Harmonic Suppression Technique of Magnetic Field Coupling Type Wireless Power Transmission System Using ATAC Circuit

The magnetic field coupling type wireless power transmission system is a revolutionary wireless power transmission method that can secure a transmission distance of about several meters while having efficiency of up to 90% and three dimensional movement freedom. However, it is required to strictly match the resonance frequency of the transceiver. For example, in power transmission using a resonance circuit with Q = 500, it is necessary to adjust the resonance frequency of the transmitter and receiver within 0.1% accuracy. Furthermore, in order to improve efficiency and simplify the power supply, the power supply can be composed of a class D amplifier, but there some harmonics include the transmission magnetic field due to rectangular signal generation by the switch control; then harmonics may affect radio equipment. In this paper, we propose a harmonic suppression method to suppress harmonic generated in magnetic field, employing Automatic Tuning Assist Circuit (ATAC) that enables to set resonance frequency automatically without using high Q resonance circuit.