摘要
全桥DC/DC变换器由于具有很高的磁芯利用率,其控制方式又灵活多样,因而在中大功率DC/DC变换器中应用广泛。移相全桥控制简单,无需外加辅助开关便可实现开关管的ZVS,因此得到了广泛应用。在实际应用中,为了防止因开关管开关特性不一致使变压器初级产生直流分量而导致的“偏磁”问题,常需要在变压器初级加一隔直电容,加入隔直电容之后,变换器工作过程也相应发生了变化。本文分析了带有隔直电容的移相全桥ZVSDC/DC变换器的工作过程,着重研究了隔直电容对变换器性能的影响,并进行了仿真研究。最后在一台2kW样机上进行了实验验证。实验结果表明,加入隔直电容可以减小占空比丢失,但同时减小了滞后臂ZVS范围,增大了次级整流二极管的电压应力。
Full-bridge DC / DC converter is widely used due to it′s high-usage of magnetic core and various control methods. Phase-shift control is usually used because ZVS can easily be achieved without additional switches. In order to avoid DC component current of the transformer,blocking capacitor is usually used in phase-shift full-bridge ZVS DC / DC converter in practical application.With the adding of the blocking capacitor,the operating principle of the converter is changed.The operating principle of the phase-shift full-bridge ZVS DC / DC converter with blocking capacitor is analyzed in this paper.The effect of blocking capacitor on the converter′s performance is especially investigated. Finally,the simulation is given,and a 2 kW prototype is built for experimental verification. It′s shown that the use of the blocking capacitor can reduce the duty-cycle loss,while it reduces the ZVS range of the lagging leg. And the voltage stress of the rectifier diodes is increased too.
出处
《电力电子技术》
CSCD
北大核心
2005年第3期11-13,共3页
Power Electronics
