Hai-Jiao Guo received the BSc degrees in Physical department from Shanghai Normal University, China in 1982, the MS and the Ph.D. degree in electrical engineering from the Tohoku University, Japan in 1988 and 1993 respectively. He was an Assistant Professor with the Department of Electrical Engineering, Tohoku University, Japan from 1990 to 1996, and Associate Professor from 1996 to 2004. Since 2004, he has been with the Dept. of Elect. &Infom. Engng, Tohoku Gakuin University, Japan, where he is currently a professor. He served as the chairman of the department from April 2014 to March 2016. His research areas include in robust design of digital servo system, and its application in the power electronics field, such as high-performance drive of motors and inverter/converter.
Speech Title: A New Sinusoid Current Control Method of Brushless DC Motor (BLDCM) Based on Internal Model Principle
Abstract: As a current control method, in popular high-performance vector-controlled brushless DC motor drivers, it is a conventional way to transform the alternate current to direct current by coordinating transformation technique, then using the PI controller to control the motor current. However, the amount of calculation increased in the coordinate transformations and the reverse transformation. In addition, at many practical cases, the current of motors contains various harmonics, so in the process of coordinate transformations, the transformation errors are at risk, then a usual PI controller cannot assure of zero steady-state errors. It directly affects the control accuracy. We propose a new sinusoid current control method of BLDCM based on “Internal Model Principle”. Considering the desired current in driving BLDCM is sinusoidal waveform, it is possible directly using “Internal Model Principle” in the current control loop to completely eliminate the steady-state current error. First, we introduce a transfer function contained the lossless resonant element into current control loop and verify that the current steady-state error can be completely eliminated. Then the design method of the current controller parameters is discussed. To confirm the effectiveness of the proposed control method, a simulation model has been constructed and many interesting results have been obtained.

Prof. Yiming Zhang, National High-Level Talent, IEEE Senior Member, College of Electrical Engineering and Automation, Fuzhou University, China. He received the B.S. and Ph.D. degrees in electrical engineering from Tsinghua University, Beijing, China, in 2011 and 2016, respectively. From 2017 to 2019, he was a Postdoctoral Researcher with San Diego State University, San Diego, CA, USA. From 2019 to 2020, he was a Research Fellow with Nanyang Technological University, Singapore. He is now a full professor with Fuzhou University, Fuzhou, China. He has authored 1 book from Springer, authored or co-authored more than 80 technical papers in journals and conference proceedings. His research interests include wireless power transfer for electric vehicles and mobile phones, and power electronics converters.
Prof. Yiming Zhang was the recipient of the National Oversea High-Level Talent Program and Outstanding Doctoral Dissertations of Tsinghua University in 2016. He was recognized as an Outstanding Reviewer for the IEEE Transactions on Power Electronics in 2019 and a Distinguished Reviewer for the IEEE Transactions on Industrial Electronics in 2020.
Speech Title: Free Positioning Wireless Charging for Consumer Electronics based on Antiparallel Windings
Abstract: Free positioning wireless charging for consumer electronics allows the devices to be charged at arbitrary positions and angles to improve user experience. However, a user-initiated sudden movement of the device during charging can cause hazards due to the abrupt variation of the coupling coefficient. To solve this issue, the coupling coefficient variation at different positions should be mitigated, which is also good for the design and high-efficiency operation of power electronics converters. A design methodology to employ antiparallel windings to smooth the coupling coefficient variation is presented. Two optimization methods are proposed: turn-by-turn optimization and winding-by-winding optimization. The hexagonal coil is compared with the square coil and proved to achieve better performance than the latter. Experimental results have validated the effectiveness of the proposal.

Prof. Hsin-Chuan Chen, University of Electronic Science and Technology of China, Zhongshan Institute, China