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  Subjects -> ELECTRONICS (Total: 207 journals)
Showing 1 - 200 of 277 Journals sorted by number of followers
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 281)
Control Systems     Hybrid Journal   (Followers: 236)
IEEE Transactions on Geoscience and Remote Sensing     Hybrid Journal   (Followers: 174)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 165)
Electronic Design     Partially Free   (Followers: 125)
Electronics     Open Access   (Followers: 125)
Advances in Electronics     Open Access   (Followers: 122)
Electronics For You     Partially Free   (Followers: 114)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 112)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 90)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 88)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 87)
IEEE Transactions on Industrial Electronics     Hybrid Journal   (Followers: 85)
IEEE Transactions on Software Engineering     Hybrid Journal   (Followers: 84)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 79)
IET Power Electronics     Open Access   (Followers: 76)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 65)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 62)
IEEE Embedded Systems Letters     Hybrid Journal   (Followers: 60)
IEEE Transactions on Industry Applications     Hybrid Journal   (Followers: 57)
Advances in Power Electronics     Open Access   (Followers: 56)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 52)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 50)
IEEE Nanotechnology Magazine     Hybrid Journal   (Followers: 45)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 45)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 41)
IET Microwaves, Antennas & Propagation     Open Access   (Followers: 35)
IEEE Transactions on Biomedical Engineering     Hybrid Journal   (Followers: 35)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 31)
International Journal of Power Electronics     Hybrid Journal   (Followers: 30)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 27)
Microelectronics and Solid State Electronics     Open Access   (Followers: 27)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 26)
Journal of Sensors     Open Access   (Followers: 25)
Electronics Letters     Open Access   (Followers: 25)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 23)
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 22)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 19)
IEEE Reviews in Biomedical Engineering     Hybrid Journal   (Followers: 19)
IEEE/OSA Journal of Optical Communications and Networking     Hybrid Journal   (Followers: 19)
Journal of Artificial Intelligence     Open Access   (Followers: 18)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 18)
IET Wireless Sensor Systems     Open Access   (Followers: 17)
Circuits and Systems     Open Access   (Followers: 16)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 16)
IEEE Transactions on Signal and Information Processing over Networks     Hybrid Journal   (Followers: 14)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 14)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 14)
Archives of Electrical Engineering     Open Access   (Followers: 14)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 13)
Advances in Microelectronic Engineering     Open Access   (Followers: 12)
IEEE Transactions on Learning Technologies     Full-text available via subscription   (Followers: 12)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 12)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 12)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 12)
IEEE Solid-State Circuits Magazine     Hybrid Journal   (Followers: 11)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 11)
IEEE Women in Engineering Magazine     Hybrid Journal   (Followers: 11)
IEEE Transactions on Broadcasting     Hybrid Journal   (Followers: 11)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 10)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 10)
International Journal of Antennas and Propagation     Open Access   (Followers: 10)
IETE Journal of Research     Open Access   (Followers: 10)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 9)
IETE Technical Review     Open Access   (Followers: 9)
Batteries     Open Access   (Followers: 8)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 8)
IEEE Transactions on Autonomous Mental Development     Hybrid Journal   (Followers: 8)
Journal of Power Electronics     Hybrid Journal   (Followers: 8)
China Communications     Full-text available via subscription   (Followers: 8)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 8)
Open Journal of Antennas and Propagation     Open Access   (Followers: 8)
Metrology and Measurement Systems     Open Access   (Followers: 8)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 8)
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal   (Followers: 8)
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 8)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 8)
Solid-State Electronics     Hybrid Journal   (Followers: 7)
Nanotechnology, Science and Applications     Open Access   (Followers: 7)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
IEEE Magnetics Letters     Hybrid Journal   (Followers: 7)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 7)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 6)
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Annals of Telecommunications     Hybrid Journal   (Followers: 6)
Electronic Markets     Hybrid Journal   (Followers: 6)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 6)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 6)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access   (Followers: 5)
Journal of Electronics (China)     Hybrid Journal   (Followers: 5)
Journal of Field Robotics     Hybrid Journal   (Followers: 5)
Energy Storage Materials     Full-text available via subscription   (Followers: 5)
IEEE Pulse     Hybrid Journal   (Followers: 5)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 5)
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 5)
Batteries & Supercaps     Hybrid Journal   (Followers: 5)
IEEE Transactions on Services Computing     Hybrid Journal   (Followers: 5)
Networks: an International Journal     Hybrid Journal   (Followers: 4)
Wireless and Mobile Technologies     Open Access   (Followers: 4)
IEEE Transactions on Haptics     Hybrid Journal   (Followers: 4)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 4)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 4)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 4)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Sensors International     Open Access   (Followers: 3)
Nature Electronics     Hybrid Journal   (Followers: 3)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Superconductivity     Full-text available via subscription   (Followers: 3)
EPE Journal : European Power Electronics and Drives     Hybrid Journal   (Followers: 3)
Machine Learning with Applications     Full-text available via subscription   (Followers: 3)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 3)
Informatik-Spektrum     Hybrid Journal   (Followers: 3)
IETE Journal of Education     Open Access   (Followers: 3)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 2)
Power Electronics and Drives     Open Access   (Followers: 2)
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal   (Followers: 2)
Advancing Microelectronics     Hybrid Journal   (Followers: 2)
Transactions on Electrical and Electronic Materials     Hybrid Journal   (Followers: 2)
Energy Storage     Hybrid Journal   (Followers: 2)
Journal of Information and Telecommunication     Open Access   (Followers: 2)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 2)
Advanced Materials Technologies     Hybrid Journal   (Followers: 2)
EPJ Quantum Technology     Open Access   (Followers: 2)
e-Prime : Advances in Electrical Engineering, Electronics and Energy     Open Access   (Followers: 2)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 2)
IET Smart Grid     Open Access   (Followers: 2)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 2)
Journal of Nuclear Cardiology     Hybrid Journal   (Followers: 1)
Transactions on Cryptographic Hardware and Embedded Systems     Open Access   (Followers: 1)
ACS Applied Electronic Materials     Open Access   (Followers: 1)
Frontiers in Electronics     Open Access   (Followers: 1)
IEEE Letters on Electromagnetic Compatibility Practice and Applications     Hybrid Journal   (Followers: 1)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
IET Energy Systems Integration     Open Access   (Followers: 1)
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access   (Followers: 1)
International Journal of Hybrid Intelligence     Hybrid Journal   (Followers: 1)
Open Electrical & Electronic Engineering Journal     Open Access   (Followers: 1)
Ural Radio Engineering Journal     Open Access   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Електротехніка і Електромеханіка     Open Access   (Followers: 1)
Edu Elektrika Journal     Open Access   (Followers: 1)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 1)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
Automatika : Journal for Control, Measurement, Electronics, Computing and Communications     Open Access  
npj Flexible Electronics     Open Access  
Elektronika ir Elektortechnika     Open Access  
Emitor : Jurnal Teknik Elektro     Open Access  
IEEE Solid-State Circuits Letters     Hybrid Journal  
IEEE Open Journal of Industry Applications     Open Access  
IEEE Open Journal of the Industrial Electronics Society     Open Access  
IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology     Hybrid Journal  
IEEE Open Journal of Circuits and Systems     Open Access  
Journal of Electronic Science and Technology     Open Access  
Australian Journal of Electrical and Electronics Engineering     Hybrid Journal  
Solid State Electronics Letters     Open Access  
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Journal of Engineered Fibers and Fabrics     Open Access  
Jurnal Teknologi Elektro     Open Access  
IET Nanodielectrics     Open Access  
Elkha : Jurnal Teknik Elektro     Open Access  
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Jurnal Teknik Elektro     Open Access  
IACR Transactions on Symmetric Cryptology     Open Access  
Acta Electronica Malaysia     Open Access  
Bioelectronics in Medicine     Hybrid Journal  
Chinese Journal of Electronics     Open Access  
Problemy Peredachi Informatsii     Full-text available via subscription  
Technical Report Electronics and Computer Engineering     Open Access  
Jurnal Rekayasa Elektrika     Open Access  
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Visión Electrónica : algo más que un estado sólido     Open Access  
Telematique     Open Access  
International Journal of Nanoscience     Hybrid Journal  
International Journal of High Speed Electronics and Systems     Hybrid Journal  

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Similar Journals
Journal Cover
IEEE Transactions on Power Electronics
Journal Prestige (SJR): 2.215
Citation Impact (citeScore): 9
Number of Followers: 87  
 
  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: Aug. 2022
      Issue No: Vol. 37, No. 8 (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: Aug. 2022
      Issue No: Vol. 37, No. 8 (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: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Bridge-to-Bridge Independent Control Method for Dual-Active-Bridge
           Interlinking Converter

    • Free pre-print version: Loading...

      Authors: Haixu Shi;Kai Sun;
      Pages: 8757 - 8761
      Abstract: In dual-active-bridge (DAB) converters, the driving-synchronization signal is supposed to be required to be transmitted across the primary bridge and the secondary bridge to realize a phase shift for power flow. In this letter, a novel bridge-to-bridge independent (B2I) control method is proposed. In this control method, cross-bridge transmission of sampling/driving signals is not required. Thus, full modularity of each side in the DAB converter was realized. B2I control is suitable for high-voltage series low-voltage parallel (HSLP) modular DAB interlinking converter in medium-voltage dc applications because: first, the bridge-level modularity of B2I control benefits electromagnetic compatibility and insulation design with the HSLP connection; second, B2I control features series-side voltage sharing; and third, B2I control can adapt for various operation modes of microgrids.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A High-Efficiency 80-kW Split Planar Transformer for Medium-Voltage
           Modular Power Conversion

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      Authors: Sizhao Lu;Deyun Kong;Shuang Xu;Linglin Luo;Siqi Li;
      Pages: 8762 - 8766
      Abstract: A high-efficiency medium-frequency split planar transformer (MFSPT) based on low-cost ferrite core (PC40) is proposed for medium-voltage modular power conversion. By adopting a split planar structure, high electrical insulation is achieved with high efficiency, high power density, as well as excellent heat dissipation performance at the same time. A finite-element analysis simulation is carried out to investigate the distribution of the magnetic field and electric field in the MFSPT. The designed MFSPT prototype achieves a power density of 21.1 kW/L and electrical insulation of 42 kV. The performance of the proposed MFSPT is experimentally evaluated on an 80 kW, 43 kHz CLLC converter and the peak efficiency of the CLLC converter is 99.33%. This letter shows for the first time that high power, high power density, high efficiency, and high electrical insulation can be achieved simultaneously by using the split planar structure. This letter is accompanied by a supplementary file demonstrating the applied voltage insulation test.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Machine-Learning-Based Fault Diagnosis Method With Adaptive Secondary
           Sampling for Multiphase Drive Systems

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      Authors: Zicheng Liu;Lanlan Fang;Dong Jiang;Ronghai Qu;
      Pages: 8767 - 8772
      Abstract: Dueto various kinds of stator phase arrangements, existing fault diagnosis (FD) methods cannot be applied to different types of multiphase machines. Spurred by the era of big data and artificial intelligence, an improved machine-learning-based FD method with adaptive secondary sampling filtering is proposed for the multiphase drive systems. Experimental results of the proposed method on both five-phase and six-phase motor drive platforms validate its satisfying generalization capability as well as high accuracy and strong robustness.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A New Thyristor-Based DC Circuit Breaker Using Diode Clamping Switching

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      Authors: Kejun Qin;Shunliang Wang;Junpeng Ma;Ji Shu;Junjie Zhou;Tianqi Liu;
      Pages: 8773 - 8779
      Abstract: It has been widely accepted to apply dc circuit breakers (DCCBs) to protect dc grids. Nevertheless, existing DCCBs have one or more following limitations: insulation recovery scheme of mechanical switch, additional precharge power supply, high conduction loss, unreliable current-breaking process, and unidirectional design. In this letter, a new DCCB with low conduction loss, simple precharging scheme, and reliable breaking ability is proposed. The proposed DCCB could break both fault and operating current actively with the same simple operation sequences. Moreover, bidirectional topology possessing all advantages mentioned previously is also presented. Topology introduction, parameters designing, and scaled-down experiment of the proposed DCCB are all presented in the letter.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Oscillatory Stability Region Analysis of Black-Box CIGs

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      Authors: Wei Liu;Jan Shair;Shuangxi Wu;Xiaorong Xie;
      Pages: 8780 - 8784
      Abstract: Most of the existing stability analysis methods are capable of determining the oscillatory stability of black-box converter interfaced generators (CIGs) under given operating conditions only but can hardly identify the critical operating conditions. In this letter, an oscillatory stability region (OSR) is defined with the short-circuit ratio and output power as variables, and a method to obtain the OSR for the black-box CIG is proposed. First, the CIG is modeled as a variable-operating-point impedance model (VOPIM) through perturbation tests. Then, the critical operating points, for which the CIG system has a zero-damping oscillation mode, are determined by VOPIM-based oscillatory stability analysis so as to obtain the OSR. Finally, the accuracy of the OSR is verified through control hardware-in-the-loop tests. The OSR is of significant meaning for the control strategy and operation plan optimization of the CIGs.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Improved Trapezoidal Voltage Method for Dead-Time Compensation in
           Three-Phase Voltage Source Converter

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      Authors: Lei Wang;Jianping Xu;Qiang Chen;Zhengge Chen;Rui Huang;
      Pages: 8785 - 8789
      Abstract: The dead-time between the switches in the upper and the lower bridge of voltage source PWM converters produces input current distortion, called as dead-time distortion. The dead-time distortion can be compensated by trapezoidal voltage. The conventional trapezoidal voltage compensation method (TVCM) only controls the angle of the trapezoidal voltage. By the control of the angle and amplitude of the trapezoidal voltage simultaneously, an improved TVCM is proposed to further reduce the dead-time distortion. The experimental results are provided to verify the analysis results.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Compact and Free-Positioning Omnidirectional Wireless Power Transfer
           System for Unmanned Aerial Vehicle Charging Applications

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      Authors: Shuai Wu;Chunwei Cai;Xichen Liu;Wenping Chai;Shiyan Yang;
      Pages: 8790 - 8794
      Abstract: Compact design in receiver and misalignment tolerance are two basic considerations for practical applications of wireless power transfer (WPT) in unmanned aerial vehicles (UAVs). To balance these two requirements, a novel magnetic design with the composite interval-acted parallel- & vertical-flux throw, orthogonal two-dimensional flux pick-up, and power-flow summed output is proposed in this letter. The resulting magnetic structure includes a target-shaped transmitter and two quadrature receivers, and the transmitter consists of four annular-type coils which are magnetized in a bipolar mode, making it possible to form a magnetic field with a parallel- and vertical-flux complementary distribution. Moreover, by integrating two orthogonal receiving coils into one receiver, a stable summed output current can supply the UAV onboard load with only a small size receiver. A UAV WPT prototype is established based on the proposal. The results show that the prototype can deliver 325 W with a system efficiency of 86%, and especially the variation of the output current is within ±0.76 A for different landing positions and directions. The overall system efficiency is from 87.3% down to 83.1%.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Decoupled Modulation Scheme for Harmonic Current Suppression in Five-Phase
           PMSM

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      Authors: Wusen Wang;Zaixin Song;Yuxin Liu;Chunhua Liu;
      Pages: 8795 - 8799
      Abstract: Harmonic currents always exist in a five-phase permanent magnet synchronous machine due to some disturbances. This letter proposes a unique modulation scheme to synthesize the control voltage in the harmonic subspace, xy-space, to suppress harmonic currents actively. The advantage of the proposed modulation scheme is that it is decoupled from the modulation process in the αβ-space, thereby not affecting the torque output or dq-axis currents. First, according to the αβ-space control voltage reference, the action time ranges of two large and two middle voltage vectors adjacent to the control voltage reference are determined. Second, the ranges are divided into several segments equally. Then, the best action time is selected from these segments to generate a proper control voltage in xy-space. Finally, the switching pattern of the inverter is designed with the selected action time. Experiments have been implemented to verify the effectiveness of the proposed modulation scheme.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Circulating Power Suppression Structure for
           Three-Winding-Transformer-Based Converter

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      Authors: Zhixing Yan;Ting Tang;Zehui Yu;Run Chen;Zhen Lai;Gengning Ying;Ningrui Yang;Jun Zeng;Junfeng Liu;Renjun Hu;
      Pages: 8800 - 8804
      Abstract: A circulating power suppression structure for a three-winding-transformer-based converter is proposed in this letter. The equivalent circuit models of the dual-transformer-based and three-winding-transformer-based converter are derived, which illustrates their merits and demerits. With the proposed structure, the drawbacks of these two transformer-type converters can be overcome, and their advantages can be combined. Useless circulating loss in three-winding-transformer can be reduced to mW level and can be omitted. The complex and coupled dual-transformer parameter design problem can be solved. The analysis and performance of the proposed structure are fully validated by experimental results.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Capacitive Power Transfer System With Integrated Wide Bandwidth
           Communication

