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

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Similar Journals
Journal Cover
IEEE Journal of Emerging and Selected Topics in Power Electronics
Journal Prestige (SJR): 1.657
Citation Impact (citeScore): 7
Number of Followers: 52  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2168-6777 - ISSN (Online) 2168-6785
Published by IEEE Homepage  [228 journals]
  • IEEE Journal of Emerging and Selected Topics in Power Electronics

    • Free pre-print version: Loading...

      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • IEEE Industry Applications Society

    • Free pre-print version: Loading...

      Abstract: Provides a listing of current committee members and society officers.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Guest Editorial Special Issue Commemorating 40 Years of WEMPEC,
           1981–2021

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      Authors: Giri Venkataramanan;Thomas Jahns;
      Pages: 1320 - 1325
      Abstract: In the 1970s, a small community of pioneering researchers around the world in industry and academia were laying the groundwork for the discipline of solid-state power electronics as we know it today. Near the end of that formative period, the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC) was founded in 1981 by Profs. Donald W. Novotny and Thomas A. Lipo at the University of Wisconsin–Madison. Prof. Robert D. Lorenz joined the embryonic WEMPEC program faculty in 1984, bringing his unique expertise and passion for motor drive controls.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Reviewing Thermal-Monitoring Techniques for Smart Power Modules

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      Authors: Sven Kalker;Lukas A. Ruppert;Christoph H. van der Broeck;Johannes Kuprat;Markus Andresen;Timothy A. Polom;Marco Liserre;Rik W. De Doncker;
      Pages: 1326 - 1341
      Abstract: The increasing demand for higher power device utilization and reliability in power electronic systems is driving the integration of condition monitoring and active control in power electronic systems. With thermal heat dissipation being the limiting factor of module lifetime and performance, thermal real-time monitoring is key in this transition. However, this requires the availability of highly accurate and high-bandwidth temperature information with minimal phase lag. This article reviews key methods for temperature extraction in power modules: temperature sensing, thermal estimators, and thermal observers. While previous research has examined individual techniques of these methods in great detail, this article presents a methodological overview that provides insight to how different technologies may contribute to next-generation thermal-monitoring solutions. In this context, this article discusses how different technologies can be effectively combined to improve their overall performance. It finally discusses key challenges that must be addressed such that minimally invasive temperature sensing and thermal monitoring become an industrial practice in the future of power electronics.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Power Device Interface Characterization With Low-Cost Thermal System
           Identification

    • Free pre-print version: Loading...

      Authors: Timothy A. Polom;Robert D. Lorenz;
      Pages: 1342 - 1352
      Abstract: This article develops a technique, requiring no dedicated temperature sensing calibration step, to rapidly characterize transient heat transfer in packaged, power semiconductor components. It is presented as an alternative to traditional step response characterization methods by exploiting the phase delay metric native to frequency response function (FRF) analysis in the field of system identification. This article presents the principles of power device physics and transient waveform analysis to identify the design space in which FRF data extracted from experiments are robust. Electronic circuitry is introduced, providing the needed, periodic heat actuation, and a measurement strategy leveraging direct processing of a temperature-sensitive electrical parameter (TSEP). The developed method is applied to make a key measurement confirming the high-frequency-only thermal FRF sensitivity to component die-attach condition. The measurement is shown to align with an output from a partial differential thermal model embedding a single, corrective scaling factor. Overall, this article highlights the emergent opportunity to measure a packaged power device’s transient thermal impedance with standard lab equipment and the ongoing opportunity to realize converter degradation self-sensing.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Next-Generation Variable Capacitors to Reduce Capacitance Variable Time
           Using SiC MOSFETs and p-i-n Diodes in 13.56-MHz RF Plasma Systems

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      Authors: Juhwa Min;Beomseok Chae;Yongsug Suh;Jinho Kim;Hyunbae Kim;
      Pages: 1353 - 1362
      Abstract: This article introduces a novel method of reducing the capacitance variable time of a vacuum variable capacitor (VVC) impedance matching circuit of 320 V/1 kW/13.56 MHz common to radio frequency (RF) plasma systems. Our method replaces the VVC with an electrical variable capacitor (EVC) that uses power electronics technology to reduce capacitance variable time. Simulation and testing of the proposed circuit showed that the variable time of the EVC was maintained below $81~mu text{s}$ , and that due to the fast switching action of the power semiconductor switch, the proposed circuit can be applied in the impedance matching circuit of high-power and high-frequency RF plasma systems.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Analytical Expressions for Inductances of 3-D Air-Core Inductors for
           Integrated Power Supply

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      Authors: Chandra Shetty;Youssef Kandeel;Liang Ye;Séamus O’Driscoll;Paul McCloskey;Maeve Duffy;Cian Ó Mathúna;
      Pages: 1363 - 1383
      Abstract: This work presents analytical expressions for the dc inductance of 3-D air-core inductors with circular cross-sectional pillars (CCSPs) and rectangular cross-sectional pillars (RCSPs). We consider the following four types of inductor structures: 1) a toroid with CCSP; 2) a toroid with RCSP; 3) a solenoid with RCSP; and 4) a solenoid with CCSP. For each type, a unique analytical model is developed for obtaining dc inductance. High-frequency (1–100 MHz) effects on inductance are also discussed. The inductance values predicted by the proposed analytical models of the first three types of inductor structures are in an acceptable agreement with numerical finite-element analysis (FEA) solutions, where the maximum difference is 7.3%. Also, our analytical model for the fourth-type inductor reduces the error, when correlated with FEA inductance value, up to $6times $ compared with previously published models. A comparison of results using the proposed analytical expressions with published measured values as well as our measurement data demonstrates the error ranging from 0.5% to 16.2%, while conventional formulas show errors of up to 143%. The results of the proposed models could serve as a good initial estimate for power supply-on-chip (PwrSoC) and power supply in package (PSiP) applications.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Velocity Profile-Based Evaluation and Improvement of Lifetime of Power
           Devices in Railway Propulsion Inverters

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      Authors: June-Seok Lee;Ui-Min Choi;
      Pages: 1384 - 1394
      Abstract: In the work reported in this article, the converter-level lifetime evaluation of power devices in a railway propulsion inverter is performed to assess and compare operating strategies of a railway vehicle in terms of reliability. Two groups of velocity profiles are considered for the lifetime evaluation, wherein all the velocity profiles have the same running distance and time. The first group consists of three operation velocity profiles with the same acceleration at starting and stopping, but with different cruising ranges. In the second group, three operation velocity profiles with different coasting times and acceleration values are considered. A strategy to improve the lifetimes of power devices in propulsion inverters is proposed for vehicles on a busy railway line.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • An End-to-End Modeling and Prototyping Platform for Power Electronics and
           Electric Drives

    • Free pre-print version: Loading...

      Authors: Siddharth Raju;Lakshmi Narayanan Srivatchan;Ned Mohan;
      Pages: 1395 - 1408
      Abstract: Pedagogical methodology of incorporating hands-on laboratory with academic coursework improves retention and understanding. Adopting this laboratory-based approach for electric drives and power electronics has been limited due to the prohibitive cost of facilities, software, and equipment. Furthermore, the multidomain skills necessary to implement motor controls and the safety concerns while working with power electronics have dissuaded many universities from offering these laboratories. This article presents an extremely low-cost electric drives laboratory using a newly developed model-based simulation software and real-time control platform. An undergraduate-level and a graduate-level electric drives laboratories developed and adopted by multiple universities are discussed in detail. Finally, this article presents a comparison of this laboratory to other alternatives.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Model Predictive Sliding Control for Cascaded H-Bridge Multilevel
           Converters With Dynamic Current Reference Tracking

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      Authors: Tingting He;Mingli Wu;Dylan Dah-Chuan Lu;Kejian Song;Jianguo Zhu;
      Pages: 1409 - 1421
      Abstract: This article presents a model predictive sliding control (MPSC) strategy with the dynamic reference tracking for cascaded H-bridge (CHB) multilevel converters. The nonlinear predicted sliding mode control (PSMC) and linear model predictive control (MPC) are combined as a two-level cascaded control structure. The proposed approach aims to get rid of time-consuming tuning to reach the good performance in the presence of uncertainties and disturbances, such as proportional–integral (PI). The MPC scheme is designed to predict the future optimal current and voltage vectors with a designed cost function. The high-level PSMC algorithm is proposed for the dynamic current reference with less chattering problems. The stability of the proposed strategy is analyzed with the Lyapunov direct method. The design principle of the system parameters is introduced with a step-by-step tuning procedure. With the proposed method, the response time can be reduced from 60 to 30 ms during the start-up conditions in the simulation tests. The overshoot of the cell voltages can be eliminated with low-harmonics current and dc-link voltage targets tracking. The validity and effectiveness of the proposed method are implemented by the experimental tests on a laboratory two-cell CHB converter. Compared with the PI-based MPC approach, the current total harmonic distortion (THD) can be reduced and the dc-side performance, including overshoot/undershoot and response speed, can be improved.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Iterative Gradient Descent-Based Finite Control Set Predictive Current
           Control With Least-Squares Optimized Duty Cycles

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      Authors: Haotian Xie;Fengxiang Wang;Qian Xun;Yingjie He;José Rodríguez;Ralph Kennel;
      Pages: 1422 - 1433
      Abstract: Finite control set predictive current control (FCS-PCC) is widely recognized as a competitive control strategy in the field of electrical drives, due to its superiority of fast dynamic response and low switching frequency. However, FCS-PCC is penalized by its inherent drawback that the discrete nature of switching states leads to relatively high torque and current deviations. In this article, an iterative gradient descent (GD) method combined with least-squares (LS) optimized duty cycles is presented to improve the steady-state performance of FCS-PCC. Unlike the cost function optimization in the conventional FCS-PCC, the quadratic programming problem is solved from a geometric perspective, by obtaining the GD that minimizes the tracking deviation in the fastest manner. To synthesize the GD, the optimal stator current derivatives in the current and previous iteration are employed, and their duty cycles are determined by the LS method. The abovementioned procedures are iteratively repeated in the dichotomy-based periods. The experimental performance of the proposed GD-based FCS-PCC is verified at an 8-kHz sampling frequency, which is compared with that of conventional and dichotomy-based FCS-PCC (DFCS-PCC). It is validated that the proposed algorithm outperforms the conventional and DFCS-PCC at both the steady state and the transient state.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Self-Synchronizing Stationary Frame Inverter-Current-Feedback Control for
           LCL Grid-Connected Inverters

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      Authors: Ahmad Afif Nazib;Donald Grahame Holmes;Brendan P. McGrath;
      Pages: 1434 - 1446
      Abstract: Current regulation of inductive–capacitive–inductive (LCL) grid-connected inverters usually requires multiple current sensors to actively damp the filter resonance. Inverter-side current regulation avoids this issue because of its inherent LCL filter damping properties but does not accurately control the grid-side current, particularly with distorted grids. Furthermore, both strategies typically require high-quality voltage sensors to maintain precise grid synchronization. This article proposes a novel current control strategy for LCL grid-connected inverters that only requires inverter-side current sensors. The strategy uses the resonator output states of a stationary reference frame (SRF) proportional resonant (PR) current regulator to estimate the grid voltage phase and filter capacitor current and, thus, achieve self-synchronized indirect regulation of the grid-side current. The effectiveness of the approach has been verified using simulation and matching experimental investigations.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Demodulation-Based Method for Instantaneous Phase-Angle Estimation of
           Unbalanced Three-Phase Voltage Systems

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      Authors: Md. Shamim Reza;Md Maruf Hossain;
      Pages: 1447 - 1456
      Abstract: This article proposes an open-loop-based demodulation technique for the instantaneous phase-angle estimation of three phase voltage systems. The proposed demodulation-based method relies on the Clarke transform, finite-impulse-response filters, and algorithms for phase-angle and frequency deviation estimation. When compared to a frequency-locked loop (FLL) based on dual second-order generalized integrators and a phase-locked loop (PLL) relying on adaptive delayed signal cancellation operator, the proposed one does not use any integrators, recursive signals, and feedback of frequency or phase angle, thus unconditionally stable and relatively simple tuning is achieved. In addition, the proposed method is computationally efficient due to avoiding interpolation, square-root, trigonometric functions or their inverse operations. Moreover, under equal dynamic condition, the proposed one generates improved steady-state accuracy in a range of the frequency deviation specified by standard and grid code. Simulated and experimental results are presented to verify the efficacy of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Active Power Filtering With a Low Switching Frequency Converter

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      Authors: Yong-Yao Shen;Meng-Jiang Tsai;Yu-fan Liou;Po-tai Cheng;
      Pages: 1457 - 1465
      Abstract: This article focuses on the relationship between the controller and the control delay of the low switching frequency converter with active power filtering function. This article also investigates the effect of the current transformer (CT) probe on the measured signals for a long-distance compensation of the nonlinear loads. A one-step deadbeat controller under consideration of the CT model is presented to meet the demands with the control delay compensation and the correction of the distorted measured signals. Finally, the laboratory test results will be used to support the aforementioned analysis.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Multivector Model Predictive Power Control for Grid Connected Converters
           in Renewable Power Plants

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      Authors: Mohammad Ebrahim Zarei;Dionisio Ramirez;Milan Prodanovic;Giri Venkataramanan;
      Pages: 1466 - 1478
      Abstract: Model-based predictive power control (MPPC) is a well-known and useful technique for control of electric drives and renewable energy generation systems. However, this strategy relies on the knowledge of accurate system models and parameter values, and would otherwise lead to tracking errors in applications because of inevitable parameter uncertainties. Also, step delays in MPPC implementations have to be compensated to eliminate errors. This article proposes a predictive control application to control active and reactive powers exchanged between the grid and the grid side converter (GSC) interfacing renewable energy sources such as wind farms or photovoltaic. The proposed MPPC minimizes the power tracking error based on a proposed cost function and the control system output is the voltage reference for the electronic converter that is converted into switching pulses by the modulation stage. The proposed control strategy is designed to eliminate tracking errors and has fixed switching frequency while featuring a fast-dynamic response, low current THD, and low computational burden. The method has been evaluated using MATLAB/Simulink environment and an experimental 5-kW grid-connected voltage source converter. Finally, the proposed MPPC method has been critically compared to the previous MPPC approaches.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Capacitance Requirement Reduction in Single-Phase PFC With Adaptive
           Injection of Odd Harmonics

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      Authors: Leandro da Silva;Sérgio Vidal Garcia Oliveira;Douglas Pereira da Silva;Gustavo Ceretta Flores;Yales Rômulo De Novaes;
      Pages: 1479 - 1488
      Abstract: This article presents an adaptive harmonic injection approach for single-phase power factor correction (PFC) converters that reduce capacitance requirements and allow the use of smaller and more reliable film capacitors instead of electrolytic capacitors. Many applications require the converter’s rated power only during temporary intervals, whereas most of the time, the output power is much lower. In the proposed approach, the converter operates with a unity power factor below a given output power level. When the output power exceeds this value, then odd harmonics are linearly injected into the input current reference, up to the limits presented by IEC 61000-3-2. This approach reduces the voltage ripple across the power ripple buffering capacitor (PRBC), reducing the required capacitance value. The proposed approach is applied to the $theta $ -converter using enhanced automatic power decoupling (EAPD) control. The dynamic model to control PRBC average voltage is presented. A 1-kW prototype is built to validate the approach using a metalized polypropylene film capacitor as the PRBC. At full power, injecting third and fifth harmonics, the PRBC capacitance can be reduced from 22 to $15~mu text {F}$ or 32%. It represents a further reduction in capacitance requirements for a converter that already requires low capacitance.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Generalized Predictive dc-Link Voltage Control for Grid-Connected
           Converter

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      Authors: Tao Wang;Z. Q. Zhu;Nuno M. A. Freire;David A. Stone;Martin P. Foster;
      Pages: 1489 - 1506
      Abstract: The main function of the grid-connected converter in many applications is to control the dc-link voltage with high performance, i.e., strong disturbance rejection capability and good dynamic response. Take the grid-connected pulsewidth modulation (PWM) rectifier of a motor drive system as an example, good disturbance rejection capability is essential for the dc-link voltage control to address the varying loads on the motor side, and the dynamic process of the dc-link voltage control is preferred to be fast and overshoot-free, so as to adaptively adjust the dc-link voltage according to the motor speed and reduce the switching losses. However, the performance of the conventional proportional-integral (PI)-based dc-link voltage control is not always satisfying and can be further improved. In this article, the generalized predictive control (GPC) method is applied to the dc-link voltage control of a grid-connected converter for the first time, which can provide both good disturbance rejection capability and satisfying dynamic performance. Moreover, stability analysis of the proposed GPC-based dc-link voltage control strategy is theoretically studied, and a parameter tuning guideline is provided. The effectiveness and advantages of the proposed method are validated with experimental results.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Disturbance Rejection Analysis of a Droop-Controlled DC Microgrid Through
           a Novel Mathematical Modeling

