nielebock;Dong Dong;Rolando Burgos;
      Pages: 13343 - 13357
      Abstract: This article presents the analysis and realization of a modular interconnected filter building block (FBB) operating under a single and multichannel (parallel three-phase converter blocks) configuration without loss of attenuation to any harmonic components. Emphasis is on the design of coupled inductor (CI) and boost inductor. In order to achieve a modular scheme with interleaved operation, indirect coupling between converters is realized using the secondary loop (SL)-based interconnection with inserted impedance. Here the “SL” serves as an additional pass for average grid side currents for N channels. A building block type configuration has been proposed using this topology, inspired by the power electronics building block (PEBB) nature. The purpose of the loop is to interconnect the parallel converters in series using an arrangement of CIs. In addition, a boost inductor has been introduced in the SL to realize a power factor correction rectifier operation. The CI serves as the circulating current filter while reflecting channel currents toward the SL. To meet conducted electromagnetic interference (EMI) limits, a two-stage LCLC filter has been integrated with the FBB by introducing the point of common coupling (PCC) connection between two stages for filter size reduction. A design procedure is presented to meet power quality, circulating current, and EMI limits as per industry standards (EN-55011 and IEEE-519/1594). The proposed FBB has been characterized using 3L-NPC converters enabled with 1.2 kV Silicon Carbide based modules with comprehensive performance validation up to three channels in parallel with 15-kW power rating per channel.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • $N$ -Parallel+Modular+Three-Phase+AC–DC+Converters+by+an+Arrangement+of+Coupled+Inductors&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&rft.date=2022&rft.volume=37&rft.spage=13358&rft.epage=13367&rft.aulast=Nielebock;&rft.aufirst=Sungjae&rft.au=Sungjae+Ohn;Ripun+Phukan;Dong+Dong;Rolando+Burgos;Dushan+Boroyevich;Mondal+Gopal;Sebastian+Nielebock;">A Scalable Filter Topology for $N$ -Parallel Modular Three-Phase AC–DC
           Converters by an Arrangement of Coupled Inductors

    • Free pre-print version: Loading...

      Authors: Sungjae Ohn;Ripun Phukan;Dong Dong;Rolando Burgos;Dushan Boroyevich;Mondal Gopal;Sebastian Nielebock;
      Pages: 13358 - 13367
      Abstract: Modularity in hardware improves the manufacturability of power electronics systems and reduces maintenance costs. By paralleling modular ac–dc converters, the current capacity of SiC-based power conversion systems can be easily expanded. However, it is questionable which filter topology can be chosen for an arbitrary number of the converters ($N$). Considering interleaving, filters without any coupling may result in an overdesign. Meanwhile, filters that magnetically couple the paralleled converters may suffer from complexity in mechanical structure and $N-1$ redundancy. Based on these observations, this article proposes a filter structure that can be easily scaled to any number of converters. The proposed structure is comprised of a coupled inductor (CI) forming a loop of secondary windings, a single boost inductor on that loop, and a normally on normally closed (NONC) contactor per converter. Circulating currents are attenuated by the CI for any $N$. A single inductor rated for each channel realizes a boost inductor for a whole $N$-converters, which can bring a significant benefit on power density and cost. When one of the converter faults, the faulty converter can be easily isolated from the system by the NONC contactor, thus achieving $N-1$ redundancy. The proposed filter topology is experimentally verified with a 20-kW full-SiC modular ac–dc converter.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Dynamic Current Balancing Method for Paralleled SiC MOSFETs Using
           Monolithic Si-RC Snubber Based on a Dynamic Current Sharing Model

    • Free pre-print version: Loading...

      Authors: Jianwei Lv;Cai Chen;Baihan Liu;Yiyang Yan;Yong Kang;
      Pages: 13368 - 13384
      Abstract: The dynamic current imbalance between paralleled SiC mosfets will cause unbalanced losses and reduce current capacity. The existing current balancing methods will make the circuit more complex or hard to design and implement. Hence, this article proposes a dynamic current balancing method by connecting monolithic Si-RC snubber between paralleled mosfets, which maintains a simple circuit structure and is easy to implement. Balanced dynamic currents can be achieved by adjusting the RC snubber connecting location. Meanwhile, low voltage spike and low switching oscillation can be achieved by using RC snubber. First, an analytical current sharing model is established for paralleled SiC mosfets. The key parameter affecting the balance of the drive circuit and then affecting the dynamic current sharing is obtained for the first time. Based on the conclusions of the model, this article then presents the current balancing method using RC snubber. Then, a power module with monolithic Si-RC snubber is designed, fabricated, and tested. Experimental results verify the current sharing model and the current balancing method. The current difference of the optimized module is reduced by more than 50% under different conditions. Finally, the effectiveness of this method in the module with more paralleled mosfets is verified.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Secondary-Side Semiactive 3-Phase Interleaved Resonant Converter
           Employing Multimode Modulation Scheme for Fast EV Charger Applications

    • Free pre-print version: Loading...

      Authors: Zhe Shi;Yu Tang;Yuliang Zhang;Yingjun Guo;Hexu Sun;Lin Jiang;
      Pages: 13385 - 13397
      Abstract: A secondary-side semiactive three-phase interleaved (SS-SA3PI) resonant converter employing a multimode modulation scheme for fast EV charger applications is proposed. A multimode modulation scheme is used to widen the output voltage range without dynamic switching problems. By using secondary-side semiactive control, the resonant converter does not need to operate in the fs < fr state to achieve boost operation. The minimum switching frequency of the converter is equal to the resonant frequency, which reduces the size of the magnetic components. Thus, the power density of the converter is improved. Compared with the traditional 3-phase interleaved LLC converter controlled by PFM, this converter widens the output voltage range without adding any circuit components. This article introduces the control mode, working principle and characteristics of the proposed converter in detail. A 10 kW experimental prototype is built to realize the output voltage of 100–1000V, which verifies the feasibility and effectiveness of the scheme.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Partial Power Processing Multiport DC–DC Converter With Radial
           Module Connections

    • Free pre-print version: Loading...

      Authors: Yuwei Liu;Yihua Hu;Guipeng Chen;Huiqing Wen;
      Pages: 13398 - 13412
      Abstract: The partial power processing (PPP) concept has been extensively employed in many two-port converters to achieve high efficiency and high-power density by modifying one of the original converter ports to be connected in series between input and output. This is attractive but is confined to two-port applications, and how to extend it to multiport applications is not clear. Hence, this article aims to explore a generalized PPP multiport scheme by arranging the connection of the module rather than the converter. For a PPP single-input(output)-N-outputs(inputs) converter, one terminal of all N+1 modules is connected together to construct a radial structure, and another terminal is series/parallel connected with the input/output port. Each module only needs to process partial power caused by the voltage or current difference between input and output. Therefore, the required power rating of components is effectively reduced, contributing to low cost as well as low power loss. In this article, a PPP single-input dual-output converter with active bridge modules is also taken as an example to be introduced in detail, designed and experimented upon, which validates that high efficiency and high-power density can be achieved.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • LLC Resonant Converter Modulations for Reduced Junction Temperatures in
           Half-Bridge Mode and Transformer Flux in the On-the-Fly Morphing Thereto

    • Free pre-print version: Loading...

