Side-Variant Active Shielding Coils for High Power Wireless Charging Systems

A side-variant active shielding method for wireless power transfer (WPT) systems is proposed in this paper. It consists of four separate shielding coils; two on the ground assembly and two on the vehicle assembly with one on each lateral side of the car. The general idea is to operate these side-variant active shielding coils so that effective shielding is achieved where needed. At the same time, overcompensation by exceeding the required leakage field reduction should be avoided, as this can result in lower system efficiencies. The proposed side-variant active shielding method is applied to a 50kW WPT system and demonstrated for different positions. The simulation results show the shielding method's effectiveness and its capability to enlarge the operating range of a WPT system. As different shielding coil combinations can be used for the same position, the proposed side-variant active shielding method enables an additional degree of freedom for the system operation.