移相全桥ZVS变换器的研究与优化设计

Research and optimization design of phase-shift full bridge ZVS converter

传统的移相全桥ZVS变换器存在诸多缺点,如滞后桥臂零电压范围小、副边占空比丢失、副边寄生震荡、变压器磁饱和等问题.针对这些问题进行分析,设计了一种改进型的移相全桥ZVS变换器.其主要采用饱和电感做谐振电感来增大零电压范围及减小副边占空比丢失,增加二极管钳位电路来抑制副边寄生震荡,加入隔直电容来防止变压器磁饱和.利用Saber仿真软件对设计电路进行了仿真,其结果表明理论设计合理.本研究组研制了一台48V/1KW、50kHz的样机,经测试该变换器能在30%及以上负载范围内实现零电压开关,电压纹波小于2%,30%负载时效率达到74%,60%及以上负载时效率达到85%以上.

The traditional phase-shift full bridge（PSFB）zero voltage switch（ZVS）converter has several defects,such as the ZVS realization of lag bridge arm,secondary duty cycle loss,secondary parasitic oscillation,transformer magnetic saturation.In this paper,these key points were analyzed and an improved PSFB ZVS converter was put forward,by using saturation inductor as resonant inductor to increase the range of ZVS and reduce the loss of duty cycle,adding clamp circuit to suppress secondary parasitic oscillation,and the block capacitor is added to avoid transformer magnetic saturation.Saber software was used to simulate the circuit in the paper,the results show that the theoretical design is reasonable.Furthermore,a prototype of 48V/1KW,50 kHz was built up,the performance of the prototype is as follows：the converter reach zero voltage switch at 30%load,the ripple is less than 2%,the efficiency up to 74% at 30%load,the efficiency up to 85% at 60% or more load.