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      Authors: Shaoge Zang;Qi Zhu;Lei Zhao;Aiguo Patrick Hu;
      Pages: 8805 - 8810
      Abstract: This letter proposed a novel method for compensation network design used in capacitive power transfer (CPT) systems to achieve simultaneous power and data delivery. The proposed method combines both ladder filter and resonant circuit designs, allowing the existing double-sided CL compensation topology to exhibit different characteristics under the power channel and the communication channel. The proposed system significantly reduces the design complexity and increases the bandwidth for data transfer while maintaining the circuit resonance at the wireless power transfer frequency. The system is compatible with both amplitude shift keying (ASK) and frequency shift keying (FSK) modulation methods, passing the high-frequency data carrier with an approximately unity gain. Detailed circuit parameter design and system performance analysis are presented, and a new metric power to signal is introduced to analyze the effect of the data communication on the power transfer. A prototype CPT system rated at 10 W is built, which demonstrates a 81.2% dc–ac efficiency and a data transfer rate of 10 kbps by using either ASK or FSK modulation techniques.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Transformerless Series-Connected Current Source Converter

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      Authors: Ling Xing;Qiang Wei;Yunwei Li;
      Pages: 8811 - 8815
      Abstract: Series-connected current source converters (SC-CSCs) are a good candidate for high-power, medium-/high-voltage applications. However, existing SC-CSCs require the use of bulky and costly transformer. In this article, a transformerless SC-CSC is proposed. The operation principle of the proposed SC-CSC is presented, and the modulation is developed. A case study is conducted to verify the performance of the converter.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Misalignment-Tolerant Dual-Transmitter Electric Vehicle Wireless Charging
           System With Reconfigurable Topologies

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      Authors: Yiming Zhang;Wenbin Pan;Hui Wang;Zhiwei Shen;Yuanchao Wu;Jiqing Dong;Xingkui Mao;
      Pages: 8816 - 8819
      Abstract: Wirelesscharging for electric vehicles (EVs) enjoys many benefits, such as convenience, safety, and automation. One of the major issues concerning EV wireless charging is misalignment tolerance along the door-to-door direction of the EV. This letter proposes a misalignment-tolerant dual-transmitter EV wireless charging system with a reconfigurable topology. At central positions, the system can be reconfigured to the S-S (series-series) topology where the two transmitting coils are connected in series to feed the load. At boundary positions, the two transmitting coils form the LCCC-S (inductor-capacitor-capacitor-capacitor-series) topology to enhance power transfer capability and tolerate weak couplings. In this way, not only the output power can be smoothed with door-to-door misalignment, but also wireless charging is guaranteed at weak couplings. Experimental results reveal that within the cover area of the transmitting coils, high-efficiency stable output can be achieved.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Fast Positive-Sequence Component Extraction Method With Multiple
           Disturbances in Unbalanced Conditions

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      Authors: Xiaokang Liu;Binbing Wu;Liancheng Xiu;
      Pages: 8820 - 8824
      Abstract: Fast and accurate acquisition of current components is a key factor for an active power filter to realize transient control under unbalanced conditions. In this letter, a robust real-time algorithm, which rapidly separates the positive-sequence component (PSC) from multiple decaying dc (DDC) components, dc bias component, negative-sequence component, and harmonics, is proposed. To this end, first, the multiple DDC components are detected in the multiple disturbance and unbalanced grid context, by making use of the periodicity of remaining components. The dc bias can be obtained accordingly, followed by the detection of a compound signal encompassing the positive-sequence component, negative-sequence component, and harmonics. Specifically, the compound signal can be extracted precisely, based on the detected DDC and dc bias components, with one grid cycle response time, or approximately, within half grid cycle. A switching logic of the two approaches is designed to shorten the overall convergence time and improve steady-state accuracy. The PSC is then effectively extracted by constructing the virtual orthogonal signal of the compound signal and using dq-frame filtering. Compared with the existing transient control techniques, the proposed scheme guarantees one grid cycle response time and simultaneously suppresses multiple disturbances. Finally, experimental results verify the effectiveness of the proposed method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Fast Short-Circuit Protection Method for SiC MOSFET Based on Indirect
           Power Dissipation Level

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      Authors: Wenyuan Ouyang;Pengju Sun;Minghang Xie;Quanming Luo;Xiong Du;
      Pages: 8825 - 8829
      Abstract: This letter proposes an indirect power dissipation level short circuit protection (IPDL-SCP) method for silicon carbide (SiC) metal-oxide semiconductor field-effect transistors (mosfets). Due to differences between normal conducting and short-circuit (SC) conditions, this method is triggered by the voltage oscillation vss at the parasitic inductance (Lss) of the source and directly monitoring vds of SiC mosfet. For verification, the short circuit protection circuit is tested and proved functional on the SC test bench. Experimental results show that the protection circuit can respond to both hard switching fault (HSF) and fault under load (FUL), while the fastest response delays are 75 ns for HSF and 170 ns for FUL. Comparisons with other commonly used SC protection methods have also been made, which show that the proposed IPDL-SCP method has better performance in shorter protection delays.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Physical Explanation of Threshold Voltage Drift of SiC MOSFET Induced by
           Gate Switching

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      Authors: Huaping Jiang;Xiaowei Qi;Guanqun Qiu;Xiaohan Zhong;Lei Tang;Hua Mao;Zebing Wu;Honggang Chen;Li Ran;
      Pages: 8830 - 8834
      Abstract: Silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs) are regarded as the key device for the next generation of power electronics. However, wide applications are hindered by the threshold voltage instability. How the threshold voltage drifts under both static and dynamic gate stress has been reported. But the underpinning mechanism remains to be revealed, which is the basis of the exploration of the application solutions. This letter is to investigate why the threshold voltage drifts. It is found that the local electric field plays the key role behind the threshold instability, which is a function of dVGS/dt. Based on that, a physical model is proposed and experimentally verified. These findings provide not only a way to understand the mechanism but also a hint of how to mitigate the threshold instability by active gating in power electronics applications.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • True Nulls-Free Magnetoinductive Waveguides Using Alternate Coupling
           Polarities for Batteryless Dynamic Wireless Power Transfer Applications

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      Authors: Chawalit Rakluea;Apisak Worapishet;Sarawuth Chaimool;Yan Zhao;Prayoot Akkaraekthalin;
      Pages: 8835 - 8854
      Abstract: A dynamic wireless power transfer (DWPT) system using the conventional magnetoinductive (MI) waveguide suffers from periodic power nulls resulting from standing waves. Although numerous methods have been developed to mitigate the nulls, additional active circuitry was required, increasing the complexity. In this article, the MI waveguide with alternate magnetic coupling polarities between successive resonator cells is proposed for a true nulls-free DWPT system with no use of active components. Two configurations of the alternately coupled MI (ACMI) waveguide are developed—one with the incorporation of a quadrature-phase termination for a linear waveguide, and the other with the adoption of a circular waveguide. Extensive analysis of the generalized ACMI waveguide is provided, and the developed configurations are theoretically verified to maintain power transfer efficiency, independent of the free-positioned load. Practical implementation of DWPT systems using the linear and circular ACMI configurations with seven resonator cells at 13.56-MHz operation are experimentally demonstrated to exhibit no power transfer nulls and achieve up to fivefold reduction in efficiency variation, as compared to their MI counterparts. Comparisons with theoretical calculation are given for verification of the analysis integrity. An experimental model of a batteryless DWPT system is also demonstrated using the circular waveguide as accompanied by a video.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Small-Step Discretization Method for Modeling and Stability Analysis of
           Cascaded DC–DC Converters With Considering Different Switching
           Frequencies

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      Authors: Huayv Ji;Fan Xie;Yanfeng Chen;Bo Zhang;
      Pages: 8855 - 8872
      Abstract: Cascaded dc–dc converter is the main component of the dc distributed power system. It is valuable to establish the accurate model for studying the stability of cascaded dc–dc converters. However, the cascaded dc–dc system has many operating modes, such that the existing classic methods, e.g., state-space average model and discrete-mapping model, are difficult to explore to analyze cascaded dc–dc converter system, especially that with different switching frequencies. To overcome this drawback, this article promulgates a new modeling and stability analysis method for cascaded dc–dc converter. Small-step method, discretization method, and Euler method are exploited to modeling. All stages of the system are considered, therefore, accurate; and stability is divided into three categories according to the different definitions. Then, the cascaded systems with the same or different switching frequencies are studied using the presented method. As an example, two-stage peak current-mode controlled boost converter is scrutinized. Finally, simulations and experiments are manipulated to verify the correctness of the new method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Integrated Inductor Design for a Highly Compact Embedded Battery Charger

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      Authors: Bima Nugraha Sanusi;Ziwei Ouyang;
      Pages: 8873 - 8885
      Abstract: An integrated inductor for a highly compact embedded battery charger is designed in this article. A zero-voltage switching (ZVS) buck converter is the selected topology to achieve high power density. ZVS is achieved by sizing the inductor based on energy balance and introducing the $k$ factor. A novel four-leg magnetic core structure is proposed as the integrated inductor. By introducing a modified parameter $alpha _{mathrm{eff}}$ to the improved generalized Steinmetz equation method, the optimal switching frequency for core losses can be found. From the constructed inductor model and semiconductor loss calculation, the design tradeoff and optimization is analyzed. The optimal $f_{mathrm{sw}}$ is found to be around 2 MHz, which is when the performance factor for the core material peaks. As a proof of concept, a highly compact prototype, featuring stacked printed circuit board solution, with 16.2 × 19.2 × 6 mm$^{3}$ dimension is built. The input voltage ranges from 6 to 12 V, and the converter is capable of delivering up to 10 A at the 4-Voutput. Converter peak efficiency of 96% is achieved, and the inductor design has a power density of 113.6 W/cm$^{3}$. This shows improvement over several state-of-the-art designs. This article is accompanied by a video demonstrating the flux distribution in the magnetic core over the switching period.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • The High-Power Piezoelectric Transformer With Multiple Outputs Based on
           Sandwiched Piezoelectric Transducers

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      Authors: Sha Wang;Junjie Shan;Hua Tian;Shuyu Lin;
      Pages: 8886 - 8894
      Abstract: This article develops a high-power piezoelectric transformer based on the sandwiched piezoelectric transducer with multioutput characteristics. An advanced high-power voltage transformation technology is realized via using the superior mechanical robustness of the sandwiched piezoelectric transducers. High-power sandwiched piezoelectric transformers (s-PTs) with the unique crisscrossed structure are constructed by four sandwiched piezoelectric transducers with two modes, i.e., antiphase mode and in-phase mode, due to the coupled vibration of the central metal cuboid. Moreover, the related electromechanical equivalent circuit model (EECM) of the s-PTs is established in which two loss factors are introduced into this model, and its impedance characteristics, voltage gains, and power gains are studied as well. The accuracy of EECM is verified by the finite element method and experiments. Results reveal that s-PT has three outputs, and its voltage gains and power ratios are affected by load resistance and loss. The output power of the s-PTs can reach at least 45 W, and the s-PTs can keep the efficiency of ∼35% under high-input electric power, which provides a new idea for high-power piezoelectric transformers.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Low-Complexity Model-Predictive Control for a Nine-Phase Open-End Winding
           PMSM With Dead-Time Compensation

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      Authors: Haifeng Wang;Xiaoqin Zheng;Xibo Yuan;Xinzhen Wu;
      Pages: 8895 - 8908
      Abstract: The heavy computational burden and the complexity in pulse generation based on multivector synthesis represent serious challenges for applying finite control set model-predictive control (FCS-MPC) in multiphase open-end winding (OW) drive systems. In this article, a low-complexity model-predictive control with dead-time compensation is proposed for the nine-phase OW permanent magnet synchronous machine drive system. First, to simultaneously eliminate voltage vectors on the third, fifth, and seventh harmonic planes, three vectors in the same direction are selected to synthesize the virtual vector (VV). In addition, a multivector synthesis algorithm is designed to generate a symmetrical pulse sequence. Then, in order to suppress the harmonic voltage vector caused by the dead time, an additional voltage vector was added to the VV. Finally, the deadbeat principle was introduced to calculate the reference voltage vector, and the optimal voltage vector is determined according to the position of the reference voltage vector, which reduces the computational burden successfully. The proposed method is studied and compared with traditional FCS-MPC schemes. Simulation and experimental results have verified the effectiveness of the proposed method, which reduces the computational burden and complexity and enables the use of FCS-MPC for multiphase OW drive systems.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Power Adaptive Impedance Reshaping Strategy for Cascaded DC System With
           Buck-Type Constant Power Load

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      Authors: Bangbang He;Wu Chen;Xin Li;Liangcai Shu;Xinbo Ruan;
      Pages: 8909 - 8920
      Abstract: It is well-known that the low-frequency negative input impedance of the constant power load (CPL) is the major cause of the cascaded system instability, and the heavier the power, the worse the stability. In this article, a power adaptive load-side parallel virtual impedance (PALPVI) control strategy is proposed to improve the stability of the cascaded dc system with buck-type CPL. First, a parallel impedance with power adaptability is derived followed up with the derivation of the corresponding compensation controller transfer function to realize it virtually. Considering that the compensation controller is highly dependent on the circuit parameters and needs extra current sensors to acquire the power information, a simplification of the compensation controller is made based on the open-loop characteristics of the buck-type CPL. The final PALPVI control strategy does not require the circuit parameters or any current sensor and has almost no side effect on the dynamic performance. Finally, a 48–24–12 V cascaded dc system is fabricated to verify the feasibility and effectiveness of the proposed PALPVI control strategy.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Selective Pole Placement and Cancellation for Proportional–Resonant
           Control Design Used in Voltage Source Inverter

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      Authors: Bowei Lin;Li Peng;Xinmin Liu;
      Pages: 8921 - 8934
      Abstract: The proportional–integral (PI) control is usually applied in synchronous reference frame to regulate the output voltage of three-phase voltage source inverter (VSI). However, the PI controller is constrained by the capability of suppressing harmonic and negative sequence components; besides, its direct application in single-phase VSI is limited. While the proportional–resonant (PR) control can track ac reference and achieve harmonic suppression in stationary frame for both single-phase and three-phase VSI. Due to the high order of the resonant controller, lots of efforts are needed during the parameter design to get a satisfactory performance, such as trial-and-error. In this article, the way to approximately reduce the order of the resonant controller in the discrete time domain is presented, and then a method of selective pole placement and cancellation for the PR control design used in VSI is proposed. With the proposed method, the closed-loop pole-zero distribution of the PR control structure used in the VSI is well handled, and the parameters of the feedback controller and the reference feedforward controller are directly calculated by placing the selected poles and zeros in desired positions. The procedure of the parameter design is facilitated, and the performance of the VSI with PR control is improved.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Generalized Clarke Transformation and Enhanced Dual-Loop Control Scheme
           for Three-Phase PWM Converters Under the Unbalanced Utility Grid

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      Authors: Yuhang Zou;Li Zhang;Yan Xing;Zhe Zhang;Hao Zhao;Hongjuan Ge;
      Pages: 8935 - 8947
      Abstract: Three-phase grids imbalance causes serious alternating input current distortion in three-phase pulsewidth modulation (PWM) rectifiers where the conventional control scheme is employed. In this article, a generalized Clarke transformation is proposed to convert three-phase unbalanced sinusoidal quantities to two orthogonal sinusoidal quantities with equal amplitudes. Then, these two orthogonal sinusoidal quantities could be converted to two direct quantities by the Park transformation. Furthermore, based on the generalized Clarke transformation, an enhanced dual-loop control (EDLC) scheme is proposed to control the three-phase PWM rectifier in the synchronous rotating frame. Finally, a 5-kW Vienna-type rectifier prototype was built to verify the proposed generalized Clarke transformation and the proposed EDLC control scheme. Experimental results show that, by using the proposed EDLC scheme, the low current total harmonic distortion is achieved even both the amplitude and phase of the utility grid voltages are unbalanced.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Modulated Model Predictive Control With Branch and Band Scheme for
           Unbalanced Load Compensation by MMCC-STATCOM

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      Authors: Xuejiao Pan;Li Zhang;Yongfei Li;Kang Li;Han Huang;
      Pages: 8948 - 8962
      Abstract: This article presents a novel modulated model-predictive control (MMPC) scheme for modular multilevel cascaded converter-based static synchronous compensator (STATCOMs) (MMCC-STATCOMs) to compensate unbalanced load current and regulate reactive power flow. By adding a common-mode voltage (CMV) to the phase-voltages of the star-connected MMCC current model, the method allows natural injection of a nonsinusoidal voltage to the neutral point of the converter, hence achieving interphase cluster voltage balance. Moreover, the imposed CMV is shown to extend the operating ranges of MMCC-STATCOMs when used for negative sequence current compensation. The proposed MMPC method incorporates a modified branch and bound algorithm to optimize the per-phase switch duty ratios. It is shown to be computationally more efficient compared to model-predictive control schemes using the optimal voltage level method combined with voltage sorting schemes. Experimental results with different weighting factors confirm the effectiveness of this control scheme and compared favorably with the conventional scheme of injecting only a sinusoidal zero-sequence voltage.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Direct Actual-Power Control Scheme for Current-Fed Dual-Active-Bridge
           DC/DC Converter Based on Virtual Impedance Estimation

