A Novel High Controllable Voltage Gain Push-Pull Topology for Wireless Power Transfer System

Wireless Power Transfer (WPT) is commonly used to transmit power from a transmitting coil to various movable power devices. In the WPT system, due to a resonant tank inherent characteristic, the system cannot achieve a high output voltage gain. This paper proposes a novel current-fed push–pull circuit to realize high output voltage gain by adding a bi-directional switch between the resonant network and inverter. To obtain a high voltage gain, this paper proposes energy storage and energy injection mode to realize an energy boost function. A duty cycle control method for mode switching is also proposed. The proposed method allows the converter to operate with a variable voltage gain over a wide range with high efficiency. Experimental validation shows that the system gain of a proposed circuit can achieve a variable gain from 2 to 7 of which the converter can be two times higher than the classical system with the same condition.