Wireless power transfer system based on magnetic resonant coupling with directional coupler

This paper presents an investigation of a new wireless power transmission (WPT) system based on magnetic resonant coupling with introduced directional or additional coupled inductances. Two coupled resonant circuits reveal two resonant frequencies with highest efficiency of power transfer. It is suggested that a directional coupler or two additional coupled inductances can be used to track these resonant frequencies. According to the observed reflection frequency characteristic the frequency of the PWT system operation can be adjusted. Moreover, the resonant frequency of the transmitter side can be changed assuring high efficiency of the system in a wide range of coupling coefficients i.e. distances between transmitter and receiver.