Active-Clamp Forward Converter With Lossless-Snubber on Secondary-Side

This paper proposes a novel active-clamp forward converter (ACFC) with a lossless-snubber on the secondary-side, which combines a resonant capacitor and a clamping diode with an output inductor in parallel. The conventional ACFC achieves zero-voltage-switching on switches of the primary-side during dead time for reducing the switching loss and voltage spike. Unfortunately, on the secondary-side of transformer, the voltage spike damages the free-wheeling diode and rectifier diode due to the reverse recovery current and junction-capacitor of the diode and leakage inductance of the transformer. This paper proposes a lossless-snubber on the secondary-side operation for reducing the voltage spike on the free-wheeling diode and forward-rectifier diode. Therefore, the converter proposed in this paper is suitable for high-output-current applications. Experimental results are shown to verify the analysis and design procedure of the proposed forward converter.