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      Authors: Niloofar Ghanbari;Subhashish Bhattacharya;
      Pages: 1507 - 1518
      Abstract: DC microgrids are gaining interest by the increase in dc loads and renewable resource penetrations. Photovoltaic (PV) arrays are the primary renewable resources utilized in dc microgrids with variations in their productions. Power variations are seen as disturbances from other sources’ point of view. The droop control method is frequently used to control dc microgrids and assures power sharing among parallel-connected converters. It is of great interest to assess droop controller functionality in rejecting disturbances, and maintain constant output voltage. Therefore, there is a need for a comprehensive converter and controller modeling to study the effect of disturbances on the system behavior. In this article, the converter’s small-signal model is utilized in deriving the system state space model. Via the derived model, the effect of different circuit parameters on time and frequency responses is studied. The line resistances’ effect on the parallel operation of converters is also studied. To verify the droop controller’s functionality, the converter’s output impedance is derived. Disturbances are applied to the load current, and the system response is analyzed. Finally, the dc microgrid plug and play feature is addressed by proposing an algorithm for deriving the multiple converters’ mathematical model. Simulations and hardware-in-the-loop (HIL) experiments are conducted to verify the mathematical model and controllers’ performance.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Gen-3 10-kV SiC MOSFET-Based Medium-Voltage Three-Phase Dual Active
           Bridge Converter Enabling a Mobile Utility Support Equipment Solid State
           Transformer

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      Authors: Anup Anurag;Sayan Acharya;Subhashish Bhattacharya;Todd R. Weatherford;Andrew A. Parker;
      Pages: 1519 - 1536
      Abstract: The emergence of medium-voltage silicon carbide (SiC) power semiconductor devices, in ranges of 10–15 kV, has led to the development of simple two-level converter systems for medium-voltage applications. A medium-voltage mobile utility support equipment-based three-phase solid state transformer (MUSE-SST) system, based on Gen3 10 kV SiC MOSFETs, is developed to interconnect a three-phase 4160 V/60 Hz grid to a three-phase 480 V/60 Hz grid to provide a shore-to-ship power interface for naval vessels. The MUSE-SST system consists of three power conversion stages, namely, MVac/MVdc stage (MV: active front-end converter), MVdc/LVdc stage (dual active bridge converter), and LVdc/LVac stage (LV: active front-end converter). The galvanic isolation is introduced in the MVdc/LVdc stage using MV/LV high-frequency transformers (HFTs). This article demonstrates the operation of the three-phase Y– $Delta $ connected dual active bridge converter used in the MVdc/LVdc stage of the MUSE-SST system. Equations for phase currents, power flow, and zero-voltage switching (ZVS) boundaries are derived for all possible modes for the three-phase Y– $Delta $ configuration. A detailed parasitic simulation model is derived by measuring and experimentally verifying the parasitic elements of the HFT. A brief discussion regarding the design considerations required for the hardware development of the medium- and low-voltage sides of the three-phase dual active bridge converter is also provided. Successful tests demonstrating the operation and feasibility of the medium-voltage dual active bridge converter, at medium-voltage levels (7.2 kV dc-link voltage), are shown. The results indicate that these devices can accelerate the growth and deployment of the medium-voltage SiC-based converter for isolat-d and bidirectional medium- to low-voltage dc systems.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Soft-Switching Bidirectional Switched-Capacitor DC–DC Converter With
           Multiple Phase Shift Control Methods

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      Authors: Liangzong He;Xinyong Xu;
      Pages: 1537 - 1547
      Abstract: In this article, a bidirectional bridge modular switched-capacitor (BBMSC) dc–dc converter is proposed with soft switching and multiple phase shift control methods, including in-bridge single phase shift (ISPS) control, out-of-bridge single phase shift (OSPS) control, and dual phase shift (DPS) control method. The topology, phase shift control scheme, and operating states are analyzed. Then the circuit characteristics, such as output power and current stress characteristics, are given to analyze and compare the advantages of different phase shift control methods. In addition, the efficiency characteristics of various phase shift control methods are compared and analyzed from the perspective of magnitude of reverse power. A 300-W experimental prototype is constructed to verify the working principle and efficiency characteristic. The comparison of different phase shift control methods is validated by experimental results.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Simple and Effective Adaptive Deadtime Strategies for LLC Resonant
           Converter: Analysis, Design, and Implementation

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      Authors: Yuqi Wei;Quanming Luo;Zhiqing Wang;H. Alan Mantooth;
      Pages: 1548 - 1562
      Abstract: Deadtime is a critical design target for soft switching dc/dc converters. On the one hand, the deadtime is necessary to ensure the safety operation of the devices in one switching leg; on the other hand, enough deadtime is required to achieve zero voltage switching (ZVS) operation. Due to the complexity of LLC converters, traditionally, the deadtime selection is either based on engineering experience or inaccurate analysis of the converter, which leads to an unoptimized deadtime. Specifically, a large deadtime will lead to efficiency degradation due to the body diode conduction during deadtime. The ZVS operation cannot be completely achieved with a small deadtime, which will also degrade the converter efficiency. Therefore, there is a demand for an accurate analysis of the deadtime effect on LLC converters. In this article, an accurate and in-depth analysis of the deadtime effect on the LLC converter is performed with the aid of the time-domain analysis (TDA). However, the proposed adaptive deadtime strategies can also be implemented based on the experiment or simulation results for those who do not have access to the TDA of LLC converters. Based on the analysis, novel adaptive deadtime strategies are proposed for the LLC converter. Compared with the traditional fixed deadtime strategy, around 1% efficiency improvement is achieved for a 125-W experimental prototype during the whole operating range.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Novel LLC Converter With Topology Morphing Control for Wide Input
           Voltage Range Application

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      Authors: Yuqi Wei;Quanming Luo;H. Alan Mantooth;
      Pages: 1563 - 1574
      Abstract: Wide voltage gain range applications are challenging for dc/dc converters, and the system efficiency would be degraded in order to satisfy the voltage gain requirement. Inductor–inductor–capacitor (LLC) resonant converters have gained popularity owning to its high efficiency feature. However, wide voltage gain range applications also challenge the LLC converters from the following three aspects: 1) large switching frequency operating range is required to meet the voltage gain requirement, which degrades the converter electromagnetic interference (EMI) performance and challenges the optimization of magnetic components; 2) small inductor ratio is required to boost the voltage gain, which increases the resonant tank root-mean-square (rms) current and conduction loss; and 3) control instability issues may occur at both maximum voltage gain and minimum voltage gain, which reduce the converter reliability. To address these issues, in this article, a novel LLC converter with topology morphing control is proposed for wide voltage gain range applications. Three operation modes, dual full-bridge (DFB), hybrid full-bridge and half-bridge (HFBHB), and dual half-bridge (DHB), can be achieved by adopting the topology morphing control, which can cover a wide voltage gain operation range. Operational principles, design considerations, and experimental validations of the proposed converter are presented.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A 13-Level Switched-Capacitor Multilevel Inverter With Single DC Source

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      Authors: Vishal Anand;Varsha Singh;
      Pages: 1575 - 1586
      Abstract: In this article, a novel 13-level inverter single source, switched-capacitor multilevel inverter (SSC-MLI) is proposed. This topology is suitable for renewable energy applications using less input voltage source magnitude. This structure is capable of boosting the input voltage six times with the help of switched capacitors. The capacitors are automatically balanced without any control algorithms, complex circuits, or closed-loop controllers. The advantages of the proposed structure are high-power density and high efficiency by the use of only switches. Since, there are no diodes there is no forward conduction loss, and no reverse recovery delay. The maximum blocking voltage across the individual switch is three times the input voltage. The functionality of the SSC-MLI is described in detail. The capacitance calculation and optimum value of capacitors are discussed. A suitable comparison is presented for the proposed structure with the existing literature to check the inverter performance. The power loss for exiting a 13-level inverter is presented. The simulation is carried out for both pure resistive and inductive load. Later, the experimental results are presented for variation in frequency, dynamic change in load, variation in modulation index, and step-change in input voltage to validate the proposed topology performance and feasibility.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Balancing of Common DC-Bus Parallel-Connected Modular Inductive Power
           Transfer Systems

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      Authors: Hakan Polat;Enes Ayaz;Ogün Altun;Ozan Keysan;
      Pages: 1587 - 1596
      Abstract: The aim of this article is to design a modular, fault-tolerant multi-transmitter (Tx)/multi-receiver (Rx) parallel-connected common dc-bus inductive power transfer (IPT) system to replace slip rings in wind turbines or brushless exciters. In parallel-connected common dc-bus systems, current unbalance is a major issue that results in thermal stresses and over current or voltages. In this article, two different new current balancing methods are proposed: cross-coupled Rx modules and intentional detuning of Rx-side resonant frequency. These methods are investigated both analytically and experimentally for a single Tx and two Rx system for a 500-W prototype. The proposed methods are tested independently, and then, the combined current balancing method is also investigated. For the same misalignment case, cross coupled/detuned has a 55.8% current balancing improvement compared with decoupled/fully tuned topology.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Medium-Voltage Current Source Inverter for Synchronous Electrostatic
           Drives

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      Authors: Peter Killeen;Aditya N. Ghule;Daniel C. Ludois;
      Pages: 1597 - 1608
      Abstract: Macroscale synchronous electrostatic machines (SEMs) require medium-voltage (5 kV) and high fundamental frequencies (high pole number ~96) to be competitive with traditional electromagnetic machines. This article focuses on the design, modeling, and characterization of a medium-voltage current source inverter hardware platform to meet the low current and high-frequency requirements of SEMs. The inverter stage utilizes junction field effect transistor (JFET) supercascodes for the medium-voltage switches. A full-bridge front end regulates the necessary dc-link current and provides some of the voltage gain from the low-voltage dc input. A sensitivity analysis shows that the system losses have a quadratic dependence on the output voltage and a linear dependence on switching frequency and dc-link current. Minimal dependence on output power and fundamental frequency was measured. Averaged modeling shows a right-half-plane (RHP) pole exists for the dc-link control. Two methods for stabilizing the machine drive were proposed and validated. Active damping via virtual resistance on the dc link was used to shift the pole to the left half-plane. The second method utilizes the $q$ -axis voltage decoupling to remove the voltage disturbance of the inverter controller on the dc-link current. The impacts on system stability and disturbance rejection were measured and correlate with modeling.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • On the Stability of Volts-per-Hertz Control for Induction Motors

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      Authors: Marko Hinkkanen;Lauri Tiitinen;Eemeli Mölsä;Lennart Harnefors;
      Pages: 1609 - 1618
      Abstract: This article deals with the stability analysis of volts-per-hertz (V/Hz) control for induction motors. The dynamics of the electrical and mechanical subsystems of the induction motor model are nonlinearly coupled by the electromagnetic torque and the backelectromotive force. Under open-loop V/Hz control, the nonlinear interaction is known to give rise to small-signal oscillations while operating at medium speeds under light loads. In this article, it is shown that the interaction also causes a nonoscillatory unstable mode to appear at low speeds under heavy loads (despite the perfect flux level), manifesting itself as a flux collapse or surge. It is also shown that the electrical subsystem with the rotor speed input and the electromagnetic torque output has nonpassive operating regions, which indicates a risk of detrimental interactions with the mechanical subsystem. Finally, a feedback design is proposed in order to enlarge the passive and stable regions and improve the damping. The theoretical results are validated by means of simulations and experiments on a 45-kW induction motor drive.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Parameter Robustness Improvement of Predictive Current Control for
           Permanent-Magnet Synchronous Motors

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      Authors: Shuang Wang;Yayuan Hu;Jianfei Zhao;Yuanyuan Zhang;
      Pages: 1619 - 1626
      Abstract: A predictive current control with parameter robustness (PR-PCC) method of permanent magnet synchronous motor (PMSM) is proposed in this article. First, a cost function is designed to calculate the increment of the optimal voltage vector at the current instant, which is based on incremental PMSM model. The incremental PMSM model is used to eliminate the influence of the motor flux parameter. Second, the optimal voltage vector that minimizes the cost function is obtained by combining the increment of the optimal voltage vector with the idea of iteration. At the same time, a current observer based on the incremental model is designed to compensate one-step sampling delay. In this way, the feedback current of $dq$ -axis accurately followed the reference current. In comparison with the conventional pulse width modulation predictive current control (PWM-PCC) method, the proposed method can significantly reduce the steady-state error of $dq$ -axis current caused by inductance, flux, and resistance parameters mismatch quickly. Finally, experimental results of the proposed method and the conventional PWM-PCC are presented in this article to verify the validity of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • An Online Estimation Method for Both Stator Inductance and Rotor Flux
           Linkage of SPMSM Without Dead-Time Influence

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      Authors: Peng Wang;Keman Lin;Xu Zhang;Shuai Wang;Jian Ai;Mingyao Lin;
      Pages: 1627 - 1638
      Abstract: It is essential to estimate stator inductance and rotor flux linkage online for fault diagnosis and high-performance control of surface-mounted permanent magnet synchronous machine (SPMSM). The current injection method is a popular way to estimate the two parameters. However, the dead-time influence of voltage-source-inverter (VSI) and the stator inductance variation caused by injected current could not guarantee the converge of the estimation. To solve the above two problems, a method of injecting square-wave angle for online parameter estimation is proposed in this article. First, the theory of eliminating dead-time influence with and without square-wave angle injection is analyzed. Next, the least square algorithm is adopted to estimate stator inductance without injection. Then, the rotor flux linkage is estimated by injecting a square-wave angle. The saturation effect of estimation is also analyzed, and both parameters are estimated without acquiring any nominal values. At last, the appropriate amplitude and frequency of square-wave angle are determined by the parameter error and convergence analysis. The proposed method is evaluated with simulation and extensive experiments under various speed and load conditions. It is noteworthy that not less than two parameters are estimated without the dead-time influence and the injection will not cause inductance variation, which is different from the previous work.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Multisector Three-Phase PMSM Drive System With Low-Frequency and
           High-Frequency PWM Noise

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      Authors: Yongxiang Xu;Wentao Zhang;Yingliang Huang;Jibin Zou;
      Pages: 1639 - 1648
      Abstract: Multisector three-phase permanent magnet synchronous motors (PMSMs) possess better performance against traditional motors. With the application of pulsewidth modulation (PWM) and consideration of switching losses, ear-piercing high-frequency noise from the motors has become unacceptable in sensitive environments. A drive topology covering $K$ paralleled inverters with special open-winding magnetically coupled inductors is presented to feed the multisector motor. In this article, a comprehensive suppression strategy with low-frequency compensation based on an adaptive-linear-neuron algorithm is proposed to eliminate the PWM noise around odd carrier multiples, and reduce the harmonics near even carrier multiples under 2K multiple through the impedance of the coupled inductors. Apart from the analysis of the elimination principle and advantages of the drive system, the simulation verification is also conducted. Finally, the detailed experimental results have verified the effectiveness of the proposed strategy in a two-sector three-phase PMSM drive system.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Low Vibrations and Improved NVH in Permanent Magnet Synchronous Machines
           Due to Injection of Flux-Linkage Harmonics

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      Authors: Martin Harries;Annegret Woerndle;Rik W. De Doncker;
      Pages: 1649 - 1657
      Abstract: Harmonic currents have a significant influence on the vibration behavior of electrical machines. Nevertheless, it remains a challenge to determine the optimum amplitude and phase position of the harmonic currents. This article concentrates on the injection of flux-linkage harmonics to enable acoustic optimization for permanent magnet synchronous machines (PMSMs). The test bench verification of this method using a commercial drive from a luxury class hybrid car proves that vibrations of the problematic mode zero are almost completely eliminated. The total sound pressure level of the machine is reduced by approximately 10 dB compared to the usual field-oriented control. Besides the advantage on the acoustic behavior, this article evaluates the impact of the harmonic flux-linkage injection on current amplitude, average torque, and efficiency.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Loss-Reduction-Oriented Optimization Methodology of
           Hybrid-Magnetic-Circuit Variable Flux Memory Machine for Global Efficiency
           Improvement

