A Misalignment-Tolerant Autonomous Wireless Power Transfer System for Battery Charging Based on Detuning Control

This article proposed an autonomous wireless power transfer system with misalignment tolerance and improved control degree of freedom based on detuning control for battery charging, in which the outputs can be regulated continuously and smoothly without additional dc-dc converters while maintaining soft-switching or zero-phase-angle operation of the inverter. Theoretical analysis shows that constant current (CC) or constant voltage (CV) independent of coupling coefficient and load can be achieved without information exchange between transmitter and receiver, which eliminates wireless communication. Furthermore, when the detuning ratio is controlled to be constant, a transfer efficiency insensitive to the variation of the coupling coefficient can be obtained. A prototype with a 6-A charging current and a 36-V charging voltage is built to support the feasibility of the proposed method. Experimental results demonstrate that within the coupling coefficient range of 0.283-0.456, CC and CV with transfer efficiency greater than 91.5% can be achieved.