A Novel Soft Switching Non-Isolated Bidirectional dc–dc Converter Without Any Extra Auxiliary Switch

In this article, a new zero-voltage-switching (ZVS) non-isolated bidirectional dc–dc converter (BDC) without any extra auxiliary switch is introduced. In the proposed converter, by applying an auxiliary circuit, a soft switching condition is provided for all semiconductor elements regardless of the power flow direction and without any extra voltage stress. Each of the main switches provides soft switching conditions for the other switch. Additionally, each of the switches can be used as a synchronous rectifier switch in both power flow directions. The auxiliary circuit only consists of two coupled inductors with the converter main inductor and two diodes, which operate with a zero-current-switching (ZCS) condition. Since all of the converter inductors are implemented on a single core, the presence of coupled inductors does not increase the converter volume considerably. The detailed operating analysis of the proposed bidirectional converter and the design method of the main circuit is presented. Also, the theoretical analysis of the proposed bidirectional converter is verified with a 100 W experimental prototype converter.