Analysis of Load-Independent ZCS Parallel-Resonant Inverter With Constant Current

This article presents a load-independent zero-current switching (ZCS) parallel-resonant inverter with a constant output current. The proposed inverter features constant-current output inherently without the need for any control method. Moreover, ZCS is achieved despite load variations, ensuring high power efficiency even at MHz-order switching frequencies. We conduct a comprehensive circuit analysis of the proposed inverter and provide a step-by-step parameter design method for achieving load-independent conditions. Additionally, a 25 W, 1 MHz prototype of the proposed inverter was implemented. In the circuit experiment, constant current output and ZCS were achieved across the entire range of load variations, which demonstrated the effectiveness of the proposed load-independent inverter.