A Comparison of Compensation Networks for Wireless Charger for Electric Vehicles

In compliance with the SAE J2954 International Standard, a Class 2 Wireless Power Transfer (WPT) system operating at 85 kHz capable of producing an output of 7.7 KW is designed for maximum efficiency of 80%. The project has adopted the design methodology of the Inductive Power Transfer (IPT) method which, works on the principle of electromagnetic induction wherein power is wirelessly transmitted from a primary coil which forms the ground assembly, placed on the floor to the secondary coil forming the vehicle assembly, located underneath the vehicle. The coupling factor is chosen in the range of 0.9 - 1.5, and the gap between the coils is optimized to 20 cm. Compensation networks improve the power transfer efficiency of coils, and hence a comparative analysis of Series-Series (SS) topology and Inductance-Capacitance-Capacitance (LCC) topology is presented here.