      Authors: Philipp Rehlaender;Oliver Wallscheid;Frank Schafmeister;Joachim Böcker;
      Pages: 13413 - 13427
      Abstract: LLC resonant converters are typically unsuitable to be applied for wide voltage-transfer ratio applications. With a full-bridge inverter, however, they can be operated in a variety of different modulation modes to extend the operating range. Most notably, by permanently turning on one switch and turning off the other switch of the same bridge leg, the LLC can be operated in half-bridge mode reducing the gain by a factor of two. In this modulation, however, the switch that is permanently turned on is stressed by the complete resonant current while exhibiting no switching losses. This article proves that the frequency-doubler modulation can better balance the losses among all switches and should be the preferred mode of operation favored over the conventional half-bridge modulation. This article analyzes the beneficial loss distribution and proposes an on-the-fly morphing modulation to the frequency-doubler modulation and reverse. Furthermore, the morphing magnetizing current offset of the morphing is analyzed to show that the offset can be influenced by the design of the magnetizing inductance and through the morphing modulation itself. Finally, an improved morphing modulation is presented showing that the morphing flux offset can be reduced substantially. Experimental measurement results on a 1.8 kW prototype show that by employing the frequency-doubler modulation, the maximum inverter temperature can be reduced by about 20 K and that the maximum transformer flux deviation during morphing can be reduced significantly on average by 78%. Both results enable the use of switches with a lower on-state resistance and the application of transformers with a smaller core cross-section.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Simplified Approach for Acquisition of Submodule Capacitor Voltages of the
           Modular Multilevel Converter Using Low Sampling Rate Sensing and
           Estimation

    • Free pre-print version: Loading...

      Authors: Bishwajyoti Purkayastha;Tanmoy Bhattacharya;
      Pages: 13428 - 13438
      Abstract: The modular multilevel converter (MMC), used in high-voltage dc applications, consists of hundreds of submodules in each arm. The operation and control of the MMC require sensing of the capacitor voltage of each submodule. The transmission of the sensed data from hundreds of submodules over individual channels leads to wiring complexity. This work suggests that time-multiplexing can be used to transmit the sensed data of multiple submodules across a common serial interface bus. Time multiplexing, however, decreases the sampling rate. Since the submodule capacitor voltage has both ac and dc components, an adequate sampling rate must be maintained to avoid the aliasing of ac components. In this article, an estimation scheme is investigated for reconstructing the ac components of the submodule capacitor voltages within the processing platform, leaving just the dc component to be transmitted over the common bus. The mathematical analysis of the data transmission system and proposed estimation scheme is performed, and the influence on the closed-loop performance is studied. The proposed scheme is experimentally verified in the laboratory.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Bidirectional Five-Level Buck PFC Rectifier With Wide Output Range for
           EV Charging Application

    • Free pre-print version: Loading...

      Authors: Anekant Jain;Krishna Kumar Gupta;Sanjay K. Jain;Pallavee Bhatnagar;
      Pages: 13439 - 13455
      Abstract: AC-to-DC conversion is integral to the two-stage charging interface of electric vehicle (EV) batteries. For such chargers, the use of multilevel rectifiers (MLRs) reduces voltage ratings of power switches, while achieving a high-quality input voltage waveform. Balancing of capacitors in MLRs, however, is an important challenge. In this work, a power factor correction (PFC) five-level rectifier with self-balanced switched capacitors is proposed. Each leg of the presented topology comprises five power switches and one switched capacitor, where the voltage ratings of power switches are equal to the output dc voltage. It does not require an additional filter capacitor on the dc side, as the load appears in parallel always with a switched capacitor of one of the legs. The five-level operation with continuous conduction leads to the elimination of the capacitive filter on the ac-side and inductive filter on the dc-side. This article presents the operating principle, modulation strategy, closed-loop control, and design aspects of the proposed rectifier. The proposed topology is validated through experimental results and a comparison is made with other topologies. Following three features of the proposed topology make it suitable for EV battery charging applications—buck operation with a wide output regulation, the possibility of bidirectional flow of power needed for vehicle-to-grid systems, and easy realization of its three-phase version by simply adding one more leg. These features too have been demonstrated with experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • SVPWM for Five-Level Active Neutral-Point-Clamped Converter Based on
           Multispace Voltage Vector Mapping and Midpoint-Voltage Self-Balancing
           Strategy

    • Free pre-print version: Loading...

      Authors: Qingqing Zhao;Naizhe Diao;Xianrui Sun;Chonghui Song;Xiaolong Zhao;Yongfu Wang;
      Pages: 13456 - 13467
      Abstract: This article proposes a space vector pulsewidth modulation using space voltage vector mapping and the midpoint-voltage self-balancing strategy to overcome the shortcomings of the existing active neutral-point-clamped five-level inverter modulation. Through multispace mapping, the five-level topology is converted into multiple two-level topologies for calculation. It greatly simplifies the computational burden. By adopting the midpoint-voltage self-balancing strategy, the midpoint-voltage self-balance is achieved, since the switching sequence of different sectors compensates each other for balancing the midpoint voltage. Therefore, this algorithm realizes that there is no or only a minimum number of switch tube actions when the reference voltage vector swaps different sectors. It reduces the switching loss and effectively avoids equipment damage caused by the simultaneous switching of multiphase switches. In addition, it also realizes the floating-capacitor voltage control by reasonably distributing the redundant switch states. Simulations and experiments verify the effectiveness of the proposed method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Transformerless High-Gain Three-Port Converter With Low Voltage Stress and
           Reduced Switches for Standalone PV Systems

    • Free pre-print version: Loading...

      Authors: Ling Qin;Tianhong Qian;John Long Soon;Waqas Hassan;Min Tian;Lei Zhou;Lei Ren;
      Pages: 13468 - 13483
      Abstract: This article proposes a high-gain transformerless three-port converter (TPC) for standalone photovoltaic (PV) systems. The TPC is designed and developed based on a dual-inductor high-gain two-port converter by utilizing one of the buffer capacitors to derive the third part for PV input. A hybrid pulse-frequency modulation scheme unified with a pulsewidth modulation control strategy is adopted, which realizes the maximum power point tracking control, load voltage regulation, and bidirectional energy flow at the battery port. The proposed TPC offers the unique advantages of high voltage gain, continuous battery port current, reduced power semiconductors, lower voltage stresses, common ground shared by all the ports, low-cost gate driver, and small size of the rear-end inductor. The working principle, steady-state characteristics, small-signal models, and the control method, including design conditions, are comprehensively analyzed. The correctness of the theoretical analysis is verified by developing a 300-W experimental prototype, which shows that the maximum efficiency is 97.7%.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Dual-Buck Three-Switch Leg Converters With Reduced Number of Passive
           Components

    • Free pre-print version: Loading...

      Authors: Fazal Akbar;Usman Ali Khan;Ashraf Ali Khan;Hafiz Furqan Ahmed;Ahmad Elkhateb;Honnyong Cha;Jung-Wook Park;
      Pages: 13484 - 13498
      Abstract: Like conventional two-switch leg converters, the three-switch leg converters also have short-circuit risks and a dangerous shoot-through current is generated if switches of the same leg are turned on simultaneously. In this article, a new dual-buck structure is proposed for three-switch leg converters. The proposed structure is reliable because of no shoot-through concerns and high quality of output waveforms can be obtained due to the reduction in pulsewidth modulation deadtime. Unlike the conventional dual-buck three-switch leg that uses many passive components such as four current limiting inductors and three external diodes, the new dual-buck three-switch leg uses only one current limiting inductor with two external diodes. To verify the performance, the proposed three-switch legs are used in single-phase dual-output inverter and detailed theoretical analysis, simulation, and experiments are performed. Both continuous and discontinuous modulation schemes are applied and it has been figured out that discontinuous modulation scheme can improve the dc-link voltage utilization in the common-frequency mode of operation.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Quasi-Single-Stage Current-Fed Resonant AC–DC Converter Having
           Improved Heat Distribution

    • Free pre-print version: Loading...

      Authors: Waqar Uddin;Tsegaab Alemayehu Wagaye;Minsung Kim;
      Pages: 13499 - 13512
      Abstract: This article presents a quasi-single-stage current-fed resonant ac–dc converter having improved heat distribution. Secondary-side switches are turned off with the voltage closed to zero at high instantaneous power and with the voltage closed to the half of the output voltage at low instantaneous power. Switching losses at the primary-side bottom switches are reduced; this change improves the heat distribution over the switches. The primary-side duty-cycle fixed at 0.5 results in negligible input current ripple; this trait can significantly reduce the size of filter inductor at the grid side. Experimental results show the effectiveness of the proposed ac–dc converter and its improved heat distribution against a conventional solution.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A High-Precision Sensor Based on AC Flux Cancellation for DC Bias
           Detection in Dual Active Bridge Converters

    • Free pre-print version: Loading...

