一种采用无源钳位电路的新型零电压零电流开关变换器

A Novel ZVZCS Converter Using Passive Clamp Circuit

针对传统的全桥移相PWM零电压零电流(ZVZCS)DC-DC变换器存在的缺点,提出了一种在副边采用无源钳位电路的新型全桥移相PWMZVZCSDC-DC变换器。这种变换器可以有效实现超前桥臂开关管的零电压开关,以及滞后桥臂开关管的零电流开关。这里详细分析了此变换器的工作原理以及变换器各个阶段的工作模态,并且分析了此变换器实现软开关的条件。理论分析表明这种变换器具有副边电压应力低,实现软开关负载范围大,辅助电路损耗小等优点。通过一台0.8kW,60kHz的样机进行了实验,验证了理论分析的正确性。实验结果证明该变换器能够在较宽的负载范围内实现滞后桥臂的零电流关断,适用于大功率应用IGBT的场合。

A novel full-bridge phase-shift PWM ZVZCS （zero-voltage and zero-current switching）DC-DC converter using passive clamp circuit is proposed based on the characteristic of conventional full-bridge phase-shift PWM ZVZCS DC-DC converter. The converter can achieve zero-voltage-switching （ZVS） for leading-leg switches and zero-current-switching（ZCS） for lagging-leg switches effectively. The principle and operation modes of the converter are analyzed, and the necessary condition of soft switching is also analyzed. By using the passive clamp circuit, the proposed converter can reduce voltage stress in secondary side, and widen load range for soft switching. The losses of the auxiliary clamp circuit are very low. The proposed theory has been verified on a 0.8kW, 60kHz experimental converter. The soft switching of lagging leg can be achieved in wide load range, so this converter is suitable for large power application where IGBT is used.