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      Authors: Yue Zhang;Li Ding;Nie Hou;Yunwei Li;
      Pages: 8963 - 8975
      Abstract: High dynamic performance is an essential requirement for the dual-active-bridge (DAB) dc/dc converters. As dc voltage sources, they should maintain the desired output voltage instantly under all working conditions. However, the previous literature mainly focus on the dynamic control of the voltage-fed DAB converters, and the existing control schemes for the current-fed DAB converters achieve limited dynamic performance. Aiming at improving the dynamic performance, a direct actual-power control (DAPC) scheme based on virtual impedance estimation (VIE) is proposed for the current-fed DAB converters in this article. The proposed DAPC scheme is based on a parallel structure instead of the series structure of existing control schemes, and it realizes fast dynamic control through combining actual power control with the VIE method. The proposed DAPC scheme can obtain the fastest transient response for the output voltage without voltage overshoot in transient conditions, such as load step change, input voltage fluctuation, and the desired output voltage step change. Besides, a leakage inductor precharging method is integrated into the DAPC scheme to avoid the current mismatching. Finally, the proposed DAPC schemes are compared with two existing control schemes and tested in a scale-down experimental prototype. Experimental results verify the effectiveness of the proposed DAPC scheme.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A High-Efficiency Fast-Transient LDO With Low-Impedance Transient-Current
           Enhanced Buffer

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      Authors: Xiao Zhao;Qisheng Zhang;Yaping Xin;Shuoyang Li;Lanya Yu;
      Pages: 8976 - 8987
      Abstract: This article proposes a new low-impedance transient-current enhanced (LTE) buffer, which is applied for low-dropout regulator (LDO) with large off-chip capacitor. The LTE buffer is based on current-shunt feedback technique and two ac coupling networks, which can achieve an extremely low output impedance and high charging/discharging current of the gate of power transistor at load transient response, while maintaining low-quiescent current consumption under the full-load range. In addition to containing the LTE buffer, the proposed LTE-LDO employs recycling-folded-cascode amplifier as the error amplifier, which has the advantage of high loop gain, loop bandwidth, and current efficiency. Meanwhile, simple Miller compensation with a nulling resistor is employed for frequency compensation and a complete small-signal analysis under different load current conditions is given in this article. This design has been implemented in semiconductor manufacturing international corporation 0.18 $mu$m complementary metal–oxide–semiconductor process and the experimental results show that the quiescent current consumption is about 48 $mu$A, and the maximum current efficiency of the LTE-LDO is 99.976$%$. The measured transient response shows that under the condition of 1 $mu$F load capacitance, when the load current changes to 200 mA/100 ns, the output voltage change is 76 mV.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Hybrid Multivector FCS–MPC for Six-Phase Electric Drives

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      Authors: Angel Gonzalez-Prieto;Cristina Martin;Ignacio González-Prieto;Mario J. Duran;Juan Carrillo-Ríos;Juan Jose Aciego;
      Pages: 8988 - 8999
      Abstract: Standard finite control set model predictive controllers (FCS–MPC) suffer from a deteriorated current quality when applied to multiphase drives. This problem has been recently mitigated with the concept of virtual voltage vectors. Its application ensures reduced current harmonics by limiting the x–y voltage injection. An intensive research effort has been done seeking for the best vector combination to provide an optimized performance in FCS–MPC. On one hand, multivector strategies including a null vector refine the effective voltage production with enhanced current quality but the dc-link utilization decreases. On the other hand, the exclusive use of large virtual vectors (LVVs) ensures a higher dc-link utilization at the price of a poorer current quality at low-voltage operation. This article first proposes an extended version of multivector strategies using a zero vector by including a quartet of voltage vectors. The usage of five switching states into the predictive approach (MV5–MPC) improves the current quality but still lacks a suitable utilization of the dc-link voltage. To overcome this limitation, the proposed MV5–MPC is combined with LVV–MPC to provide a hybrid solution that simultaneously achieves a higher current quality and a satisfactory dc-link utilization. Experimental results confirm the effectiveness of the proposal.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Real-Time SIL Validation of a Novel PMSM Control Based on Deep
           Deterministic Policy Gradient Scheme for Electrified Vehicles

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      Authors: Soumava Bhattacharjee;Sukanta Halder;Ye Yan;Aiswarya Balamurali;Lakshmi Varaha Iyer;Narayan C. Kar;
      Pages: 9000 - 9011
      Abstract: Vector control plays a critical role in a permanent magnet synchronous motor (PMSM) drive to deliver the desired torque in electrified vehicle applications. Motor speed and stator current control depend on various nonlinear motor parameters that influence the performance of PMSM. Moreover, tuning of speed and current controller parameters using conventional control techniques also depends on these PMSM parameters. To enhance the robustness of vector control and tracking methodology against PMSM parameter uncertainties and load disturbances, a novel deep reinforcement learning (DRL) based advanced speed and current control technique is proposed in this article. The proposed method mitigates the effects of disturbance due to parameter variations as well as the load torque. The novel architecture delivers closed-loop reinforcement learning agents trained with the deep deterministic policy gradient learning algorithm in the plant environment where the cost of exploration is expensive. First, an overview and need for the proposed DRL vector control architecture are provided. Subsequently, the design and training methods for the proposed DRL controller are elicited. Thereafter, the proposed control scheme is validated with real-time software-in-the-loop testing under various conditions and compared against adaptive proportional–integral control of the same PMSM in OPAL-RT simulator.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Adaptive Nonlinear Parameter Estimation for a Proton Exchange Membrane
           Fuel Cell

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      Authors: Yashan Xing;Jing Na;Mingrui Chen;Ramon Costa-Castelló;Vicente Roda;
      Pages: 9012 - 9023
      Abstract: Parameter estimation is vitalfor modeling and control of fuel cell systems. However, the nonlinear parameterization is an intrinsic characteristic in the fuel cell models such that classical parameter estimation schemes developed for linearly parameterized systems cannot be applied. In this article, an alternative framework of adaptive parameter estimation is designed to address the real-time parameter estimation for fuel cell systems. The parameter estimation can be divided into two cascaded components. First, the dynamics with the unknown parameters are estimated by a new unknown system dynamics estimator (USDE). Inspired by an invariant manifold, this USDE is designed by applying simple filter operations such that the information of the state derivative is not required. Second, an adaptive law driven by the function approximation error is proposed for recovering unknown model parameters. Exponential convergence of the estimated parameters to the true values can be proved under the monotonicity condition. Finally, experimental results on a practical proton exchange membrane fuel cell system are given to verify the effectiveness of the proposed schemes.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Voltage Spike Suppression Strategy Based on De-Re-Coupling Idea for the
           Three-Phase High-Frequency Isolated Matrix-Type Inverter

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      Authors: Hongchen Liu;Youzheng Wang;Patrick Wheeler;Xue Zhou;Kuang Zhu;
      Pages: 9024 - 9034
      Abstract: In order to solve the problem of high voltage spikes on the secondary side of the high-frequency transformer when the three-phase high-frequency isolated matrix inverter (HFIMI) operates under the conventional modulation strategies, a new modulation strategy is proposed without introducing an auxiliary circuit. In the proposed scheme, the H-bridge inverter adopts phase-shift control. The matrix converter (MC) adopts the voltage-type de- and recoupling idea, and the decoupled positive and negative group inverters are, respectively, applied with a modified Space vector pulse width modulation (SVPWM) strategy to operate synchronously with the H-bridge inverter. When the H-bridge inverter is in dead-zone mode, the switching tubes of MC are all turned on to provide continuous flow paths for leakage inductance and output filter inductance current and suppress high voltage spikes. The operating mode of the three-phase HFIMI under the proposed modulation strategy is analyzed in detail, the realization conditions for soft switching are designed, and the soft-switching ranges are also discussed. The feasibility and validity of the voltage spike suppression strategy are verified by building a 3-kW principle prototype. The experimental results show that the voltage spikes are effectively suppressed, all switches achieve zero-voltage soft-switching, and the peak efficiency of the three-phase HFIMI can reach 95.2%.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • High-Precision Control Method for High-Power MRI Gradient Power Amplifiers

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      Authors: Keqiu Zeng;Saijun Mao;Gert Rietveld;Jelena Popovic;Hui Yu;Liguo Wang;Kun Liu;Zhiding Zhou;
      Pages: 9035 - 9046
      Abstract: In magnetic resonance imaging (MRI), high-power gradient power amplifiers (GPAs) are required to drive the gradient coils to generate strong and high-fidelity gradient fields. High precision is an essential requirement for the GPAs since precision directly impacts MRI imaging quality. Various aspects of the GPA have been the subject of research in the past years; however, high-precision GPA control that meets the stringent requirements of MRI applications is still a challenge. This article proposes a novel multi-rational-delay variables state space control method and an efficient out-of-band signal injection method to achieve GPA control accuracy at the level of one part per million at MVA output power levels. First, a systematic modeling and design method of the state space controller for high-power GPA is introduced utilizing state vectors with multi-rational-delay variables. This method improves the GPA dynamic performance significantly. Second, an efficient out-of-band signal injection method is presented to further improve the control precision at low output current, enabling the fulfillment of the challenging high-precision MRI requirements over the full GPA output range. Finally, the high-precision control method is validated in a GPA demonstrator with 500 A/1000 V output. Key results are a 30% improvement in current pulse reproducibility with respect to the conventional control method and a factor of 2.5 less noise at low currents. These experimental results validate the proposed novel method for the high-precision control of GPAs in MRI applications and prove its capability to contribute to significantly improved MRI image quality.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Active Flux Estimation in the Estimated Reference Frame for Sensorless
           Control of IPMSM

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      Authors: Abebe Teklu Woldegiorgis;Xinglai Ge;Huiming Wang;Yun Zuo;
      Pages: 9047 - 9060
      Abstract: Active flux model of permanent magnet synchronous motors simplifies the model and eases sensorless control implementation. However, incorporating the current model (CM) that depends on the estimated electrical position for active flux estimation may cause performance degradation. The conventional active flux observer analysis revealed that position error influences sensorless control performance, especially during transient conditions. Thus, two improvement strategies named method-1 and method-2 are proposed in this article. Method-1 is based on an adaptive gain observer-based approach designed to discard the effect of position error. The observer gains are dependent on the estimated reference frame currents, which leads to the observer complexity. Method-2, on the other hand, uses the position error from the estimated active flux to obtain the true CM active flux without changing the conventional observer gains. Thus, the effect of position error on active flux estimation is discarded. Method-1 and method-2 fully decoupled the speed-position identification and the active flux observer. Meanwhile, a feedforward compensated phase-locked loop is adopted for speed-position identification. The proposed sensorless control strategies have been extensively validated using the Texas digital signal processor (TMS320F28335) and RT-LAB real-time simulator. The experimental results indicated that the proposed methods improved the sensorless control and active flux estimation performance.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Efficient Modeling and Systematic Design of Enhanced Phase-Locked Loop
           Structures

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      Authors: Masoud Karimi-Ghartemani;Houshang Karimi;S. Ali Khajehoddin;Seyed Milad Hoseinizadeh;
      Pages: 9061 - 9072
      Abstract: This article presents approaches for efficient modeling and systematic design of enhanced phase-locked loop (ePLL) structures. While different ePLL structures have found a wide acceptance for various applications, their modeling and design aspects have not been fully and systematically reported in the existing literature. This article fills this gap by presenting an effective modeling approach for both the single- and three-phase ePLLs. The models are derived with a view to minimize the number of parameters to be adjusted to simplify the design. The models are then used to develop systematic design algorithms for their parameters. As an example, application of the ePLL in a grid-connected inverter is formulated and studied through simulation and experimental results. The design and simulation files are made available.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Power Dynamic Decoupling Control of Grid-Forming Converter in Stiff Grid

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      Authors: Fangzhou Zhao;Xiongfei Wang;Tianhua Zhu;
      Pages: 9073 - 9088
      Abstract: This article proposes a grid-forming based decoupling approach, which effectively mitigates the dynamic interactions between active and reactive power, especially suitable for system stabilization in ultrastrong grids with short-circuit ratio over 30. The physical coupling behaviors are first revealed by analytical studies, where two potential resonances, respectively, located in 40–50 Hz and 0–10 Hz are discovered with mathematical proofs. Based on the results, the decoupling controller is then designed with transfer function approximation for practical usage. The control method not only suppresses the couplings but also cancels two pairs of conjugate poles through decoupling paths. Thanks to the cancellation, the stability margin is remarkably increased in stiff grids, and therefore, a significant bandwidth boost on the power synchronization control can be realized if desired. The experimental results are finally performed to verify the proposed decoupling method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Power Losses Reduction of T-Type Grid-Connected Converters Based on
           Tolerant Sequential Model Predictive Control

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      Authors: Bo Long;Dawei Shen;Tianxu Cao;Jose Rodriguez;Cristian Garcia;Josep M. Guerrero;Kil To Chong;
      Pages: 9089 - 9103
      Abstract: Three-level T-type converters (3LT2C) with inductance–capacitance–inductance filters have high power quality of grid current, particularly in the low-voltage system. However, the switching loss and conduction losses degrade the overall efficiency of 3LT2C. The generated heat due to the losses endangers the reliability of the device and shortens its service life. To relieve the power losses as well as maintain high-quality current output, a low-loss-tolerant sequential model predictive control (LL-TSMPC) is proposed. First, based on the energy loss analysis under switching transitions per commutation, the prediction models of both switching loss and conduction loss are established. Second, the total loss reduction is considered as one control objective in LL-TSMPC. Finally, because multiobjective model predictive control (MPC) requires selecting appropriate weighting factors, complicating the design to solve this problem, TSMPC-based lexicographic optimization is introduced to eliminate the tradeoff factors and simplify the MPC controller design. The proposed method is tested on the hardware platform with the rated power of a 10-kW prototype. The experimental results show that the LL-TSMPC method can effectively reduce the switching losses while maintaining the high power quality of the grid current.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Asymmetric Phase-Shift Modulation Strategy of DAB Converters for Improved
           Light-Load Efficiency

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      Authors: Gen Chen;Zhangyong Chen;Yong Chen;Chenchen Feng;Xintong Zhu;
      Pages: 9104 - 9113
      Abstract: Dual active converter (DAB) can achieve high efficiency when the voltage ratio (the ratio of the input voltage to the output voltage equivalent to the primary side) is one, but when the voltage ratio is not one, the light-load efficiency drops sharply. Based on the realization logic of DAB light-load, this article proposes a modulation method with asymmetric compression duty cycle, which only increases one degree of freedom and does not need additional components to significantly improve the light-load efficiency. First, this article introduces the existing problems and solutions of the traditional scheme and puts forward a new modulation strategy. Then, the operating modes and power characteristics are analyzed. Then, the influence of duty cycle compression on reflux power and current stress is analyzed. Finally, a prototype with an input voltage of 100–200V, an output voltage of 50 V, and a full load power of 300–600 W is built to verify the analysis.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Efficiency Optimization Scheme for Isolated Triple Active Bridge DC–DC
           Converter With Full Soft-Switching and Minimized RMS Current

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      Authors: Jia Li;Quanming Luo;Ting Luo;Di Mou;Marco Liserre;
      Pages: 9114 - 9128
      Abstract: This article performs a comprehensive steady-state performance optimization for the isolated triple active bridge (TAB) dc–dc converter adopting the five-variable modulation (FVM) technique. First of all, a universal analytical model suitable for all the hardware conditions of the TAB converter is established using frequency-domain analysis method. Second, considering the influence of port voltages and the energy stored in parasitic capacitances, a simplified and accurate zero-voltage switching (ZVS) constraint is derived without complicated condition judgments. Based on this, aiming at reducing the overall system losses, a comprehensive efficiency optimization modulation scheme with FVM is proposed in this article. Distinct from the previous optimization methods, the proposed scheme is not only a multiobjective optimization with minimized circulating current level and full-ZVS operation. It is also a generic optimization scheme covering all the five operation modes, and there is no individual optimization for each mode, which greatly simplifies difficulty of implementation. Afterward, to overcome the cumbersome optimization process, an advanced particle swarm optimization algorithm is used to seek the global optimal operating point in the entire power flowing range. Extensive simulation is carried out using MATLAB/Simulink. And the steady-state characteristics of the proposed scheme are fully compared with the traditional phase shift modulation method. Finally, a 1.2 kW laboratory platform is built. A significant efficiency improvement under light-load condition up to 21% is achieved, which substantiates the feasibility of the proposed optimization scheme.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Highly Efficient Sensorless Multicontrol Mode Compressor IPMSM Drive With
           Seamless Transitions

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      Authors: Anton Dianov;
      Pages: 9129 - 9137
      Abstract: Motor drives with interior permanent magnet synchronous motors are typically used with vector or rectangular control (RC). Both of these control methods have well-known pros and cons; therefore, the most appropriate control mode is selected at the stage of drive design. Then, at the experimental verification of the drive prototype, the optimal pulse-width modulation (PWM) frequency is detected and the operation of motor drive is adjusted to this frequency and the corresponding sampling time. The systems constructed according to this algorithm have efficiency with one peak, which is typically selected to be at the rated mode motor drive. As a result, motor drives operate in other modes with lower efficiency, which is subject to further improvements. This article proposes the usage of multicontrol mode, which combines the benefits from each control method. The author suggests usage of the RC at lower speeds and vector control at higher speeds. Furthermore, the PWM frequency of motor drives is also changed, depending on the operating speed, which improves drive performance. This combination of control methods results in efficiency, which has several maximums and increases overall drive efficiency.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Mechanism and Suppression of Frequency-Decrease Effect Related to the Low
           Modulation Frequency Ratio in a High-Ratio MMC-Based DC Transformer

