Harmonic current reduction method of hand-held resonant magnetic field charger (HH-RMFC) for electric vehicle

The hand-held resonant magnetic field charger (HH-RMFC) is a convenient equipment of charging the batteries without any electrical contact. Due to high coupling coefficient of HH-RMFC, the single phase power inverter with square wave encounter relatively small reactance at its harmonic frequencies. Thus, the current flowing through the Tx and Rx windings can be distorted. The distorted current with large amount of harmonics may act as magnetic near field noise to the adjacent sensitive electronic devices such as sensors, controller and communication devices in electric vehicles (EVs). Moreover, the current harmonics have the effect of increasing losses and thermal stress in power system. In this paper, a reduction method of the harmonic currents in HH-RMFC is proposed. The circuit simulation results show that the harmonic currents flowing through Tx and Rx windings in HH-RMFC can significantly be reduced by applying the proposed method. The circuit simulation results show that proposed method can reduces THD of Tx current and Rx current by 15.64 % and 14.11 %, respectively.