Abstract：The input and output voltage ranges of the bidirectional DC-DC converter are too small. Therefore, a high gain symmetric bidirectional LCLC resonant converter is proposed. The proposed resonant converter does not use the magnetizing inductor of transformer to participate in resonance, but connects a parallel LC branch on the primary side of the transformer. Thus, the converter still has a large gain with a large inductor ratio, which takes into account the efficiency and a wide gain range at the resonance point. The proposed resonant converter can also ensure the soft switching both on the primary and secondary sides, and realize the symmetric bidirectional operation. This paper establishes the fundamental wave equivalent model by the first harmonic approximation method, obtains the gain formula, and analyzes the effect of resonant parameters on DC gain characteristics. Finally, a bidirectional experimental prototype of 100-200V/24-48V 500W was built, and the experimental results verified the theoretical analysis and the proposed topology. The maximum efficiency of the prototype could reach 96.3%.
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2020, Vol. 35 
