Arbitrary power distribution and efficiency optimization for dual-receiver inductive power transfer system with variable coupling

In wireless charging application for electric vehicles, multi-receiver inductive power transfer (IPT) systems hold enormous potential. However, the coupling and charging rates between vehicles exhibit significant disparities and unpredictable variations, which causes the systems’ efficiency deviate from their optimal state. This paper presents an analytical model for solving optimal control variables, which considers arbitrary loads and couplings. Based on the proposed model, with further considering coupling and load restriction, the feasible regulation trajectories of primary inverter and secondary active rectifier phases are derived. Besides, a maximum efficiency point tracking (MEPT) control strategy is designed for achieving selective power distribution and constant current output characteristics simultaneously. Finally, an IPT experiment with dual loads is designed and carried out. The experimental results show that the desired power distribution can be maintained for each receiver even in the face of load voltage, demand current and coupling variations. Furthermore, the efficiency of the proposed system can be improved by up to 3%, reaching a maximum of 89.13% compared to the system without MEPT.