Development of an Isolated Class-Φ<sup>2</sup><sub>2</sub> DC-DC Converter with Bidirectional Operation

This paper introduces the bidirectional functionality of a flyback converter achieved using a soft-switching technique. The proposed method can harness electrical energy more efficiently than conventional circuits, which are restricted to unidirectional power supplies. We focused on the flyback converter circuit, which uniquely integrates soft-switching and bidirectional operation, thus facilitating superior power conversion. Specifically, we assessed the power conversion efficiency of the assembled circuit during the boost and buck operations at a switching frequency of 1MHz. The empirical results demonstrated that the power conversion efficiency was 83.2% in boost operation and 81.9% in buck operation. Furthermore, we successfully implemented bidirectional operation by simply adjusting the duty cycle and phase of the switching devices.