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      Authors: Chuyang Wang;Li Zhang;Bo Wang;Lan Xiao;
      Pages: 9138 - 9152
      Abstract: The high-ratio MMC-based DC transformer is the crucial device for the interconnection between different DC distribution networks. Compared to the typical MMC, the transformer has a similar structure and low modulation frequency ratios (FR). Thus, it also has the severe frequency-decrease effect and similar operating performance deterioration. However, because of the extremely lower FRs that are close to 1, the feature of the frequency-decrease effect in the transformer has different manifestations. And because of the two-stage structure which combines the MMC and rectifiers, more factors emerged in the transformer to determine the frequency-decrease effect. Therefore, this study further develops the theory and elaborates the frequency effect's mechanism that is originally from the MMC to adapt to the more complex structure of the transformer. A quantitative analysis of the frequency-decrease effect is then provided, demonstrating that because of the transformer's two-stage structures, two types of FRs and concomitant factors exist in the transformer, thus having a combined effect on the harmonic distributions of capacitor voltages and causing more proportional voltages' harmonics distorting into the slope harmonics. Based on the analysis, the study entirely redesigns the FRs and regulates the modulation strategy of the transformer to fundamentally eliminate the frequency-decrease effect. The study also confirms that the FRs in the two sides cannot be set to the same, and their decimal part cannot cause extra low-frequency harmonics. The frequency-decrease effect, the deteriorations, and the efficiency and comparisons of the proposed methods are finally demonstrated via simulations and experiments.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Fuzzy Approximation for FCS-MPC in Power Converters

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      Authors: Xing Liu;Lin Qiu;Youtong Fang;Kui Wang;Yongdong Li;Jose Rodríguez;
      Pages: 9153 - 9163
      Abstract: Standard model predictive control is an optimization-based control strategy that can handle multiple control objectives and system nonlinear constraints. However, it typically suffers from the limitation of the uncertainties in practical systems, such as external unknown disturbances and parametric uncertainties. Motivated by aforementioned limitation, in this article, a novel robust model predictive control framework, endowed with the merits of fuzzy logic system and finite control-set model predictive control solution, is proposed. The main objective of this article is to enhance the system robustness while guaranteeing adaptability to different conditions. More specifically, a fuzzy approximation point of view, which has a good potential to approximate the unknown nonlinear functions, is deployed and incorporated into the proposed design, which allows one to explicitly take the system nonlinear dynamics and uncertainties into account. The novelty of the proposed methodology relies on the fact that any prior knowledge and explicit information of system model parameters are not required, thereby resulting in considerable enhancement of robustness. Furthermore, the input-to-state stability of the approximation error system is proven through Lyapunov analysis, and it demonstrates that the estimated errors are uniformly ultimately bounded. Finally, the interest of the proposal is experimentally confirmed for modular multilevel converter.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Adaptive Dynamic Reference Control for Power Converters in a Microgrid

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      Authors: Vijesh Jayan;Amer M. Y. M. Ghias;Josep M. Guerrero;Adel Merabet;
      Pages: 9164 - 9174
      Abstract: This article proposes an adaptive dynamic reference (ADR) control for power converters in a microgrid. Conventionally, two separate controllers are required to control the input current and the dc bus voltage. The proposed ADR control eliminates the need for an additional controller by utilizing a simple discrete-time model to generate appropriate input current reference for the dc bus voltage regulation. The proposed technique is easy to design and guarantees a dynamic convergence of the dc bus voltage to its nominal reference even during nonidealities in the system, such as model parameter uncertainties, sensor imperfections, and unmodeled dynamics. A simple design procedure of the control parameters for the desired converter response is also provided based on a theoretical analysis. Unlike traditional linear controllers, the control parameter design of the proposed model is independent of the converter’s operating point. Finally, the performance of the proposed technique is validated experimentally by using a finite control set model predictive control of a typical grid-connected application and is compared with both conventional dynamic reference control and traditional linear controller.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A New Model Predictive Current Controller for Grid-Connected Converters in
           Unbalanced Grids

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      Authors: Euan T. Andrew;Khaled H. Ahmed;Derrick Holliday;
      Pages: 9175 - 9186
      Abstract: Distributed energy resources are often connected to low-voltage distribution networks where the grid voltages may be unbalanced. This leads to an unwanted ripple in the output active power at twice the fundamental grid frequency. In this article, a new model predictive current controller is proposed for unbalanced grids. The variable switching frequency of existing model predictive controllers is fixed and the power quality is improved. A Kalman filter estimator is used to extract the positive and negative sequence components. A new calculation time compensation technique is proposed, which offers superior accuracy to existing approaches. A grid voltage discretization compensation strategy is outlined, and its effectiveness is demonstrated. Finally, the system stability is verified theoretically. Simulation and laboratory results are included to prove the robustness of the proposed controller and support the theoretical analysis.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A State Observer for Sensorless Control of Power Converters With Unknown
           Load Conductance

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      Authors: Wei He;Mohammad Masoud Namazi;Tao Li;Romeo Ortega;
      Pages: 9187 - 9199
      Abstract: In this article, the sensorless control problem of a large class of power converters with unknown load conductance is investigated. A reduced-order generalized parameter estimation-based observer (GPEBO) is presented to reconstruct the unmeasurable states and estimate the unknown load conductance of the system. Three nice features of this observer are as follows: finite-time convergence (FTC) is guaranteed, an alertness preservation is imposed to be able to estimate a possibly time-varying load, and the required excitation condition is very weak and can be satisfied in normal operation of power converters. Then, replacing the estimated states and parameter, in a certainty equivalent manner, in a PI passivity-based controller, a sensorless control scheme is proposed to stabilize the systems with exponential convergence. By virtue of the FTC property of the GPEBO, the global exponential stability of the overall closed-loop system is established. Simulation and experimental results of the proposed controller with application to the boost and Ćuk converters are given to assess its effectiveness.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • $LCL$ +Filters&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&rft.date=2022&rft.volume=37&rft.spage=9200&rft.epage=9211&rft.aulast=Rodríguez;&rft.aufirst=Rasool&rft.au=Rasool+Heydari;Hector+Young;Freddy+Flores-Bahamonde;Sadegh+Vaez-Zadeh;Catalina+González-Castaño;Sanaz+Sabzevari;José+Rodríguez;">Model-Free Predictive Control of Grid-Forming Inverters With $LCL$ Filters
           

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      Authors: Rasool Heydari;Hector Young;Freddy Flores-Bahamonde;Sadegh Vaez-Zadeh;Catalina González-Castaño;Sanaz Sabzevari;José Rodríguez;
      Pages: 9200 - 9211
      Abstract: With the increasing penetration of distributed energy resources into islanded microgrids, a grid-forming inverter (GFI) has become the key element interfacing renewable energy sources. Usually, the GFI is employed with an output filter to minimize the harmonic content achieving high-quality output voltage regulation. To this end, model-predictive control (MPC) has been widely proposed to control the output voltage of GFI systems due to the high-quality performance, fast control response, and straightforward handling of constraints. However, an accurate model of the system is required for the conventional MPC to avoid a suboptimal performance under uncertainties. To overcome this known drawback, a novel model-free predictive control is proposed in this article. Consequently, the output voltage of an $LCL$-filtered GFI is regulated without the knowledge of the physical model.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Nonlinear Behavior and Reduced-Order Models of Islanded Microgrid

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      Authors: Jingxi Yang;Chi K. Tse;Dong Liu;
      Pages: 9212 - 9225
      Abstract: An islanded microgrid consisting of grid-forming converters, being a high-order nonlinear system, exhibits rich nonlinear dynamical phenomena. The use of appropriate reduced-order models offers useful physical insights into the behavior of the system without the need for excessive computational resources. In this article, we derive a number of reduced-order models capable of describing the slow-scale dynamics of an islanded microgrid comprising a number of grid-forming converters. It is shown that slow-scale Hopf and homoclinic bifurcation behaviors arise from the stability of the voltage loops of grid-forming converters and are unrelated to the transmission network dynamics. Therefore, omitting the network dynamics does not affect the accuracy of reduced-order models in representing the slow-scale dynamics of the system. This is especially beneficial for modeling the microgrid with a complex transmission network. Furthermore, on this basis, all inner loops can be omitted when studying saddle-node bifurcation, leading to the development of power-flow-based reduced-order models. Finally, the stability of an islanded microgrid with a complex transmission network is evaluated.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • $LCL$ +Inverter&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&rft.date=2022&rft.volume=37&rft.spage=9226&rft.epage=9240&rft.aulast=Preindl;&rft.aufirst=Liwei&rft.au=Liwei+Zhou;Matthias+Preindl;">Optimal Tracking and Resonance Damping Design of Cascaded Modular Model
           Predictive Control for a Common-Mode Stabilized Grid-Tied $LCL$ Inverter

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      Authors: Liwei Zhou;Matthias Preindl;
      Pages: 9226 - 9240
      Abstract: A cascaded modular model predictive control (MMPC) method is designed for a modified nonisolated $LCL$ grid-connected inverters to provide resonance damping, improved dynamic performance, and leakage current attenuation capabilities. The continuous control set model predictive control strategy is applied for the proposed method. The active damping function of the inner loop MMPC is analyzed in detail to illustrate the mechanism of improving the system dynamic performance. The cascaded MMPC method is compared with the conventional proportional-integral (PI) control methods with/without a notch filter to show the merits in resonance damping and dynamic response. The optimal control parameters design procedure is elucidated with the tuning mechanism of the MMPC weighing factor and PI gain. With the proposed optimal MMPC design method, the dynamic performance of rising time and overshoot are improved compared to the conventional PI control methods with/without the notch filter. The simulation and experimental results verified the proposed control design method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Internal Model Direct Power Control With Improved Voltage Balancing
           Strategy for Single-Phase Cascaded H-Bridge Rectifiers

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      Authors: Haoran Liu;Lei Ma;Wensheng Song;Lin Peng;
      Pages: 9241 - 9253
      Abstract: Single-phase cascaded H-bridge rectifiers (CHBR) are widely studied for vehicular power electronic transformers. In this article, an internal model direct power control (IM-DPC) with a voltage balancing strategy is proposed to improve the control performance of CHBR. First, a modified power control structure is built by the relationship of coordinate transformation. On this basis, the IM-DPC method is presented to obtain a straightforward design for the inner-loop. This approach can be implemented without phase-locked loop, and coordinate transformation is not necessary as well. Then, a first-order transfer function between the difference of dc-side voltage square and that of power is constructed. Further, a novel calculation structure for the compensation duty cycle is proposed. Through the proposed voltage balancing control scheme, the dynamic performance of the dc-side voltage is improved when load unbalancing occurs. The coupling effect between the overall control for the CHBR is also eliminated. Finally, experimental prototype tests are conducted to verify the effectiveness of the proposed method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Efficient Sorting Algorithm for Capacitor Voltage Balance of Modular
           Multilevel Converter With Space Vector Pulsewidth Modulation

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      Authors: Aswini Kumar Muthavarapu;Jayanta Biswas;Mukti Barai;
      Pages: 9254 - 9265
      Abstract: Thisarticle presents an efficient analogue sorting algorithm for balancing the submodule (SM) capacitor voltages of modular multilevel converter (MMC). The proposed analogue sorting algorithm offers the advantage of fast convergence rate without any need of recursive loops for the implementation on embedded devices. It can be easily implemented with combinational logic operations on field programmable gate array (FPGA) and provides less hardware and computational overhead. The functionality and performance of the proposed analogue sorting algorithm is evaluated with the simulation model of three phase five-level MMC in MATLAB/Simulink environment. The real time implementation of the proposed sorting algorithm with the SM capacitor voltage balancing strategy is implemented on Altera/Cylone - I (EP1C12Q240C8N) FPGA. A five-level continuous space vector pulsewidth modulation (CSVPWM) is realized on a PIC microcontroller (PIC18F452). A down-scaled model of single-phase five-level MMC is designed and constructed to investigate the reliable and stable operation of MMC with the proposed analogue sorting algorithm and SVPWM method. Simulation and experimental results are presented for validation.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Current-Sensorless Energy-Shaping Output Voltage-Tracking Control for
           dc/dc Boost Converters With Damping Adaptation Mechanism

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      Authors: Seok-Kyoon Kim;Kyo-Beum Lee;
      Pages: 9266 - 9274
      Abstract: This article exhibits an output voltage-derivative observer-based output voltage-tracking technique for dc/dc boost converters without current feedback, taking the model-plant mismatches (caused by parameter and load variations) and model nonlinearity into consideration. In contrast to extant passivity-based approaches, the proposed solution includes observers to estimate the output voltage derivative and does not require exact model information, which offers a few features: converter parameter information-free output voltage-derivative observers including the modified disturbance observation algorithm for improving the high-frequency disturbance rejection capability as a replacement of the estimation error integral actions, and the observer-based output voltage and its derivative error stabilizer with a damping adaptation mechanism assigning the desired energy function to the closed-loop system. Experimental verification is provided to demonstrate the practical advantages of the proposed solution using a 3-kW bidirectional converter.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Improved Switching Ripple Modulation Strategy for Simultaneous Power
           Conversion and Data Communication in DC–DC Converters

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      Authors: Jinghui Chen;Jiande Wu;Keming Liu;Ruichi Wang;Wuhua Li;Xiangning He;
      Pages: 9275 - 9284
      Abstract: Switching ripple communication (SRC), which modulates the PWM carrier with digital data and takes the switching ripple as a signal carrier, helps power electronic converters to transfer digital data along with power. This article discusses the theory and implementation of SRC technology. It proves that the modulation using square wave and sinusoidal wave carriers is compatible. The fundamental principles of frequency hopping–differential phase shift keying (FH–DPSK) modulation are then analyzed in detail, and an improved FH–DPSK scheme is proposed to suppress output voltage disturbances, thereby maintaining power quality, reducing communication noise, and separating power control and data modulation. Furthermore, to evaluate the reliability of the communication technique, the effect of power conversion on communication is discussed in detail. Finally, a buck converter with a switching frequency of 100/83.3 kHz is set up, and the experiment achieves a 16.7 kbps bit rate using quaternary modulation, demonstrating the correctness of the scheme.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Variable Turn-OFF Gate Voltage Drive for Voltage Balancing of High-Speed
           SiC MOSFETs in Series-Connection

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      Authors: Ye Zhou;Liang Xian;Xu Wang;
      Pages: 9285 - 9297
      Abstract: Active gate drive with high accurate and self-adaptive closed-loop control is a promising approach to solving the imbalanced voltage problem of series-connected silicon carbide (SiC) mosfets. However, due to the inherent time propagation mismatching between Si- and SiC-based devices, behavior adjustment through Si-based ICs during the switching transient takes at least tens of nanoseconds, which limits the minimum allowable turn-off time of each series unit. In this article, a novel active gate drive with a variable gate voltage regulator (GVR) is proposed. It uses a single P-channel mosfet to determine the connection timing of a precharged capacitor in series with the input capacitance in which way the switching transient of each device in the stack is adjustable. It is more advantageous when applied to the low-power SiC mosfet applications with relatively smaller external gate resistors. Two sampling and voltage balancing control circuits based on different processors are proposed for the GVR to adapt to different switching frequencies and costs. Its operational principle and design guidelines are specified and its performance on voltage balancing control is experimentally verified. Analytical assessment on switching losses and costs, compared with the previous work, is provided.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Graph-Model-Based Generative Layout Optimization for Heterogeneous SiC
           Multichip Power Modules With Reduced and Balanced Parasitic Inductance

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      Authors: Yu Zhou;Yuting Jin;Yu Chen;Haoze Luo;Wuhua Li;Xiangning He;
      Pages: 9298 - 9313
      Abstract: Multichip silicon carbide power modules with integrated snubbers are promising for large-capacity converters with high speed and cost efficiency. In the design stage, the parasitic inductance of module layout generally attracts the primary efforts of designers because of its severe impact on dynamic performance, e.g., voltage overshoot and transient current imbalance. However, due to the complexity of the heterogeneous layout, the solution space and development efficiency are always limited by the traditional manual design approach. Thus, this article proposes a generative method to optimize the layout autonomously. First, a graph model is built to describe heterogeneous layouts with all interconnectivity and design constraints retained. Based on the model, integer programming is introduced to generate layout templates with variable geometric topologies. Then, coupled with a self-developed discrete extractor, the Pareto-front is obtained by genetic algorithm, providing a tradeoff boundary for loop inductance and branch mismatch. The proposed method is systematic, flexible, and requires few designers’ expertise. A 1200 V/240 A half-bridge module is designed and fabricated to validate its capability. The experimental results show that the loop inductance of 5.59 nH is achieved, and less than 5% of the transient current imbalance is realized under 6.2 A/ns turn-on in the rated.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Integrated GaN Overcurrent Protection Circuit for Power HEMTs Using
           SenseHEMT