      Authors: Guanqun Qiu;Li Ran;Hao Feng;Huaping Jiang;Hua Mao;Jinxiao Wei;
      Pages: 13513 - 13524
      Abstract: DC bias in a transformer is a threat to the safe and efficient operation of dual active bridge (DAB) converters. Detecting a dc component in milliamperes mixed with a large ac current is difficult. This article proposes a current sensor based on ac magnetic flux (MF) cancellation. The proposed sensor utilizes a current transformer (CT) to extract the ac component in the measured current. Then, a power op-amp copies the CT signal to an additional winding to generate an ac MF opposite to that of the main ac current. Hence, the sensor range required to measure the dc is greatly reduced for a much smaller absolute measurement error. Using only a CT and a simple op-amp circuit, the proposed solution features low complexity and power consumption. The relative error in a range of 15-A ac current is 0.038%, showing a five-fold improvement compared to off-the-shelf sensors. The proposed sensor is verified on a 1-kW DAB prototype, where the dc bias is suppressed to nearly null owing to the proposed sensor.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Lifetime-Based Selection Procedures for DC Circuit Breaker Varistors

    • Free pre-print version: Loading...

      Authors: Zhi Jin Zhang;Matthew Bosworth;Chunmeng Xu;Andrew Rockhill;Peter Zeller;Maryam Saeedifard;Lukas Graber;Michael Steurer;
      Pages: 13525 - 13537
      Abstract: Varistors are widely used in dc circuit breaker (DCCB) application as fault energy absorption elements, which is not an application the varistors are originally designed for. The fault energy stress adversely impacts the varistor lifetime, thus affecting DCCB reliability and performance. This article presents two methods for choosing the appropriate varistor type and arrangement in a DCCB by linking 1) varistor lifetime and 2) DCCB component- and system-level parameters. The first method uses a set-based design approach with random Latin hypercube sampling to narrow down viable solutions. In comparison, the second method relies on a point-based design approach and proposes an integer programming problem to optimize varistor lifetime. Both procedures are applied to the selection of varistors in 1) a 12 kV DCCB rated for 2-kA nominal current and a peak fault current of 15 kA and 2) a reduced-scale 1.2-kV DCCB hardware prototype, using publicly available varistor data. The article shows the possibility of design for varistor lifetime in DCCB applications, and concludes that both selection procedures provide consistent, reasonable, and verifiable results. However, the results also pinpoint the significant gaps and call for future work on impulse stress versus lifetime relationships for DCCB varistors.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • In-Depth Design and Multiobjective Optimization of an Integrated
           Transformer for Five-Phase LLC Resonant Converters

    • Free pre-print version: Loading...

      Authors: Jianing Wang;Jiawen Hu;Wei Pei;Zhiqing Yang;Jiacai Zhuang;Xing Zhang;
      Pages: 13538 - 13553
      Abstract: High-power isolated dc–dc converters are preferred in the medium-voltage cascaded H-bridge (CHB) photovoltaic (PV) generation systems due to high power density and galvanic isolation. However, high-power transformers in dc–dc converters can result in high power losses and poor heat dissipation due to thick isolation materials. The three-phase LLC (3P-LLC) converter has been reported suitable for high power applications. Comparing to the single-phase counterpart, the 3P-LLC converter employs three discrete transformers, leading to a larger core area for better heat dissipation. To further increase the power density and the heat dissipation capability of resonant converters, increasing the phase number and integrating magnetic components are considered. This work proposes a five-phase LLC (5P-LLC) resonant converter for the CHB PV application. To increase the power density, a five-phase magnetic integrated transformer (5P-MIT) is proposed and designed with an optimal limb structure to avoid local flux saturation. To further increase the power density, reduce the transformer losses, and enhance the heat dissipation capability, multiobjective optimization is developed to meet multiple design requirements simultaneously. A design case is studied to show the advances of the proposed 5P-MIT. To further investigate the proposed 5P-LLC, a down-scaled prototype is developed with a 5P-MIT. Experiments are conducted to verify the analyses and the functionality.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Inverter Design Considerations for Variable-Pole Induction Machines in
           Electric Vehicles

    • Free pre-print version: Loading...

      Authors: Elie Libbos;Elisa Krause;Arijit Banerjee;Philip T. Krein;
      Pages: 13554 - 13565
      Abstract: This article proposes a generalized inverter design framework for a variable-pole induction machine (IM). It quantifies the advantages of pole changing and a high number of inverter legs on converter efficiency and size. The framework is used to design an 18-leg drive that reconfigures a six-pole IM to four- and two-pole while increasing torque capability at maximum speed by a factor of 2.2 compared to a conventional 3-leg fixed-pole design. The framework also shows that a three-leg drive must be oversized by a factor of 1.5 to reach the same torque capability using an identical-sized machine. The proposed 18-leg drive has 50% less losses and requires 62% less dc-link capacitance compared to a 3-leg converter. The framework is used to propose a loss minimization method for the combined machine and converter, with pole count as an operational degree of freedom at partial load and high speed. As a result, variable-pole operation reduces combined machine and drive losses by up to 45% compared to a conventional three-leg drive with the same IM. An 18-leg experimental GaN-based 890 VA inverter driving a toroidally wound IM was designed, built, tested, and compared to a 3-leg inverter to validate the proposed framework.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Comparative Analysis and Optimization of Novel Pulse Injection Sensorless
           Drive Methods for Fault-Tolerant DC Vernier Reluctance Machine

    • Free pre-print version: Loading...

      Authors: Weiyu Wang;Xing Zhao;Shuangxia Niu;Weinong Fu;
      Pages: 13566 - 13576
      Abstract: Multiphase dc-excited Vernier reluctance machine (DC-VRM) exhibits the merits of robust structure, small torque ripple, and good fault-tolerant ability. Developing advanced sensorless drive methods can further promote its application in the safety-critical system. In this article, pulse injection sensorless drive methods are optimized in a six-phase DC-VRM parallel H-bridge drive system to strengthen their acceleration performance and fault-tolerant ability. The acceleration performance studied in this article corresponds to the acceleration speed during the startup stage. By the full-phase alternative pulse injection method (APIM), each phase can be excited independently to avoid mutual-inductance influence on position estimation, but this method suffers from a long communication delay and relatively poor acceleration performance. A reduced-phase APIM can reduce detection time, but the lack of detected phase may influence position estimation accuracy and fault-tolerant ability. To solve these problems, a novel vertical-axis synchronous pulse injection method is proposed and compared with previous methods in this article. The key is to inject detection pulses into vertical-axis phases simultaneously, thus reducing the detection time and improving the torque generation. It is proved that the influence of mutual inductance on position estimation can be ignored, and the detection accuracy and acceleration performance can be improved without deterioration of fault-tolerant ability.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Short-Circuit Characteristic of Single Gate Driven SiC MOSFET Stack and
           Its Improvement With Strong Antishort Circuit Fault Capabilities

    • Free pre-print version: Loading...

      Authors: Rui Wang;Asger Bjørn Jørgensen;Hongbo Zhao;Stig Munk-Nielsen;
      Pages: 13577 - 13586
      Abstract: The single gate driven series connected power device stack possesses the advantages of high compactness and low cost. However, research of its short circuit (SC) characteristic remains uncovered. This article fills this gap and points out that, with the single gate driver it has the potential of over-current limitation. Furthermore, based on it, an improved single gate driven silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (mosfet) stack with strong antishort circuit fault capabilities is proposed. By adding auxiliary circuits to adjust the driving process of the single gate driver, the SiC mosfet stack can be automatically turned off in both SC conditions of fault under load and hard switch fault, while the normal working principle of the stack is not influenced. Neither active control nor overcurrent detection is required, which is the biggest merit of the proposed topology. Its design and analysis are presented in detail, followed by the validation by conducting simulations and experiments.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Sensorless Control Strategy of Injecting HF Voltage Into d-Axis for
           IPMSM in Full Speed Range

    • Free pre-print version: Loading...

