High Efficiency Wireless Charging of Electric Vehicles


Jacobs Hall, Room 2512, Jacobs School of Engineering, 9500 Gilman Dr, La Jolla, San Diego, California 92093

Chris Mi, Ph.D.
San Diego State University
Chris Mi, Ph.D.


Wireless power transfer (WPT) technology offers significant improvement in convenience and electric safety for electric vehicle (EV) charging. Our research aims at novel designs that con-siderably reduce size and cost while increasing the coupling coefficient and improving the misalignment capability. We will first introduce the basics of WPT, followed by discussion of a double-sided LCC topology which further enhances the system efficiency. Experiments show that tens of kilowatts of power transfer can be achieved over 200mm distance with an efficiency of 97% (DC-DC), and a misalignment tolerance of up to 300mm. We will then dis-cuss the capacitive wireless power transfer (CPT) for EV charging applications. It has been an established myth that good efficiency and stability of control was only possible at low power levels (in the tens of watts) and with low transfer distances (in the millimeter range) for CPT. We have shown that it is possible to achieve excellent efficiencies at the power level and dis-tance applicable to EV charging, breaking the established myth, enabling a paradigm change on EV charging, and making low cost wireless power transfer possible A double-sided LCLC topology was proposed. A 2.4kW CPT system was designed with four 610mm × 610mm alu-minum plates at a distance of 150mm. The experimental prototype reached a DC-DC efficien-cy of 92% at 2.4kW output power. The CPT system provides a lower cost and better misalign-ment capability then inductive wireless power transfer systems. 

Speaker Bio:
Chris Mi is a fellow of IEEE, Professor and Chair of the Department of Electrical and Computer Engineering and the Director of the US DOE funded GATE Center for Electric Drive Transportation at San Diego State University. He is also an adjunct professor at the Uni-versity of California, San Diego. He was previously a professor at the University of Michigan, Dearborn from 2001 to 2015. He received the B.S. and M.S. degrees from Northwestern Poly-technical University, China, and the Ph.D. degree from the University of Toronto, Canada. Previously he was an Electrical Engineer with General Electric Company.
His research interests are in power electronics. He has published more than 130 journal arti-cles and delivered over 50 invited talks and keynote speeches. He has also served as a panel moderator and panelist in major IEEE and SAE conferences. Dr. Mi is the recipient of the “Distinguished Teaching Award” and “Distinguished Research Award” of University of Michigan, Dearborn. He is a recipient of the 2007 IEEE Region 4 “Outstanding Engineer Award,” “IEEE Southeastern Michigan Section Outstanding Professional Award.” and the “SAE Environmental Excellence in Transportation (E2T) Award.” Dr. Chris Mi was a Distin-guished Lecturer (DL) of the IEEE Vehicular Technology Society.
Dr. Mi is the Area Editor of IEEE Transactions on Vehicular Technology, associate editor of IEEE Transactions on Power Electronics and IEEE Transactions on Industry Applications, Guest Editor-in-Chief of IEEE Journal of Emerging and Selected Topics in Power Electronics - Special Issue on WPT, IEEE Transactions on Power Electronics - Special Issue on WPT, and IEEE Transactions on Industrial Electronics - Special Issue on Dynamic Wireless Power Transfer. He is the topic chair of the 2011 IEEE International Future Energy Challenge and General Chair of the 2013 IEEE International Future Energy Challenge. He was the General Chair of 2009 IEEE Vehicle Power and Propulsion Conference, Co-Chair of IEEE Workshop on Wireless Power Transfer, Program Chair of the 2014 IEEE International Electric Vehicle Conference (IEVC), Co-Chair of the IEEE Transportation Electrification Conference (ITEC- Asian). He is Academic Affairs Chair of IEEE Power Electronics Society and the Chair e-Learning Committee for the IEEE Future Direction’s Transportation Electrification Initiative.

Travis Spackman (tspackman@eng.ucsd.edu)