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      Authors: Wan Lin Jiang;Samantha Kadee Murray;Mohammad Shawkat Zaman;Herbert De Vleeschouwer;Peter Moens;Jaume Roig;Olivier Trescases;
      Pages: 9314 - 9324
      Abstract: GaN power high-electron-mobility transistors (HEMTs), with their fast switching transients and poor overcurrent tolerance, require overcurrent protection (OCP) circuits that can respond in under $text{0.5}, mu text{s}$. Monolithically integrating digital and analog circuits with GaN power devices is enabled by recent advancements in high-voltage GaN integrationplatforms. Thus, integrated OCP designs can be used to reduce the protection response time, the area penalty, and the assembly complexity. This work presents the first fully integrated, senseHEMT-based GaN OCP integrated circuit (IC) with an adjustable current limit and programmable blanking time, suitable for a wide range of power applications. The IC, implemented on a 200-V GaN-on-Silicon-on-Insulator (GaN-on-SOI) process, contains a power HEMT with a senseHEMT for current sensing, a totem-pole-based gate driver, an analog comparator, and a set of logic circuits to enable high-speed closed-loop OCP. The fabricated design is tested in both a clamped switching setup and a 12–48 V boost converter. The minimum OCP response time is estimated to be 36 ns with $dI_{D}/dtgeq text{30},text{A}/mu text{s}$, one of the fastest amongst state-of-the-art OCP circuits for GaN.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • High-Efficiency Low-EMI Buck Converter Using Multistep PWL and PVT
           Insensitive Oscillator

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      Authors: Hong-Yi Huang;Harreez M. Villaruz;Nieva M. Mapula;
      Pages: 9325 - 9332
      Abstract: This article presents a high-efficiency buck converter with electromagnetic interference (EMI) reduction. The proposed buck converter employs a simple method of piecewise linear (PWL) modulation to mitigate EMI significantly. Since EMI reduction tradesoff with efficiency and ripple content, this work also integrates the design of process, voltage, and temperature (PVT) insensitive crystal-less oscillator. This technique limits the modulated switching frequency to remain within range across all process corners, supply voltage. and operating temperatures, thereby limiting the range of efficiencies and ripple content that the buck converter will incur throughout its operation. As a result, the tradeoff between efficiency and ripple content is optimized while maintaining lower output voltage spurious noise tone. The chip was implemented using the 0.18 μm 1p6m CMOS process. The measured results show that the power spectrum's peak noise is at −60.37 dBm, and the minimum efficiency is 93% with a ripple content of less than 43.7 mV for worst-case considering PVT variations at 2.2 V input, 1.7 V output with 100 mA load current.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Improved EMI Behavioral Modeling Method of Three-Phase Inverter Based on
           the Noise-Source Phase Alignment

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      Authors: Peng Zhou;Xuejun Pei;Kun Zhang;Yue Shan;
      Pages: 9333 - 9344
      Abstract: The electromagnetic interference (EMI) behavioral model (BM), including active one-port networks, is widely used to guide the EMI filter design. To build BM, the series and shunt impedance insertion (SSII) based modeling method is normally adopted. During the SSII-based modeling, the time-domain measurements under different impedance insertion cases are introduced. However, the noise-source phases are time-varying, which means that the noise-source phases are different under multiple measurements. The different noise-source phases cause the errors of BM. To address this shortcoming, this article investigates the effect of the noise-source phases on BM for the first time. The improved BM method based on the noise-source phase alignment is proposed. The improved BM method effectively improves the EMI prediction accuracy of BM with an error of 6 dB or less. The effectiveness of the improved modeling method for the conducted emissions estimation is verified in the three-phase inverter test prototype.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Common High-Frequency Bus-Based Cascaded Multilevel Solid-State
           Transformer With Ripple and Unbalance Power Decoupling Channel

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      Authors: Jiaxun Teng;Zemin Bu;Xiaofeng Sun;Huanshuai Fu;Wei Zhao;Xin Li;
      Pages: 9345 - 9361
      Abstract: A novel three-port cascaded multilevel solid-state transformer (CM-SST) is proposed in this article, which is based on modular multilevel converter submodules (SM) interconnected by high-frequency link (HFL), forming a decoupling channel to SMs and a low-voltage dc port. The common high-frequency bus in HFL helps to reduce the numbers of secondary full bridges in the form of multiplexing. The decoupling channel achieves the automatic balancing of capacitors voltage and natural elimination of SM ripple power, so the arms second-order circulating current can be eliminated from the root cause. Therefore, the CM-SST can simultaneously realize the switches decreasing, capacitance size reducing, arms circulating current elimination, and control simplification. In this article, the topology, equivalent model, HFL design, ripple-power decoupling, power loss, and control scheme are analyzed in detail. In addition, an evaluation of CM-SST compared with the traditional methods is provided, including sizing, components count, control, and efficiency. Finally, the correctness and effectiveness of the proposed scheme are verified by the simulation and experiment.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Improved Modulation Strategy for Reactive Energy Transmission Loss of
           Auxiliary Commutated Circuit of Novel Parallel RDCL Inverter

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      Authors: Si Li;Ming Yang;Yu Ma;Jiang Long;Yangyang Chen;Dianguo Xu;Frede Blaabjerg;
      Pages: 9362 - 9376
      Abstract: To overcome the challenges of large reactive energy transmission loss and high current stress, which ocurr during the operation of auxiliary commutated circuit (ACC) of novel parallel resonant dc-link inverter (PRDCLI), an improved modulation strategy for reactive energy transmission loss is herein proposed based on the discontinuous pulsewidth modulation (DPWM), which adopts sawtooth carrier wave with alternating positive and negative slopes and shunt dead zone. Compared with the original modulation strategy, based on minimizing the ACC operation frequency, the proposed modulation strategy is able to realize all switches soft-switching, and avoid the superposition of resonant current and load current during the operation of ACC, thus, effectively reducing the reactive energy transmission loss and the current stress of auxiliary switches of the ACC. Under the proposed modulation strategy, the equivalent circuits in different operation modes are divided, and the operation principle, voltage/current stress, loss distribution, and optimal parameter design method of novel PRDCLI are researched. Eventually, the proposed modulation strategy is verified by experiments on a 5-kW/40-kHz prototype made by SiC mosfet.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Generalized Simplified Virtual Vector PWM to Balance the Capacitor
           Voltages of Multilevel Diode-Clamped Converters

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      Authors: Qamar Muhammad Attique;Kui Wang;Zedong Zheng;Hong Zhu;Yongdong Li;Jose Rodriguez;
      Pages: 9377 - 9391
      Abstract: This article presents a generalized simplified virtual vector pulsewidth modulation (SVVPWM) to attain the capacitor voltage balancing of multilevel diode-clamped converter (DCC) for all operational conditions, which is not possible by using conventional space vector pulsewidth modulation (PWM) and carrier-based PWM methods. Virtual vector PWM is a solution presented in the literature to sort out this issue but it becomes more complex for higher level converters. The proposed SVVPWM method is simple and easy to implement for any level converter because it converts the space vector (SV) diagram of any level converter to three-level SV diagram. The SVVPWM assures the natural voltage balancing under steady states and ideal operations. Under dynamic operations, a generalized equation that describes the influence of neutral point currents on dc-link capacitor's voltage has been derived and a general decoupled voltage balancing control for n-level DCC is presented. The proposed modulation method is implemented on five-level and seven-level DCCs to authenticate the effectiveness of decoupled voltage balancing control. Simulation and experimental results demonstrate that the proposed modulation strategy is easy to implement and effectively controls the balance of the capacitor voltages for the whole range of modulation index and load power factor.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Design and Optimization of a Magnetron DC–DC Isolated Power Supply
           With High Efficiency

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      Authors: Junkun Zhang;Bing Gao;Zhixing He;Lei Wang;Renjie Hou;Yang Liu;An Luo;Yandong Chen;Rong Han;
      Pages: 9392 - 9405
      Abstract: High-efficiency high voltage dc power supply is the core equipment for magnetron in the microwave industry. This article presents an input-parallel output-serial modular high isolated resonant converter for the magnetron. However, the high stray capacitance of the high isolation transformer brings some challenges, such as high turn-off current, longer dead time, increasing gain, and transformer optimization. A simplified model including the stray capacitances is built to deal with these problems, and the minimum turn-off current is derived after the detailed time-domain analysis. The appropriate deadtime and the maximum magnetic inductance needed for the proposed converter are obtained with the minimum turn-off current. Then, a 15 kW, 60 kV isolation multiple-windings output transformer is designed and optimized for the converter. The insulation design, core shape, losses, and parasitic parameters are calculated thoroughly. The Pareto optimization process optimizes the switching frequency and the transformer's turns to obtain higher efficiency and a more stable gain. The finite element method and time-domain simulation verified the optimized design results. Finally, a 0.8/2.5 kV, 15 kW all-SiC dc–dc converter module is developed to validate the proposed design. The results indicate that the module efficiency is as high as 98.6%.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Compact Solid-State Marx Modulator With Fast Switching for Nanosecond
           Pulse

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      Authors: Jung-Soo Bae;Tae-Hyun Kim;Seong-Ho Son;Chang-Hyun Gwon;Hyoung-Suk Kim;Chan-Hun Yu;Sung-Roc Jang;
      Pages: 9406 - 9414
      Abstract: This article describes the compact solid-state Marx modulator (SSMM) with a fast rising time and a short pulsewidth based on the modular structure. By stacking of the TO-263-7 packaged silicon carbide mosfets having high voltage and fast switching capabilities, the designed circuit consists of three components, including the Marx capacitor, an on switch for applying pulse to the load, and an off switch to pull down the pulse. The off switch connected in parallel with load is chosen as a mosfet instead of a diode that is used in the conventional Marx generator. Because the off switch provides a discharging path for the stored energy on the parasitic capacitance, it is highly related to the fast falling time. In order to provide complementary driving signal and power for on/off switches, the simple control algorithm with a minimum component count and a reliable drive circuit against the noise are proposed. In addition, the synchronization of all the gate signals and a compact configuration for minimizing the stray inductance are essential to shorten the rising, falling, and pulsewidth. Based on the proposed circuit, the following specifications of the developed SSMM are achieved: the output voltage of 10 kV, the pulsewidth of less than 50 ns, and the rising and falling times of less than 15 ns.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A MHz-Pulse-Transformer Isolated Gate Driver With Signal-Power Integrated
           Transmission for Medium-Voltage SiC MOSFETs

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      Authors: Zhehui Guo;Hui Li;
      Pages: 9415 - 9427
      Abstract: The conventional isolated gate driver (GD) solution for the medium-voltage (MV) SiC mosfet separates the signal and power transmissions and requires a bulky GD power supply (GDPS). This article presents a signal-power integrated GD for MV SiC mosfets with a compact footprint. The proposed GD transmits both the pulsewidth modulation (PWM) signal and GD power by 20-MHz modulated class-E resonant flyback converters, where the transmitted GD power can maintain constant within the full PWM duty-cycle range (i.e., 0%–100%). In addition, the PWM signal transmission of the proposed GD achieves a low total propagation delay time < 75 ns by utilizing the fast transient of 20-MHz RFCs and the edge-based envelope detector. A printed-circuit-board-based coreless transformer is integrated into the proposed GD to achieve an insulation voltage higher than 10 kVRMS and a low coupling capacitance of 5.85 pF. The common-mode transient immunity of proposed GD is higher than 100 V/ns, which is beneficial to drive MV SiC mosfets with high dv/dt. The proposed GD does not require additional GDPSs nor fiber-optics, which achieves a smaller size compared to conventional isolated GDs and is promising to be integrated into SiC mosfet module packages. Experimental results on 3.3 kV and 10 kV SiC mosfets are provided to validate the effectiveness of the proposed GD.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A PFM Boost Harvester With System-Level Self-Tuned Maximum Power Point
           Tracking

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      Authors: Edward Lee;Venkata Chaitanya Krishna Chekuri;Saibal Mukhopadhyay;
      Pages: 9428 - 9442
      Abstract: This article presents a low-overhead energy harvesting and delivery system (EHDS) with pulse frequency modulated (PFM) integrated voltage regulator (IVR) power conversion and self-tuned maximization of system output power. A novel load-inclusive time-based maximum power point tracking (LI-TB-MPPT) is developed to provide centralized tuning of PFM-IVR operation based on both source capabilities and load demand on-the-fly, and a configurable fractional sample and hold circuit provides adaptive harvesting window control. The proposed EHDS enables robust harvesting while relieving the use of high passives, with over two orders of magnitude reduction, at the cost of only slight decrease in end-to-end efficiency compared to prior works. Furthermore, a low-overhead wake-up assist circuit utilizes cold-configuration of harvesting sources for efficient and accelerated cold-start. The proposed EHDS is demonstrated in a 65 nm CMOS process with commercial photovoltaic energy harvesting modules. Using only 1.2 and 1 $mu$H of passives, measured results show a peak 74.9% end-to-end efficiency (simulated up to 85% at 47$mu$H) and a fast startup time of 3.8 ms. Up to 15% increase in conversion efficiency against load and input voltage variations is achieved with LI-TB-MPPT. The results demonstrate a compact solution for self-sustained cost-restricted stand-alone systems.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Simple and Seamless PWM Scheme of Isolated Bidirectional AC–DC Converter
           for Reducing Voltage Spike

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      Authors: Jeong-Tae Kim;Sung-Min Park;
      Pages: 9443 - 9454
      Abstract: This article proposes an improved modulation scheme based on unipolar sinusoidal pulsewidth modulation for a single-phase single-stage isolated bidirectional ac–dc converter. A direct ac–ac conversion system connected with a high-frequency transformer typically suffers from high-voltage spikes because of the leakage inductors of the high-frequency transformer and the grid filter inductors, resulting in reduced reliability and large power losses. The proposed modulation scheme can eliminate the high-voltage spikes in bidirectional power flow without the use of additional circuits while realizing zero-voltage switching. In addition, because the proposed method does not require individual gate control of the bidirectional power switches, the generation of gate signals can be simplified using the proposed modulation scheme. A simulation model and a 1.2 kW grid-connected ac–dc converter based on silicon-carbide metal–oxide–semiconductor field-effect transistors are implemented to validate the effectiveness of the proposed modulation scheme.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Modulation Method for Capacitance Reduction in Active-Clamp
           Flyback-Based AC–DC Adapters

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      Authors: Huan Li;Sinan Li;Weidong Xiao;Shu Yuen Ron Hui;
      Pages: 9455 - 9467
      Abstract: Recent developments of fast-charging power delivery protocols are driving ac–dc adapters to 100-W power ranges. Conventional solutions in this power range employing a two-stage topology and a big twice-line frequency buffer capacitor are generally costly and bulky. This article presents a patent-pending modulation method for an active-clamp flyback converter, allowing for a single-stage adapter design with reduced capacitance requirements and higher efficiency. This is achieved by exploiting the inherent energy storage capability of the clamping capacitor while turning it into an active power buffer. No hardware modifications are needed, while all salient features of active-clamp flyback converter, i.e., soft switching and leakage recycling, are retained. Operating principles and detailed controller design are discussed, and a 100-W laboratory prototype is built. The prototype achieves 94% peak efficiency and up to 92% size reduction of the buffer capacitor. The experimental evaluation shows that the new single-stage solution enabled by the proposed modulation method is superior to the conventional two-stage and single-stage solutions in terms of cost, conversion efficiency, and power density.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Parallel Primary Windings Scheme for the Flyback Input-Series
           Transformer-Integration Converter

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      Authors: Tao Meng;Hongqi Ben;Shigang Wang;Chunyan Li;
      Pages: 9468 - 9480
      Abstract: A parallel primary windings (PWs) scheme is investigated for the integrated-transformer of the flyback input-series transformer-integration (ISTI) converter. Compared to the existing layer-by-layer PWs, the parallel PWs are easy to be manufactured, and active input voltage sharing performance of the converter can be improved if the parallel PWs scheme is adopted. Energy influences of the stray capacitances are slightly larger in the parallel PWs than those in the layer-by-layer PWs, but this difference will decrease as the layer number of each PW increases. Based on the two-transistor flyback ISTI converter, the parallel PWs is analyzed in detail compared to the layer-by-layer PWs, through which applications of the parallel PWs scheme are concluded. Finally, experimental comparisons have been done on a laboratory-made flyback ISTI converter with five different integrated-transformers, and the theoretical analysis is verified by the experimental results.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A 13.56-MHz ZVS Inverter for Radio-Frequency Capacitively Coupled Plasma
           Power Supply

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      Authors: Si Chen;Xinbo Ruan;Ying Li;
      Pages: 9481 - 9491
      Abstract: Plasma power supply is an important equipment to output an adjustable radio-frequency voltage for generating capacitively coupled plasma (CCP). Nowadays, radio-frequency power amplifier (RFPA) is popular for implementing plasma power supply. However, a bulky matching network is needed to be located between the RFPA and CCP, resulting in low power density and high system complexity. In this article, a buck-type inverter is proposed to directly power CCP, which not only outputs an RF ac voltage with low harmonics, but also realizes zero-voltage-switching for power switch over a wide capacitive load range. The derivation of the buck-type inverter is presented, and a step-by-step parameters design approach is proposed. Finally, a 13.56-MHz, 28-W prototypeis fabricated and a CCP discharge experiment is carried out. The experimental results are provided to verify the effectiveness of the proposed buck-type inverter and parameters design approach. The power density of prototype is 15 W/in3, which is much higher than traditional plasma power supply with 0.06 W/in3.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Analysis and Design of a Two-Phase Series Capacitor Dual-Path Hybrid DC-DC
           Converter

