中文摘要：

提出了一种新型的含并联辅助电路的零电流转换（ZCT）全桥DC／DC变换器拓扑结构。该变换器采用脉宽调制（PWM），通过在原边增加一个由电容和电感构成的并联有源辅助电路，在开关管状态发生变化时，控制辅助电路的谐振电流．实现了主开关管和辅助开关管的零电流开关（ZCS）．也实现了输出整流二极管的软换流。使整流二极管承受的电压相对较低．即为输出电压，特别适合于开关器件为IGBT的高电压大功率场合．消除了IGBT拖尾电流引起的开关损耗，改善了电路性能。分析了变换器的工作原理及零电流开关的实现条件．给出了主电路拓扑结构和谐振网络相关参数设计。根据所选取的参数对主电路进行了仿真研究，结果验证了电路分析的正确性和可行性。

英文摘要：

A PWM-based ZCT（zero-current-transition）full-bridge DC/DC converter is presented,which has a shunt active auxiliary circuit of a capacitor and an inductor,added to the primary winding. When the switch changes state ,the resonant current of the active auxiliary circuit is controlled to realize the ZCS of the main and auxiliary switches and the soft commutation of the output rectifier diodes ,which makes the voltage endured by output rectifier diode just the output voltage. It is especially suitable for high power and high voltage applications of IGBT as power switch. The switching loss caused by its tail current is avoided and the circuit performance improved. The operational principle of converter and the conditions of ZCS are introduced. The main circuit and the parameter of resonant net are designed and the simulative results show its correctness and feasibility.