Design and Optimization of Magnetic Coupler Based on Series-Series Compensation for EV Wireless Chargers

In this paper, a systematic design and optimization procedure of magnetic coupler based on series-series compensation for electric vehicle (EV) wireless chargers considering the power level and efficiency constraint values has been expounded. The mathematical optimization model and the electromagnetic field calculation combined with the analytical model are the theoretical basis for the optimal design of the magnetic coupler. This paper establishes a three-dimensional finite element model for a 3.3 kW rectangular magnetic coupler, which is optimized and constructed. In addition, the characteristics of series-series (SS) compensation are analyzed. Based on the mistuning phenomenon of SS compensation, zero-voltage switching of the input-side inverter is realized by fine-tuning the value of the primary side compensation capacitor. Thereby, the switching loss has been eliminated. The proposed optimization methodology is a solution for EV wireless chargers considering the power level and efficiency constraint values with adequate guarantees of output performance and anti-offset capability. The optimization design methodology is universal and applies to different power levels and efficiency constraint values, which will provide more references for practical applications.