The design of the loosely coupled power supply of this paper is based on class E power amplifier circuit.
We analyze this modified circuit by cancelling mutual inductance and solve it in time-domain by dividing four working states. By analyzing the relationship that the circuit frequency changes with the coupling coefficient and switch-on time of the MOSFET, as well as analyzing the relationship between output power and switch-on time of the MOSFET, we propose a kind of power control strategy—switch on the MOSFET when the current is zero-crossing and control the switch-on time by the average current. This strategy can stabilize the power output, and experimental verification is conducted in the last.