Zero voltage switching Forward-Flyback Converter with efficient active LC snubber circuit

This paper describes a Boundary Mode Forward-Flyback Converter (BMFFC) with zero-voltage switching that is able to process power efficiently. The theoretical analysis and operating principle of the BMFFC are presented in detail. A non-dissipative LC snubber that recycles energy to the input source is employed in order to suppress the voltage spike caused by the leakage inductance of the transformer. The relatively large snubber capacitor also significantly reduces turn-off loss. Following a detailed design procedure, a 200W prototype with a 25-50VDC input and 230VDC output was constructed and tested in order to evaluate the performance of the BMFFC.