Bidirectional Flyback Converter for Power Management between Lithium Battery and DC distribution System

Because the power supply using a DC distribution system can increase the conversion efficiency and reduce cost, the AC distribution system will be replaced by the DC distribution one in the future. This paper proposes a bidirectional flyback converter to regulate powers between DC buses and battery packs. To recover energies trapped in leakage inductances between primary and secondary windings of transformer, two active clamp circuits are introduced in the bidirectional flyback converters. Since switches in the bidirectional flyback converter can be merged to form the proposed bidirectional flyback converter, the proposed converter has several advantages, such as less component counts, lighter weight, smaller size, lower cost and higher conversion efficiency. In order to prove the feasibility of the proposed converter, a prototype of the proposed bidirectional flyback converter under a DC bus voltage of 12V and a battery pack voltage of 10V ~ 16.8V has been implemented. It is applied to a bidirectional power transfer system application under lower step-up and step-down voltage (0.67 ~ 1.5) condition.