Enhancing Efficiency in Bidirectional Resonant DC-DC Converter

In this paper, bidirectional LLC resonant DC-DC converters with the primary auxiliary windings in transformers of resonant circuits are proposed. Even if resonant capacitors are used on the primary and secondary sides, the proposed converter regardless of the direction of power flow can operate with the high gain characteristics of LLC resonant converter without mutual coupling of resonant capacitors. The analysis and operating characteristics of proposed bidirectional LLC resonant converter are investigated. A 3.3kW prototyped bidirectional LLC resonant converter connected to the 750V
DC
buses is designed and tested to verify the validity and applicability of this proposed converter.