Analysis of an integrated flyback and zeta converter with active clamping technique

An integrated converter with active clamping technique to achieve zero voltage switching (ZVS) is presented. In the proposed converter, the flyback and zeta topologies are used in the input and output sides to achieve the following features: to share the power switches in the transformer primary side, to achieve the partial magnetising flux reset and to share the load current. The input power is delivered to the load by the interleaved operation. The active clamping circuit, besides contributing to reduce commutation losses, resets the energy stored in the leakage inductances of both converters and the magnetising inductance of the zeta converter. The magnetising inductance of the flyback converter is reset by the load. Based on the resonance with the resonant inductance and output capacitance of switches, switches can be turned on at ZVS during the transition interval. Experimental results, taken from a laboratory prototype rated at 360 W, input voltage of 200 V, output voltage of 12 V and switching frequency of 125 kHz, are presented to demonstrate the converter performance.