ZHANG Xueyi, REN Liquan, XIONG Xinbo, KONG Pengsheng, LI Zhongqi, YANG Minsheng
In electric vehicle wireless power transfer systems, realizing efficient transmission while reducing magnetic leakage has been a technical challenge. To address this issue, the paper proposes a sunken shielding coil structure applied to a multi-radio wireless power transfer system, which reduces the magnetic leakage from the target surface without affecting the transmission efficiency of the system. Firstly, a method of calculating the magnetic field of a rectangular coil based on the vector magnetic potential is submitted, by which the magnetic leakage from the target surface of the system is analyzed, providing a theoretical basis for the subsequent magnetic leakage optimization; secondly, a method of magnetic leakage optimization is introduced, and each coil parameter meeting the requirements is obtained by applying the method, which provides a key support for the realization of high-efficiency wireless power transfer; lastly, a set of dual-sunken shielded coil structures with magnetic shielding structure is developed based on the coil parameters obtained; and lastly, a set of dual-sunken shielding coil structures with magnetic shielding structure applied to multiple wireless power transfer systems is developed based on the coil parameters obtained, which will not impact the system transmission efficiency. Finally, based on the obtained coil parameters, a dual-position electric vehicle wireless charging system with magnetic shielding structure is developed, and the effectiveness of the proposed shielding structure and method is fully confirmed through simulation and experiment. The results show that the proposed shielding structure not only reduces the maximum leakage magnetic field in the target area by 25% but also achieves a transmission efficiency of up to 95% when the output power of the system is constant at 4 kW.