      Authors: Shifan Dong;Minglei Zhou;Xiaojie You;Chenchen Wang;
      Pages: 13587 - 13597
      Abstract: This article presents a sensorless control strategy by injecting high-frequency (HF) voltage into the d-axis for the interior permanent magnet synchronous motor (IPMSM) in the full speed range. The defined quadratic virtual back electromotive force model can be adopted in the full speed range, and thus, there is no need to design a transition algorithm from the zero–low speed to the medium–high speed. Besides, the accurate model of IPMSM is applied to eliminate the error caused by ignoring the stator resistance. Furthermore, the estimation error caused by the filter and system delay during demodulating the HF current in the conventional HF voltage injection method is avoided. Compared with the method of injecting HF voltage into the q-axis, the proposed method has smaller torque ripple and smaller injected voltage. The effectiveness of the proposed method is verified by experimental results.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Maximum Torque Per Total Ampere Strategy for Vector-Controlled Brushless
           Doubly Fed Induction Machine Drive Taking Iron Loss Into Account

    • Free pre-print version: Loading...

      Authors: Hamidreza Mosaddegh Hesar;Hossein Abootorabi Zarchi;Gholamreza Arab Markadeh;Amir Khazaee;
      Pages: 13598 - 13605
      Abstract: The aim of this study is to introduce the maximum torque per total ampere (MTPTA) control strategy for brushless doubly fed induction machine drives taking iron loss into account. In this regard, the condition for realizing the MTPTA is investigated in the presence of iron loss by a theoretical approach. It is shown the proposed strategy is realized when the MTPTA criterion tracks zero as reference signal. As a result, the current is not only shared between the stator windings fairly but also total stator currents are minimized for a given torque. The experimental results confirm the performance of the proposed control strategy.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Performance and Analysis of N-State Random Pulse Position SVPWM With
           Constant Sampling Frequency

    • Free pre-print version: Loading...

      Authors: Peiran Zhang;Shanming Wang;Yituo Li;
      Pages: 13606 - 13625
      Abstract: Random pulsewidth modulation (RPWM) with variable carrier frequency generally disperses the dominant PWM harmonics more effectively than the RPWM with constant carrier frequency. But variable carrier frequency results in variable sampling frequency, which changes controller parameters and makes RPWM difficult to use in closed-loop applications. To significantly disperse dominant harmonic clusters located nearby the PWM frequency and its multiples, while maintaining constant sampling frequency, in this article, N-state random pulse position space vector pulsewidth modulation is proposed. This method randomly selects one of the N selected carrier patterns with equal probability in each carrier period, resulting in N different pulse position states. By applying two-dimensional Fourier analysis, the additional multiplication factor in the derivation results, named harmonic dispersion coefficient in this article, can intuitively explain the principle from the perspective of mutual cancellation of complex vectors in different directions. All dominant PWM harmonics are significantly dispersed except those located nearby the Nth PWM frequency and its multiples when using the proposed method. Besides, power losses and switching counts are detailed discussed. Both simulation and experimental results verify the effectiveness of the method at last.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Reconsideration on Capacitor Ripple Voltage of CHB-StatCom: Observation,
           Modeling, Analysis, and Application of Ripple Effect From Design
           Perspective

    • Free pre-print version: Loading...

      Authors: Qianhao Sun;Qiang Song;Biao Zhao;Zhanqing Yu;Jingwei Meng;Bin Cui;Zhengxuan Li;Rong Zeng;
      Pages: 13626 - 13640
      Abstract: The ripple effect phenomenon wherein the capacitor ripple voltage generates the fundamental-frequency output ac voltage of a cascaded H-bridge-based static synchronous compensator (CHB-StatCom) is revealed and investigated in this work. First, an observation method of the ripple effect for the CHB-StatCom is presented. Then, the reason why CHB-StatCom has a ripple effect is explained. Subsequently, the accurate mathematical model of the CHB-StatCom considering ripple effect is reformulated. Based on the remodeled mathematical model, the cognition inaccuracy of the conventional design of a CHB-StatCom is analyzed, and a new cost-majorization-oriented (CMO) design principle is proposed to optimize the cost of CHB-StatCom. The proposed CMO design needs a lower dc-link voltage to generate the same maximum fundamental-frequency output ac voltage compared with the conventional design, thereby reducing the cost of CHB-StatCom. The simulation and experimental results validate the correctness and effectiveness of the analysis.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Influence of Thermal Coupling on Lifetime Under Power Cycling Test

    • Free pre-print version: Loading...

      Authors: Yushan Zhao;Erping Deng;Maoyang Pan;Yiming Zhang;Yongzhang Huang;
      Pages: 13641 - 13651
      Abstract: In this article, the influence of thermal coupling in power modules on lifetime under power cycling test (PCT) is investigated. In a full-bridge power module for electric vehicle application, the thermal coupling is strong due to high power density and causes lateral temperature difference. In PCT, at the same maximum junction temperature Tvjmax and temperature swing ΔTvj, the influence of thermal coupling on lifetime and failure mode is investigated. The root cause of why thermal coupling influences lifetime and the failure mode is discussed by finite-element analysis. Transient thermal impedance is used to calibrate the simulation model. The Influence of thermal coupling on chip surface and solder layer temperature distribution is analyzed under the same test conditions. Furthermore, two parameters are extracted from the temperature distribution of chip surface as flags of failure mode determination. Finally, taking thermal coupling into account, combined with direct copper bonding structure, an improved layout is recommended in terms of lifetime.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Universal Sensorless Open-Circuit Fault Detection and Isolation Method of
           Dual-Active-Bridge Converters With Low-Cost Diagnostic Circuit

    • Free pre-print version: Loading...

      Authors: Shahamat Shahzad Khan;Huiqing Wen;
      Pages: 13652 - 13667
      Abstract: As one of the promising power interfaces between the energy storage components and the dc link, dual active bridge (DAB) converters have gained extensive researches. Its reliability and healthy operation under one or even multiple unexpected open-circuit faulty conditions have become one of the main design challenges. Conventional fault detection (FD) and fault isolation (FI) methods exhibit obvious limitations in terms of detection speed, number of FD signatures, universality, accuracy, computational burden, and implementation cost due to the added sensors. To fill in this gap, this article presents a robust, fast, accurate, and low-cost FD and FI method for DAB converters, which is applicable under various operational conditions. The proposed method will adopt the differential switch node voltage between the primary and secondary bridge of DAB converters as the universal fault signature for complete FD and FI. The corresponding fault diagnostic circuit is simple, compact, low cost, and easy in implementation. This sensorless fault diagnostic technique can detect the switch open-circuit fault within a quarter of a switching cycle and realize the fault isolation accurately. A DAB prototype with a fault diagnostic circuit was designed, and main experimental results under various faulty conditions were provided to validate the advantages of the proposed method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Open-Circuit Fault Diagnosis Method in NPC Rectifiers Using Fault-Assumed
           Strategy

    • Free pre-print version: Loading...

