Coupling Extraction and Maximum Efficiency Tracking for Multiple Concurrent Transmitters in Dynamic Wireless Charging

Abstract

We propose a fast maximum efficiency tracking, which instantly optimizes all. TX coils’ currents using runtime-extracted mutual inductances, for simultaneously activated multiple TXs whose output levels are different each other. For fast control, we propose a theory to runtime extract all the mutual inductances between multiple TXs and an RX. Here, one prerequisite of extracting the values of mutual inductances is to acquire its relative ratios between the mutual inductances. It is proposed that the relative ratio can be obtained by reflected resistances and coil currents of each TX, which are ac quantities but can easily be measured using dc input property of LCC inverter. Using the ratio information in conjunction with RX dc output, the exact values of mutual inductances can be extracted. The aim of the proposed method is to enable fast (no iteration) maximum efficiency tracking for multiple TXs, which entails the optimization of the relative ratios among TX currents, as well as the RX load optimization. A 200-W RX moves at 10 km/h, and the controller can track the optimum target TX currents in response to time-varying magnetic couplings