Abstract：A bidirectional LLC resonant converter with synchronous control method is proposed in this paper. In order to achieve the bidirectional operation capability, an auxiliary inductor is added in the converter. In this way the topology in forward operation and backward operation is exactly the same. Also, the auxiliary inductor can help the MOSFETs to achieve soft switching. The control scheme of the proposed bidirectional LLC converter is very simple and it’s easy to be achieved. When the switching frequency is lower than the resonant frequency, all the switches can achieve ZVS; when the switching frequency is higher than the resonant frequency, soft switching condition is same with the traditional LLC resonant converter. So the efficiency of the proposed converter is high, and it’s attractive in the applications which required bidirectional power flow capability. The operation principle of the proposed synchronous LLC resonant converter is different from the traditional LLC converter, and a new equivalent model is proposed to analyze the characters in detail. A prototype is built and experimental results are given to verify the theoretical analysis.
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2015, Vol. 30 