      Authors: Mingyun Chen;Yigang He;
      Pages: 13668 - 13683
      Abstract: This article proposes a new open-circuit (OC) fault diagnosis method for power switches in three-level neutral-point-clamped (NPC) rectifiers. This method is based on fault assumption by introducing a new voltage deviation for diagnosis, which is the difference between the switching-state-based voltage and the fault-assumed-based voltage, where the fault-assumed-based voltage is the estimated pole voltage when all inner switches are assumed to be in the OC state. After average and sum operations, diagnostic variables are developed from three-phase voltage deviations without extra hardware and precise modeling. Since the fault characteristics of each switch reflected by diagnostic variables are not changed by other concurrent OC faults, multiple-switch faults can be diagnosed in the same way as single-switch faults. As a result, the proposed method can detect both single-switch and multiple-switch faults without complex diagnostic rules and procedures. Besides, adaptive thresholds are designed by considering voltage imbalance, current amplitude, and power factor. Owing to the self-adjusting characteristics of thresholds, the proposed method provides reliable diagnostic results in various operating states of NPC rectifiers and has good robustness against transient changes. Experiments are performed to confirm its effectiveness and robustness.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Data-Driven Method With Mode Decomposition Mechanism for Remaining
           Useful Life Prediction of Lithium-Ion Batteries

    • Free pre-print version: Loading...

      Authors: Jianguo Wang;Shude Zhang;Chenyu Li;Lifeng Wu;Yingzhou Wang;
      Pages: 13684 - 13695
      Abstract: Lithium-ion batteries offer excellent advantages of high efficiency, small size, and low cost, but their instability and inconformity remain challenging. Sudden failure of batteries may cause serious accidents, endangering the safety of people’s lives and properties. Advanced remaining useful life prediction methods for batteries can effectively avoid those accidents. In this article, we proposed a novel hybrid method with the purpose of enhancing battery remaining useful life prediction precision and robustness. Based on improved complete ensemble empirical mode decomposition with adaptive noise algorithm, utilizing a special-designed interpolation reconstruction mechanism, the battery capacity degradation series was decomposed into a trend subseries and several fluctuation subseries. Weighted least square support vector machine and long short-term memory network are then established to perform prediction for the trend subseries and the fluctuation ones, respectively. A complementary series of experiments is designed to verify the effectiveness of the proposed method. The simulation results represent that the proposed method achieves higher prediction accuracy and robustness over other comparison models. The proposed approach provides a promising and effective alternate for lithium-ion batteries remaining useful life prediction without relying on the cell dynamic process, which is meaningful for cases with limited measurement parameters or limited computational power.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A High Voltage Gain ZVT Quasi-Z-Source Converter With Reduced Voltage
           Stress

    • Free pre-print version: Loading...

      Authors: Milad Heidari;Morteza Esteki;Sayed Ali Khajehoddin;Hosein Farzanehfard;
      Pages: 13696 - 13710
      Abstract: In this article, a new high voltage gain quasi-Z-source (QZS) dc–dc converter suitable for renewable energy applications is presented. The proposed converter utilizes a zero voltage transition auxiliary circuit with coupled inductors to provide soft-switching conditions for all switches for a wide range of output power. In addition, a switched capacitor circuit is employed to obtain a higher voltage gain and lower voltage stress. The main advantages of the proposed converter include high voltage gain, high efficiency, reduced switch and diode voltage stress, continuous input current, and common ground between the output and input, which are important features for photovoltaic applications. In this circuit, the reverse recovery problem of diodes is alleviated. Operating principles and design considerations of the proposed converter are analyzed. Moreover, to prove the validity of the theoretical analysis, a 200-W prototype of the proposed converter is implemented and the experimental results are shown.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Analytical Damping Contribution Assessment Method of Multiconverters
           System Based on Energy Network Model

    • Free pre-print version: Loading...

      Authors: Letian Wang;Jing Ma;Peng Cheng;Hongfei Shao;Yaqi Shen;
      Pages: 13711 - 13729
      Abstract: Multiconverters connected to grid can induce subsynchronous oscillation (SSO). This article proposed an analytical damping contribution assessment method that can explicitly reveal how (positively or negatively) and to which degree each converter in the multiconverters system changes the system stability level. First, the energy network model of the multiconverters system that satisfies energy conservation is proposed. On this basis, a theory proof is presented that the real part of eigenvalue of SSO mode in the multiconverters system is equal to the sum of coefficient in the aperiodic components of the derivative of dynamic energies injected by each converter and dissipation energy of network, which illustrates analytically how the SSO stability level is shaped. The dynamic energy showing a decreasing trend is good for the oscillation to disappear, and the faster the dynamic energy decreases, the faster the oscillation amplitude decreases. Thus, how and to which degree converter changes stability level can be revealed by the changing trend and rate of its dynamic energy, respectively. Moreover, the expression of dynamic energy is brief, which is, thus, readily for online use, and is universal for converters with different control strategies. Finally, hardware in loop tests verifies that, eliminate converters’ rapidly increasing dynamic energy, the unstable SSO converges rapidly, and eliminate converters’ slowly increasing dynamic energy, the unstable SSO converges but slowly, and eliminate converters’ decreasing dynamic energy, unstable SSO diverges more rapidly, which demonstrates that dynamic energy can precisely assess damping contribution of converter.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Fixed-Frequency Phase-Shift Modulated Capacitor-Clamped LLC Resonant
           Converter for EV Charging

    • Free pre-print version: Loading...

      Authors: Jiayang Wu;Sinan Li;Siew-Chong Tan;Shu Yuen Ron Hui;
      Pages: 13730 - 13742
      Abstract: LLC resonant converter has been widely employed in electric vehicle (EV) charging applications. However, conventional frequency-modulated LLC converters generally demand a wide frequency variation range and are difficult to scale up, while the traditional phase-shifted (PS) LLC converters have the issues of ease of losing soft-switching condition and high turn-off current. In response to these challenges, this article proposes a new method for EV charging applications based on the capacitor-clamped LLC converter topology and fixed-frequency PS modulation. Compared with traditional PS LLC converters, the proposed method can achieve 1) smaller phase shift variation range, 2) lower turn-off current, and 3) wider soft switching range, resulting in higher efficiency. An 825-W prototype with 200 V input and 125–210 V output range verified the features of the proposed idea, and the efficiency reaches 97.82% at the maximum output power.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Single Grid-Current Sensor-Controlled Weak-Grid-Following Inverters: A
           State-and-Disturbance-Observer-Based Robust Control Scheme Achieving
           Grid-Synchronization and Disturbance Rejection

    • Free pre-print version: Loading...

      Authors: Cheng Cheng;Shaojun Xie;Lin Tu;Lingjuan Tan;Qiang Qian;Jinming Xu;
      Pages: 13743 - 13754
      Abstract: With the aim of reducing the number of sensors, this article investigates the single-sensor grid-following control for the LCL-filtered inverter system, and proposes an intuitive robust stability analysis method in the linear framework to handle power control and grid voltage variations in engineering practice. Specifically, through the use of a state-and-disturbance observer, the lumped-disturbance compensated suppression and nominal system full-state feedback technologies are equivalently realized. And the lumped-disturbance estimation carrying voltage phase information at the point of common coupling is further used as synchronization target of the phase-locked loop (PLL) to achieve grid-following control, and the resulting phase-shift is further corrected by accurate phase compensation. In addition, due to the nonlinear nature of the PLL and the power control and grid voltage variations, the system analysis is faced with the dilemma of complex nonlinear analysis or small-signal analysis without a fixed equilibrium point. In this case, a PLL small-signal model with bounded parameter perturbation characterizing power control and grid voltage variations is developed, and further incorporated into the output impedance modeling of the single-sensor grid-following controlled inverter. According to the edge theorem, the system stability in the studied uncertain region is analyzed via four edge output impedances, and appropriate control parameters are selected accordingly. Finally, the experimental results from a downscaled prototype are provided to verify the effectiveness of the proposed single-sensor grid-following control scheme.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Zero Leakage Current Single-Phase Quasi-Single-Stage Transformerless PV
           Inverter With Unipolar SPWM

    • Free pre-print version: Loading...

