Analysis and Research of a Soft-Switching Bidirectional DC–DC Converter Without Auxiliary Switches

In this paper, a soft-switching topology is proposed for the bidirectional dc-dc converter. In order to achieve soft-switching conditions, the auxiliary circuits including a small inductor and two capacitors are introduced to the bidirectional dc-dc converter. By generating and keeping a recycle current in the auxiliary circuits, the proposed topology can provide soft-switching conditions for both switches of the bidirectional dc-dc converter in fixed frequency control application. Meanwhile, no auxiliary switches are introduced. Due to the existence of the auxiliary circuits, the proposed topology can also reduce the current ripple in the main inductor. Based on this soft-switching method, a family of bidirectional soft-switching dc-dc topologies is derived. These topologies have the similar structures and the same characteristics. The topology deduction, operating principles, and design guidelines are presented in detail. Finally, an experimental prototype is built to verify the analysis and characteristics of the proposed topologies.