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      Authors: Yijie Wang;Jinfeng Zhang;Yueshi Guan;Dianguo Xu;
      Pages: 9492 - 9502
      Abstract: Inthis article, a two-phase series capacitor dual-path hybrid dc–dc converter with the step-down ratio of less than 1/6 is proposed for the first time. In this converter, the output current is divided into capacitance- and inductance-path, so the average value and ripple of inductance current are reduced. On the same time, the conduction loss caused by inductance equivalent series resistance (ESR) is also reduced. The addition of series capacitor leads to desirable characteristics, including lower switching stress, switching loss, parasitic output capacitance loss on mosfet, automatic phase current balancing, duty ratio extension, etc. A 120 W prototype has been designed to demonstrate theoretical analysis. Obtained efficiency was up to 93.18% at full load. Experimental results show good agreement with theoretical analysis and high feasibility of proposed converters.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Integrated Driver With Bang-Bang Dead-Time Control and Charge Sharing
           Bootstrap Circuit for GaN Synchronous Buck Converter

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      Authors: Ching-Jan Chen;Pin-Ying Wang;Sheng-Teng Li;Yen-Ming Chen;Yu-Cheng Chang;
      Pages: 9503 - 9514
      Abstract: This article proposes a high-frequency integrated gate driver for gallium nitride (GaN) synchronous buck converter. The proposed adaptive bang-bang dead-time control minimizes dead-time at any load condition. Thus, it mitigates the excessive power loss caused by GaN device reverse conduction in high-frequency applications. The proposed charge sharing bootstrap circuit ensures sufficient gate overdrive voltage with reduced chip area. Fabricated in a TSMC 0.25-μm BCD process, the driver integrated circuit enabled GaN-based buck converter to operate at 10 MHz switching frequency with minimal dead-time to as low as 0.4 ns under light load and heavy load conditions. Compared with fixed dead-time control, the proposed work improves around 5% efficiency under heavy load condition. The fully integrated bootstrap circuit with 100 and 60 pF (HV) capacitor obtained the lower than 0.6 V driving voltage drop with only 45% capacitance and around half of the voltage drop compared with a conventional bootstrap circuit. Besides, the proposed driver successfully tackled the parasitic ringing and dead-time overcharging issues in the GaN converter.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Resonant Bridgeless Buck PFC Converter With Reduced Components and Dead
           Angle Elimination

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      Authors: Fatemeh Sahlabadi;Mohammad Rouhollah Yazdani;Jawad Faiz;Ehsan Adib;
      Pages: 9515 - 9523
      Abstract: The inherent dead angles of the input line current in buck power factor correction (PFC) converter deteriorates the power factor (PF). This article introduces a new bridgeless single-phase buck (PFC) converter with reduced components. This converter is designed to operate in discontinuous conduction mode (DCM) to achieve inherent PFC with a simple structure. The DCM operation gives additional advantages, such as low turn-on losses and reduced complexity of the control circuitry. Unlike the buck PFCs, in which dead angle is the main drawback, in the proposed converter the PF is improved and the dead angle is eliminated by applying an auxiliary switch. Besides, the efficiency is further improved by employing the bridgeless structure. The switching losses are eliminated due to achieved zero current switching (ZCS) at the turn-on and turn-off of the main switches, and also ZCS at the turn-on and zero voltage switching at turn-off of the auxiliary switch. The proposed topology is successfully implemented on a 120 W prototype converter at 110 Vrms input voltage and 48 V output voltages, and its performance is experimentally verified. The results show the total harmonic distortion of 5.3% and efficiency of 93.1% at the rated load.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Bidirectional Q-Z-Source DC Circuit Breaker

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      Authors: Lifang Yi;Jinyeong Moon;
      Pages: 9524 - 9538
      Abstract: In this article, a novel Z-source dc circuit breaker topology with a Q-shaped impedance network (Q-Z-source circuit breaker) is presented. The new topology has a better performance and is more resilient properties than those of the recently published O-Z-source circuit breaker. The new Q-Z topology provides bidirectional protection but only requires one semiconductor switch in its current path during normal operation, leading to a simpler and smaller physical structure and a lower conduction penalty. It also drastically improves the sensitivity issue on the magnetic coupling coefficient that manifests in the existing O-Z-source circuit breaker. In a realistic, practical application with a nonideal magnetic coupling coefficient, the new topology requires a smaller capacitance that can be translated into lower weight and/or lower cost. Detailed mathematical models are built to analyze and compare the short-circuit fault responses of a variable coupling coefficient. The bidirectional snubber circuit and its connection to the Q-Z topology are discussed for achieving faster fault clearing. Finally, a prototype is built in the laboratory to verify the theoretical analysis and improved performance of the proposed bidirectional Q-Z-source dc circuit breaker.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Control Strategy of a Five-Phase Induction Machine Supplied by the Current
           Source Inverter With the Third Harmonic Injection

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      Authors: Marcin Morawiec;Filip Wilczyński;
      Pages: 9539 - 9550
      Abstract: In the five-phase induction machine (IM), it is possible to better use the electromagnetic circuit than in the three-phase IM. This requires the use of an adequate converter system which will be supplied by an induction machine. The electric drive system described, in this article, includes the five-phase induction machine supplied by the current source inverter (CSI). The proposed novelty—not presented previously—is the control system structures for the five-phase IM, which is supplied by CSI. The proposed control systems allow for independent control of IM state variables in the first and the second system plane to inject the third harmonic. However, the third harmonic must be suitably associated with the fundamental harmonic. In the proposed solution, the machine vector model is not transformed into the (d–q) coordinate system that is connected to the rotor flux vector but utilizes the stationary system (α–β). The nonlinear model linearization is based on the demonstrated nonlinear variables transformation for i-orthogonal (α–β) (i) planes. Voltage control is applied to the control system structure. The control variables of the five-phase IM are the voltage in the dc link and the angular speed of the output current vector. In the control strategy, the control variables are determined for both system planes. Therefore, the transformation of these control variables to the dc link of CSI is proposed. The proposed control structure allows for independent control of variables in the first and second system planes. It leads to the possibility to increase the value of electromagnetic torque up to 12% for the five-phase IM, which has not been used before in the case of the machine supplied by the CSI. All theoretical issues are confi-med by experimental tests in the 5.5 kW five-phase IM.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Datasheet Driven Switching Loss, Turn-ON/OFF Overvoltage, di/dt, and dv/dt
           Prediction Method for SiC MOSFET

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      Authors: Cheng Qian;Zhiqiang Wang;Guoqing Xin;Xiaojie Shi;
      Pages: 9551 - 9570
      Abstract: This article presents quick analytical prediction methods of switching loss, turn-on/off overvoltage, di/dt, and dv/dt for SiC metal–oxide–semiconductor field-effect transistor based on device datasheet. First, the switching process is analyzed and the simplification principles are discussed based on charge conservation and flux conservation. Second, the analytical equations of switching loss, turn-on/off overvoltage, di/dt, and dv/dt are derived. Third, experimental results under different operating conditions are presented to validate the proposed methods. It is found that the average prediction error is 10.11%. Finally, relationships between switching performance and different parameters, such as parasitic capacitance, parasitic inductance, dc-voltage, and load current, are analyzed and summarized based on the proposed prediction methods.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Analysis and Control of Current Harmonic in IPMSM Field-Oriented Control
           System

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      Authors: Zhiwei Chen;Tingna Shi;Zhichen Lin;Zhiqiang Wang;Xin Gu;
      Pages: 9571 - 9585
      Abstract: There is a certain amount of current harmonics in interior permanent magnet synchronous motor. In order to accurately control the current harmonic, this article focuses on three aspects: establishing current harmonic calculation model, extracting current harmonic, and designing current harmonic regulator. A current harmonic calculation model, which considers the effect of voltage harmonics induced by current controllers and digital control delay on the initial phase angle of voltage harmonics, is established for the first time. With the help of multiple synchronous rotating frame transformation, a current harmonic extraction method more suitable for motor drive field, which aims to extract the current harmonic characteristics of d-axis and q-axis currents, is proposed. On this basis, the controlled quantity and control quantity are unified in d–q coordinate frame for analyzing the coupling relationship of current harmonic characteristics. And then a PI current harmonic regulator, including current harmonic decoupling and voltage harmonic initial phase angle compensation, is constructed, so as to realize the effective control of current harmonics. Finally, the effectiveness and superiority of the proposed method are verified by simulation and experiments.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Model Predictive Direct Speed Control With Novel Cost Function for SMPMSM
           Drives

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      Authors: Liguo Yang;Hongmei Li;Jiandong Huang;Zheng Zhang;Haonan Zhao;
      Pages: 9586 - 9595
      Abstract: The model predictive direct speed control (MPDSC) can improve the speed dynamic performance effectively. However, due to the large difference between the mechanical and electrical time constants, short prediction could result in large current ripples at steady state, which becomes a critical problem. Besides, the conventional MPDSC methods have not deeply investigated the online-adjustable weighting factor design and the problem of id transient oscillation. In this article, a model predictive direct speed control with novel cost function is proposed. In the proposed method, two different q-axis current references are generated, one to improve the speed dynamics, and the other to ensure the low current ripples. The two current tracking are assigned with different weighting factors unified in one cost function. In order to determine which current tracking to play a major role under different operations, the speed error is designed as weighting factor. With the proposed cost function and designed weighting factor, the high speed dynamics and low steady current ripples can be achieved simultaneously. Finally, the effectiveness of proposed method is verified by experiments.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Multiple-Models Adaptive Disturbance Observer-Based Predictive Control for
           Linear Permanent-Magnet Synchronous Motor Vector Drive

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      Authors: Cong Bai;Zhonggang Yin;Yanping Zhang;Jing Liu;
      Pages: 9596 - 9611
      Abstract: To achieve high-performance control of the precise linear permanent-magnet synchronous motor (LPMSM) control system, a composite robust current regulation method with good dynamic response and disturbance rejection performance is proposed. First, a continuous time model predictive current control is utilized to obtain superior current response. Since the predictive current control has a strong dependence on the precise mathematical model of the controlled plant, there will be static current error and even system instability when model mismatch and parameter variation. Then, aiming at this problem, the adaptive disturbance observer is applied to compensate the lumped disturbance. However, the adaptive disturbance observer designed based on the single model adaptive law has some disadvantages, such as low precision, long regulation time, poor transient response, and so on. Consequently, a multiple-models adaptive disturbance observer is proposed, which improves the convergence speed of disturbance estimation and system's robustness against parameter perturbation and model mismatch. Finally, a 0.9-kW LPMSM is used as a case study, and the experimental results show the effectiveness of the proposed solution, both during the transient and steady-state operating conditions.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • $dv/dt$ )+Profiling&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&rft.date=2022&rft.volume=37&rft.spage=9612&rft.epage=9628&rft.aulast=Wei;&rft.aufirst=Wenzhi&rft.au=Wenzhi+Zhou;Mohamed+Diab;Xibo+Yuan;Chen+Wei;">Mitigation of Motor Overvoltage in SiC-Based Drives Using Soft-Switching
           Voltage Slew-Rate ( $dv/dt$ ) Profiling

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      Authors: Wenzhi Zhou;Mohamed Diab;Xibo Yuan;Chen Wei;
      Pages: 9612 - 9628
      Abstract: In silicon carbide (SiC) device based motor drives, the high-voltage slew-rate (dv/dt) associated with the fast-switching transitions results in excessive motor overvoltage, due to the reflected wave phenomenon, which increases the motor winding insulation stress and causes premature failure while raising electromagnetic interference (EMI) problems. This article proposes a soft-switching voltage slew-rate profiling approach to mitigate the motor overvoltage in SiC-based cable-fed drives. The proposed approach optimizes the rise/fall time of the output voltage according to the cable length, without altering the switching speed of the SiC devices. Since increasing the switching rise/fall time using conventional approaches, such as increasing the gate resistance, results in an increased switching power loss, the proposed profiling approach is implemented using a soft-switching inverter. The optimum rise/fall time that can significantly mitigate the overvoltage is derived using frequency- and time-domain analysis. The auxiliary resonant commutated pole inverter (ARCPI) is adopted as an example of the soft-switching inverter to experimentally verify the proposed slew-rate profiling approach for the overvoltage mitigation. The analysis and experimental results show that the motor overvoltage is fully mitigated when the output voltage rise/fall time is set as the cable antiresonance period, i.e., four times of the wave transmission time along the cable. Furthermore, the slew-rate profiling approach along with the ARCPI reduces the switching loss and improves the EMI performance at the high-frequency region, compared with the conventional hard-switching converter. Specifically, the maximum efficiency of the ARCPI is about 99%.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Maximum Torque Operation of Open-Winding Induction Motor Dual Drives Using
           a Floating Capacitor Bridge in the Field Weakening Region

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      Authors: Saeed Wdaan;Chatumal Perera;John Salmon;
      Pages: 9629 - 9640
      Abstract: A field weakening controller is presented that extends the speed range of a dual inverter drive using a floating capacitor bridge. The controller utilizes the stator current reference frame to decouple the motor demand into active and reactive components. This is used so that the main bridge supplies the real power and the floating bridge supplies the reactive power until the floating bridge reaches its maximum voltage. The main bridge is then used to supply some of the reactive demand, which in turn adds additional voltage boost that is used to extend the drive’s constant power region, improve the motor speed acceleration performance, output power, and torque. It is found that the presented controller can increase the drive speed extension ratio to 9.2 times the base speed compared to 5 when always operating the main bridge at unity power factor. The motor maximum fundamental voltage is 1.82 p.u when compared to that of a single inverter drive. This controller performance is demonstrated experimentally using both transient and steady-state analysis. The controller is also compared with other two field weakening controllers using the same regulator tunings and experimental setup.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Active Disturbance Rejection Control of a Magnetic Screw Motor for High
           Tracking Performance

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      Authors: Guohai Liu;Lixian Fang;Zhengmeng Liu;Qian Chen;Jiahao Zhang;
      Pages: 9641 - 9651
      Abstract: A magnetic screw motor integrated by a magnetic screw and a permanent magnet synchronous motor offers high thrust density without friction and loss. However, its internal structure is complicated, resulting in difficulty to control its linear displacement to track the given signal in time and even getting out of control due to interference. In this article, to improve the tracking performance and anti-interference performance of the system, an active disturbance rejection controller (ADRC) is adopted to improve the current loop and makes up for nonlinear regional control in the closed-loop control system. To ensure the stability of the proposed scheme in the entire operation range, the design and the stability analysis are carried out in the continuous-time domain. The novel control algorithm enhances the flexibility of the magnetic screw motor by optimizing the nonlinear function in ADRC. In addition, to highlight the high-performance control of the ADRC for the magnetic screw motor, sliding mode control and PI control are added to compare with it. Finally, the reciprocating motion control is added to show the diversity of the functions of the magnetic screw motor, which verifies the effectiveness and feasibility of the control algorithm.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Carrier Transition Techniques for Parallel Connected VSCs Using
           Cross-Coupled Inductors

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      Authors: Chenhui Zhang;Marius Takongmo;Saeed Wdaan;Wael A. M. Telmesani;Dohitha Yapa;John Salmon;
      Pages: 9652 - 9662
      Abstract: Parallel inverters can be connected using cross-coupled inductors (CIs) to produce high-quality line voltages in three-phase ac systems. Since no fundamental flux is present in the inductor cores, their size can be made considerably smaller than alternative inductor configurations. Interleaved switching and phase-shifted carriers (PS-PWM) can be used to produce multilevel three-phase line voltages. A modified approach (MPS-PWM) improves the quality of the line voltages by changing the phase of the carriers, carrier swapping, based upon the magnitude of the modulating signals. Since carrier swapping in MPS-PWM can cause the inductor circulating currents and flux patterns to jump and have dc offsets, two carrier transition techniques are presented to eliminate these jumps: carrier manipulation and pulse injection. These techniques represent open-loop PWM control, dependent only on the carrier phase change being used, and can easily be applied to an arbitrary number of parallel-connected inverters. The circulating currents and inductor flux patterns follow predictable patterns, allowing the CIs to be designed more precisely. The relative merits of using MPS-PWM over PS-PWM are assessed using measurements of the load current total harmonic distortion and the line voltage harmonic volt–seconds. The feasibility of the parallel inverter system described is verified using simulations and results from an experimental laboratory prototype.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Operation and Control of Bipolar-Type Modular Solid State Transformer With
           Active Circulating Current Injection and Arm Voltage Adjusting Method

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      Authors: Jianqiao Zhou;Jianwen Zhang;Jiacheng Wang;Gang Shi;Jiajie Zang;Xin Feng;Xu Cai;
      Pages: 9663 - 9673
      Abstract: Modular multilevel converter (MMC) based solid state transformer (M-SST) shows promise in hybrid ac/dc distribution grids. To further meet low voltage dc (LVdc) users’ requirements, a bipolar-type M-SST (BM-SST) is developed in this article, which not only has medium voltage ac and dc ports but also directly provides a bipolar low voltage dc (BLVdc) port for various LVdc sources and loads such that an extra SST or voltage balancer for achieving similar outcomes could be saved. Featuring various ac and dc ports, easy voltage conversion, and flexible power control capability, BM-SST is most suitable for multiple ac and dc grids interconnection as an energy hub. The most crucial issue of BM-SST is how to deal with the unbalanced power caused by the bipolar LVdc port which leads to submodule capacitor voltage deviation and uncontrollable circulating current between upper and lower arms of MMC. An arm voltage regulation (AVR) combing with active circulating current injection (ACCI) method is proposed in this article to eliminate the unbalanced power and its negative effects. Based on detailed circuit analysis of the BM-SST, the coordinated control of the BM-SST with optimum AVR&ACCI is designed. Moreover, the effects of AVR&ACCI method on current stress, voltage stress, and power loss of BM-SST are evaluated. The feasibility of the proposed BM-SST has been verified by experimental results.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Mixed Conduction Mode-Controlled Bridgeless Boost PFC Converter and Its
           Mission Profile-Based Reliability Analysis