      Authors: Fan Peng;Guohua Zhou;Nengmou Xu;Siya Gao;
      Pages: 13755 - 13766
      Abstract: Power inverters for distributed photovoltaic (PV) power generation systems usually need to fulfill several requirements, e.g., the safety, the voltage boost capability, and the reduced volume and the cost. An improved transformerless single-phase quasi-single-stage common-mode PV inverter with four switches and an improved unipolar modulation strategy are proposed in this article. The inverter features double-grounded to solve potential safety issues caused by the leakage current. In addition, its voltage boosting is accomplished by a quasi- single-stage conversion structure so that PV system efficiency can be improved. Meanwhile, it benefits continuous input current so is suitable for PV application. In this article, the operation principle of the proposed inverter, the improved modulation strategy, and two grid-tied control strategies are introduced. The voltage and current stresses of the components are analyzed, and parameter design guideline is further given. Both the off-grid and grid-tied experiments were conducted to verify the theoretical analysis.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Flexible Transfer Converters Enabling Autonomous Control and Power
           Dispatch of Microgrids

    • Free pre-print version: Loading...

      Authors: Ronghui An;Jinjun Liu;Zeng Liu;Zhaoqi Song;
      Pages: 13767 - 13781
      Abstract: For grid-connected or interconnected microgrids, the transition to an autonomous and decentralized architecture was hampered by two perplexing issues: how to guarantee voltage-supporting capacity, while fully and controllably utilizing local power generation, and how to switch between islanded and grid-connected modes flexibly and seamlessly. Through a combination of benefits of interlinking converters and switches, the flexible transfer converters (FTCs), positioned at the interfaces between the utility grid and microgrids, are offered as a solution in this article. The basic concepts and classifications of the FTC are first presented, and a general-purpose FTC and a universal control strategy for distributed generations are then proposed as an example, which contribute to appropriate power dispatch and flexible mode transfer in a communication-free design, leading to a fully autonomous microgrid. Simple and economic operation rules, as well as high interoperability with existing assets, makes this solution promising for distributed microgrid applications. Further, generalized small-signal models of the target system are derived for stability analysis and parameter design. Finally, comprehensive case studies in simulations and experiments are provided to validate its effectiveness.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • An Interleaved Soft Switched High Step-Up Boost Converter With High Power
           Density for Renewable Energy Applications

    • Free pre-print version: Loading...

      Authors: Ramin Rahimzadeh Khorasani;Hamed Moradmand Jazi;Nilanjan Ray Chaudhuri;Arash Khoshkbar-Sadigh;Mahdi Shaneh;Ehsan Adib;Patrick Wheeler;
      Pages: 13782 - 13798
      Abstract: In this article, a novel soft switched interleaved boost structure with a simple auxiliary circuit is proposed which is suitable for stand-alone loads or ac grid applications. In this topology, coupled inductors and switched capacitor cells of parallel modules are merged to obtain high voltage conversion ratio. The converter also has the capability of adding extra switched capacitor cells to attain very high voltage gain. To provide soft-switching condition in the wide range of output power, a new zero-voltage transition auxiliary circuit is employed which is responsible for soft switching of both phases and benefits from low conduction losses, the minimum number of semiconductor elements, and only one auxiliary gate-driver. These merits provide very high efficiency at both full-load and light loads. More importantly, no auxiliary magnetic components are utilized by taking advantage of the leakage inductance of coupled inductors for the resonant network. All semiconductor components operate under soft switching alleviating the reverse recovery problem and switching losses. Besides, the converter benefits from common ground between input and output which simplify voltage feedback. The experimental results of the interleaved converter prototype with 400-V output voltage at 400 W and 100 kHz switching frequency are provided. The full load efficiency of 98% was achieved and the power density was observed 1.9 W/Cm3.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Power Model Free Voltage Ripple Suppression Method of Three-Phase PWM
           Rectifier Under Unbalanced Grid

    • Free pre-print version: Loading...

      Authors: Tianbao Song;Yun Zhang;Fei Gao;Xinshan Zhu;Jiali Shan;Zhiguo Kong;
      Pages: 13799 - 13807
      Abstract: Under the condition of the unbalanced grid, the second-order harmonic voltage ripple exists on the dc bus of the three-phase PWM rectifier. In this article, the internal relationship between the dc bus voltage ripple and the dc bus impedance is revealed. In addition, this article proposes a voltage ripple suppression method free from the power model, which can improve the system robustness against the parameter variations. By shaping the dc bus impedance, the voltage ripple is effectively suppressed without adding additional devices. In addition, the design criterion and the implementation of the virtual capacitor are analyzed in detail. Finally, experimental results show the accuracy of the theoretical analysis and the effectiveness of the proposed method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Tri-Port Current-Source Soft-Switching Medium-Voltage String Inverter
           for Large-Scale Solar-Plus-Storage Farms

    • Free pre-print version: Loading...

      Authors: Zheng An;Xiangyu Han;Vikram Roy Chowdhury;Joseph Benzaquen;Rajendra Prasad Kandula;Deepak Divan;
      Pages: 13808 - 13823
      Abstract: This article presents a tri-port current-source soft-switching medium-voltage string inverter (TMVSI) to reduce the Levelized cost of energy (LCOE) of large-scale solar-plus-storage (SPS) farms. Throughout this work, the topology, operating principle, circuit simulation, control, and hardware design of the TMVSI are introduced. In addition, three key challenges compromising the performance of the TMVSI are addressed in this article. First, a new feed-forward compensation for model predictive control of the TMVSI is proposed to compensate for sampling and computational delay and high dc-link ripple with low computational cost and high scalability. Second, the use of laminated permanent magnets is proposed to reduce the losses of the MV medium-frequency transformer (MFT) in the TMVSI while increasing its saturation current. Finally, an improved U-shape winding pattern is proposed to decrease the leakage inductance of the MV MFT and reduce the voltage stress across semiconductor switches without adding cost or complexity. The effectiveness of the TMVSI is validated by experiments at up to $20,mathrm{kW/500,V}$ in different test cases with custom-built prototypes. The contributions of this work make the TMVSI a viable solution to SPS farms and unleash its potential for LCOE reduction.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Efficient and Fast Active Equalization Method for Retired Battery Pack
           Using Wide Voltage Range Bidirectional Converter and DBSCAN Clustering
           Algorithm

    • Free pre-print version: Loading...

      Authors: Wang Lujun;Ke Jinyang;Zhan Min;Tian Aina;Wu Tiezhou;Zhang Xiaoxing;Jiang Jiuchun;
      Pages: 13824 - 13833
      Abstract: This article presents an efficient and fast echelon battery equalization method based on wide voltage range bidirectional converter combined with DBSCAN (density-based spatial clustering of applications with noise) clustering control strategy. Thanks to the wide voltage range and bidirectional buck-boost characteristics of the four-switch bidirectional converter, the battery energy can be reasonably redistributed between the battery and the super capacitor. The converter operating in synchronous rectification mode can not only achieve bidirectional energy flow in a wide voltage range, but also has a high energy conversion efficiency. The DBSCAN clustering algorithm is used to divide all battery cells into groups, and each group may contain one or more adjacent and nonadjacent battery cells. First, the nonadjacent single cells are balanced and integrated into adjacent group with the closest voltage. Then, the groups with different voltages are balanced by group-to-group, thereby realizing rapid balance of the entire battery pack. In order to verify the effectiveness of the proposed method, simulations and experimental verification were carried out. The experimental results show that, comparing with traditional battery balancing methods, the proposed method achieves shorter balancing time and higher balancing efficiency.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Cascaded Controller for Controlling DC Bus Voltage in Mismatched Input
           Powers

    • Free pre-print version: Loading...

