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提出一种新型的宽输入电压范围的双桥LLC谐振变换器.该变换器可以看作是由全桥LLC电路和半桥LLC电路共同构成.相比于传统的变频控制,该变换器采用定频PWM控制,励磁电感值对变换器增益影响较小,可简化谐振参数选择过程,且更有利于磁性元器件的设计.变换器在全负载范围内能够实现原边开关管的ZVS开通和副边二极管的ZCS关断.首先详细介绍该变换器的拓扑结构和驱动时序及工作原理,然后对增益特性及软开关进行分析.最后搭建1台120~240 V输入、24 V/20 A输出的实验样机,对理论分析进行验证.“,”A novel dual-bridge LLC resonant converter for wide input voltage range is proposed,which can be seen as a combination of a half-bridge LLC circuit and a full-bridge LLC circuit. The converter employs fixed-frequency PWM control,and compared with the traditional PFM control,the effect of excitation inductance value on the voltage gain is little,the selection process of resonance parameter can be simplified,and therefore it is beneficial for the design of magnetic components. ZVS turn-ON of primary switch tube and ZCS turn-OFF of secondary rectifier diodes can be achieved under all loading conditions,respectively. Firstly the topology structure,driving schedule and operation principle of the converter are introduced in detail. Then the gain characteristics and soft switch ZVS are analyzed. Finally,a 24 V/20 A output prototype with input voltage ranging from 120 V to 240 V is built to verify the theoretical analysis.