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      Authors: Wei Liu;Hui Yang;Heyun Lin;Shukang Lyu;
      Pages: 1658 - 1670
      Abstract: Due to the existence of multiple magnetization states (MSs) of the low coercive force (LCF) PMs, the losses minimization of variable flux memory machine (VFMM) under different MSs are unable obtained simultaneously. This article proposes a loss-reduction-oriented (LRO) optimization methodology for overall efficiency improvement in VFMM. Firstly, a recently developed hybrid-magnetic-circuit (HMC) VFMM is selected as a design example to investigate the proposed optimization methodology. Subsequently, the architecture and overall flowchart of the proposed LRO optimization methodology are introduced and given, which includes two rounds of optimization, namely, dual-operating-mode rough optimization (DOM-RO) and multiple-operating-mode elaborate optimization (MOM-EO). Besides, a computationally efficient multimode field-circuit coupled (MMFC) model is established in finite element (FE) software to account for multiple operating modes within two simple case studies. On this basis, the proposed optimization methodology is applied to the HMC-VFMM, in which the LRO objective function is defined in terms of the time proportions of various MSs in an overall driving cycle. According to the optimization results, the electromagnetic characteristics of the machine are investigated, especially the machine loss and its efficiency maps under different MSs are analyzed. Finally, a prototype is manufactured and tested to verify the validity of the proposed optimization strategy.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Design of a Double-Side Flux Modulation Permanent Magnet Machine for Servo
           Application

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      Authors: Yuting Gao;Martin Doppelbauer;Jing Ou;Ronghai Qu;
      Pages: 1671 - 1682
      Abstract: Flux modulation machine (FMMs), which operate on magnetic gearing effect, have high torque density and low pulsating torque. Therefore, FMMs are very suitable for servo machines. In this article, based on the specific application in a servo system, a double-side (DS)-FMM, which has permanent magnets (PMs) on both stator and rotor, is proposed and designed. First, the structure and the evolution process of the DS-FMM are introduced. Then, the design optimization is presented, and the effects of main design parameters on torque density, cogging torque, torque ripple, and power factor, which are the most important performance indexes for servo machines, are analyzed. Moreover, in order to ensure the operation safety, the thermal and mechanical verifications are carried out. Besides, the proposed DS-FMM is compared with a regular PM servo machine in terms of torque density, cogging torque, torque ripple, power factor, and so on. Finally, to validate the design of the DS-FMM, a prototype is built and tested. The experimental results coincide well with the theoretical design.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Reluctance Synchronous and Flux-Modulation Machines Designs: Recent
           Progress

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      Authors: Ion Boldea;Lucian Nicolae Tutelea;Ana Adela Popa;
      Pages: 1683 - 1702
      Abstract: Electric machines provide the conversion of mechanical energy to electrical energy (in the generating mode) and vice versa (in the motoring mode), via magnetic energy storage in their airgap (mainly) and in their permanent magnets (PMs) (if any). They are crucial in electric energy conversion and processing and for motion (torque, speed, and position) control in all industries, for better productivity, energy savings, and less harm to environment. Traveling field electric machines are still standard as synchronous and induction machines. The former (synchronous) need dc rotor excitation, or PMs or magnetically salient rotor to create a-fixed-to-rotor traveling field while the latter (induction) implies a cage (or wound) rotor winding. The average torque is nonzero as stator and rotor traveling fields are at standstill with each other. In an effort to take advantage of the variable reluctance concept in producing nonzero magnetic co-energy (and torque) in the machine versus variation of rotor position, better reluctance synchronous machines (RSMs) (line-start or inverter-fed) in terms of efficiency $times $ power factor, torque density, and costs without and with assisting PMs have been introduced lately. High magnetic saliency is implicit and requires a high ratio of pole pitch to airgap and a distributed ac stator winding, in the hope to meet the IEC 4, 5 standards of efficiency. On the other hand, better magnetic materials (with lower core losses) and higher fundamental frequency provided by pulsewidth modulation (PWM) static power converter (including silicon carbide (SiC) arrival) up to 1 kHz, in general, and the high price (and scarcity) of high energy PMs have triggered formidable Research and Development worldwide efforts to investigate many machine topologies without and with PMs (mainly ferrites or bonded NdFeB of lower cost), with mainly concentrated ac windings based on the princip-e of “flux-modulation (F-M)” provided by variable reluctance (magnetic anisotropy) concept. This article aims to summarize recent progress in reluctance electric machines, without and with PM assistance of synchronous and “F-M” types in terms of topologies, modeling, design, control, and merits and demerits based on comprehensive-technical and economic performance indexes.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Torque Pulsation Reduction During Magnetization in Variable Flux Machines

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      Authors: Bigyan Basnet;Pragasen Pillay;
      Pages: 1703 - 1711
      Abstract: This article proposes two methods to minimize the pulsating torque during magnetization in a variable flux-permanent magnet synchronous machine (VF-PMSM). The VF-PMSM is demagnetized and remagnetized by injecting a current pulse to achieve high speed and high torque requirements. During demagnetization and remagnetization, a $d$ -axis current pulse is injected to change the magnetization state (MS). These MS changing current pulses will change the magnet flux linkage based on the amplitude of the pulse. However, the injected $d$ -axis current abruptly changes the magnet torque as well as reluctance torque and results in a pulsating torque. Since the remagnetization current is much higher than the machine-rated current, the pulsating torque is more severe during the remagnetization process. Thus, it is preferred to magnetize the magnet at zero speed and unloaded conditions. To solve this problem, a $q$ -axis current reference during the remagnetization is determined by two different methods: voltage limit method and load torque method. The derived $q$ -axis current reduces the torque pulsation during the remagnetization. The effectiveness of the proposed scheme is experimentally verified on a manufactured VF-PMSM prototype.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Tutorial on General Air-Gap Field Modulation Theory for Electrical
           Machines

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      Authors: Ming Cheng;Peng Han;Yi Du;Honghui Wen;Xianglin Li;
      Pages: 1712 - 1732
      Abstract: This tutorial paper presents the mathematics behind the widely observed air-gap field modulation phenomena in electrical machines and derives the duality between electrical machines and switching converters. A bibliometric analysis of the existing research on various machine types is presented to show the historical development of electrical machines from the perspective of the number of publications, showing the necessity and urgency of unifying the analysis of operating principles/torque production mechanisms before the development of the general air-gap field modulation theory in 2017. The theoretical framework and its applications are reviewed. Detailed examples of how to use the developed theory to analyze the operating principle/torque production, conduct the quantitative analysis of parameters and basic performance, and make innovations from topologies of typical electrical machines are also included for verification as well as self-study.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Design and Validation of an Unconventional 39-Slot PM Synchronous Motor
           With Asymmetric and Unbalanced AC Windings

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      Authors: Metin Aydin;Yucel Demir;Ersin Yolacan;Mehmet Gulec;Ayman M. El-Refaie;
      Pages: 1733 - 1744
      Abstract: One of the main issues in manufacturing rotors for integer slot surface-mounted permanent magnet (PM) synchronous motors is the rotor skew. Motor manufacturers typically prefer to avoid skewing due to the added complexity and the difficulty in controlling the accuracy of the skewing and achieving the required outcome. This article proposes a design that minimizes torque ripple without using any kind of skewing in the rotor using asymmetric ac windings with unconventional stator slot-pole combinations. First, feasible slot and pole combinations are reviewed for PM synchronous motors. Theory behind unconventional asymmetric and unbalanced ac winding PM motors is presented. A lumped-parameter magnetic equivalent circuit for such unconventional stator is provided for a 1.7-kW PM motor. Detailed 2-D finite element analysis (FEA) is performed and compared with the lumped parameter model. A prototype motor is manufactured, and open-circuit as well as full-load tests are performed. Good agreement between the analytical, FEA, and test results is obtained.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Slotless-PM Machine Design for an Integrated Generator-Rectifier
           Architecture for Off-Shore Wind Turbines

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      Authors: Dongsu Lee;Samith Sirimanna;Phuc Thanh Huynh;Elie Libbos;Arijit Banerjee;Kiruba S. Haran;
      Pages: 1745 - 1755
      Abstract: Integrated generator-rectifier architecture has been shown to substantially improve power density, efficiency, and reliability of the electric drivetrains in wind turbines. From a power-electronic perspective, the architecture processes a majority share of the incoming power through passive diodes operating at the generator’s fundamental frequency. This article presents a design methodology of a 10-MW generator, which involves a specific low-reactance generator to minimize the commutation voltage drop at the passive rectifiers as well as prevent power imbalance between different generator ports. Appropriate phase shifts between the multiple passive ports to eliminate the need for a dc-link capacitor improve the drivetrain reliability. The proposed design adopts a slotless permanent magnet (PM) generator, where the reactance is greatly constrained by eliminating the stator slots. In addition, a Halbach PM-array structure reduces the reactance by removing the rotor back iron. The design methodology uses these features along with a multiobjective optimization framework to maximize power density and efficiency while retaining a low reactance. Co-simulation of the generator and integrated power electronics shows that the proposed architecture is suitable for off-shore wind generators. Finally, a subscale generator is tested to verify the low-reactance design of the proposed generator.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A High Torque Density Claw-Pole Permanent-Magnets Vernier Machine

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      Authors: Yuanzhi Zhang;Dawei Li;Peng Yan;Xiang Ren;Ronghai Qu;Jimin Ma;
      Pages: 1756 - 1765
      Abstract: Permanent magnets vernier (PMV) machine is gaining more and more attention due to its high torque density contributed by multi-orders working harmonics, especially low-pole-pair numbers harmonics. Spoke-array PM machine seems to be a good way to increase the machine working harmonics. But the flux barrier effect is revealed and it explains why the advantages of the spoke-array PMV (SAPMV) machine are not fully used. Thus, its low-pole-pair numbers harmonics could be further enhanced. In this article, a novel structure—claw-pole PMV (CPPMV) machine—is first proposed and its working principle is investigated. Then, the CPPMV machine is compared with the surface-mounted PMV machine, the SAPMV machine, and the SAPMV machine with alternate flux bridges in terms of their electromagnetic performances using equivalent circuit analysis and FEM. The result shows that claw-pole structure can enhance the magnetic flux modulation effects, which increases the machine torque density. At last, a CPPMV machine prototype is manufactured and tested. Experimental results indicate that it reaches a torque density of 30.5 kNm/ $text{m}^{3}$ and a power factor of 0.84 underrated conditions.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Design and Analysis of Fractional Pole-Pair Linear Permanent Magnet
           Machine

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      Authors: Li Fang;Dawei Li;Chaojie Shi;Ronghai Qu;
      Pages: 1766 - 1776
      Abstract: A novel concept of fractional pole-pair linear permanent magnet machine (FP-LPM) has been proposed recently. It is found that using a fractional pole-pair number in linear permanent magnet machine (LPM) could effectively reduce slot cogging force as well as back electromotive force (EMF) unbalance. Thus, thrust ripple is curtailed, which improves its thrust quality and enhances its application potential. However, some issues of FP-LPM still remain unsolved, such as phase split and current phase adjustment, and also, structure optimization is different from the traditional topology due to extra auxiliary tooth. This article contributes to giving a detailed designing methodology, including winding arrangement, regulations of choosing slot/pole combination, and effective end optimization method of FP-LPM. Thus, this article can give helpful guidance in designing FP-LPM to satisfy different application demands. Finally, an 18-slot/29-pole FP-LPM vernier machine (FP-LPMVM) is designed and constructed using the proposed method, and the test results verify the research conclusions.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Active Harmonic Suppression of Low-Reactance Multiphase Slotless Permanent
           Magnet Synchronous Machines

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      Authors: Zaixin Song;Chunhua Liu;Senyi Liu;Wusen Wang;
      Pages: 1777 - 1787
      Abstract: Harmonic suppression plays a key role in the current control of dual-three-phase (DTP) permanent magnet synchronous machines (PMSMs). Existing current control schemes are scarcely verified by designed DTP motor prototypes or consider the impact of inherent electromotive force (EMF) harmonics quantitatively. Also, few studies discuss the low-reactance case, which requires additional concerns for current prediction and modulation. Therefore, this article conceives and presents an improved deadbeat-based active current harmonic control scheme particularly for low-reactance PMSMs. From the aspect of motor design and finite-element analysis, the quantitative effect of EMF harmonics on control behaviors is analyzed. Based on the nonideal mathematical model (MMM) of the designed slotless PMSM with analyzed EMF harmonics, the proposed scheme is first introduced theoretically and verified by simulation. Subsequently, the slotless PMSM prototype fabrication and control experiments validate the proposed scheme and recognize the necessity of active harmonic suppression.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Topology Exploration and Analysis of a Novel Winding Factor
           Modulation-Based Hybrid- Excited Biased Flux Machine

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      Authors: Yuan Mao;Shuangxia Niu;
      Pages: 1788 - 1799
      Abstract: This article presents a novel permanent magnet (PM)-assisted flux-controllable machine, namely, the hybrid-excited biased flux machine (HEBFM). The proposed machine can implement flexible flux regulations (i.e., either field weakening or strengthening) by integrating the field current winding with the half consequence PM poles in the stator. The topology of the HEBFM can be explored in multipole cases, which contributes to improved flexibility for flux control and winding regulation. Compared with the conventional flux-controllable machines, the proposed machine gains the merits of owning: 1) extended flux control range via the modulation of winding factor (i.e., winding factor modulation); 2) stable and compact structure; 3) reduced demagnetization risk of PMs; and 4) capability of topology exploration. In this article, the operation principle and electromagnetic performance of the proposed machine are analyzed using the finite-element method (FEM). Besides, the torque and torque ripple are optimized based on multiobjective differential evolution (DE) coupled with FEM. Finally, a prototype is manufactured and tested to validate the effectiveness and feasibility of the proposed machine designs.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Combined Random Forest and NSGA-II for Optimal Design of Permanent Magnet
           Arc Motor

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      Authors: Zhenbao Pan;Shuhua Fang;
      Pages: 1800 - 1812
      Abstract: This article presents an optimization design method for a double-stator hybrid excited permanent magnet arc motor (DS-HE-PMAM). The proposed optimization method combining the machine learning algorithm random forest (RF) and the nondominated sorting genetic algorithm-II (NSGA-II) contributes to achieving high average torque, low torque ripple, high back electromotive force (EMF), and low total harmonic distortion of the back EMF. First, the motor structure and working principle of the DS-HE-PMAM are illustrated. The selection of parameters to be optimized is determined based on an analytical model. Then, a variable importance measure-based new sensitivity analysis method is implemented to evaluate the influence of each structural parameter on the selected design objectives. The finite-element analysis (FEA)-based DS-HE-PMAM model is developed to obtain the sample data regarding input structural parameters and output design objectives. Based on the sample data, a powerful machine learning algorithm called RF is employed to fit the function relationship between output design objectives and input structural parameters. After that, an intelligent search algorithm named NSGA-II is introduced to search for the optimal solution to the structural parameters combination and obtain the optimal motor performances. Finally, the electromagnetic characteristics of the initial and optimized models of the DS-HE-PMAM are compared and analyzed, and both FEA and prototype experiments verify the feasibility and superiority of the proposed optimization method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Review and Analysis of Coaxial Magnetic Gear Pole Pair Count Selection
           Effects

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      Authors: Bryton Praslicka;Matthew C. Gardner;Matthew Johnson;Hamid A. Toliyat;
      Pages: 1813 - 1822
      Abstract: Magnetic gears perform the same function as mechanical gears using magnetic fields instead of interlocking teeth. A review of the design processes used in the literature demonstrates that a critical design parameter, pole pair count, is often given inadequate consideration. In addition to reviewing the existing prototypes, this article uses a parametric simulation study to analyze the impacts of pole pair counts on gear performance and illustrate how the optimal pole counts vary with gear ratio and various design parameters. This article also introduces new ripple factors, which better correlate with torque ripple than the cogging factor ( $C_{T}$ ) used in previous articles, and illustrates why designs with noninteger gear ratios tend to have much smaller torque ripples than designs with integer gear ratios. While selecting the pole counts to minimize symmetry can reduce torque ripple, designs without any symmetry are shown to experience unbalanced magnetic forces on each rotor. Thus, it is recommended to select pole counts that result in an even number of modulators but not an integer gear ratio. This article also reveals that for a fixed gear ratio, a nontrivial optimum pole count minimizes the electromagnetic losses.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Characteristics Analysis of Consequent-Pole Ferrite Magnet Vernier Machine
           Using Novel Equivalent Magnetic Circuit

