A ZCS bidirectional flyback converter

This paper addresses the design and analysis of a zero-current-switched (ZCS) bi-directional flyback dc/dc converter. The converter is based on extending a previously developed unidirectional ZCS flyback converter and replacing the output diode with a controlled switch, which acts as either a rectifier or a power control switch in the corresponding power flow direction. By adding an auxiliary winding in the coupled inductor, a switch, and a capacitor, the hard-switching design is converted into a soft-switching one. The technique utilizes the leakage inductance of the flyback coupled inductor to create zero-current-switching conditions for all switches in both power flow directions, leading to reduced switching losses, stresses, and electromagnetic interference. The operating principles of the converter and experimental results have been presented.