Soft switching active-clamped dual series-resonant converter

A soft switching active-clamp dual series-resonant converter is proposed in this paper. Two small transformers are used at the proposed topology to provide more load power. An active-clamp circuit is used to absorb the energy stored in the leakage inductor of transformer, to clamp voltage stresses across switches, and to realize the ZVS turn-on of switches in order to alleviate the switching losses. In order to remove the reverse-recovery problem on output diodes, the ZCS turn-off is realized by choosing the properly angle frequency on the secondary side. Analysis of mode operation, design considerations and experimental results of the proposed ZVZCS converter are described in detail. Finally, a 200W ZVZCS prototype treated under V_in=48V, V_o=200V is implemented to verify the practicability of the proposed converter.