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      Authors: Zhengge Chen;Jianping Xu;Pooya Davari;Huai Wang;
      Pages: 9674 - 9686
      Abstract: Given the telecom base transceiver station (BTS) load mission profiles, a mixed conduction mode (MCM) control for a bridgeless boost PFC converter (IPOS boost) is proposed to mainly improve its power factor and reduce the input current total harmonic distortion (THD${_{mathit{i}}}$) in the light-load conditions. The principle of the MCM control and the efficiency analysis are introduced. Then, the experimental verification is performed to show the control effectiveness and performance improvements. Furthermore, a mission profile-based reliability assessment for the PFC converter is presented to analyze the IPOS boost under the classical average current (AVC) control and the proposed MCM control, along with its conventional boost counterpart under the AVC control. Considering the measured efficiency data and BTS typical mission profiles in a rural area, the analysis results indicate that given 20 years of operation, the accumulated failure of the IPOS boost under the AVC controls is 0.27%, and is further decreased to 0.24% by just the software update with the proposed MCM control. By contrast, the accumulated failure of the conventional boost counterpart under the AVC control is 2.06%, much higher than the IPOS boost.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Wideband Series Harmonic Voltage Compensator for Enhancing Stability of
           Microgrids

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      Authors: Jacky Chun-Tak Lai;Henry Shu-Hung Chung;Yuanbin He;Weimin Wu;Frede Blaabjerg;
      Pages: 9687 - 9702
      Abstract: A wideband series harmonicvoltage compensator (WSHVC) for mitigating the adverse effect of unknown grid impedance and load condition on the stability of microgrids with multiple grid-connected inverters (GCIs) is presented. The concept is based on extending the concept of series active power filter. A wideband series voltage source inverter is used to compensate for the high-frequency harmonic voltage caused by the impedance at the point of common coupling, thereby creating a virtually zero high-frequency impedance at the output of the GCIs. The system stability is then assured under any operating condition. The bandwidth of the WSHVC ranges from the second harmonic of the grid frequency to 8 kHz, which is sufficiently higher than the cut-off frequency of typical GCIs. Such fast dynamic behavior is realized by a novel fixed-frequency predictive control scheme with nonlinear switching surfaces. Since the WSHVC handles harmonic power only, its volt-ampere rating is lower than that of the entire system. A 500 VA prototype for a 6.5 kVA testbed with three commercial GCIs, nonlinear load, and adjustable grid impedance has been evaluated. The power dissipation of the WSHVC is less than 1% of the VA rating of the testbed. The effectiveness of the WSHVC on improving system stability is studied.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Design of Common DC-Link Capacitor in Multiple-Drive System Based on
           Reduced DC-Link Current Harmonics Modulation

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      Authors: Silpa Baburajan;Haoran Wang;Fabio Mandrile;Bo Yao;Qian Wang;Dinesh Kumar;Frede Blaabjerg;
      Pages: 9703 - 9717
      Abstract: Many industrial applications are recently utilizing the advantages of a common dc-bus-based multiple-drive (multidrive) system, such as low installation cost, space savings as well as improved reliability, and flexibility. One of the main drawbacks of such systems is the requirement for a bulky dc capacitor due to the presence of large dc-link current ripples from the harmonic interaction between these multidrive and pulsewidth modulation (PWM) switching. This problem not only increases the cost and volume of the dc-link capacitors but also decreases its lifetime, which must be considered in the design from the industrial aspect. This article proposes a new dc-bus capacitor design method for a multidrive system, focused on the capacitor sizing, cost reduction, and lifetime improvements. First, an analytical model to obtain the dc-link capacitor current in a multidrive system is proposed, which would aid the designers to configure the dc-capacitor current in systems having numerous multiple drives. Next, using the developed analytical model, the dc-link current harmonics are reduced through optimal interleaving of the fundamental output currents in addition to the phase shifting of the carrier waves of the parallel connected inverters. Finally, new capacitor sizing/design is proposed considering the lifetime, power loss, cost, and volume of the dc-link capacitor bank. The proposed approach reduces the volume and cost of dc-cap bank by 50%, and increases the lifetime by four years ($sim$35 000 h), considering the worst-case scenarios. Experimental and analytical results are given for validation of the proposed method. The results could serve as a guideline for designing the dc-link capacitor in multidrive applications in a low-cost manner.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Hypothesis Method for T-Type Three-Level Inverters Open-Circuit Fault
           Diagnosis Based on Output Phase Voltage Model

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      Authors: Weiwei Zhang;Yigang He;
      Pages: 9718 - 9732
      Abstract: The open-circuit (OC) faults for T-type three-level inverters often share similar distorted output features, which are usually distinguished by adopting invasive methods. The purpose of this article is to locate the OC fault by rebuilding the established phase voltage model according to the hypothesis method. Based on the vector decomposition principle and voltage-second balancing theory, the output phase voltage model is established considering neutral point voltage unbalance and time-offset injection. The hypothetical phase voltage vector and residual for fault reasoning can be obtained by inputting the suspected OC faults positions to the model. The hierarchical fault diagnosis scheme involves two steps. First, the group-level fault can be located according to voltage residual vector amplitude and angle. Considering the impact of parameter error, dead time, and delay time, an adaptive residual vector amplitude threshold is designed. Next, the device-level fault can be located by building two suspected phase voltage models to approximate the real system. Furthermore, the fault location rules under zero-crossing (ZC) and non-ZC conditions are summarized. Especially, the proposed hypothesis method has correctness verification ability to avoid misdiagnosis. Experimental results show the robustness and effectiveness of the proposed low coupling fault diagnosis method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Condition Monitoring of DC-Link Electrolytic Capacitor in Back-to-Back
           Converters Based on Dissipation Factor

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      Authors: Moein Ghadrdan;Saeed Peyghami;Hossein Mokhtari;Frede Blaabjerg;
      Pages: 9733 - 9744
      Abstract: Condition-monitoring systems are used to determine the best timing for predictive maintenance of power electronics converters. These monitoring systems can significantly reduce the converter repair time and increase system availability. In this article, an investigation has been conducted on the possibility of using the dissipation factor as a lifetime indicator of electrolytic capacitors. A criterion is also proposed based on the dissipation factor to detect electrolytic capacitors’ end of useful life. A method has been presented for measuring the dc-link capacitor dissipation factor in a back-to-back converter. Using this technique, it is possible to estimate the switching component of the capacitor current by measuring the output currents of the converter without a need to measure the capacitor current directly. The proposed method is simulated, and the impact of various factors, such as switching frequency, capacitor series inductor, and the network filter on the accuracy of the dissipation factor measurement, is discussed. Experimental results are also provided to validate the acceptable accuracy of the proposed method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • An Online Groundwall Insulation Monitoring Method Based on Transient
           Characteristics of Leakage Current for Inverter-Fed Motors

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      Authors: Feng Niu;Yunlong Wang;Shaopo Huang;Lijian Wu;Xiaoyan Huang;Youtong Fang;Tao Yang;
      Pages: 9745 - 9753
      Abstract: With the wide application of inverter-fed motors (IFMs), it is necessary to monitor the groundwall (GW) insulation status to guarantee the reliable operation of motor drive system. This article first proposes a mathematical model of leakage current in IFM to analyze its time domain characteristics, and then an online GW insulation monitoring method is proposed based on the transient characteristics of leakage current. By using the initial oscillation amplitude, oscillation period, and attenuation time of leakage current, the phase, position, and severity of GW insulation degradation can be identified. The proposed method is validated using an IFM, and the experimental results agree well with theoretical analysis.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Monitoring Power Module Solder Degradation From Heat Dissipation in Two
           Opposite Directions

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      Authors: Zedong Hu;Borong Hu;Li Ran;Peter J. Tavner;Hua Kong;Philip A. Mawby;Ruizhu Wu;
      Pages: 9754 - 9766
      Abstract: Solder degradation is still a main failure mechanism for power semiconductor modules. This study proposes a monitoring method to detect the relative change in heat dissipation from a module in two opposing directions, affected by the degradation—upward via the silicone gel and downward via the solder layer to the heatsink. The method is based on external module package measurements, and a condition indicator $gamma $ is defined as the ratio of heat transfer rates in the two directions. The expected response of $gamma $ to the level of degradation is analyzed for different module operating points and external environment conditions. The method is demonstrated by experiment.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Power Loss Reduction Control for Modular Multilevel Converters Based on
           Resistor Controllable Submodule

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      Authors: Chengkai Liu;Fujin Deng;Jianzhong Zhang;Xu Cai;Zhe Chen;Frede Blaabjerg;
      Pages: 9767 - 9776
      Abstract: A bleeding resistor is usually adopted to be parallel with the capacitor in the submodule (SM) to avoid static voltage imbalance caused by auxiliary power supply during start-up process of modular multilevel converters (MMCs). However, the bleeding resistor causes unnecessary power loss during normal operation. In this article, a resistor controllable SM based on a normally-on silicon carbide (SiC) junction field-effect transistor is proposed to reduce the power loss on bleeding resistor at normal operation of MMCs. The proposed control can not only ensure the static voltage balance during start-up of MMCs, but can also completely eliminate the power loss on bleeding resistor during normal operation of MMCs for high efficiency. In addition, the proposed control can shorten the SM capacitor discharging time at shut-down process. Experimental studies are conducted and the results confirm the effectiveness of the proposed control.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Novel Diagnostic Method for Single and Dual Power Switch Open-Circuit
           Faults of Six-Phase FTPMSM System Even in Fault Tolerant Operation

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      Authors: Jinquan Xu;Si Guo;Hong Guo;Xinlei Tian;
      Pages: 9777 - 9789
      Abstract: This article proposes a new diagnostic method based on average current Park vector (ACPV) for single and dual power switch open-circuit faults of six-phase fault-tolerant permanent magnet synchronous motor (FTPMSM) system, which can be applied for the system both in nonfault and fault tolerant operation conditions. The fault diagnosis structure is composed of two parts: the ACPV moduli-based fault detection and the ACPV polarity-based fault location. By analyzing the ACPV before and after the fault, the normalized ACPV moduli-based fault detection is proposed by using the ACPV components in three orthogonal subspaces, which has good robustness to the speed and load changes. The ACPV polarity-based fault location is then proposed to locate the faulted power switches of the FTPMSM system. Finally, the effectiveness of the proposed fault diagnosis method is validated by a six-phase FTPMSM experimental platform. The fault diagnosis approach has the advantageous features of simple implementation, good robustness to various disturbances, no requirement of the extra sensors, and low computational burden, which can achieve single and dual power switch open-circuit fault diagnosis for the FTPMSM system both in normal and fault tolerant operation conditions.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Phase Feedforward Damping Control Method for Virtual Synchronous
           Generators

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      Authors: Mingxuan Li;Peng Yu;Weihao Hu;Yue Wang;Sirui Shu;Zhenyuan Zhang;Frede Blaabjerg;
      Pages: 9790 - 9806
      Abstract: Damping control plays an important role in suppressing the oscillation modes of virtual synchronous generators (VSGs). The most widely used damping control method through a frequency deviation feedback path is confronted with multiple challenging inherent contradictions among the different control objectives, resulting in seriously degraded control performance of VSGs. To resolve these contradictions fundamentally, this article proposes a novel phase feedforward damping (PFD) control method for VSG from the perspective of restructuring the damping controller. It replaces the traditional frequency deviation feedback path with a novel damping controller utilizing a phase feedforward path. Then, considering the grid-connected and islanding operation modes, respectively, a detailed comparative study of the traditional damping-based VSG (Tra-VSG) and the PFD-based VSG (PFD-VSG) is conducted. Both the theoretical and experimental results demonstrate convincingly that the proposed PFD control method can reconcile the different control objects of VSG, and thus, compared with Tra-VSG, PFD-VSG exhibits vastly superior response performance of the active power and the frequency in both grid-connected and islanding operation modes.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Analysis and Improvement of Large-Disturbance Stability for Grid-Connected
           VSG Based on Output Impedance Optimization

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      Authors: Mingxuan Li;Sirui Shu;Yue Wang;Peng Yu;Yonghui Liu;Zhenyuan Zhang;Weihao Hu;Frede Blaabjerg;
      Pages: 9807 - 9826
      Abstract: Except for the benefits of mimicking synchronous generators, virtual synchronous generators (VSGs) still face particular small- and large-disturbance stability problems in practical applications. Therein, the large-disturbance stability is a much more dramatic and intractable problem, such as a short circuit or line tripping. Accordingly, this article explores this challenging problem from the perspective of output impedance optimization for VSGs. First, focusing on the potential risk of overcurrent during the electromagnetic process, the dynamic performances of different virtual impedance control structures used in VSGs are comparatively analyzed, and the output impedance boundary for suppressing the transient current is derived. Then, the output impedance boundaries for maintaining electromechanical transient stability are discussed in depth by using Lyapunov stability theory, which provides novel virtual impedance optimal design guidelines exclusively for the large-disturbance stability. Furthermore, a large-disturbance stability enhancement strategy based on adaptive virtual impedance control is proposed, which can limit the electromagnetic transient current and improves the electromechanical transient stability simultaneously. Finally, experiments validate the accuracy of the theoretical analysis and the effectiveness of the proposed strategy.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Digital Current Controller Based on Active Resistance Term Feedback for
           SPMSM Drives

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      Authors: Xin Yuan;Jie Mei;Jiahao Chen;Yuefei Zuo;Christopher H. T. Lee;
      Pages: 9827 - 9839
      Abstract: Improving the control performance of surfaced-mounted permanent magnet synchronous machine (SPMSM) drives, digital current controllers with active resistance term feedback (ARTF) based on an exact zero-order hold (ZOH) equivalent discrete SPMSM model have been developing. Derived from the ARTF structure, few approaches are developed to suppress the ARTF delay effect on the digital current controller. To fill this gap, an improved digital current controller with the proposed digital internal mode control current estimator is designed. In the proposed structure, the predicted current can be effectively utilized as the ARTF delay compensation and feedback of the current controller at the same time. Compared with other state-of-the-art digital current controllers with ARTF, the performance evaluation of dynamic response, disturbance rejection, and parameter robustness is originally carried out based on the exact ZOH equivalent discrete SPMSM model. Furthermore, the experimental results are able to fully verify the correctness of the proposed method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Three-Port Converter With Single Coupled Inductor for High Step-Up
           Applications

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      Authors: Tsorng-Juu Liang;Kuo-Fu Liao;Kai-Hui Chen;Shih-Ming Chen;
      Pages: 9840 - 9849
      Abstract: The output voltages of renewable energy resources are relatively low for practical applications. Hence, a converter with high voltage gain is needed. This article proposes a high voltage gain nonisolated three-port converter for a renewable energy source with energy storage applications. A coupled inductor with three windings is used for transferring energies among photovoltaic (PV), battery, and the load. When the battery provides energy to the load, two primary windings with opposite polarities are connected in series. Thus, the effective primary turns is reduced for improving the voltage gain. In addition, the energy stored in the leakage inductor is recycled to the output so as to suppress voltage stress on the power switches and improve system efficiency for energy transference from either PV or battery to the load. Both PV and the battery can provide power to the load independently, thus sharing the load power coordinately. The operation principles, steady-state analyses and key parameter design of the proposed topology are then described in detail. Finally, an experimental prototype is implemented to verify the theoretical analyses with PV, battery, and load voltages of 48 V, 24 V, and 200 V, respectively.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Current Progress on Power Management Systems for Triboelectric
           Nanogenerators

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      Authors: Tingshu Hu;Haifeng Wang;William Harmon;David Bamgboje;Zhong-Lin Wang;
      Pages: 9850 - 9864
      Abstract: This article presents a review on the development of power management systems (PMSs) for triboelectric nanogenerators (TENGs). The TENG is the most recent technology to harvest ambient mechanical energy from the environment and human activities. Its invention was motivated by the prospect of building self-powered systems. The TENG has several appealing advantages, such as high power density, high voltage output, high efficiency at low frequency, and low cost. However, due to the TENG's unique nonlinear electrical property and capacitive behavior, the development of its PMS has presented great challenges as compared to other energy harvesters. The objective of PMS design has evolved from boosting the peak output power, to increasing the energy stored in a capacitor, and to increasing the steady-state output power of a resistive load by using a power converter. Driven by the need to build self-powered systems, the switches in the TENG PMS have evolved from active switches to passive switches. The past decade has witnessed exciting breakthroughs in the development of TENG PMS, yet there are still unlimited opportunities in exploring TENG's energy generation mechanism and vast potential in boosting energy extraction from the TENG by designing effective power converter topologies.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Integrated Maximum Power Point Tracking System for Photovoltaic Energy
           Harvesting Applications

