Analysis and study of compact inductive power transfer systems for EV charging

The double-sided LCC topology provides an efficient compensation method for electric vehicle (EV) wireless charging systems. However, the existence of two compensation coils results in an electric vehicle wireless charging device with a large volume, high power consumption, and low efficiency. To solve these problems, this paper proposes a wireless charging structure in which the compensation coils are separately integrated into the transmitting and receiving coils. First, the number of turns of the transmitting coil is optimized to maximize the coupling coefficient of the transmitting coil. Secondly, to minimize the redundant coupling effect, the relative placement of the compensation coils is studied. Based on the proposed coil integration method, it is possible to ignore the redundant coupling between the compensation coils and the transmitting and receiving coils. Then, the Ansys Maxwell and Ansys Twin Builder are used to build a joint simulation circuit to construct the proposed wireless charging system. Simulation and experimental results show that the system output power is 3.09 kW with a gap of 150 mm, and that the transmission efficiency is 95.49%. In addition, the integrated solution has a high transmission efficiency in the presence of front-to-back misalignment and vertical misalignment of electric vehicles.