An Active Clamping Strategy for Class-E Inverter in Wireless Power Transfer System

Class-E inverter is a potential candidate for high-frequency WPT system due to its soft switching feature. However, because of the voltage stress on the switch, the output power is seriously restricted. To solve this problem, this paper proposes an active clamping class-E amplifier, in which a large capacitance and a MOSFET connected in series are added on the both ends of the shunt capacitance in traditional class-E inverter. The additional MOSFET is control by a voltage detection circuit which detects the voltage on the shunt capacitance in real time. Corresponding strategy is verified on a wireless power transfer platform.