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      Authors: Ioannis Mandourarakis;Vasiliki Gogolou;Eftichios Koutroulis;Stylianos Siskos;
      Pages: 9865 - 9875
      Abstract: The integrated circuits employed for power management in photovoltaic (PV) energy harvesting applications are required to perform an efficient maximum power point tracking (MPPT) process for maximizing the power production of the PV source during the continuously changing atmospheric conditions. Among the alternative MPPT methods, the perturbation and observation (P&O) technique has the advantages of operational and implementation simplicity. In this article, a novel PV MPPT control system for on-chip implementation of the P&O MPPT method is presented, which, compared to the past-proposed on-chip MPPT systems, has the advantage that it is implemented based on purely digital CMOS circuits without requiring the use of complex circuits, such as multipliers, sample and hold units, or analog-to-digital converters. Therefore, it can be easily implemented on-chip with low design complexity while simultaneously retaining the high-performance features of the P&O MPPT technique. The proposed PV MPPT system has been fabricated using the XFAB XH018 0.18-μm CMOS technology. The experimental results verify the successful operation of the on-chip PV MPPT control unit and its ability to achieve a high MPPT efficiency over a wide range of operating solar irradiation values.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Analysis and Design of a Nonisolated DC Transformer With Fault Current
           Limiting Capability

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      Authors: Yanan Ye;Xiaotian Zhang;Jiuyang Jin;Yue Wang;Xu Yang;
      Pages: 9876 - 9888
      Abstract: The dc–dc converter, also termed as dc transformer, plays an important role in the future dc grids. It is used to interconnect network segments or lines with different voltage levels. A nonisolated modular multilevel dc–dc converter is presented in this article, which can realize bidirectional power regulation and dc fault current limiting. The control strategy is simplified and the current stresses are decreased due to the employment of autotransformers. The nonisolated structure can reduce the requirements of autotransformers, because only part of the transmitted power flowing though the autotransformers. The operation principle and control strategy of this converter are illustrated in detail. The analyzes of power transmission, submodule (SM) capacitor voltage ripple, the optimal configuration, and the efficiency of this converter are also provided. The optimal design methods of the dc transformer are proposed to reduce the costs and power losses according to the analysis results. Simulations performed in power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC) and experiments based on a down-scaled prototype verify the operation principle, control strategy, and theoretical analysis. The simulation results and experiment results show the performances of the converter under steady state, power regulation, and fault conditions.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Comparison of CCM- and CRM-Based Boost Parallel Active Power Decoupler for
           PV Microinverter

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      Authors: Yidi Shen;Michael D’Antonio;Shiladri Chakraborty;Arafat Hasnain;Alireza Khaligh;
      Pages: 9889 - 9906
      Abstract: Single-phase inverter or rectifier systems often make use of an active power decoupler (APD) to balance the mismatch between constant dc power and fluctuating ac power. This article deals with the comparison of continuous conduction mode (CCM) and critical conduction mode (CRM) operation-based design of a parallel boost-type APD for photovoltaic microinverter applications. From a design perspective, multiobjective analysis of efficiency, volume, and cost is explored within a decision space including planar inductors, gallium nitride based devices, film capacitors, switching frequency, and modulation (CCM vs. CRM). The theoretical study analyzes all possible design configurations within CCM and CRM and identifies Pareto-optimal designs, from which the selected CRM design can achieve reduced system volume and lower cost with the use of smaller inductor core, while operating with similar California Energy Commission efficiency drop as the selected CCM design. From a control perspective, a pulsewidth modulation based control strategy is proposed to implement closed-loop CRM modulation that does not rely on zero-crossing detection. Closed-loop systems are designed for the optimal CCM and CRM realizations, and the final system characteristics are compared. Experimental results, obtained using two separate 40-V, 400-W hardware prototypes for CCM and CRM, are presented to verify the analyses.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Overview of Power Converter Control in Microgrids—Challenges,
           Advances, and Future Trends

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      Authors: Jiefeng Hu;Yinghao Shan;Ka Wai Cheng;Syed Islam;
      Pages: 9907 - 9922
      Abstract: As the electronic interfaces between distributed energy resources and the electrical network, power converters play a vital role in voltage stabilization and power conversion. So far, various power converter control methods have been developed. Now it is urgently needed to compare and understand these approaches to support the smart microgrid pyramid. This article provides an overview of the state-of-the-art of parallel power converter control in microgrid applications. The most important control schemes to address existing challenges, including concentrated control, master–slave control, droop mechanism, virtual synchronous generators, virtual oscillator control, distributed cooperative control, and model predictive control, are highlighted and analyzed in detail. In addition, the hierarchical control structure, as well as future trends, are reviewed and discussed.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Data-Driven Modeling and Control Considering Time Delays for WPT System

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      Authors: Qijun Deng;Zhifan Li;Jiangtao Liu;Shuaiqi Li;Peng Luo;Kaicong Cui;
      Pages: 9923 - 9932
      Abstract: A controller for output voltage and power regulation is important for the wireless charging system. For the controller design, it is crucial to establish the accurate system model with considering the time delay, as high time delay exists due to wireless communication, data sampling, and processor calculations for a practical wireless power transfer system. Presently, the common modeling methods, such as the coupled-mode method are based on circuit theories and the component parameters. However, the exact parameters are hard to get due to the diversity of the equipment and application scenarios. Especially, the circuit theories modeling cannot deal with the time delay from hardware limitation and wireless communication. Alternatively, a data-driven modeling method based on the simplified refined instrumental variable method is proposed in this article to get the control-oriented model with time delay. Moreover, based on the estimated model, a controller based on the internal model control is designed to regulate the output voltage. It is shown that the models obtained based on different sampling times are able to accurately describe the system dynamics and the controllers designed based on them are able to achieve the desired control performance.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Pulse Density Modulation Based Mutual Inductance and Load Resistance
           Identification Method for Wireless Power Transfer System

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      Authors: Ruimin Dai;Wei Zhou;Yonghong Chen;Zhehui Zhu;Ruikun Mai;
      Pages: 9933 - 9943
      Abstract: In wireless power transfer (WPT) system, the information of mutual inductance and load resistance is usually needed for the front-end to regulate power and efficiency. To acquire the values of these two parameters without wireless communication system and without affecting the output power, this article proposes an identification method based on the pulse density modulation (PDM) technique. The underlying principle is to obtain a range of interharmonics by altering the sequence of PDM. First, the PDM strategy brings in interharmonics, which can be identified through fast Fourier transmission (FFT). Then, these interharmonics are used to established multiple sets of equation related to front-end impedance and the two unknowns. Finally, with the least-square approximation, mutual inductance and load resistance can be estimated. This article notices that the sequence of PDM strategy could affect the amplitudes of interharmonics, and selects the sequences to maximize the magnitudes for less sensitivity to measurement errors. Experimental results show that the relative errors of identification are less than 5% when the nominal values of capacitors are the same as actual values, and reach 7.40% when considering the nominal values may deviate from the actual values. Besides, the output power and efficiency are not affected during the identification process. This proposal requires only magnitudes of voltage and current in the transmitter side, no other hardware is needed, and works with the fixed frequency, which is suitable for any frequency range.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Design and Multiobjective Optimization of an Auxiliary Wireless Power
           Transfer Converter in Medium-Voltage Modular Conversion Systems

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      Authors: Keyao Sun;Jun Wang;Rolando Burgos;Dushan Boroyevich;Joshua Stewart;Ning Yan;
      Pages: 9944 - 9958
      Abstract: This article proposes an optimized design for a wireless power transfer converter serving as an auxiliary power supply in a medium-voltage, high $mathrm{d}v/mathrm{d}t$ modular conversion system. A CLLC-CL circuit topology is implemented to generate a load-independent output voltage with a coupling-coefficient-independent resonant frequency. The output voltage of the circuit can be tuned by changing one pair of resonant LC parameters, which decouples the circuit gain from the coil design. Essential parameters of coil and magnet are extracted analytically or numerically to avoid time-consuming 3-D finite element analysis simulations for the subsequent optimization. After the design of the circuit and coil, a multiobjective optimization is carried out with objectives being efficiency, isolation capacitance, and insulation rating of the converter. Finally, experiments demonstrate a 48- to 48-V dc–dc converter with 100 W output power, 92.78% efficiency, 2.78 pF isolation capacitance, and 27 kV insulation rating to validate the optimization result.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Continuous Reduced-Order Dynamic Model Based on Energy Balancing for
           Inductive Power Transfer Systems

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      Authors: Wenli Shi;Jianning Dong;Thiago Batista Soeiro;Junjun Deng;Calvin Riekerk;Pavol Bauer;
      Pages: 9959 - 9971
      Abstract: Resonant circuits are commonly used in inductive power transfer (IPT) systems for the charging of electric vehicles because of the high power efficiency. Transient behaviors of the resonant circuits, which play a significant role in the design and analysis of IPT systems, are cumbersome to model analytically because of the high-order. This article develops a reduced-order continuous dynamic model based on the energy interactions among the resonant tanks. By applying the proposed energy balancing method (EBM), the order of the dynamic model is reduced to half of the number of the passive components in the resonant circuits. To show the accuracy of the EBM, the dynamics of a series–series (SS) compensated IPT system are modeled using Laplace phasor transformation (LPT) and EBM separately and the results are compared. The order of the EBM is found to be one-fourth of that of the LPT method. The sensitivity of the EBM to the switching frequency is discussed when the zero voltage switching turn-on operation is attained. Besides, to prove the advantage of reducing the order of the dynamic model, model predictive controls (MPCs) based on EBM and LPT are developed. The transient performances of the MPC controllers are simulated and the control inputs are applied to an experimental setup. Finally, experiments are conducted to verify the accuracy of the proposed EBM under zero and nonzero conditions and the effectiveness of the developed MPC controller.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Magnetic Design Considerations for High-Power Wireless Charging Systems

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      Authors: Patrick A. J. Lawton;Feiyang J. Lin;Grant A. Covic;
      Pages: 9972 - 9982
      Abstract: This article proposes methods of predicting and preventing thermal failure within high-power ferrite structures of electric vehicle (EV) wireless charging inductive power transfer (IPT) by improving their ferrite layouts. A high-power IPT magnetic design suitable for wirelessly charging an EV at 50 kW using a heuristic approach is presented, where the chosen design achieves reduced heating within the magnetic structure. Recommendations are made that both avoid ferrite fracturing due to magnetic hotspots and cause temperature differentials across ferrite tiles, and regarding airgap distribution between ferrite tiles to reduce loss-inducing circulating flux within the ferrite structure without reducing coupling. Power transfer was simulated in ANSYS and PLECS under misaligned conditions, and validated experimentally with 93.7% system efficiency. Thermal tests performed under rated volt-amps found the magnetics temperatures (after 30 min) could be reduced from 168 to 67 °C using an improved magnetic layout that reduced the thermal gradients within the ferrite tiles by 70%. Leakage fluxes were targeted and validated to be below 15 μT, 950 mm from the center of the vehicle under rated power and worst-case misaligned conditions.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Coil Positioning Method Integrated With an Orthogonal Decoupled
           Transformer for Inductive Power Transfer Systems

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      Authors: Zhuhaobo Zhang;Shaoting Zheng;Zirui Yao;Dehong Xu;Philip T. Krein;Hao Ma;
      Pages: 9983 - 9998
      Abstract: Misalignment between primary and secondary coils in inductive power transfer systems decreases power capacity and efficiency. In this article, a secondary coil positioning method integrated with an orthogonal decoupled transformer is proposed. This nested rectangular and solenoidal structure consists of a pair of double-D coils and a pair of solenoidal coils. The coils are integrated spatially and decoupled magnetically. Based on their directional selectivity characteristics, a coil positioning method is proposed prior to the power path activation. Coordinates can be obtained with polynomial fit calculations. The positioning method is compatible with power transfer and has merits of less auxiliary equipment, higher compatibility, and higher positioning precision considering both horizontal and vertical misalignment cases. The transformer performance is simulated with a three-dimensional finite element modeling tool and verified experimentally on a 3.2-kW prototype. In the preactivation sensing process, points distributed throughout a ±180 mm × 180 mm positioning range were tested. Experimental results show that 92% of tested points are accurate to within 10 mm given a 210 mm vertical distance. When air gap variations are taken into consideration, 90% of tested points are accurate to within 12 mm over the tested range. In the power transfer stage, the maximum full-power dc–dc system efficiency is 94.6%.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Reticulated Planar Transmitter Using a Three-Dimensional Rotating
           Magnetic Field for Free-Positioning Omnidirectional Wireless Power
           Transfer

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      Authors: Tianxu Feng;Zhiping Zuo;Yue Sun;Xin Dai;Xueying Wu;Lujing Zhu;
      Pages: 9999 - 10015
      Abstract: This article proposes a free-positioning omnidirectional wireless power transfer (WPT) system with a reticulated planar transmitter, which enables multiple receivers to be powered simultaneously in arbitrary positions and orientations. The reticulated planar transmitter is equipped with four interleaved and overlapped meander coils, thus, a three-dimensional (3-D) rotating magnetic field is generated with the designed excitation current. Therefore, only a planar single-coil (such as a loop-type coil) is required to realize free-positioning omnidirectional WPT. According to the theoretical modeling of the magnetic field, the excitation current that can generate a 3-D rotating magnetic field is given. To obtain a uniform and strong magnetic field distribution, the transmitter grid width is optimized. Furthermore, an excitation current modulation strategy based on phase-shift control is presented to regulate the amplitude of the excitation current. The experimental results show that the output power is greater than 13.1 W no matter how the center of the receiver moves or rotates freely within 400 × 400 mm. When five receivers are powered simultaneously in different positions and orientations, 82.5 W total output power and 55.6% efficiency can be achieved. The experimental results demonstrate that free-positioning omnidirectional WPT can be realized with only planar single-coil receivers by using the proposed reticulated planar transmitter and its excitation current modulation strategy.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Fast-Speed GMPPT Method for PV Array Under Gaussian Laser Beam Condition
           in Wireless Power Transfer Application

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      Authors: Weiyang Zhou;Ke Jin;Ran Zhang;
      Pages: 10016 - 10028
      Abstract: The laser power transfer system is one of the most promising systems in the long-range wireless power transfer field. However, the low efficiency at photovoltaic (PV) receiver limits the performance of an implemented system due to the Gaussian laser beam. Since the irradiance profile of the Gaussian laser beam is not uniform, the PV array exhibits complex output characteristics with multiple peaks, leading that the conventional maximum power point tracking (MPPT) method is not acceptable either on tracking accuracy or on tracking speed. In this article, a simple and rapid voltage-location global MPPT (VL-GMPPT) method is proposed for PV array under Gaussian laser beam condition (GLBC) in terms of reducing the voltage searching range. In order to do so, the mathematical model of PV array's global maximum power point (GMPP) is developed under GLBC. Then, the VL-GMPPT method incorporates voltage-location mechanism to directly move the operating point to the vicinity of GMPP and employs IncCond method to accurately find the GMPP. The experimental and simulation results are shown to verify the proposed GMPPT method. It was found that the proposed method can reduce 90% of tracking time that is consumed by the conventional global searching method.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • A Soft-Switched Power-Factor-Corrected Single-Phase Bidirectional AC–DC
           Wireless Power Transfer Converter With an Integrated Power Stage

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      Authors: Junwei Liu;Fei Xu;Chuan Sun;K. H. Loo;
      Pages: 10029 - 10044
      Abstract: Bidirectional ac–dc wireless power transfer (WPT) converters are widely used in grid-connected electric vehicle systems for grid-to-vehicle and vehicle-to-grid applications. They usually apply a two-stage topology with a bidirectional ac–dc power factor correction converter and a bidirectional dc–dc WPT converter. Such a two-stage topology cannot achieve high efficiency and low cost. Recently, single-stage matrix bidirectional ac–dc WPT converters have been proposed. However, the matrix-converter-based topologies do not utilize remarkably lower count of power switches and generate large double-line frequency ripple in the dc-side voltage or current. This article proposes a new single-phase bidirectional ac–dc WPT topology with an integrated power stage to overcome the drawbacks of the matrix-converter-based topologies and retain the advantages of single-stage topologies. Description of the proposed topology with the modulation and control methods, theoretical analysis, and reference design procedure are presented in detail. Finally, a scaled-down laboratory prototype with 500-W output power is implemented with experimental results presented to validate the principle, analysis, and design.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
  • Design and Control of a Decoupled Multichannel Wireless Power Transfer
           System Based on Multilevel Inverters

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      Authors: Yuxin Liu;Chunhua Liu;Xingran Gao;Senyi Liu;
      Pages: 10045 - 10060
      Abstract: Traditional multichannel wireless power transfer (WPT) systems suffer from the complex system structure and cross-interference among receivers. To solve such problems, this article presents the design and control methods of a decoupled multichannel WPT system based on multilevel inverters. A single-phase multilevel inverter is utilized to drive the transmitter circuit with a voltage waveform consisting of multiple components. Particularly, these components are independent in the frequency spectrum, and their amplitudes can be controlled independently. Moreover, primary compensation is used to offer multiple frequencies for the primary circuit. Additional damping filters are used in the secondary circuits to reduce the cross-interference between the receivers. In addition, the features of the system topology are analyzed, and an exact parameter design method is presented. Furthermore, combined with the neutral point voltage balance strategy, a simple vector-based control method is proposed to regulate the transmitted power in each power channel. As a result, the power can be transferred to loads through the designed power channels simultaneously without mutual interference. Finally, both simulation and experiment of a 1-kW experimental prototype with SIC-MOSFET are given to verify the feasibility of the proposed multichannel WPT system and the control strategy.
      PubDate: Aug. 2022
      Issue No: Vol. 37, No. 8 (2022)
       
 
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