Performance analysis and circuit design of an interleaved active clamp zero voltage switching Flyback-Forward boost converter

An isolated interleaved zero voltage switching (ZVS) Flyback-Forward boost type converter with active clamp scheme is designed in this paper. Both the main and the clamp switches can operate with ZVS soft switching performance to reduce the switching losses. Furthermore, the leakage energy is recycled and the turn-off voltage spikes on the main switches are absorbed by the active clamp circuit. In addition, there are two coupled inductors in the designed converter and the secondary windings of the coupled inductors are in series to achieve boost type conversion. The coupled inductor can work in the Flyback mode when the corresponding main switch is in the turn-on state and in the Forward mode when it is in the turn-off state, which takes full use of the magnetic core and improves the power density. Experimental results verified the theoretical analysis and the effectiveness of the ZVS Flyback-Forward converter.