      Authors: Mohammad Afkar;Roghayeh Gavagsaz-Ghoachani;Matheepot Phattanasak;Serge Pierfederici;
      Pages: 13834 - 13847
      Abstract: The lack of uniform production of panels in photovoltaic (PV) systems and snowball effects in fuel cell (FC) systems led us to use a separate dc–dc converter. In addition, in the PV and FC systems, the output voltage is low. Hence, dc–dc boost converters are commonly used in a series connection. Each small unit of a PV or FC operates independently. Therefore, another problem arises in the system that uses the series connection of the converter's output. Owing to the unequal electricity production of the cells, a voltage imbalance occurs at the output terminals. To create voltage balance, a modular structure grounded on a three-level boost converter was investigated. The main objective of this article is to design the control of a modular topology, allowing perfect control of the dc-bus voltage, even with mismatched input powers. The proposed control strategy ensures dynamical properties independent of the operating point, voltage balance, and robust control of the dc output voltage with respect to load perturbations. To ensure the balance of voltages and the control of currents, a sliding mode controller based on indirect synthesis was used. To control the dc–bus voltage, an energy controller is proposed that ensures dynamical performance independent of the operating conditions. The performance in terms of tracking and regulation, as well as its effect on the voltage balance of the output capacitors, was validated through simulations and experimental results. A comparison with a classical proportional integral (PI) approach for controlling the dc-bus voltage was performed.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Passivity-Based Multisampled Converter-Side Current Control of
           LCL-Filtered VSCs

    • Free pre-print version: Loading...

      Authors: Shan He;Dao Zhou;Xiongfei Wang;Frede Blaabjerg;
      Pages: 13848 - 13860
      Abstract: With the gradually decreasing cost of high-performance digital processors, multisampling current control is a potential method to reduce the control delay and improve the stability in LCL-filtered grid-connected converters. In the practical implementation, an antialiasing filter is required to remove the sampled switching harmonics and suppress the low-order aliasing. However, due to the phase lag from the antialiasing filter, the dissipative region of converter output admittance still cannot be lifted to switching frequency, which leads to a risk of system instability under wide grid admittance variation. In order to tackle this challenge, a filter capacitor voltage feedforward scheme using multisampling is proposed in this article. Consequently, the dissipation below the switching frequency is harvested for a three-phase converter. Furthermore, by doubling the multisampling rate, the proposed method can extend the dissipative region to the apparent switching frequency for a single-phase converter using unipolar modulation. The experimental results validate the effectiveness of the proposed method on a down-scaled single/three-phase converter.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Zero-Voltage Switching Regulation Strategy of Full-Bridge Inverter of
           Inductive Power Transfer System Decoupled From Output Characteristics

    • Free pre-print version: Loading...

      Authors: Jin Cai;Xusheng Wu;Pan Sun;Qijun Deng;Jun Sun;Hang Zhou;Xiaona Wang;
      Pages: 13861 - 13873
      Abstract: The soft switching of power components in inductive power transfer systems can reduce switching loss and switching stress and decrease electromagnetic interference. However, the realization of soft switching in an inductive power transfer system may change the system's constant voltage and constant current output characteristics. For this reason, in this article, a zero-voltage switching technology based on a full-bridge inverter that is decoupled from the output characteristics of the system is proposed and validated. First, the basic conditions for the full-bridge inverter to achieve zero voltage switching are derived by analyzing the working mode of the full-bridge inverter circuit. Then, the constant current, constant voltage output, and zero phase angle input conditions of a first-order/second-order/third-order compensation structure are studied using the high-order two-port network cascading rule. On this basis, a parameter adjustment strategy for an arbitrary compensation structure is proposed to achieve zero voltage switching without affecting the output. Then analytical verification of the constant current output characteristics of a double-sided inductor-capacitor-capacitor compensation structure is performed as an example. Finally, a MATLAB/Simulink model and a set of 3.3 kW prototypes are established to verify the correctness of the theoretical analysis.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Widening the Operating Range of a Wireless Charging System Using Tapped
           Transmitter Winding and Bifrequency Pulse Train Control

    • Free pre-print version: Loading...

      Authors: Xiaoqiang Wang;Liangxi He;Jianping Xu;Chi Kwan Lee;
      Pages: 13874 - 13883
      Abstract: In this article, a subharmonics switching technique named bifrequency pulse train (BF-PT) control for wireless battery charging system with tapped transmitter (Tx) winding is proposed to regulate the output power against the variation of load and coupling coefficient. The tapped Tx winding is spilt into two subwindings: subwinding I is connected to the inverter while subwinding II is in open circuit. The charging current and charging voltage can be acquired by measuring the induced current of subwinding I and the induced voltage of subwinding II, respectively, without dual-side communication. BF-PT control, which contains high- and low-frequency pulse trains, can achieve zero voltage switching over a wide operating range. The high- and low-frequency pulse trains are uniformly distributed to suppress the winding current oscillation and to minimize the output voltage ripple. When the coupling becomes weaker and/or light-load conditions, the switches are operated at the subharmonics frequency to further reduce the average switching frequency of the system. To verify the validity of the proposed method, a wireless charging system with 72 V/3 A output is fabricated. The experimental results confirmed that the proposed method is able to maintain constant current and constant voltage output regardless of the load and coupling variations.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Unipolar-Duty-Cycle Hybrid Control Strategy of Series–Series
           Compensated IPT System for Constant-Current Output and Efficiency
           Optimization

    • Free pre-print version: Loading...

      Authors: Yafei Chen;Hailong Zhang;Nan Jin;Leilei Guo;Jie Wu;Sung-Jun Park;Dong-Hee Kim;
      Pages: 13884 - 13901
      Abstract: Based on the unipolar-duty-cycle (UDC) modulation technique, this article presents a hybrid control strategy for a series–series compensated inductive power transfer (IPT) system. By adjusting the duty cycle and the operating frequency, zero-voltage switching (ZVS) and constant-current output (CCO) can be achieved with varying coupling coefficients and load. Furthermore, as the proposed strategy enables the IPT system to lower the frequency of operation, it provides higher efficiency in the overall output power range than the conventional variable-frequency control methods. The basic principle of the UDC control strategy and its characteristics are introduced, and the system performance under UDC is analyzed and compared with the performance achieved by conventional control methods. Based on this, the UDC closed-loop control scheme, which combines PI control and hysteresis control, is proposed for the dynamic tracking of the ZVS and the CCO under a wide range of coupling coefficients and load. To validate the practicability of the proposed control strategy, a 500-W experimental prototype is configured. The simulation and experimental results indicate that the proposed scheme can stably and accurately track the ZVS and the CCO under varying parameter conditions, and it significantly improves the system efficiency. Especially, the system efficiency is improved by approximately 1.75% under light-load conditions as compared with that of the conventional control method. In addition, since the proposed method employs only one control loop, the cost and complexity of the IPT system are reduced.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Asymmetric Bidirectional Capacitive Power Transfer Method With Push–Pull
           Full-Bridge Hybrid Topology

    • Free pre-print version: Loading...

      Authors: Xin Dai;Min Sun;Pengqi Deng;Rui Wang;Yugang Su;
      Pages: 13902 - 13913
      Abstract: Bidirectional capacitive power transfer technology makes it possible for energy sharing among multiple electronic devices. This article proposes an asymmetrical bidirectional power conversion topology to satisfy different input and output characteristics’ requirements and increase load variation tolerance. A π–T (CLC–LCL) resonant topology is designed for this bidirectional conversion mode with constant output voltage characteristics in both directions. A hybrid power flow regulation strategy is proposed by integrating multiple zero-voltage switching soft-switching operating points switching and phase-shifted mode. This method overcomes the problem of mixing two different type topologies (push–pull and full bridge) with two different power regulation modes (switch soft-switching operating points and phase shift), which provide a way to make two different chargers compatible. Simulation and experimental results verified the proposed method.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • H∞ Robust Control for ICPT System With Selected Weighting Function
           Considering Parameter Perturbations

    • Free pre-print version: Loading...