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      Authors: Abdur Rehman;Byungtaek Kim;
      Pages: 1823 - 1833
      Abstract: This study deals with a consequent-pole (CP) vernier motor with low-cost ferrite magnets. To investigate the magnetic behavior of the CP permanent magnet vernier machine (CP-PMVM) quantitatively, two magnetic equivalent models are newly proposed which are applied to estimate the main and the modulation flux densities in air gap, respectively. Using the proposed models, it is revealed that the CP structure substantially reduces the effective air-gap length, and thus, a CP-PMVM with half number of magnets has much higher modulation flux density than that of a regular surface PM vernier machine (SPMVM). Consequently, the CP-PMVM is expected to able to keep the vernier effect high even with thick ferrite magnets, producing higher back electromotive force (EMF) than the SPMVM does. Moreover, large variation of air-gap length due to thick magnet thickness leads to a considerable advantage of reluctance torque. For a proto-designed CP-ferrite PMVM, the electromagnetic characteristics, such as main and modulation flux densities, back EMF, dq inductances, and torque, have been investigated by using the proposed method as well as finite-element (FE) method. In addition, through the demagnetization analysis, it is proved that the proposed CP-PMVM has certainly enough antidemagnetization capability, whereas an SPMVM with ferrite magnets loses its magnetism. From the analysis results, it is confirmed that the proposed machine with less magnet volume and low-cost ferrite magnets has higher torque compared with its SPM vernier counterpart. Finally, to validate the analytical and numerical analyses, experimental results are provided.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Design and Analysis of Hybrid-Excited Flux Modulated Linear Machines With
           Zero-Sequence Current Excitation

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      Authors: Yiming Shen;Qinfen Lu;
      Pages: 1834 - 1846
      Abstract: This article investigates a hybrid-excited flux modulated linear machine (HEFMLM) with zero-sequence current excitation. With the adoption of integrated open winding, zero-sequence current can be utilized to provide the dc excitation and further improve the thrust force density. First, the machine topology, drive circuit, and operation principle are described. Then, the magnetomotive force (MMF)-permeance model is built to analytically calculate the air-gap hybrid-excited field harmonics and further verified by finite element (FE) analysis. Moreover, the electromagnetic performances including open circuit characteristics, flux regulation capability, thrust force characteristics, and demagnetization risk are comparatively studied. Due to the improved exciting field and armature MMFs with integrated winding, the thrust force capability can be significantly enhanced by 22.6% on the premise of rated copper loss. Besides, the proposed HEFMLM exhibits high thrust force density compared with the other three types of HEFMLM, benefitting from a high pole-pair number of permanent magnets (PMs) along with a more obvious magnetic gearing effect. Finally, a prototype of the HEFMLM is carried out for experimental validation.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Optimization of Rotor Salient Pole Reluctance for Typical Field Modulated
           Electric Machines

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      Authors: Honghui Wen;Ming Cheng;Jiawei Zhou;Gan Zhang;Xiaofeng Zhu;
      Pages: 1847 - 1859
      Abstract: The objective of this article is to investigate the possibility to improve the torque characters of electric machines featuring rotor salient pole reluctance from the perspective of the general airgap field modulation theory. The torque production mechanisms of two typical field modulated machines, namely, the magnetically geared machine (MGM) and the flux-reversal permanent magnet (FRPM) machine, are discussed based on the Maxwell stress tensor (MST) method, where the mono-harmonic mechanism of rotor PM machine like the MGM is revealed. Several common theoretical salient rotor pole configurations, like the upright/inverted trapezoidal configuration, are introduced in detail, based on which general and modified rotor configuration advices for the two electric machines are proposed to provide initial design and future optimization guidance. It is proven that there is a possible opportunity to make the torque characters better via reasonable selection of rotor configuration and topological parameters. Electromagnetic performances validation based on 2-D finite-element analysis, such as improved airgap magnetic field harmonic distributions, load flux linkage/electromotive force (EMF), and general torque performances of two field modulated machines is provided to demonstrate the effectiveness of theoretical analysis. It is also verified by experimental measurements on the FRPM machines with different pole pair combination.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Investigation of Torque Improvement Mechanism in Emerging Switched Flux PM
           Machines

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      Authors: Ya Li;Hui Yang;Heyun Lin;
      Pages: 1860 - 1869
      Abstract: This article aims to investigate and reveal the torque enhancement mechanism in several emerging switched flux permanent magnet (SFPM) machines using a unified torque equation with an improved winding factor function. Based on a hybrid finite-element (FE)–analytical method, the torque contributions of the major air-gap field harmonics in the conventional, C-core and E-core, and consequent-pole (CP) SFPM machines are identified and quantified by taking a conventional 12-stator-slot/13-rotor-tooth (12s13r) SFPM machine as a benchmark, which shows that the dominant torque proportions are contributed by the low-order field harmonics due to the amplification effect of the gear ratio. Besides, a low-order field harmonic impeding effect is observed in the conventional and C-core SFPM structures, resulting in a compromised torque capability. Whereas since the auxiliary teeth and stator iron bridge designs provide relatively lower magnetic reluctances for low-order harmonics, the E-core and CP structures can produce improved low-order harmonics and higher torques than the conventional one. Finally, some experiments on a CP-SFPM machine are conducted to validate the theoretical and FE analyses.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Reduction of Saturation and Unipolar Leakage Flux in Consequent-Pole PMV
           Machine

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      Authors: Huawei Zhou;Weiguo Tao;Guangyao Jiang;Guang-Jin Li;Guohai Liu;
      Pages: 1870 - 1880
      Abstract: This article proposes some effective approaches to address the inherent issues of consequent-pole (CP) permanent magnet (PM) machines, such as saturation of the salient rotor core and unipolar PM leakage flux of the end region caused by asymmetric field. The effect of CP-Halbach PM array with different magnetization directions and parameters that affect the saturation has been investigated for the CP PM machine with short pole pitch. By employing the CP-Halbach array, the saturation issue can be solved and superior performance can be obtained without reducing the PM pole arc. In addition, unequal and multistep staggered rotors with magnetic barriers have been proposed to reduce the unipolar leakage flux in the end region. Compared with regular staggered rotors, not only better electromagnetic performance can be achieved, but also the end unipolar leakage flux can be reduced. Finally, a prototype is manufactured and the predictions have been validated by measurements.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Transient Analysis and Verification of a Magnetic Gear Integrated
           Permanent Magnet Brushless Machine With Halbach Arrays

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      Authors: Libing Jing;Yonglin Pan;Tao Wang;Ronghai Qu;Po-Tai Cheng;
      Pages: 1881 - 1890
      Abstract: The magnetic gear integrated permanent magnet brushless machine (MG-IPMBM) is a kind of compact structure with high torque density and complex electromagnetic energy transfer. In order to analyze the transient characteristics of the machine, an analysis method of field circuit coupling is proposed. Both magnetic gear (MG) and permanent magnet motor are magnetized by Halbach array. Combining the analytical model of the MG magnetic field with MATLAB motor simulation module, a joint simulation model of field circuit coupling double closed-loop control system based on the Simulink-analytical method is established. The electromechanical transient response characteristics of machine under load starting, load mutation, and overload self-protection are analyzed. The simulation results show that the output speed and torque of machine can accurately follow the given value, and its unique overload self-protection ability greatly improves the safety of machine operation. In addition, a prototype is made and an experimental platform is built. The experimental results show that the output torque follows quickly, the torque ripple is small, and transient performance of the machine is good.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Analysis of Integrated Winding Configuration in Dual-Electrical-Port
           Machine

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      Authors: Ziyi Liang;Xiang Ren;Dawei Li;Ronghai Qu;
      Pages: 1891 - 1901
      Abstract: A novel winding configuration named “integrated winding” was proposed to realize function of original two sets of windings, that is, it produces two independent control magnetic fields with different pole pairs (not slot harmonics). The concrete realization method is through the coordinated operation of controllers, and two current components with different phases are injected into the same coil to generate the required magnetic fields according to star of slots. Because the magnetic field produced by the winding is only related to the instantaneous current in each coil, rather than specific connection of coils. The integrated winding not only simplifies the winding configuration but also increases the electric loading, thus improving the torque density. The general method of integrated winding configuration and current injection rule iss established. The split-phase rules of integrated winding are summarized, and the feasibility of the six-phase and 12-phase integrated windings is then proved through finite-element analysis (FEA). A prototype is fabricated, and the experimental results verify the availability of the integrated winding.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Research on Interturn Short-Circuit Fault Indicators for Direct-Drive
           Permanent Magnet Synchronous Motor

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      Authors: Caixia Gao;Ke Lv;Jikai Si;Haichao Feng;Yihua Hu;
      Pages: 1902 - 1914
      Abstract: In this article, the effects produced by interturn short-circuit faults (ISFs) on variables of the direct-drive permanent magnet synchronous motors (DDPMSMs) are investigated. A finite-element method model is established to calculate the motor variables of DDPMSM that includes average torque, second-harmonic torque, torque ripple, branch differential current, branch residual current, branch voltage, and so on. Then, the motor variables under different cases, including various fault conditions and various operating conditions, are analyzed to understand the effects of ISF. Besides, the fault indicators (FIs) are selected based on the analysis of ISF. Finally, the simulation and experimental results are compared at different fault conditions and operating conditions to fully verify the analysis of ISF and FIs. This work provides a significant reference for the fault diagnosis, fault postprocessing, and fault-tolerant control of DDPMSM.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Extending Winding Function Theory to Incorporate Secondary Effects in the
           Design of Induction Machines and Drives

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      Authors: Baoyun Ge;Wenbo Liu;Jianning Dong;Mingda Liu;
      Pages: 1915 - 1924
      Abstract: High-performance electric drive applications necessitate a high fidelity model to predict the terminal characteristics of machines in the design stage to fulfill a system-level evaluation together with the converters. This article interprets winding function theory (WFT) from the field perspective and incorporates secondary effects, such as slotting and iron nonlinearity into it to accurately predict the main flux linkage in induction machines. The method is centered on resolving the magnetic scalar potential on the two sides of the air gap and computes the flux linkage via a winding function. Its performance is benchmarked against 2-D finite-element analysis (FEA) and the state-of-the-art magnetic equivalent circuit (MEC) method. Flux linkage and torque results indicate that the relative error is within 3.1% even in a highly saturated region when comparing to FEA, while MEC using the same circuit network may present a 20% error.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Comprehensive Analysis and Design of a Pulsating Signal Injection-Based
           Position Observer for Sensorless Synchronous Motor Drives

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      Authors: Ludovico Ortombina;Dario Pasqualotto;Fabio Tinazzi;Mauro Zigliotto;
      Pages: 1925 - 1934
      Abstract: The work focuses on a new mathematical formulation for the transfer function (TF) of a pulsating injection-based position observer, as the key point for its correct design. The proposed analysis exploits the modulation/demodulation control theory to derive the TF of the whole estimator in the Laplace domain. Magnetic iron saturation effects and cross saturation between the $dq$ -axes are considered in the observer design. To test the effectiveness of the new TF representation of the observer, it is used to synthesize two different regulators, namely by the direct synthesis and the internal model principle. An extensive experimental stage is included pointing to fully verify the accuracy of the proposed model and the theoretical considerations. A comparison with the existing mathematical model of the observer is also reported to show the improvement achievable in the position estimation by the proposed observer synthesis.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Dq-Transformed Error and Current Sensing Error Effects on Self-Sensing
           Control

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      Authors: Ye gu Kang;David Diaz Reigosa;
      Pages: 1935 - 1945
      Abstract: This article presents propagation of current sensor error through $dq$ -transform and the propagated error effect on high-frequency injection (HFI)-based self-sensing control. Three-phase ac systems use Clark and Park transform with $a, b, c$ phase inputs for control purpose, i.e., $dq$ -transform. When error exists in $a, b, c$ inputs, e.g., due to quantization, gain, offset, noise, and others, the error propagates to $d$ - and $q$ -axes and $dq$ -transform becomes inaccurate; therefore, the control performance degrades. Statistical models based on variance are developed for 2- and 3-channel based $dq$ -transform. The error variance models are verified using the error probability density function (PDF) with uniformly distributed random inputs. It is shown that the error propagated in $dq$ -axes and self-sensing control performance become rotor position-dependent, following the error variance model with error that exists in current inputs. It is shown that the error variance of 2-channel based $dq$ -transform becomes three times higher on average compared to 3-channel based $dq$ -transform. It is demonstrated that 3-channel based self-sensing control results in lesser positi-n estimation error compared to 2-channel based self-sensing with a tradeoff in an additional sensor in the machine drive system.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Family of Adaptive Position Estimators for PMSM Using the Gradient
           Descent Method

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      Authors: Niklas Himker;Georg Lindemann;Karsten Wiedmann;Bastian Weber;Axel Mertens;
      Pages: 1946 - 1962
      Abstract: This article presents an evaluation of a family of adaptive position estimators (APEs) for anisotropy-based self-sensing control (SSC) of permanent magnet synchronous machine (PMSM). The APEs use the gradient descent method (GDM) to minimize a cost function and thus estimate the rotor position. Three different APEs have been developed in previous work and are revised in this article. Their dynamic performance is experimentally evaluated and compared with each other and with an encoder-based control using the same test bench. Simplified models are derived, which allow an analytic calculation of the individual speed control loop dynamics. The speed control bandwidth using the latest APE reaches almost 50% of when using a 2000 slot incremental encoder. In addition, this version of APE with GDM features parameter tuning based on analytic equations.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Speed-Sensorless Control of Induction Motors With an Open-Loop
           Synchronization Method

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      Authors: Huimin Wang;Yongheng Yang;Dunzhi Chen;Xinglai Ge;Songtao Li;Yun Zuo;
      Pages: 1963 - 1977
      Abstract: Speed estimation schemes based on the closed-loop synchronization (CLS) methods for speed-sensorless control of motor drives attract much popularity due to several advantages, for example, easy implementation, high flexibility, and acceptable performance. However, most of the existing CLS-based estimation schemes may suffer from performance degradation during frequency ramps. Considering this, an attempt of the type-3 phase-locked loop (PLL)-based scheme is made. This solution, however, may adversely affect the system dynamics and stability margin. To address these issues, an open-loop synchronization (OLS) method is proposed for speed-sensorless control of induction motor drives in this article. In the proposed scheme, the estimated speed is obtained according to the sinusoidal signals and their time-delay signals, rather than increasing the system order. With this, system dynamics and stability margin are maintained. In practice, the disturbance of dc offsets is of concern in induction motor drives. Thus, a closed-loop flux observer is adopted to guarantee the estimation performance under dc offsets. The performance of the proposed OLS scheme is investigated and compared with that of the CLS schemes and the type-3 PLL scheme through experimental tests.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Full-Order Terminal Sliding-Mode-Based Sensorless Control of Induction
           Motor With Gain Adaptation

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      Authors: Minghao Zhou;Siwei Cheng;Yong Feng;Wei Xu;Likun Wang;William Cai;
      Pages: 1978 - 1991
      Abstract: This article proposes a sensorless speed control approach of Induction motor (IM) applying full-order terminal sliding-mode (FOTSM) control theory. The speed control system consists of three feedback control loops, i.e., the speed-, flux-, and current-loops. The related controllers in these three feedback loops are designed using FOTSM to enhance the robustness and dynamic performance, eliminate the singularity, and attenuate the chattering. The virtual control technique is utilized in the outer-loop speed controller to compensate unmatched uncertainties in the system, such as load disturbance and some parameter variations. The integral-type continuous control law with gain adaptation algorithm guarantees that the current references are smooth. In the inner-loop controllers, the actual voltage control signals can force the tracking errors of the currents to converge to its equilibrium point within finite time. Meanwhile, the FOTSM observer is designed for estimating the flux and speed of the motor simultaneously. Finally, the experiment results have demonstrated the effectiveness and feasibility of the proposed sliding-mode controllers and observers for the sensorless speed control of IM.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Resolution of Rotor Position Measurement: Modeling and Impact on Speed
           Estimation

