Bifurcation Free Coil Design for Multi Power Level Wireless Charging of Electric Vehicles

Wireless charging of electric vehicles (EVs) can solve all the cable-related issues from vehicle charging, making it a more convenient and safe way to charge EVs. However, the performance of wireless charging is affected by the coupling coefficient and load variation due to the nonlinear behavior of wireless charging systems. Due to the dominant effect of bifurcation, the same transmitter cannot charge the vehicle at different charging rates. Therefore, the designing individual charging systems for different power levels is one of the major concerns with the wireless charging of EVs. Consequently, it increases the infrastructural cost of the wireless charging systems. Hence, this paper proposes a tapping-based transmitter coil with switched series compensation for multi-power level wireless charging of the EVs. Furthermore, detailed coil design steps are given to design bifurcation-free wireless charging at the required power levels. The effectiveness of the designed coil-set in terms of safety and field emissions has been validated on ANSYS Maxwell software. The bifurcation-free wireless charging of EVs with the proposed coil-set at level-l (3.7 kW) and level-2 (7.7 kW) has been validated through LTspice and MATLAB/Simulink results.