Zero-voltage switching analysis of active-clamped forward converter with current-doubler rectifier

In this paper, an active-clamped forward converter (ACFC) with current-doubler rectifier (CDR) is investigated especially in the perspective of zero-voltage switching (ZVS) operation. By employing the CDR in the secondary, ZVS condition can be obtained with much smaller leakage inductance compared to the conventional ACFC. Due to the significantly reduced leakage inductance, circulating loss is reduced while ZVS of the main switch is maintained. These can be realized without any additional components, which make the proposed converter more feasible in many applications. ZVS operation of the proposed converter is analyzed in the paper. Experimental results with a 100-W (5-V/20-A) prototype verify that the proposed converter can attain ZVS more efficiently and achieve higher efficiency.