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      Authors: Giacomo Scelba;Giulio De Donato;Abdelrahman A. M. Elsman;Luigi Danilo Tornello;Giuseppe Scarcella;Fabio Giulii Capponi;
      Pages: 1992 - 2004
      Abstract: The aim of this article is to provide an accurate modeling of the resolution of rotor position measurement and to evaluate its impact on speed estimation required for electric drive control. Starting from the space vector model of a spatially quantized rotor position measurement, the novel concept of instantaneous quantized speed is introduced, which is shown to constitute the effective input to any speed estimation algorithm. Time-harmonic formulations that are valid under periodic torque disturbances are also derived. These expressions, based on modulation theory, justify the presence of otherwise unexplained time harmonics in the measured rotor position and estimated speed, which appears when the shaft is subjected to torque disturbances. Analytical and numerical results are provided on a well-known observer structure to validate the filtering action of speed estimation algorithms on the harmonics of the instantaneous quantized speed. Finally, experimental verification on a 400 W permanent magnet (PM) servo drive is presented.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Real-Time FPGA-Based HIL Emulator of Power Electronics Controllers Using
           NI PXI for DFIG Studies

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      Authors: Mohamad Esmaeil Iranian;Meisam Mohseni;Saman Aghili;Ali Parizad;Hamid Reza Baghaee;Josep M. Guerrero;
      Pages: 2005 - 2019
      Abstract: This article presents a high-performance hardware-in-the-loop (HIL) system aimed to assist experts in developing and testing power electronics control board and their logic with real-time (RT) models of both electrical and mechanical components. For demonstrating the effectiveness of this system for HIL testing, a new industrial doubly-fed induction generator (DFIG) control board is tested based on a comprehensive wind energy conversion model developed in MATLAB/Simulink hardware description language (HDL) coder and LabVIEW environment. The interaction between MATLAB/Simulink and LabVIEW is accomplished by National Instrument (NI) intellectual property (IP) integration node, which loads very high-speed integrated circuit hardware description language (VHSIC-HDL or VHDL) codes (that enable those two software exchange RT data). LabVIEW implements a VHDL code of electrical model with fixed-point variables on an R-Series reconfigurable input/output (I/O) field-programmable gate array (FPGA) module on NI-PXIe 7858R installed on NI PXIe 1062Q chassis, and the mechanical models deployed in its PXIe 8133 central processing unit (CPU). Finally, through a uniquely developed interface board, the HIL emulator connects to an external DFIG control board. In FPGA, the model and other communicational and logging components’ step-time in each iteration is $5.0~mu text{s}$ . For verifying the results, a comparison is made between the proposed emulator system and Typhoon HIL602+ as a commercially available HIL system. It is proven that there is little or no significant deviation between the outputs of two systems. The proposed HIL emulator does not have the limitation of commercial HIL systems in adding custom-made new components.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Design and Implementation of the New Sensorless Rotor Position Estimation
           in Homopolar Salient-Pole Brushless DC Motor

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      Authors: Hassan Moradi CheshmehBeigi;
      Pages: 2020 - 2029
      Abstract: This article presents a novel method for indirect sensing of the rotor position in a homopolar salient-pole brushless dc (BLDC) motor and driving the motor smoothly from a standstill using an inductance bridge. Based on the characteristic of the phase inductance variation, the rotor position can be determined by using the inductance bridge to estimate the inductance of unknown phases. The proposed technique uses the motor winding in Hay’s bridge, and it is adjusted to achieve a balanced condition in an unaligned position when the minimum inductance occurs. In a running mode, by rotating the rotor, an idle phase inductance is changed and Hay’s bridge goes into an unbalanced condition. Then, by injecting extra voltage pulses into idle phases, the bridge output state changes. It then continues to sense the rotor position, while the motor is running by applying the same procedure. Moreover, the proposed method does not have problems like those in previous researches such as mutual inductance effects, need of large memory for locking up of the data, and losing of the estimation accuracy by the change in the sampling rate. As the main salient features of the proposed method, load independent, simplicity in implementation, and flexibility in tuning can be pointed out. Finally, experimental tests have been carried out to confirm the feasibility and practicability of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Optimized Anti-Windup Coordinating Strategy for Torque-Maximized
           

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      Authors: Zhen Dong;Zhengtao Ding;Bo Wang;Dianguo Xu;
      Pages: 2030 - 2041
      Abstract: Due to the contradiction between torque-maximized requirements and limited voltage and current constraints, voltage closed-loop flux-weakening strategy is developed to circumvent the saturation problem for maximum torque control of induction motor when the accelerating speed enters high-speed region. At the same time, since voltage inconsistency caused by the saturation is employed to construct flux-weakening controller (FC), anti-windup (AW) item in current regulator needs to be cut off to avoid the conflict. However, the replacement discards part of AWs utility and results in the distortion of command voltage, thus compromising system’s dynamic performance and making the tuning process of proportional-integral controller (PI)-based FC much trickier. To address this issue, an equivalent saturation model is presented. An optimized AW coordinating strategy is proposed, combining a novel structure, so-called virtual voltage buffer, with FC. Through an equivalent proof, it can be transformed into over-modulation block for a convenient implementation. Through its compensation in the transient period, $d$ -axis current can be quickly and smoothly manipulated in a more concise tuning process. As a result, the overall system possesses a fast acceleration capability with maximum torque and a wide speed range, while retaining a desirable system response. Simulation and experimental results verify the effectiveness of proposed method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Increasing Feasibility of Neural Network-Based Early Fault Detection in
           Induction Motor Drives

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      Authors: Dario Pasqualotto;Mauro Zigliotto;
      Pages: 2042 - 2051
      Abstract: Modern industrial plants are complex and very sensitive to costs to the business of unscheduled downtime when a motor fails. This is the case of broken bars in induction motor (IM) drives, which still represents a large share of the market. In principle, an early defect detection is made possible by advanced artificial intelligence (AI)-based techniques, but their complexity clashes with the essential nature of IMs. This article aims to bridge the gap by using motor current signature already available in standard drives and proposing a mix of simulations and data augmentation to train efficiently the neural network (NN) without the need of many broken prototypes, which is the major flaw for the industrial feasibility.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Harmonic and Fundamental Rotor Resistance Estimation Scheme for Multiphase
           Induction Motor Based on Nonsinusoidal Supply Control

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      Authors: Haseeb Hussain;Jiaqiang Yang;Guanghui Yang;
      Pages: 2052 - 2064
      Abstract: In the absence of flux measurements, techniques of field orientations depend on motor parameters, particularly on rotor resistances. During operation in flux-oriented mode, online continuous estimation of harmonic and fundamental rotor resistances is important for multiphase IM. To limit the core saturation and to achieve the synchronous and aligned air-gap flux density distribution, the harmonic plane is based on magnetizing flux-oriented control (MFOC) whereas the fundamental plane is taken as rotor flux-oriented control (RFOC). Mismatch harmonic and fundamental resistances trigger deviations in the rotor and magnetizing flux and also cause misalignment in the resultant induced electromotive force (EMF) waveform which could, in turn, be the reason for over-excitation and under-excitation. This article formulates the simultaneous online identification of rotor resistances for particularly MFOC harmonic plane while the fundamental plane is RFOC based on the dot product of rotor flux and stator current for making a model reference adaptive system (MRAS). Mismatched stator resistance and dead time of inverter have a negligible effect on the reference model during steady state. Convergence and steady-state performance can be acquired for a variation of load conditions particularly at heavy loading. The validation of the proposed approach is verified through simulation and experiment results by incorporating a multiphase platform consisting of a seven-phase induction machine.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Novel Deadbeat Predictive Current Control for PMSM With Parameter Updating
           Scheme

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      Authors: Xueping Li;Shuo Zhang;Xing Cui;Yang Wang;Chengning Zhang;Zhaozong Li;Ying Zhou;
      Pages: 2065 - 2074
      Abstract: Deadbeat predictive current control (DPCC) has been employed for permanent magnet synchronous machines (PMSMs) due to its satisfactory steady-state and dynamic performances. However, dependence on the accuracy of parameters is a major barrier for its widespread application. To address this problem, a novel control method that can update related items with internal parameters online, in which winding resistance, flux linkage, and stator inductance are considered simultaneously, is proposed in this article. First, the current prediction errors in the $d$ -axis and $q$ -axis are analyzed and stored. It has to be mentioned that the extended Kalman filter (EKF) is applied to filter the measured current and optimize the estimated current. Second, through the error of two consecutive control periods, the related items can update in real time. Finally, an updating mechanism based on DPCC is established to control the drive system. Since only measured current is used in the control system, the proposed algorithm is easy to implement. The simulation and experimental results indicate the effectiveness of the proposed method under complex parameters mismatch conditions.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Remote Plasma Source Chamber Modeling and Generator Design

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      Authors: Tsai-Fu Wu;Ling-Chia Yu;Anumeha Kumari;
      Pages: 2075 - 2087
      Abstract: This article presents the modeling of the plasma load in the vacuum chamber of a remote plasma source (RPS) and its generator is designed and implemented correspondingly. Traditionally, equivalent plasma load modeling usually acquired parameters measured by a Langmuir probe which is hard to conduct and is basically intrusive. A simple method to model the plasma load into frequency and flow rate-related equivalent RLC load without a special device is proposed in this article. Two different resonant inverters, which are operated around 400 kHz as an igniter and a sustainer of the plasma source generator, are designed based on the equivalent load. The igniter generates a high voltage of 5 kV with argon gas as a trigger to start the plasma progress and the sustainer provides a maximum power of 2.5 kVA to keep the plasma generating with nitrogen gas. To avoid interruptions of plasma generation under gas flow rate varying from 100 to 600 sccm, a simple proportional-integral (PI) control with frequency modulation on the sustainer to regulate its output current is adopted. Both system design and equivalent load modeling are verified with the simulated and experimental results in this article.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A High-Frequency Dynamically Coordinated Hybrid Si/SiC Interleaved CCM
           Totem-Pole Bridgeless PFC Converter

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      Authors: Chao Zhang;Kun Qu;Bo Hu;Jun Wang;Xin Yin;Z. John Shen;
      Pages: 2088 - 2100
      Abstract: A high-frequency dynamically coordinated Si/SiC hybrid continuous conduction mode (CCM) totem-pole bridgeless PFC (TPBPFC) converter is reported in this article. The proposed hybrid TPBPFC converter is interleaved with a low-current high-frequency SiC phase and a high-current low-frequency Si phase, in comparison to the prior-art design of two half-capacity SiC phases, resulting in a considerable cost reduction. A coordinated Si/SiC control strategy is proposed to address the un-compensable range issue in hybrid-frequency interleaving topologies, and to dynamically distribute power load between the Si and SiC phases for optimal efficiency and performance. An average current mode control (ACMC) based control algorithms and sequences are discussed in detail to enable the unique operation. A 3.3-kW hybrid TPBPFC prototype made of Si IGBTs and SiC MOSFETs is built and tested to validate the proposed design concept. Compared to the prior art two-phase all-SiC interleaved TPBPFC design, the proposed hybrid TPBPFC has demonstrated nearly identical power efficiency, THD, power factor, and effective frequency, while offering 33.5% device cost and 15.1% total cost reductions.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Reduce Response Time of Single-Phase Dynamic Voltage Restorer (DVR) in a
           Wide Range of Operating Conditions for Practical Application

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      Authors: Houkai Zhang;Guochun Xiao;Zhaolin Lu;Yubing Chai;
      Pages: 2101 - 2113
      Abstract: Voltage sag is one of the most serious power quality (PQ) problems for many loads; thus, the dynamic voltage restorer (DVR) is developed to mitigate the impact of voltage sag. However, in the practical application nowadays, according to the recent survey, for many sensitive loads, the requirement on the response time of the DVR has been even stricter (shorter in a wider range of operating conditions). Focusing on the single-phase system, the study on reducing the response time of the single-phase DVR in a wide range of operating conditions is introduced in this article. Considering the state of the art, key approaches and ideas to reduce the response time of the DVR in a wide range of operating conditions are discussed, based on which a fast detection method for the grid voltage sag based on the comparisons [combined with bool signal filters (BSFs)] of the multitimescale variables of the restructured voltages, as well as a fast and reliable commuting strategy for the bypass thyristors in the DVR based on the double-voltage-step method, is proposed in this article. The proposed detection method is capable of detecting the grid voltage sag with the time delay about 0.75 ms in a wide range of operating conditions, and the proposed commuting strategy is capable of fast turning off the bypass thyristors in the DVR reliably even with the unreliable sampled current. Then, with the widely used double-closed-loop control with double feedforward, the response time is achieved less than 3 ms in a wide range of operating conditions in a prototype of the single-phase DVR, verifying the feasibility and the performance of the proposed detection method and the commuting strategy.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • An Enhanced Differential Protection Scheme for LVDC Microgrid

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      Authors: Abha Saxena;Nikhil Kumar Sharma;Subhransu Ranjan Samantaray;
      Pages: 2114 - 2125
      Abstract: The low-voltage dc (LVDC) microgrid possesses numerous benefits and their penetration in the power system has increased rapidly in recent years. However, the detection of faults in the LVDC microgrid is a challenging issue due to the large magnitude of fault currents and fault-level variation in the microgrid. The performance of the recent current and its derivative-based protection scheme is limited in case of faults in the islanding mode of operation, different microgrid topologies, varying distributed generations (DGs) penetration, and against the measurement noise. This article presents an enhanced differential protection scheme for LVDC microgrid integrated with multiple DGs and storage. The differential current and its first derivative are processed through the decision tree (DT) algorithm for fault detection and the K-nearest neighbor (KNN) technique is utilized for fault classification. The robustness of the proposed protection scheme is tested for different fault types and fault conditions with variation in microgrid topology and operating conditions. The impact of the intermittent and volatile nature of the DGs, the presence of measurement noise, and assessment during external faults and critical no-fault cases have been investigated. The proposed scheme is tested on the MATLAB/ SIMULINK and validated on the Typhoon HIL platform for the assessment of real-time performance. The test results show that the proposed scheme can detect and classify faults with high accuracy and faster response time and, thus, can be a potential candidate for providing dependable protection measures for LVDC microgrids.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Transformerless Grid Connected Control of Wind Turbine Based on H-MMC

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      Authors: Fei Rong;Shuang Xu;Lao Pan;Zongqing Sun;
      Pages: 2126 - 2137
      Abstract: A high-power wind turbine has low rotational speed and a relatively low terminal voltage level. Thus, the wind energy conversion system (WECS) is commonly connected to the grid by an isolated boost transformer, which increases costs and room greatly. In this article, the hexagonal modular multilevel converter (H-MMC) is applied so that the high-power wind turbine can be directly connected to the medium-voltage ac grid. It has the advantages of transformerless grid connection and low ripples of capacitor voltages. As the bridge arm voltage of H-MMC contains both the low-frequency component induced by a wind turbine and the power frequency component induced by the grid, the voltage ripples of submodules (SMs) are reduced. Due to the large differences in the voltage level between the wind turbine and the grid, the low-amplitude-modulation voltage of the wind turbine side is easily obliterated by the high-amplitude-modulation voltage of the grid side, which will cause distortion of the bridge arm current. Therefore, auxiliary SMs with variable reference voltage are adopted to improve the tracking accuracy. The MATLAB/Simulink simulation and the RT-LAB hardware-in-the-loop experimental results verify the feasibility of the proposed topology and the effectiveness of the control strategy.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Comparative Study of Achievable Efficiency Between Three- and Four-Coil
           Wireless Power Transfer Systems

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      Authors: Kisong Lee;Sung Ho Chae;
      Pages: 2138 - 2146
      Abstract: In magnetic resonant wireless power transfer (WPT), intermediate resonant coils (i-RCs) can be deployed between a transmitter and a receiver as a means of improving performance, but this entails a high additional cost. In the search for a cost-effective strategy for the use of additional components of WPT, we provide a comparative analysis of the achievable transmission efficiency (TE) between three-coil (3C) and four-coil (4C) systems. In particular, we find optimal control parameters, e.g., load resistance and inductive coupling coefficient, to derive the achievable TE for each system in closed-form expressions. In comparing the achievable TEs of the two systems, we also remark on the effective use of additional coils in two main ways. First, by optimizing the load resistance, the position of the i-RC is determined to be close to the transmitter or the receiver in a 3C system for improving the achievable TE depending on the strength difference between inductive and resonant couplings. Moreover, if the i-RC is placed near the transmitter, the 3C system shows the same achievable TE as the 4C system. Second, by optimizing the inductive coupling coefficient, the achievable TE of the 3C system is not affected by the location of the i-RC, whether it is placed nearer to the transmitter or the receiver, and the 4C system always outperforms the 3C system. Through a series of experiments conducted in a variety of environments, we verify both the validity of these observations and the accuracy of the theoretical analysis.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Constant-Frequency and Noncommunication-Based Inductive Power Transfer
           Converter for Battery Charging

