A study of wireless power transfer topologies for 3.3 kW and 6.6 kW electric vehicle charging infrastructure

Inductive wireless power transfer (WPT) systems for electric vehicle (EV) charging applications are designed at 3.3 and 6.6 kW power classes. A comparison of compensation circuits between SS (series - series) and LCL-LCL topologies is carried out. Measurement results of 3.3 kW WPT system show that the SS topology has higher transfer efficiency than the LCL-LCL one with a peak transfer efficiency of 93.1 % and 89.5 % for SS and LCL-LCL topologies, respectively, at a transfer distance of 100 mm. The LCL-LCL topology is more robust than the SS topology in terms of power factor when a misalignment between coils occurs or when the frequency varies. Measurement results of 3.3 kW WPT system are consistent to the circuit simulation. The WPT systems operate at a frequency of 85 kHz.