Wireless power transfer via harmonic current for electric vehicles application

A method that only using harmonic current to transfer wireless power for electric vehicles (EV) is proposed in this paper. The frequency limit of most high voltage high current IGBT is around 20 kHz which also limits the system frequency of the transformer. Due to the gain characteristic of the resonant tank is actually a band-pass filter, using one specific harmonic current to transfer power becomes available. By doing so, the system frequency can be raised up several times while the switching frequency remain the same. Higher system frequency leads to a more compact system. A 1 kW prototype with 20 cm air gap using 3^rd harmonic power is built to verify the method.