무선전력전송 시스템의 송신 코일의 전압 전류 위상차 분석을 통한 수신측 공진주파수 추출

Abstract

This study proposes a method of identifying the resonant frequency of the receiving side in a wireless power transfer (WPT) system, adopting a double-sided LCC topology. The resonant frequency of the receiving side must match the system’s operating frequency. However, in many cases, determining the resonant frequency of the receiving side from the inverter at the transmitting side is challenging. The method proposed in this study changes the operating frequency of the inverter at the transmitting side, and by observing the phase difference between the voltage and current at the transmitting coil side, the resonant frequency of the receiving side can be identified. Therefore, the WPT system adopting the proposed method does not require additional communication systems at the transmitting and receiving sides. The proposed method was analyzed using equations and validated through simulations and experiments. The proposed method can accurately extract the resonant frequency of the receiving side with an error of less than 0.4 %.