Electromagnetic interference reduction method from handheld resonant magnetic field charger (HH-RMFC) for electric vehicle

The proposed handheld resonant magnetic field charger (HH-RMFC) is a convenient method of charging batteries in electric vehicle (EV) without any electrical contact. With close distance between Tx and Rx windings, high mutual inductance causes large reflected impedance seen by the power source. The large reflected impedance can cause distortion of current flowing through Tx and Rx windings. In frequency-domain, the distortion of current produces large current harmonics, which may have electromagnetic compatibility (EMC) issues caused by leakage magnetic field. To quantify the distortion of current, the total harmonic distortion (THD) is used. In this paper, the design method for low EMI from the HH-RMFC for EV are proposed and verified using a circuit simulator. The circuit simulation results show that THD of Tx and Rx current is below 5% using proposed method.