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      Authors: Io-Wa Iam;Iok-U Hoi;Zhicong Huang;Cheng Gong;Chi-Seng Lam;Pui-In Mak;Rui Paulo Da Silva Martins;
      Pages: 2147 - 2162
      Abstract: Compared with conductive charging, wireless inductive-power-transfer (IPT) charging exhibits higher potential as it avoids physical contact and provides convenient user experience. Regrettably, it is challenging for IPT converters to comply with the constant current (CC) and constant voltage (CV) charging profiles, while optimizing power efficiency. To achieve such goals, the existing IPT converters can apply multistage converter, dual side, or variable frequency modulation with feedback wireless communication. However, applying multistage converter increases cost and loss, while the stability of the IPT converter with dual side or variable frequency modulation can be at risk if communication fails. This article proposes a single-stage IPT converter for battery charging. With a constant operating frequency and without feedback wireless communication, the receiver side directly regulates the output to comply with the CC/CV charging profile, while the transmitter side aids in the reduction of the modulated phase shift angle at the receiver side, thus improving the efficiency. No wireless communication between the transmitter and receiver sides benefits both the hardware cost and stability. Also, we implement implicitly an output voltage regulation, further avoiding the need of an extra dc–dc converter. We verify experimentally the proposed control method in a 1-KW charging platform with a measured peak efficiency up to 94.35%.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Single-Inductor Multiple-Output (SIMO) Buck Hybrid Converter for
           Simultaneous Wireless and Wired Power Transfer

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      Authors: Albert Ting Leung Lee;Weijian Jin;Siew-Chong Tan;S. Y. Hui;
      Pages: 2163 - 2177
      Abstract: In this article, a nonisolated single-inductor multiple-output (SIMO) dc–ac buck-derived hybrid converter for simultaneously driving multiple independent ac and dc loads using only a single inductor in the power stage is proposed. Compared with the prior art, the proposed SIMO-based hybrid converter carries the conspicuous advantages of 1) a simple, compact, and low-cost implementation of the power stage; 2) reduced component count; 3) high power density; 4) increased output power, better flexibility, and scalability in realizing any combinations of ac and/or dc loads; and 5) high efficiency. By operating in pseudocontinuous conduction mode (PCCM), this hybrid converter enables wireless and wired power transfer at medium-power level without cross regulation. In practice, this converter can serve as a Qi-compliant hybrid charger with multiple transmitting coils and universal serial bus (USB) charging ports for quick and concurrent multidevice charging. A hardware prototype of a single-inductor four-output (SIFO) buck-derived hybrid converter is constructed. The experimental results show that the SIFO converter produces a rated output power of 20 W and a maximum efficiency of around 88%.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Independently Controllable Dual-Output Half-Bridge Series Resonant
           Converter for LED Driver Application

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      Authors: Hemasundara Rao Kolla;Neti Vishwanathan;Bhagwan K. Murthy;
      Pages: 2178 - 2189
      Abstract: This article presents a dual-output series resonant converter (SRC)-based light-emitting diode (LED) driver, which utilizes three switches to form two half-bridge networks. The proposed three-switch two-half-bridge structure provides reduced switch count and independent control. It uses asymmetric duty cycle control to regulate the LED operating currents and utilizes a low-frequency pulsewidth modulation (PWM) dimming scheme for each half-bridge to control the illumination of each LED load independently. All the switches in the proposed converter operate with zero-voltage turn-on to reduce the switching losses. The operating principle and detailed analysis of the proposed converter is presented and verified with experimental studies for a total load of 50 W (i.e., LED load-1 26 W and LED load-2 24 W). Also, a comprehensive comparative study of the proposed LED driver with recent counterparts is presented.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Unified Coil and Compensation Network Design for Improving Wireless Power
           Transfer Efficiency Over Wide Output Load Variation Ranges

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      Authors: Amir Masoud Bozorgi;Reza Tavakoli;Mehdi Farasat;
      Pages: 2190 - 2200
      Abstract: It is shown that the compensation network and coil design collectively affect wireless power transfer (WPT) efficiency. Based on this fact, a novel design approach of WPT systems is proposed. Unlike the majority of existing designs that aim at enhancing power transfer efficiency (PTE) at one rated operating point, the proposed design enhances the overall system PTE. This feature is essential for variable output loads, such as batteries, where their internal impedance varies during the charging period. To achieve this goal, improving the time-weighted average efficiency of the WPT system is set as the design criterion. Experimental studies of a 1.2-kW WPT system supplying constant resistive loads and battery loads verify that the proposed design enhances PTE both at rated output load and under wide output load variations.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Novel IPT Converter With Current-Controlled Semi-Active Rectifier for
           Efficiency Enhancement Throughout Supercapacitor Charging Process

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      Authors: Zhicong Huang;Dule Wang;Xiaohui Qu;
      Pages: 2201 - 2209
      Abstract: During the typical constant current (CC) charging process, the supercapacitor has a pretty wide-range load variation. However, an inductive power transfer (IPT) converter can maintain high efficiency only within a certain load range around its optimum load point. Once the supercapacitor load resistance is far away from the optimum point, which usually happens in low charging power levels, i.e., the smaller load resistances, the IPT converter will suffer from the dramatic efficiency degradation and thus a step-up load transformation is required throughout the whole charging process. In this article, a novel current-controlled semi-active rectifier (CCSAR)-based IPT converter is proposed to fulfill this requirement. The characteristic of step-up load transformation is first identified and implemented by controlling the conduction angle of the CCSAR to enhance the efficiency in the charging process. The desired charging CC is then regulated by tuning the operating frequency of the IPT inverter. To coordinate these two objectives, a bivariate control is adopted here to achieve fast, direct, and precise current output with enhanced efficiency performance over the whole load range during the CC charging process. Finally, experiment results validate the theoretical analysis well.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Flying Capacitor-Based Multilevel Inverter Architecture With Symmetrical
           and Asymmetrical Configurations

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      Authors: Chiranjeevi Sadanala;Swapnajit Pattnaik;Vinay Pratap Singh;
      Pages: 2210 - 2222
      Abstract: In this article, a novel flying capacitor-based multilevel topology is presented to minimize the size and cost. The proposed topology can operate in the symmetrical and asymmetrical configuration of dc sources and produces the 9-level and 25-level output voltage, respectively. The minimized device count, negative polarity voltage generation without auxiliary H-bridge, reduced maximum peak inverse voltage across the switches, and inherent voltage balancing across the floating capacitors are the main advantages of the proposed topology. Two extended topologies are proposed, and various necessary parameters are derived from achieving a higher number of output voltage levels. The effective comparison is furnished in terms of switches, diodes, capacitors, total standing voltage, and cost function to show minimization of device count of the proposed topology against the recent popular topologies. The extensive simulations in MATLAB $backslash $ Simulink are carried out to study the operation of proposed topology and feasibility is validated through the laboratory experimental tests. The performance of the topology under dynamical variation of frequencies, modulation indexes, and load are studied and respective results are presented.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Characteristics Analysis and Design of a Resonant dc–dc Converter With
           ZCS and Short-Circuit Fault Current Limiting Capability

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      Authors: Yujie Hu;Zixin Li;Cong Zhao;Yaohua Li;
      Pages: 2223 - 2232
      Abstract: The series-resonant dc–dc converter (SRC) which features zero current switching (ZCS) and open-loop control is widely used for providing galvanic isolation and voltage scaling. However, output short-circuit (OSC) fault is a challenge for SRC because it will cause dramatically high current in the low-impedance resonant tank. To address this issue, a resonant full-bridge dc–dc converter only using small dc-side capacitors to resonate with the resonant inductor $L_{r}$ is proposed. Under normal condition, ZCS can be achieved. When OSC fault occurs, the output dc-side capacitor can be bypassed by the antiparalleled diodes of the full bridge and the resonant current can be limited automatically by the resonant inductor $L_{r}$ without additional control. The operation principle of the converter under normal and faulty condition is analyzed. Based on these analyses, the switching frequency to achieve ZCS is designed. The resonant inductor $L_{r}$ and dc-side resonant capacitors $C_{r}$ design considerations are provided. The ZCS characteristics and the current limiting capability of the converter are verified on an experimental prototype.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Discontinuous Conduction Mode Operation of the Current-Shaping Modular
           Multilevel DC–DC Converter

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      Authors: Philippe A. Gray;Peter W. Lehn;
      Pages: 2233 - 2244
      Abstract: The current-shaping modular multilevel dc–dc converter (CS-MMC) is a recently proposed class of modular multilevel dc–dc converters for dc distribution grid applications consisting of a single string of cascaded voltage-source submodule (VSM) cells, a current-source submodule (CSM), and, notably, no series inductor. In the CS-MMC, since it is the CSM that shapes the string current and there is no series inductor, this frequency can readily be in the medium-frequency range, enabling VSM cells to be realized with low cell capacitance. In the previous work, only continuous conduction mode (CCM) operation of the CS-MMC had been considered, which led to several limitations, including elevated switching losses and low utilization of the semiconductor devices in low output voltage applications. In this work, the discontinuous conduction mode (DCM) operation is proposed for the CS-MMC that addresses these limitations. In traditional dc–dc converters, DCM is determined by the inductor current ripple. However, unique to the CS-MMC, DCM is determined by the VSM capacitor voltage ripple. In this work, the proposed DCM operational approach is presented along with its analysis and control. Both simulation and experimental results from a laboratory-scale converter system are provided for validation.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Simple Method to Combine the Output Power From Multiple Class-E Power
           Amplifiers

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      Authors: Kawin Surakitbovorn;Juan M. Rivas-Davila;
      Pages: 2245 - 2253
      Abstract: Radio frequency (RF) power amplifiers are an integral part of many academic, medical, and industrial applications. For many of these applications, the required power level is high enough such that a single amplifier circuit cannot provide enough power, and multiple amplifiers are needed. Conventionally, a power combiner network is used to isolate any mismatch between the multiple power amplifiers, combining their output powers. However, these power combiner networks have their disadvantages, including additional loss and an increase in overall system size. In this article, we present an alternative approach to designing a high-efficiency high-power RF amplifier system. Here, we offer a simple tuning method that allows output powers from multiple power amplifiers to be combined directly without the need for an extra combiner network, given that the mismatches between the amplifiers are sufficiently small. The method is specifically developed for class-E power amplifiers at kilowatts power level and is demonstrated with a 1500-W, 40.68-MHz power amplifier design, utilizing six subcircuits directly combining power.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Optimized Design of Integrated Planar Matrix Transformer for LLC Converter
           in Consumer Electronics

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      Authors: Zhaotian Yan;Lizhou Liu;Changxin Chen;Huan Liu;Wei Zhou;Ruikun Mai;
      Pages: 2254 - 2264
      Abstract: LLC resonant converter gets more and more applications in consumer electronics as it can convert the high voltage-low current state induced by wireless power transfer (WPT) into a low voltage-high current state effectively and efficiently. In this work, a planar matrix transformer structure and a new winding method are proposed in an LLC resonant converter to achieve a voltage conversion of 40–5 V after WPT in consumer electronics. This article focuses on modeling such a transformer and finding an optimal size to minimize the copper loss and the core loss with a total thickness of 2 mm. The theoretical analysis shows that the proposed winding method can minimize magnetomotive force (MMF) in both positive and negative periods and reduce the fringing magnetic fields’ influence around air gaps. The winding’s ac resistance can be reduced dramatically by such a printed circuit board (PCB) winding method. Meanwhile, such a structure can decrease copper loss by integrating the secondary winding in the UI core. An 80-W prototype is built to validate the proposed method’s feasibility with 1.5-MHz operating frequency, 40-V input voltage, and 5-V output voltage. The system owns the efficiency of 93.1% at full load condition.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Quadratic Boost Converter With Less Input Current Ripple and Rear-End
           Capacitor Voltage Stress for Renewable Energy Applications

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      Authors: Mukkapati Ashok Bhupathi Kumar;Vijayakumar Krishnasamy;
      Pages: 2265 - 2275
      Abstract: This article introduces a variant of a quadratic boost converter (QBC) with low rear-end capacitor stress by preserving its inherent abilities of less ripple continuous input current, utilization of single power switch, and quadratic voltage gain. The proposed converter utilizes two inductor and capacitor ( $LC$ ) filters with three diodes and one active switch for the quadratic conversion ratio. With the advantage of reduced rear-end voltage stress, the proposed converter can be a competent candidate in high-voltage and high-gain renewable applications. Furthermore, the operating principle and the steady-state analysis of the proposed converter in the continuous conduction mode (CCM) are discussed. In addition to the CCM analysis, a detailed discontinuous conduction mode (DCM) analysis due to the inductors $L_{a}$ and $L_{b}$ is presented. Furthermore, a comparative analysis of the proposed converter variant along with the QBC and its other variants is discussed. The discussion includes the key aspects, such as source ripple current analysis and rear-end capacitor voltage stress of QBC. Furthermore, a 200 W laboratory scaled prototype of the proposed converter is fabricated and tested to validate the theoretical and simulation analyses in CCM.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Analysis and Design of a Modular Self-Balance High-Voltage Input
           DC–DC Topology

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      Authors: Ziheng Xiao;Zhixing He;Renfeng Guan;Zongjian Li;Qianming Xu;Yandong Chen;An Luo;
      Pages: 2276 - 2289
      Abstract: In high-voltage (HV) input to low-voltage (LV) output dc/dc conversion applications, the input series output parallel (ISOP) structure is widely used and studied. Practically, the ISOP system encounters the below challenges: 1) HV isolated components, such as the HV isolated and HV input extra auxiliary power supply (APS) and the HV isolated high-frequency transformers (HFTs); 2) the submodule (SM) input voltage-sharing (IVS) control must be applied as long as the system is running, and it requires the control system to be highly reliable; and 3) scarcity of simple and high-efficient startup process with commercial APSs. To overcome the above challenges and simplify the control system, this article gave analysis and design of a modular self-balance HV input dc/dc topology without HV isolated components. A detailed time-domain SM design method, as well as the $s$ -domain SM input impedance analysis of the proposed topology, is proposed. Finally, a 4-/8-/10-kV/1-kW laboratory prototype is built to validate the effectiveness and practical feasibility of the proposed topology.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Novel Low-Frequency Virtual Space Vector Modulation With the Improved
           Continuity of Output Average-Voltage and Bus Voltage Utilization for
           Single-Phase Neutral Point Clamped Three-Level Inverter

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      Authors: Tao Chen;Peng Fu;Xiaojiao Chen;Liansheng Huang;Sheng Dou;Xiuqing Zhang;Zhenshang Wang;
      Pages: 2290 - 2304
      Abstract: In the high-power superconducting fusion converter, the single-phase neutral point clamped (NPC) three-level converter is applied to replace the traditional thyristor converter using an integrated gate-commutated thyristor (IGCT) as a power device. The operating frequency of IGCT is usually lower, only a few hundred Hz. An optimized hybrid space vector pulsewidth modulation (SVPWM)-8H is proposed to solve the problems of discontinuous output average voltage, low dc bus voltage utilization rate, dead time compensation, and neutral point potential balance. The new sectors are inserted to make the range of output average voltage of adjacent sectors intersect, which improves the continuity of output average voltage. Furthermore, some sectors are composed of four vectors to reduce the minimum working time of redundant small vectors, improving the dc bus voltage utilization ratio and the converter’s performance. Moreover, by analyzing the influence of dead time on redundant small vectors, redundant vectors are rearranged to make redundant small vectors’ working time synchronously in sector and sector switching, which reduces the influence of dead time on neutral point potential balance. Finally, by analyzing the influence of dead time on the output average voltage, dead time compensation is applied, which reduces the difficulty of compensation implementation. Simulations and experiments verify the rationality of the optimized hybrid SVPWM-8H.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Unified Modeling, Analysis, and Design of Isolated Bidirectional CLLC
           Resonant DC–DC Converters