      Authors: Yan Liang;Pan Sun;Xusheng Wu;Hang Zhou;Jun Sun;Gang Yang;Jin Cai;Qijun Deng;
      Pages: 13914 - 13929
      Abstract: H∞ control can guarantee the performance of a nominal ICPT system. However, the dynamic performance may suffer degradation when the parameter deviates from its nominal value. Thus, to enhance the overall dynamic performance of the ICPT system under parameter perturbations, an H∞ control method with a selected weighting function considering parameter perturbations is proposed in this article. First, a generalized state-space model is established to analyze the influence of parameter perturbations on the open-loop system in detail. After that, an uncertain model is established via frequency-domain analysis, generating a numerical solution of a weighting function used to describe the parameter perturbations. Then, the generalized plant with uncertainty is obtained and transferred into a standard H∞ optimal problem via small gain theory. Based on the proposed controller, the dynamic performance and robustness of the closed-loop system are analyzed and verified theoretically. Finally, simulation and experimental results further verify that the proposed H∞ control method can make the closed-loop system obtain good dynamic performance and strong robustness against parameter perturbations. The settling time is less than 6.8 ms without any overshoot when the system suffers parameter perturbations. Besides, the controller can maintain good dynamic performance in the startup and reference tracking experiments.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • High-Misalignment Tolerance Wireless Charging System for Constant Power
           Output Using Dual Transmission Channels With Magnetic Flux Controlled
           Inductors

    • Free pre-print version: Loading...

      Authors: Zhenjie Li;Hao Liu;Yusheng Huo;Jiafang He;Yuhong Tian;Jiuqing Liu;
      Pages: 13930 - 13945
      Abstract: Although the wireless charging system (WCS) achieves flexible power transmission, high system operating performance needs strong anti-misalignment capability and excellent charging controllability. Hence, this article proposes a mistuned WCS that features dual transmission channels using half-bridge inverters, magnetic flux controlled inductors (MFCIs), magnetic couplers with hybrid coils (HMCs), and the series–series compensation. Then, high misalignment tolerance and high-efficient constant power (CP) charging are achieved. First, the interrelation among the mutual inductance, adjustable inductance, load resistance, charging power, and system efficiency is analyzed based on the optimally designed system structure. Second, the circuit structure and working principle of the MFCI are illustrated. Third, the anti-misalignment capability of the optimized HMC is verified by analyzing its coupling characteristics. Then, the relative spatial position between the two HMCs is determined to ensure the negligible cross-coupling influence. In addition, the closed-loop controller's working principle and design method is analyzed to achieve high-efficient and high-controllable CP charging within a wide range of misalignment distance and load resistance. Finally, the experimental results validate the feasibility of the proposed WCS. For CP charging of 150 W, x- and y-direction misalignment ranges reach ±95% and ±47%, and system efficiency exceeds 90%, superior to the commonly used anti-misalignment methods.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Self-Synchronized Class E Resonant Rectifier by Compensating Propagation
           Delay for Multi-MHz Switching Applications

    • Free pre-print version: Loading...

      Authors: Minki Kim;Jungwon Choi;
      Pages: 13946 - 13954
      Abstract: In this article, a self-synchronized, high-frequency class E resonant rectifier is proposed to compensate for the synchronization signal mismatch due to the propagation delay. The synchronous rectification helps the power conversion system increase its efficiency by using active devices such as mosfets instead of diodes. Even with the mosfets, it is still challenging to generate an accurate synchronous signal from the input source in the multi-MHz wireless power transfer (WPT) systems due to the propagation delay from the integrated circuit (IC) components and the gate driver. In general, the propagation delay is more than 10 ns, a significant period in the multi-MHz operation. To mitigate the propagation delay, we present the self-synchronized rectifier, sensing the signal in the $C_{s}$-$L_{s}$ network. The proposed design creates a proper gate signal to the active device in the rectifier by measuring the voltage of the node between $C_{s}$-$L_{s}$ resonant filter. In the experiments, we tested the driving method in the class E rectifier at an output power of 228 W and a switching frequency of 13.56 MHz. While the total propagation delay was 8 ns, including the gate-driver and comparator, the leading phase of the sensing voltage successfully offsets the driver’s propagation delay.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Dual-Frequency WPT Based on Multilayer Self-Decoupled Compact Coil and
           Dual CLCL Hybrid Compensation Topology

    • Free pre-print version: Loading...

      Authors: Zhongyu Dai;Junhua Wang;
      Pages: 13955 - 13965
      Abstract: This article proposes a dual-frequency wireless power transfer (WPT) with dual CLCL hybrid compensation topology and multilayer self-decoupled compact coils (MLSDCCs). It extends the transmission distance corresponding to stable high transmission power and efficiency. Based on the parameter constraints of compensation capacitances and inductances, CLCL hybrid compensation topology realizes simultaneous resonance at fundamental and third harmonic frequencies. A typical inverter can meet the requirements of dual-frequency WPT without complex control or more number and improve the utilization rate of square voltage. According to interleaving and rotary stacking of unipolar and bipolar coils in MLSDCCs, the couplings between layers and unnecessary couplings of magnetic coupling mechanism (MCM) are eliminated. Only the main couplings for power transmission are retained and the volume of MCM is reduced. Finally, a 1 kW experimental platform is built. Compared with the typical single-frequency WPT, the maximum transmission power is increased by 2.8%, while the maximum transmission efficiency is only reduced by 0.53%. The main advantage is that the transmission distance corresponding to continuous high-power transmission (in the range of 95%–100% maximum receiving power) is increased by 2.75 times. When the lateral offset distance of the Y-axis is one-sixth of the coil side length, the transmission efficiency decreases by only 1.47%.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • Enhanced Power Conversion Capability of Class-E Power Amplifiers With GaN
           HEMT Based on Cross-Quadrant Operation

    • Free pre-print version: Loading...

      Authors: Xianglin Hao;Jianlong Zou;Ke Yin;Xikui Ma;Tianyu Dong;
      Pages: 13966 - 13977
      Abstract: Class-E power amplifiers are widely used in megahertz frequency power conversion systems due to their high efficiency, which can further be enhanced by virtue of wide-bandgap devices such as GaN high-electron-mobility transistors. Here, a GaN-based cross-quadrant mode Class-E amplifier is proposed, which addresses one of the major challenges for such amplifiers, i.e., to achieve both high power and high efficiency with low-voltage-rating devices. By utilizing the reverse conduction of GaN transistors, a cross-quadrant mode Class-E amplifier with small dc-feed inductance is constructed, whose circuit model is derived by virtue of the Laplace transform technique. We demonstrate an experimental prototype operating at 3.11 MHz with a 100-V GaN transistor, achieving an output power of about 6 W with the efficiency being almost 90% when the input voltage is 10 V and the load resistance is 28 $mathrm{Omega }$. Compared with conventional Class-E amplifiers, the power conversion capability of the proposed amplifier is increased up to three times from 0.49 to 1.69 with a slight reduction in efficiency. Such cross-quadrant mode amplifiers can be used to improve the power conversion capability and to reduce the peak switch voltage at the same output power level.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
  • A Frequency Regulation Strategy for Dynamic Process Noise Suppression in
           LCC-S WPT Systems

    • Free pre-print version: Loading...

      Authors: Pengqi Deng;Chunsen Tang;Yuanshuang Fan;Min Sun;Zhe Liu;Xiaofei Li;
      Pages: 13978 - 13988
      Abstract: This article proposed a frequency regulation strategy (FRS) to realize zero voltage switching (ZVS) in the dynamic process of LCC-S wireless power transfer systems, which aims at suppressing serious switching noise in the starting-up phase of the inverter. By detecting the magnitude and direction of the output current of the inverter, a delayed turn-on signal is timely applied to ensure that the inverter can achieve ZVS in all operating conditions. The origins of the mechanism of switching noise are presented, and the closed-loop stability of the system under the proposed control strategy is analyzed. The correctness of the theoretical analysis and the effectiveness of the control strategy is verified by both simulation and experiment results. This control strategy is technically effective for all resonant converters in the switching noise suppression. Finally, the method is verified in a 1.5 kW, 85 kHz, 310V LCC-S WPT system, and the experimental results show that the FRS can reduce electromagnetic interference by 13 dB in one dynamic starting-up cycle.
      PubDate: Nov. 2022
      Issue No: Vol. 37, No. 11 (2022)
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 3.238.225.8
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-