Soft-Switching Bidirectional DC/DC Converter With an LCLC Resonant Circuit

In this paper, a soft-switching bidirectional dc/dc converter with an LCLC resonant circuit is proposed. The proposed converter has the dual advantages of isolated converter and nonisolated converter. In boost mode, high efficiency can be achieved at high boost ratios. In buck mode, the circuit can also achieve automatic voltage equalization of half-bridge capacitors. In this paper, a detailed theoretical analysis of the LCLC structure is performed, and the specific operating modes of the circuit in buck and boost mode are given. The circuit modes of the soft-switching resonant process are quantitatively analyzed. The GSSA method was used to model and control the system. According to the obtained transfer function, the PID control circuit of the system is designed by using the zero-pole cancelation method, which enabled the system to obtain superior control performance. A prototype of 1000 W was made, and the experimental results are in a good agreement with the theoretical results.