Three-phase wireless power supply system using a matrix converter

This paper proposes a three-phase wireless power transfer (WPT) system with a three-phase-to-three-phase matrix converter. The proposed system directly converts power from an AC grid to high-frequency AC for WPT. The three-phase WPT system with the matrix converter is effectively expands the lifetime of the WPT system. A novel hybrid commutation method, which is suitable for the WPT system with a resonant characteristic, is proposed to avoid the commutation failure of the matrix converter. The strategy of the proposed hybrid commutation is based on an estimation of the current direction considering the resonant characteristics and elimination of commutation in the critical area. The proposed commutation method achieves an AC input-current total harmonic distortion (THD) of 4.7% with the resonant three-phase load without a current sensor on the high-frequency side. Furthermore, the proposed WPT system achieves a system efficiency of 88.2% at a load of 4 kW.