Analysis and design of a load-independent clamped class E inverter

This paper proposes a load-independent clamped Class E inverter. Compared to conventional Class E inverters, the proposed topology enables the circuit to achieve Zero-Voltage Switching (ZVS) and maintain a constant output voltage over a wide range of load variations (20 Ω to 50 Ω), without requiring any feedback control loop. Key innovations include replacing the choke inductor with a finite-valued series resonant inductor and introducing a clamping circuit comprising a clamping switch and a large-value clamping capacitor. The working principle and analytical methodology are detailed. A prototype was designed and experimentally validated under the following conditions: operating frequency of 1 MHz, input voltage of 15 V, and nominal load of 20 Ω. Results demonstrate that the topology successfully achieves load-independent constant-voltage output. The measured normalized switch voltage stress is 2.86, and a peak efficiency of 94.4 % is attained at the nominal load.