A high boost ratio bidirectional isolated DC-DC converter for wide range low voltage high current applications

This paper introduces a high boost ratio, bidirectional, isolated, dc/dc converter designed as an interface between low voltage, high current dc sources and 24 V dc systems. This converter realizes bidirectional power flow with two main switches and operates under a wide input voltage range, from 1.5 V to 12 V, with an input current as high as 300 A. An active snubber circuit is utilized to recycle the energy stored in the leakage inductor of transformer and realize zero voltage switching (ZVS) off for one main switch. The zero current switching (ZCS) on of this switch is achieved by using transformer leakage inductor, thus no additional components are needed. Furthermore, the power loss of another main switch is minimized by operating it in the Synchronous Rectification mode. Complete circuit description and operation principles are provided in this paper. A 1.2 kW lab prototype has been built and tested with full power rating. Both simulation results and experimental results are presented to verify proposed functions.