Isolated bidirectional converter with minimum active switches for high‐voltage ratio achievement and micro‐grid applications

This study proposes a novel isolated bidirectional DC/DC converter for micro‐grid system, which can fulfil battery charging and discharging. Even though the proposed converter only employs four active switches and a coupled inductor, it can achieve high‐voltage ratio without excessive duty ratio or high transformer turns ratio. The power stage of the converter is mainly developed by integrating a three‐winding coupled inductor, three‐switched capacitors, and a flyback‐behaviour converter into a novel structure. The energy stored in the leakage inductance can be totally recycled for efficiency improvement. The operation principle, steady‐state analysis, and design considerations of the proposed converter are described in detail. Finally, a laboratory prototype is built to validate the converter. The measured results have verified the correctness and the theoretical analysis.