Active Clamp Sepic Converter with Power Factor Correction

A soft switching sepic converter with active clamp scheme is presented in this paper to achieve zero voltage switching (ZVS) on the power switches. The active clamp topology is used in the circuit to limit the voltage stresses of power semiconductors. When main switch is turned off, the positive resonant inductor current flows through the anti-parallel diode of auxiliary switch so that the auxiliary switch can be turned on at ZVS. When auxiliary switch is turned off, the negative resonant inductor current will discharge the output capacitor of main switch so that the ZVS turn-on of main switch can be achieved. Finally, experiments based on a laboratory prototype rated at 300 W are presented to verify the effectiveness of the proposed converter.