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      Authors: Xiaoqiang Li;Jinwei Huang;Yongchao Ma;Xintan Wang;Jiafeng Yang;Xiaojie Wu;
      Pages: 2305 - 2318
      Abstract: Due to the bidirectional power transmission, high power density, and high efficiency, bidirectional CLLC resonant converters are attracting more and more research attention in electric vehicles and energy storage systems. However, the existing models are difficult to unify the bidirectional circuits to analyze and design the circuit factors, and thus the parameter design approach and bidirectional synchronous rectification (SR) become rather complex and cumbersome. Especially in asymmetric parameter design, a lot of calculations or iterations are needed, which seriously increase the difficulty of design. To address this concern, a bidirectional unified modeling, analysis, and design method is proposed in this article. By selecting appropriate and quantitative bidirectional circuit factors, this model unifies the forward and reverse circuits and establishes the relationship between them, which greatly simplifies the calculation or iteration of the parameter design and the complexity of bidirectional SR. In addition, this parameter design method makes the bidirectional gain reach a higher range and reduces the range of bidirectional switching frequency. Finally, this unified modeling, analysis, and design method is verified in bidirectional CLLC resonant converters including symmetrical full-bridge, asymmetrical full-bridge, symmetrical half-bridge, and asymmetrical half-bridge CLLC, respectively.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Model-Free Predictive Current Control of a PWM Rectifier Based on Space
           Vector Modulation Under Unbalanced and Distorted Grid Conditions

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      Authors: Yongchang Zhang;Zeyu Min;
      Pages: 2319 - 2329
      Abstract: Among various control strategies for pulsewidth-modulated (PWM) rectifiers, model-based predictive current control (MBPCC) based on space vector modulation (SVM) is a simple and effective method due to its quick dynamic response and good steady-state performance. However, SVM-based MBPCC (SVM-MBPCC) suffers from parameter variations and grid disturbances, which are common in practical applications due to temperature effects, saturation, grid faults, and so on. Recently, model-free predictive current control (MFPCC) based on current differences has been proposed to address the problem of parameter robustness. However, this approach suffers from stagnant updating of the current differences, and the steady-state ripples are still high due to the application of a single vector in one control period. This article proposes an SVM-MFPCC, which combines the merits of both SVM-MBPCC and MFPCC. The proposed method uses an ultralocal model rather than a conventional accurate model of the PWM rectifier, which is updated online based on the voltages and currents in past control periods. By using this ultralocal model, a voltage reference to nullify the current error can be calculated based on the principle of deadbeat control and is subsequently synthesized via SVM. Furthermore, by adding an appropriate compensation power to the original power references, the proposed method can achieve sinusoidal and balanced grid currents even under unbalanced and distorted grid conditions. The proposed method is compared to conventional SVM-MBPCC under various grid conditions, and the results of simulations and experiments confirm its effectiveness.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Optimized Parallel Hybrid Amplifier for Print-Head Piezoelectric Actuators
           With Trapezoidal Waveforms

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      Authors: Giovanni Migliazza;Emilio Carfagna;Fabio Bernardi;Emilio Lorenzani;
      Pages: 2330 - 2338
      Abstract: Most of the drivers used to control high-frequency print-head piezoelectric actuators are based on linear technology (e.g., Class AB amplifiers) which dissipate a large amount of power for this specific application. This choice is given by the necessary of very precise tracking and large bandwidth for the closed-loop voltage control of the piezoelectric load. This work highlights the critical issues of pure Class D amplifiers and hybrid (switching and linear) solutions. Then a new hybrid power amplifier topology is proposed analyzing its advantages and drawbacks for these kind of piezoelectric loads reducing energy consumption. First of all, the performance of the proposed solution is verified by simulations in LTspice environment. Experimental results showed the effectiveness of the proposed solution potentially paving the way to a larger adoption of this topology for high-frequency piezoelectric actuators. The proposed solution is patent pending.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Medium Voltage Converter Inductor Insulation Design Considering Grid
           Requirements

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      Authors: Haiguo Li;Pengfei Yao;Zihan Gao;Fei Wang;
      Pages: 2339 - 2350
      Abstract: Medium voltage (MV) SiC devices facilitate direct (without 50-/60-Hz transformer) connection of the power electronics converter to the MV grid using simple topology. Compared to the insulation design of MV inductors that have been widely used in the power system, the insulation design of the MV converter filter inductors has new challenges. Particularly, the grid impact on insulation requirements on converter filter inductors is rarely discussed. This article introduces the insulation design of a grid-side filter inductor for a 13.8-kV power conditioning system converter. The grid insulation requirements, including the short-duration power frequency overvoltage and the lightning impulse voltage, are considered in the design. To meet the requirements, the layer-to-layer insulation, winding-to-core/ground insulation, the air gap discharge between the winding and the core, the local electric field, as well as the interturn transient voltage distribution are considered. The designed inductors are validated by the 46 kV (>1 min) dc hi-pot test, 12-kV ac partial discharge test, one-hour single-phase converter full rating test, as well as three-phase converter full rating test.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Forward–Flyback Converter With Cockcroft–Walton Voltage Multiplier in
           DCM: Steady-State Analysis Considering the Parasitic Capacitances to
           Achieve the Optimal Valley-Switching Operation With 95.11% Efficiency at 3
           kV/1.5 W

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      Authors: Juan A. Serrano-Vargas;Jesús A. Oliver;Pedro Alou;
      Pages: 2351 - 2361
      Abstract: Nowadays, electrohydrodynamic (EHD) cooling systems are considered a good alternative to rotary fans and heatsinks from industrial electronic applications due to their robustness, high performance, and low weight. The EHD load tested along this article demands high voltage (3 kV) and very low current (500 $mu text{A}$ ) to produce the corona discharge and the airflow. The forward–flyback converter with Cockcroft–Walton voltage multiplier (FFCWVM) is proposed in this article as a suitable topology to supply EHD loads. The parasitic capacitances are considered throughout the steady-state analysis, leading to new operating stages and allowing for a very accurate mathematical modeling of the main resonant intervals. Consequently, the impact of a slow voltage transition in the functioning of the circuit is analyzed and the optimal valley-switching operation is calculated analytically. Finally, the theoretical analysis is validated by means of simulations and experimental results, achieving a very high efficiency (95.11%) for such low output power (1.5 W).
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A New Discrete Four-Quadrant Control Technique for Grid-Connected
           Full-Bridge AC–DC Converters

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      Authors: Snehal Bagawade;Iman Askarian;Majid Pahlevani;Praveen Jain;
      Pages: 2362 - 2379
      Abstract: This article presents a new control technique for grid-connected full-bridge AC–DC converters. The proposed control scheme is based on one-cycle control approach and enables the converter to process power in all four quadrants. In the proposed method, switching pulses are generated using a discrete control law with a superimposed fictitious reactive current term. This term enables seamless four-quadrant operation of the converter. Implementation of the discrete controller includes estimation of the current ripple based on measured values of the input current and voltages, sampled at the beginning of each switching cycle. The estimated current ripple is then used for a carrier-less implementation of the proposed control technique. A detailed controller stability analysis using Lyapunov theory is also presented. Theoretical analysis, simulation results, and experimental results show fast dynamic response for the grid current.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Study of Voltage Balancing Techniques for Series-Connected Insulated Gate
           Power Devices

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      Authors: Vaibhav Uttam Pawaskar;Ghanshyamsinh Gohil;Poras T. Balsara;
      Pages: 2380 - 2394
      Abstract: An efficient and cost-effective medium-voltage (MV) power semiconductor switch capable of high switching speed is highly desirable for many existing and emerging high-power MV power conversion applications. The emerging MV silicon carbide (SiC) 10-kV/15-kV MOSFETs and IGBTs can be the potential candidate for these applications. However, high cost, lack of reliability data, and limited availability are the major hurdles for the successful adoption of these devices. Efficient and cost-effective MV switches can also be realized by a series-connected reliable, cost-effective, and commercially available low-voltage (LV) devices. This article reviews various methods to achieve MV switch by series-connected LV power devices. Achieving equal voltage balance among series-connected devices is a challenge that can be addressed by passive snubber, voltage-clamped, gate pulse control, and active gate control techniques. A comprehensive comparison is discussed between these techniques. It concludes that the active gate control is the most effective and efficient solution in ensuring proper voltage balancing at the expense of increased control complexity. A closed-loop active gate driver circuit was developed, and its effectiveness in voltage balancing was verified experimentally.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Comprehensive Study and Validation of a Power-HIL Testbed for Evaluating
           Grid-Connected EV Chargers

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      Authors: Isuru Jayawardana;Carl Ngai Man Ho;Yi Zhang;
      Pages: 2395 - 2410
      Abstract: Integration of excessive electric vehicle (EV) chargers into the low-voltage (LV) network may introduce new challenges. Power hardware in the loop (PHIL) simulations can be used for evaluating such systems as it provides a flexible testing platform to study the overall system as well as individual devices. To facilitate a proper PHIL simulation, a precise mathematical model of the PHIL testbed is required. This article presents a comprehensive small-signal model capable of describing the dynamics of a PHIL testbed developed for evaluating grid-connected EV chargers. The PHIL testbed consists of a PHIL-based battery emulator (BE) and a grid emulator (GE) to mimic the dc side battery energy storage system (BESS) and the ac side LV grid behavior, respectively. A mathematical framework is developed to analyze the stability and predict the accuracy of both PHIL-based emulators. The BE in this article considers a switch-mode power amplifier (PA). Thus, design strategies for its linear controller are also discussed in the context of cascaded dc–dc configuration. An experimental PHIL platform based on a real-time simulator (RTS) has been used to validate theoretical predictions and confirm developed models. Finally, the validated PHIL test has been employed for analyzing the performance of a commercial EV charger and its interactions with a weak LV network simulated in RSCAD/EMTDC.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Aliasing Suppression of Multisampled Current-Controlled LCL-Filtered
           Inverters

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      Authors: Shan He;Dao Zhou;Xiongfei Wang;Frede Blaabjerg;
      Pages: 2411 - 2423
      Abstract: Multisampling control provides an attractive way to reduce the control delays in LCL-filtered grid-connected inverters. Thereby, the bandwidth and stability margin will be improved. However, high-frequency switching harmonics (SHs) are introduced in the control loop when the inverter-side current is sampled. To investigate the effect of multisampled high-frequency SHs, the relationship between the double-update pulsewidth modulation (PWM) and multiupdate PWM is deduced through geometric deduction. It is shown that the multiupdate PWM is equivalent to double-update PWM with sampling instant shift, and the equivalent Nyquist frequency is equal to the switching frequency. Moreover, the nonaveraged value of current is sampled within one switching period and aliased low-order harmonics will appear in the grid-side current. Hence, filtering the multisampled SHs is necessary, and an improved repetitive filter (IRF) is proposed to remove all the sampled SHs and keep the advantage of phase boost using the multisampling control. The method is evaluated with a single-loop inverter-side current control, and its effectiveness is verified through the simulation and experiment.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Systematic Approach of Loop Filter Tuning of TD-Based PLLs Using
           LQR-Based Approach Considering Time Delay

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      Authors: Mohd. Afroz Akhtar;Suman Saha;
      Pages: 2424 - 2434
      Abstract: A systematic design approach for loop filter (LF) tuning of transport delay-based phase-locked loops (TD-PLLs) to ensure an optimal control effort is presented in this article. The linear quadratic regulator (LQR) problem is applied to TD-PLL and nonfrequency-dependent TD-PLL (NTD-PLL) without approximating their time-delay functions through their appropriate state-space transformations. The systematic design guidelines of weighting matrixes selection for the LQR problem are discussed to ensure optimal performance of TD-based PLLs. The effectiveness of the suggested LQR method in tuning TD-PLL and NTD-PLL, considering time-delay function, is finally evaluated through extensive experimental results. Results also show the ability of the suggested method to achieve the desired dynamic performance in terms of faster system response without significant overshoot and steady-state error and with improved grid disturbance rejection capability compared with the existing tuning methodologies.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Residual Statistics-Based Current Sensor Fault Diagnosis for Smart Battery
           Management

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      Authors: Jian Hu;Xiaolei Bian;Zhongbao Wei;Jianwei Li;Hongwen He;
      Pages: 2435 - 2444
      Abstract: Current sensor fault diagnostic is critical to the safety of lithium-ion batteries (LIBs) to prevent over-charging and over-discharging. Motivated by this, this article proposes a novel residual statistics-based diagnostic method to detect two typical types of sensor faults, leveraging only the 50 current–voltage samples at the startup phase of the LIB system. In particular, the load current is estimated by using particle swarm optimization (PSO)-based model matching with measurable initial system states. The estimation residuals are analyzed statistically with Monte–Carlo simulation, from which an empirical residual threshold is generated and used for accurate current sensor fault diagnostic. The residual evaluation process is well proved with high robustness to the measurement noises and modeling uncertainties. The proposed method is validated experimentally to be effective in current sensor fault diagnosis with low miss alarm rate (MAR) and false alarm rate (FAR).
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Stable Simultaneous Inertia and Disturbance Torque Identification for
           SPMSM Drive Systems Subject to Mismatched Rotor Flux Linkage

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      Authors: Chengbo Yang;Bao Song;Yuanlong Xie;Shaowu Lu;Xiaoqi Tang;
      Pages: 2445 - 2462
      Abstract: In surface-mounted permanent magnet synchronous motor (SPMSM) drives, the distinguished orthogonal-principle-based method is presently popular for handling simultaneous inertia and disturbance torque estimation due to its simplicity and ease of implementation. Nevertheless, it is facing challenges posed by the rotor flux-linkage mismatch, zero-derivative constraint, and operating-condition limitation. To cope with these issues, this article presents an alternative scheme, which explores a stable simultaneous inertia and disturbance torque estimation with the real-time flux-linkage correction. First, an Adaline-based estimator is developed to acquire the disturbance torque. With an input-adaptive learning rate designed by the Lyapunov theory, this estimator can prevent potential convergence failure. Then, an extended sliding-mode observer for inertia estimation is proposed regarding the inertia as a new system state. By using the identified disturbance torque to devise an adaptive feedback gain, this observer guarantees the asymptotic error convergence. Finally, to counteract the flux-linkage mismatch, a flux-linkage observer with a time-varying learning rate is constructed utilizing the Adaline technique. Moreover, it attains robust convergence and only has one to-be-adjusted parameter. The effectiveness of our scheme is validated by abundant simulations and real-time experiments.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Segmented Energy Routing for a Modular AC/DC Hybrid System

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      Authors: Cheng Wang;Xiaohui Li;He Peng;Liqun He;Yaosuo Xue;
      Pages: 2463 - 2482
      Abstract: This article presents a modular ac/dc system with both distributed and centralized power ports for energy router (ER) applications. In each module of the described system, photovoltaic (PV) power generation units, battery-type energy storage (ES) units, and critical loads are connected to the cascaded H-bridge (CHB)-organized medium-voltage (MV) dc links, with fully distributed low-voltage (LV) dc power ports. Copies of modules share the centralized load bus and interact with an MV ac grid in parallel. Hybrid power port (HPO) assigns flexibility to the system but makes energy routings a necessity for stable operation. In this article, a segmented energy management strategy for the HPO-ER is proposed. In terms of the grid-side power transferring, the system ratings are intentionally designed to match significant power imbalance. Focally, a segmented energy management strategy is proposed to realize fully autonomous energy routing involving MV ac grid, distributed PV generations, distributed battery storages, and LV load. The system is proven to be stable using the derived impedance-based model considering the interaction between power blocks. The feasibility of the topology and control strategy is also verified through software simulation, laboratorial hardware prototype experiment, and hardware-in-the-loop (HIL) emulation.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • A Novel Zero-Sequence-Voltage-Balanced SVPWM With the Analyses of
           Common-Mode Voltage and Differential-Mode Current

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      Authors: Rende Zhao;Xianqiang Jiang;Cun Wang;Yansong Wang;Hailiang Xu;Qingzeng Yan;
      Pages: 2483 - 2496
      Abstract: In three-phase voltage source converters (VSCs), the high-frequency leakage current can be easily suppressed by the common-mode choke, while low-frequency component would be an unfavorable factor to the inductor design. Thus, as the excitation source, the low-frequency common-mode voltage (CMV) should be properly managed. This article analyzes the low-frequency CMV impulse by constructing a 3-D voltage vector space, and a novel modulation method is proposed to eliminate the low-frequency CMV. Meanwhile, a comparative study is conducted between the proposed method and the other four typical space vector pulsewidth modulation (PWM) (SVPWM) method from the view of CMV and differential-mode current (DMC). In the analysis, a double-current-ripple-envelopes method is proposed to describe the current ripples. Besides, the influence of modulation indexes and power factors on DMC are considered and evaluated. And a guiding rule for choosing the appropriate modulation method for three-phase VSCs is provided. Finally, the theoretical analysis and proposed method are experimentally validated under a 5-kW three-phase PWM converter.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Mathematical Modeling of EMI Spectrum Envelope Based on Switching
           Transient Behavior

