An active-clamping ZVS flyback converter with integrated transformer

This paper propose an active-clamping flyback converter using a integrated transformer. The proposed converter is composed of two active-clamp flyback converter. The presented converter can equally share the total load current between two secondaries so that the rectifier diode conduction loss can be decreased. Otherwise, the main switch of any converter as auxiliary switch for the other one, so that only two switches are required and both can achieve zero-voltage-switching (ZVS) operation. The transformers of converter are integrated into one magnetic core, therefore, the volume and copper loss of transformer can be reduced. Detailed analysis and design of this integrated magnetic active-clamping flyback converter are described. Experimental results are recorded for a prototype converter with an AC input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 5 A, operating at a switching frequency of 100 kHz.