Magnetic field distribution of resonance coupling coils of wireless charging system for EV

In this paper, a 3.7kW level magnetic resonance coupling at 85kHz wireless charging system with inductor-capacitor-capacitor (LCC) network for electric vehicle is designed. The current flowing on primary and second coil are obtained in simulation by Matlab/Simlink. A pair of circular coils with ferrites are designed and modeled using 3D FEA software ANSYS Maxwell to estimate the magnetic field distribution with the vehicle body shell. The magnetic field strength at four observation points at various regions are presented to meet the level defined in SAE J2954. A pair of aluminum shield shells are designed to reduce leakage magnetic field from resonance coupling coils. The magnetic field strength with and without shielded aluminum shell are compared to validate the shielding effectiveness. The maximum magnetic field values are decreased by 23 A/m, 13.5624A/m, 8.167 A/m, 2.6043 A/m respectively. Finally, The effectiveness of the shield plate and the safety of the vehicle seat are verified by experimental test.