新型零电流转换移相全桥DC/DC变换器

提出了一种新型零电流转换(ZCT)移相全桥DC/DC变换器拓扑。该变换器通过在原边增加一个由电容和电感构成的有源辅助电路,在开关管状态发生变化时,控制辅助电路的谐振电流,可实现主功率开关管和辅助开关管的零电流开关(ZCS),消除IGBT拖尾电流引起的开关损耗,同时减小了二极管的反向恢复损耗。辅助电路结构不会增加开关管的导通损耗,还能一定程度上克服传统零电压开关(ZVS)全桥变换器原边环流损耗大和占空比丢失严重的缺点。详细分析了该新型全桥变换器的工作原理以及实现零电流开关的条件,给出了主电路拓扑结构及相关参数选取,根据所选取参数对主电路进行仿真研究,给出了主要仿真波形,结果验证了电路分析的正确性和设计的可行性。

Zero-current -transition phase-shift full-bridge DC/DC converter

A ZCT(Zero-Current-Transition) phase-shift full-bridge DC/DC converter is proposed.An active auxiliary circuit composed of capacitor and inductor is added at the primary winding side of converter.When switch state changes,the ZCS(Zero-Current-Switching) of main and auxiliary switches are realized,the switching loss caused by IGBT's tail current is eliminated and the reverse recovery loss of diode is reduced by controlling the resonant current of the active auxiliary circuit.To a certain extent,it suppresses the primary circumfluence waste and avoids the duty cycle loss of conventional ZVS(Zero-Voltage-Switching) full-bridge converter while the switch conducting loss does not increase.The detailed illustration of its operating principle and ZCS conditions are included,and the topology of the main circuit and the selection of its parameters are presented.The simulation according to the selected parameters is carried out,and the correctness of the circuit analysis and the feasibility are verified by the simulation results. The project is supported by the Natural Science Foundation of CQ CSTC(2006BB2218).