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      Authors: Ru Zhang;Wenjie Chen;Yongxing Zhou;Zenan Shi;Ruitao Yan;Xu Yang;
      Pages: 2497 - 2515
      Abstract: Compared with Si devices, wide bandgap (WBG) devices will cause more serious electromagnetic interference (EMI) problems due to their fast switching speeds. In order to better compare and predict their EMI, this article proposes an improved mathematical modeling method to calculate the EMI spectrum envelope. It is based on an accurate time-domain decomposition of switching transient behavior together with a frequency-domain calculation. Detailed EMI spectrum envelope analytic expressions are derived with full consideration of Miller platform (MP), reverse conduction (RC), and ringing effects, while traditional calculation mainly focused on du/dt. The proposed mathematical modeling method has been applied to Si, silicon carbide (SiC), and gallium nitride (GaN) devices, respectively, and verified by comparing calculated and simulated results. In order to further verify this method, double-pulse test circuits of Si, SiC, emode GaN, and cascade GaN are built, and CM and DM EMI are also compared. The result reveals that, compared with Si devices, the MP, RC, and ringing effects of WBG devices have more serious effects on EMI.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Current-Limiting Virtual Synchronous Control and Stability Analysis
           Considering DC-Link Dynamics Under Normal and Faulty Grid Conditions

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      Authors: Seyfullah Dedeoglu;George C. Konstantopoulos;Hasan Komurcugil;
      Pages: 2516 - 2527
      Abstract: An improved nonlinear virtual synchronous control for three-phase grid-connected inverters, which can maintain a reliable operation under both normal and faulty grid conditions, i.e., balanced grid voltage sags, is proposed. The proposed controller can ensure a desired RMS current limitation at all times, provide virtual inertia and damping via the dc-link voltage and ac system frequency coupling, and realize the desired real and reactive power regulation without requiring accurate knowledge of the system parameters. Opposed to the conventional methods that use saturated PI controllers with or without antiwindup techniques to limit the reference value of the inverter current, the proposed controller includes a nonlinear bounded integrator, which limits the actual value (instead of the reference) of the inverter RMS current and leads to a fast system recovery even after significant grid voltage sags. The closed-loop stability of the entire system is rigorously proven using nonlinear singular perturbation theory. Moreover, analytic conditions for the controller parameter selection to guarantee the stability of the entire inverter system with the dc-link dynamics are provided. To prove the effectiveness of the proposed controller and its superior performance compared to the traditional approaches, extensive MATLAB/Simulink-based simulations are performed, followed by Typhoon-HIL hardware-in-the loop implementation using a TI microcontroller.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Negative-Sequence Active and Reactive Currents Compensation for Unbalanced
           Three-Phase Networks Subject to Various Line Impedance Attributes

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      Authors: Woei-Luen Chen;Yung-Hang Su;
      Pages: 2528 - 2538
      Abstract: In three-phase systems, voltage unbalance is incurred mainly by load unbalance under balanced lines. Based on the identical line impedance attributes between any two phases, a region of compensation (RoC) describing the relationship between the negative-sequence current vector and the line impedance attribute was presented. The RoC derivation arose primarily from the negative-sequence voltage across the equivalent source impedance. However, the source impedance attribute might be different between phases due to the embedded unbalanced load. A conversion from the source impedance to the line impedance was performed such that the mapping between the RoC and the impedance attribute becomes meaningful. The RoC is beneficial in narrowing the search and therefore simplifies the algorithm for determining the negative-sequence active and reactive current commands for a static synchronous compensator (STATCOM). To alleviate the current burden, the minimal voltage drop across the line impedance and a current weighting with safety boundary was incorporated. A quadrant of convergence (QoC) concluded from the experimental results agrees with the RoC and shows the effectiveness of the proposed approaches.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Analysis and Design of Multiple Resonant Current Control for
           Grid-Connected Converters

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      Authors: Chao Tang;Keliang Zhou;Yue Shu;Qingqing He;Qihong Chen;
      Pages: 2539 - 2546
      Abstract: Including “generalized integrators” for sinusoidal signals, multiple resonant control (MRSC) scheme which can accurately compensate selected sinusoidal signals, is widely used as a high-performance current control method for grid-connected converters. In this article, the plug-in digital plug-in MRSC scheme is proposed to provide a general framework for housing various MRSC schemes, which plugs the MRSC controller into a stable feedback control loop. It can take advantages of both controllers—the feedback controller provides fast response and good robustness, and the MRSC controller offers accurate compensation of the periodic signals. More critically, based on a new type of sinusoidal signal model, the sufficient stability criteria and the gain tuning rules are developed to offer a simple universal approach to the design of the digital plug-in MRSC schemes. An application case study on the digital plug-in MRSC of a 5-kVA three-phase four-wire grid-connected inverter with LCL filter is provided. Experimental results demonstrated that the proposed MRSC scheme can force the inverter to produce high-quality currents with high accuracy, fast transient response, and good robustness.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Linear Parameter-Varying Control of a Power-Synchronized Grid-Following
           Inverter

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      Authors: Milad Zarif Mansour;Mohammad Hasan Ravanji;Alireza Karimi;Behrooz Bahrani;
      Pages: 2547 - 2558
      Abstract: This article proposes a linear parameter-varying loop-shaping controller for a power-synchronized grid-following inverter (PSGFLI). This control strategy regulates the inverter output active and reactive powers at the terminal instead of the point of connection and does not require a phase-locked loop (PLL) for extracting the voltage phase angle. Hence, the prevalent stability issues exhibited when GFLIs are connected to weak grids are not present, and the proposed PSGFLI control strategy can work under both very weak and strong grid conditions without being prone to instability. In this approach, the controller parameters are functions of the operating point and are changed during the real-time operation such that the closed-loop performance is preserved in all operating points. Furthermore, since the grid impedance is a factor in the design process, a robustness analysis against grid impedance estimation error is conducted, and it is shown that discrepancies in the estimated and real grid impedances are unlikely to make the system unstable. The performance of the proposed control design is validated in MATLAB/PLECS and experiments for both strong and weak grids.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Current References Limitation Method Considering Voltage and Current
           Maximums for STATCOMs Providing Simultaneously Reactive Power and Current
           Harmonics

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      Authors: Aitor Bilbao;Gonzalo Abad;Alain Sanchez-Ruiz;Eneko Unamuno;Markel Zubiaga;Joseba Arza;Pedro Izurza-Moreno;
      Pages: 2559 - 2575
      Abstract: This article focuses the analysis on a static synchronous compensator (STATCOM) that operates simultaneously providing reactive power and several current harmonics of different frequencies (active power filter or active impedance functionalities). Being more specific, this article proposes a general limitation method that reduces the current references of the STATCOM whenever the current or voltage limit of the converter is exceeded. In a realistic operation scenario, the STATCOM’s operator may ask for certain reactive power and harmonic current reference signals, and depending on the actual grid voltage conditions (unbalances and harmonics), the required converter voltage and current may exceed their limit. Consequently, the proposed limitation method protects the STATCOM system from malfunctioning when the voltage limit is exceeded and from damages when the current limit is exceeded. Hence, this article first proposes a limitation method oriented to a STATCOM that operates solely exchanging reactive power. Second, the limitation method is generalized for a STATCOM that controls reactive power as well as several current harmonics. Then, simulation and experimental results are provided to validate the proposed limitation method, under a rich variety of working conditions. Finally, a conceptual analysis of the method is carried out confronting it against several possible limitation alternatives.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Small-Signal Stability Analysis and Criterion of Triple-Stage Cascaded DC
           System

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      Authors: Bangbang He;Wu Chen;Han Mu;Ding Zhan;Chun Zhang;
      Pages: 2576 - 2586
      Abstract: Two individually stable converters are well-known preconditions for discussing the stability of a two-stage cascaded system. However, for a multistage cascaded system, the relationship between its stability and subsystem stability is barely reported due to the lack of modeling method and in-depth stability analysis. In this article, the above problems are solved. First, the generic two-port small-signal model of the multistage cascaded dc–dc converters is established, and its equivalent minor loop gain is calculated, which can be used to assess system stability. On this basis, the stability condition of the triple-stage cascaded dc system is further deduced and compared with its two subsystems. Then, an interesting conclusion is obtained that the whole system may be stable even if some of its subsystems cannot operate stably individually. Besides, according to the deduced stability condition, some existing stability criteria of the triple-stage cascaded dc system are explained uniformly, and a bus equivalent impedance criterion (BEIC) is proposed. Finally, the case study and experiments are carried out to verify the correctness of the theoretical analysis.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Mitigation of Circulating Current in Three Phase Quasi-Z-Source Parallel
           Inverters With PV and Battery Storage

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      Authors: Muhammad Asif Hasan;Sanjoy Kumar Parida;
      Pages: 2587 - 2594
      Abstract: This article presents an insightful analysis on parallel operation of three-phase quasi-Z-source inverters with photovoltaic (PV) and battery storage on input side. Coordinated operation of PV and battery during charging and discharging mode through self-tuned mechanism is also explained. The analysis also includes PV-battery source dynamics, which establishes an interlink between common-mode voltage (CMV), filter ground, and the load neutral currents. This has been utilized to propose a new controller, which reduces the circulating current in quasi-Z-source parallel inverters fed with PV-battery. The performance of proposed controller is verified through experimental validation under equal and unequal load-sharing conditions. Results establish the correctness of analysis and effectiveness of the proposed controller.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • An Optimal Zero-Sequence Voltage Injection Strategy for DVR Under
           Asymmetric Sag

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      Authors: Zhenyu Li;Xiao Guo;Ziming Wang;Ranchen Yang;Jun Zhao;Guozhu Chen;
      Pages: 2595 - 2607
      Abstract: This article introduces an optimal zero-sequence voltage injection strategy (OZVIS) for the three-phase dynamic voltage restorer (DVR), which can effectively reduce the output voltage magnitude of DVR in case of asymmetric sags in a three-phase, three-wire power system, so as to improve the compensation capacity of the device. The conventional compensation strategy improves the active power or reduces the voltage amplitude of the DVR through phase rotation, but the two functions are difficult to achieve together. In this article, the operation principle of OZVIS is first introduced. Then, the optimality and effectiveness of the strategy are theoretically demonstrated by means of a plane geometric modeling approach. In addition, the reduction extent using OZVIS in different voltage sag types is quantified, which is based on the minimum energy compensation strategy. Furthermore, a digital “plug-in” algorithm implementation for the proposed strategy is elaborated. Finally, the experimental results will be shown to verify the feasibility and effectiveness of OZVIS under an asymmetric situation. Moreover, the adaptability under a symmetric situation will also be illustrated.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • An Inrush Current Limiting Method for Grid-Connected Converters
           Considering Grid Voltage Disturbances

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      Authors: Haiguo Li;Zihan Gao;Shiqi Ji;Yiwei Ma;Fei Wang;
      Pages: 2608 - 2618
      Abstract: To support the electric power grid, some grid-connected converters are required to ride through abnormal grid conditions, including voltage disturbances. However, at the moment, when a grid voltage disturbance happens, a large inrush current could be induced due to the large difference between the grid and converter output pulsewidth modulation (PWM) voltages. This inrush current could be more severe in the faster switching SiC-based multilevel converter, which only needs a small filter inductance to meet its normal operation requirements, such as harmonics and peak ripple currents. In this article, a PWM mask method is used to limit the inrush current. With this method, the inrush current can be effectively limited to a preset value and can help the converter ride through grid voltage disturbances. The method is validated through experiments conducted on a single-phase SiC-based five-level converter considering low voltage, high voltage, and phase angle disturbances.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Current Measurement Offset Error Compensation in Vector-Controlled SPMSM
           Drive Systems

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      Authors: Sangmin Lee;Heonyoung Kim;Kibok Lee;
      Pages: 2619 - 2628
      Abstract: Current measurement offset errors occur in current sensors and related circuits, because of various factors, such as thermal drift, aging, and nonlinearity. The current offset error results in undesired torque ripples, which deteriorate the speed and torque control performances of vector-controlled drive systems. This study proposes an online current measurement offset error compensator for vector-controlled surface permanent magnet synchronous motor (SPMSM) drive systems. The proposed compensator requires only phase current sensors and no additional hardware. This method is applicable for all systems using two and three phase current sensors. The current offset error is estimated using the motor parameters, stator current, and command voltage in the stationary reference frame. This scheme can continuously adjust the current offset during motor operation. In addition, this study analyzes the effect of parameter errors and confirms that the proposed method is robust to variations in the machine parameters. Simulation and experimental results are provided to verify the performance of the proposed current measurement offset error compensation method.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • 2-D Thin Coil Designs of IPT for Wireless Charging of Automated Guided
           Vehicles

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      Authors: Eun S. Lee;Seung H. Han;
      Pages: 2629 - 2644
      Abstract: As the automated guided vehicles (AGVs) play an important role in automated logistics systems, the wireless power transfer (WPT) technologies become a viable solution to provide the AGV with the automatic power charging service. In order to install the WPT systems to the small confined space in the AGV, a 2-D thin coil design is necessary for the receiver (Rx) system installed in the AGV. To greatly reduce the thickness of the Rx coil, including resonant capacitors, an ac/dc rectifier, and dc-link capacitors, an 2-D coil design for a minimum core loss is newly proposed in this article. Based on a finite-element-method (FEM) 3-D simulation analysis, various coil structures have been comparatively evaluated to find the most appropriate core structure. Furthermore, to obtain the highest coil efficiency at nominal operating condition, the appropriate number of turns design is established. Thus, according to the coil design guideline of the proposed inductive power transfer (IPT) system, the appropriate number of turns for transmitter (Tx) and Rx coils $N_{mathrm {1,op}}$ and $N_{mathrm {2,op}}$ can be appropriately selected for the high efficient operation of the IPT coils. The 2.5-kW prototypes of the IPT systems for wireless charging of AGV were fabricated and verified by simulations and experiments. The results showed that the total thickness of the coil sets including all the components is 32.0 mm for the Rx coil. The measured maximum coil efficiency for $P_{L} =2.5$ kW at 40-mm coil distance was 98.9% by the proposed IPT coil design procedure. The measured temperatures at the ferrite core and coil for the Rx coil were managed below 53.3 °C and 59.3 °C during 2.5-kW wireless charging, respect-vely, under a 10-min charging and 20-min AGV operation cycle, which provides the thermal-stable operation of the proposed IPT systems.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Pressureless Sintered-Silver as Die Attachment for bonding Si and SiC
           Chips on Silver, Gold, Copper, and Nickel Metallization for Power
           Electronics Packaging: The Practice and Science

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      Authors: Meiyu Wang;Yunhui Mei;Weibo Hu;Xin Li;Guo-Quan Lu;
      Pages: 2645 - 2655
      Abstract: Low-temperature silver (Ag) sintering is emerging as a cutting-edge die-attach technology for power electronics packaging. However, the industry still has concerns about completely accepting this technology. One of the reasons is a lack of knowledge about the mechanism and process of sintered silver bonding on various metallization. Before, we reported a preliminary assessment of the die-shear strength and microstructures of Si dummy device attached on Ag, Au, and Cu metallization. This research will go deeper into the practice and science of attaching Si and SiC devices with sintered-Ag on substrates with up to seven most widely used metallizations, including electroplated Ag, Ni/Au, and Ni, electroless-plated Ni(P)/Ag, Ni(P)/Au, and Ni(P), and native Cu on DBC substrate. All sintered-Ag die-attach were pressureless in the air at temperatures ranging from 220 °C to 300 °C. The mechanical, electrical, and thermal parameters, as well as the microstructural analyses, were assessed. The purpose of this research is to gain a better understanding by: 1) discussing effects of devices and substrate metallizations on the mechanical, electrical, and thermal characteristics; 2) reviewing fundamental mechanisms of interfacial adhesion for sintered-Ag bonding, and 3) providing practical considerations for developing Si and SiC sintered-Ag die-attaching profiles on the widely used substrate metallization.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
  • Create Change IEEE SmartVillage

    • Free pre-print version: Loading...

      Pages: 2656 - 2656
      Abstract: Advertisement, IEEE.
      PubDate: April 2022
      Issue No: Vol. 10, No. 2 (2022)
       
 
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