Interleaved soft-switching buck converter with coupled inductors

This paper presents an interleaved soft-switching buck converter with coupled inductors to extend duty ratio for high step-down voltage applications. In the proposed converter, a single-capacitor turn-off snubber is introduced to limit rising rate of active switches to reduce turn-off loss. To handle the energy trapped in the leakage inductance of the coupled inductors, simple passive-clamp circuits are added to the proposed converter, which can effectively recycle the energy and suppress voltage spike. To highlight the merits of the proposed converter, its performance indexes, such as voltage gain function and component stresses, are analyzed and compared with those of the conventional interleaved buck converter. In this study, the prototype of the proposed converter, input voltage of 150-200 Vdc, output voltage of 12 Vdc, and full load power of 240 W has been implemented and verified, from which experimental results have shown that 85% conversion efficiency can be achieved at the full load condition.