一种箝位软开关移相全桥电路研究

摘要

针对传统移相全桥电路存在的变压器及次级二极管电压振荡问题,提出一种在变压器初级插入一个耦合电感及箝位二极管臂的方案.该电路既能实现滞后臂开关管的零电压开通(ZVS),又能抑制变压器寄生电容和初级谐振电感产生的变压器电压振荡及伴随的次级整流二极管尖峰电压.详细阐述了电路各阶段工作过程,重点分析了耦合电感和卸能电阻的设计.最后设计了一个1.5 kW直流变换器电路,测试结果表明开关管均实现了ZVS,变压器电压被有效箝位,次级二极管的电压尖峰得到了抑制.%To solve the voltage spike of the transformer and rectifier diodes in traditional phase-shifting full-bridge converter,a new circuit inserting a coupling-inductor and voltage-clamping diode leg is proposed.This converter can get zero-voltage switching-on(ZVS) for the lagged-leg power switches, suppress the voltage spike of the transformer and diodes produced by the resonant inductor and parasitic capacitor of the transformer. The operation theory of each stage is explained.The designs of the coupling-inductor and energy-damping resistor are also presented.A 1.5 kW converter is testing and the results prove the ZVS of the power switches is realized and the overshoots of the transformer and rectifiers are suppressed.