Shielding Design for High-Frequency Wireless Power Transfer System for EV Charging with Self-Resonant Coils

This paper provides a complete design solution for a 6.6 kW wireless power transfer system based on compact self-resonant (SR) coils with shielding considered. The high frequency parasitic capacitance introduced by the shielding material is analyzed in detail, and a shielding geometry optimization method is proposed. Using ferrite for shielding and a PTFE spacer, the total thicknesses of coils are only 11.4 mm and 7.4 mm for the transmitter and receiver, respectively. The system is validated with fabricated SR coils, achieving 92.3% DC-DC efficiency and 7.1 kW/dm ³ volumetric power density. This paper demonstrates the first 6.6-kW WPT system for EV charging using compact self-resonant coils at MHz with practical shielding implementation.