Coupled-Inductor-Based Bidirectional Resonant Converter With Reduced Component Count and Load-Independent Voltage Gain

The bidirectional dc/dc converter is a critical part to interface the dc-bus with energy storage system in dc microgrid. This article proposes a coupled-inductor-based bidirectional resonant converter with center-aligned pulsewidth modulation (PWM) method and reduced component count. The structure of dual half-bridges with coupled inductor makes the current analysis more complex than the full-bridge PWM resonant converter. Hence, a method of performance analysis based on the symmetrical Pi model is proposed and the corresponding parameter design process is introduced. In addition, fixed switching frequency operation, load-independent voltage gain, full-load range zero-voltage-switching (ZVS), automatic bidirectional power transfer, and bidirectional power limitation can be realized in the proposed PWM converter. An experimental prototype with rated power of 1000 W is built to demonstrate the operation and performance of the proposed converter.