一种新型有源次级钳位全桥零电压零电流软开关PWM变换器

A Novel FB-ZVZCS PWM Converter Using Improved Secondary Active Clamping Circuit

提出了一种新型的全桥移相零电压零电流变换器拓扑结构。新的变换器通过导通副边辅助电路中的钳位MOSFET,使得滤波电感两端电压被钳位为零,输出滤波电容的电压全部作用在原边漏感上,实现原边电流的迅速复位,从而创造出良好的滞后臂零电流开关(zero current switching,ZCS)条件。新拓扑在有效零电压零电流开关(zero voltage zero current switching,ZVZCS)范围,最大占空比等方面都优于其它拓扑结构。该文详细分析了新拓扑的工作过程和各项特性,并试制样机,验证了理论分析的正确性和新拓扑的有效性。理论分析和实验结果都证实了新拓扑非常适合中大功率场合应用。

A novel full bridge （FB）-phase shift （PS）-zero voltage zero current switching （ZVZCS） converter is proposed. By turning on the clamp MOSFET during the primary current circulating period, this converter clamps the voltage on the output filter inductor at zero, so the voltage of the output filter capacitor is reflecting to the primary, and is applied to the leakage inductance to quickly reset the primary circulating current. This new topology has advantages in several aspects such as effective ZVZCS range, maximum duty cycle and so on. The operations and characteristic of the new topology are presented in detail; the feathers, analysis and design considerations are illustrated and verified on a prototype. Both the theory analysis and the experimental result proved that the new topology suits high power and high voltage output application perfectly.