Abstract：The three-phase interleaved LLC resonant converter has the advantages of high power density and small output current ripple, and has received extensive attention in the fields of electric vehicle charging and new energy power generation. In this paper, the original and secondary sides of the transformer of the LLC converter are set to star connection, and a new control strategy is proposed. Under different input voltages, the controller is controlled to work in three-phase interleaved mode, single-phase full-bridge mode and single-phase half-bridge mode by detecting the switching frequency to maintain output voltage stability. Regarding the switching of single-phase full-bridge mode and single-phase half-bridge mode, a flexible transition method of gradually changing the duty cycle of the trigger pulse is designed based on the digital controller to effectively reduce the output voltage jitter during the switching process. The influence of MOSFET parasitic parameters is analyzed in detailed, the limiting conditions of the excitation inductance of the transformer are obtained, and the wide voltage gain of the converter and the full range soft switching are realized, thereby improving the efficiency of the converter. Finally, experiments have verified the feasibility and superiority of the control strategy of wide voltage gain LLC resonant converter.
冯兴田, 邵康, 崔晓, 马文忠, 王玉彬. 基于多模态切换的宽电压增益LLC谐振变换器控制策略[J]. 电工技术学报, 2020, 35(20): 4350-4360.
Feng Xingtian, Shao Kang, Cui Xiao, Ma Wenzhong, Wang Yubin. Control Strategy of Wide Voltage Gain LLC Resonant Converter Based on Multi-Mode Switching. Transactions of China Electrotechnical Society, 2020, 35(20): 4350-4360.
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2020, Vol. 35 
