一种新型全桥零电压转模 PWM DC-DC变换器

针对移相全桥ZVS PWM DC-DC变换器滞后桥臂零电压开关范围窄、占空比丢失严重以及转换效率较低等缺点，该文提出了一种新型的全桥ZVT PWM DC-DC变换器拓扑。这种电路在传统移相ZVS PWM DC-DC变换器的基础上增加了两个无源网络，其中一个并联在原边的主电路中，为滞后桥臂实现零电压开关提供条件；另一个串联在变压器的副边，以减小变压器的导通损耗。这种电路有宽零电压负载范围，占空比丢失小等优点，可以提高了开关电源的效率，且输出性能好。该文分析了变换器的工作原理以及滞后桥臂零电压开关的实现条件。该文采用了DSP作为控制芯片，实现了系统的双闭环控制。最后研制了一台功率为600W，工作频率为100kHz的样机，实验结果验证了这种新型全桥ZVT PWM DC-DC变换器相关理论的正确性。

Novel Full-bridge ZVT PWM DC-DC Converter

Traditional full-bridge ZVS PWM DC-DC converter have several shortages, such as narrow ZVS load range for the lagging leg, serious loss of duty cycle and fairly low converting efficiency etc. A novel full-bridge ZVS PWM DC-DC converter topology is proposed in this paper. This converter adds two passive circuits, one is paralleled in the primary to supply the condition of ZVS for the lagging leg, the other is in series to the secondary to reduce the conduction loss of the transformer. This topology circuit has some virtues such as wide load ZVS range, small duty cycle loss etc. It can improve the efficiency, and have good characteristic of output. Then this paper analyzed the operating principle and the ZVS qualifications of the lagging leg. This paper uses DSP as control chip, and has achieved double control for system. Finally, a 600W ZVT PWM DC-DC converter prototype which operates at 100kHz switching frequency was developed, and the experiments showed us the validation of the correlative theory.