Title: High Efficiency Wireless Charging of Automatic Guided Vehicles
Wireless power transfer technology offers significant improvement in convenience and electric safety for electric vehicle (EV) charging. Both capacitive and inductive wireless power transfer technology have been investigated for various applications.
In this talk, we discuss a tightly-coupled inductive power transfer (IPT) system for the low-voltage and high-current charging of automatic guided vehicles (AGVs). There are two major challenges in the system design. First, the self-inductances and coupling coefficient of a tight-coupled magnetic coupler are sensitive to airgap variation. Second, the low-voltage and high-current condition can result in an extremely small load resistance that induces difficulty to optimize the efficiency. There could be a large amount of high-order harmonic currents in a tightly-coupled IPT system, and we have provided an effective circuit design method to reduce the harmonics. Through comparison, the integrated-LCC compensation circuit is selected as the solution, and it shows four merits: good robustness to airgap variation, easy controllability, convenience to optimize the system efficiency, and low high-order harmonic current distortion. Aiming at the AVG charging application, a prototype is implemented and the magnetic coupler size is 220mm×200mm×10mm. Experimental results show that it achieves 1.78 kW power transfer from 300 V DC source to 24 V battery with 86.1% efficiency and 73.8A charging current across an airgap of 15 mm. In zero- and full-loading conditions, when the airgap distance varies between 5 mm to 25 mm, the system power variation is within ±36.7% and the efficiency is not significantly affected.
Chris Mi is a fellow of IEEE and fellow of SAE, 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, San Diego, California, USA. 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 Polytechnical University, Xi’an, China, and the Ph.D. degree from the University of Toronto, Toronto, Canada, all in electrical engineering. Previously he was an Electrical Engineer with General Electric Canada Inc. He was the President and the Chief Technical Officer of 1Power Solutions, Inc. from 2008 to 2011. He is the Co-Founder of Mia Motors, Co-founder and CTO of SNC Technology, Inc.
His research interests are in electric and hybrid vehicles. He has taught tutorials and seminars on the subject of HEVs/PHEVs for the Society of Automotive Engineers (SAE), the IEEE, workshops sponsored by the National Science Foundation (NSF), and the National Society of Professional Engineers. He has delivered courses to major automotive OEMs and suppliers, including GM, Ford, Chrysler, Honda, Hyundai, Tyco Electronics, A&D Technology, Johnson Controls, Quantum Technology, Delphi, and the European Ph.D School. He has offered tutorials in many countries, including the U.S., China, Korea, Singapore, Italy, France, and Mexico. He has published more than 100 articles and delivered 30 invited talks and keynote speeches. He has also served as a panelist in major IEEE and SAE conferences.
Dr. Mi is the recipient of “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.” He was also a recipient of the National Innovation Award and the Government Special Allowance Award from the China Central Government. In December 2007, he became a Member of Eta Kappa Nu, which is the Electrical and Computer Engineering Honor Society, for being “a leader in education and an example of good moral character.”
Dr. Mi was the Chair (2008-2009) and Vice Chair (2006-2007) of the IEEE Southeastern Michigan Section. Dr. Mi was the general Chair of the 5th IEEE Vehicle Power and Propulsion Conference held in Dearborn, Michigan, USA in September 6-11, 2009. Dr. Mi is one of the three Area Editors of the Editor of IEEE Transactions on Vehicular Technology, associate editor of IEEE Transactions on Power Electronics, Associate Editor of IEEE Transactions on Industry Applications. He served on the review panel for the NSF, the U.S. Department of Energy (2007–2010), the Natural Sciences and Engineering Research Council of Canada (2010), Hong Kong Research Grants Council, French Centre National de la Recherche Scientifique, Agency for Innovation by Science and Technology in Flanders (Belgium), and the Danish Research Council. He is the topic chair for the 2011 IEEE International Future Energy Challenge, and the General Chair for the 2013 IEEE International Future Energy Challenge. Dr. Chris Mi is a Distinguished Lecturer (DL) of the IEEE Vehicular Technology Society.
He is also the General Co-Chair of IEEE Workshop on Wireless Power Transfer sponsored by six IEEE Societies (PELS, IAS, IES, VTS, MAG, and PES), Guest Editor-in-Chief of IEEE Journal of Emerging and Selected Topics in Power Electronics - Special Issue on WPT, Guest Co-Editor-in-Chief of IEEE Transactions on Power Electronics Special Issue on WPT, Guest Editor of IEEE Transactions on Industrial Electronics - Special Issue on dynamic wireless power transfer, and steering committee member of the IEEE Transportation Electrification Conference (ITEC- Asian). He is the program chair for the 2014 IEEE International Electric Vehicle Conference (IEVC) in Florence Italy December 17-19, 2014. He is also the chair for the IEEE Future Direction’s Transportation Electrification Initiative (TEI) e-Learning Committee and developed an e-learning module on wireless power transfer.