一种Boost型双向桥式直流变换器的软开关分析

Soft-switching Analysis of a Boost-integrated Bidirectional Active Bridge DC/DC Converter

传统双向桥式直流变换器可应用于能量双向传递供电系统中,但其输入输出电流断续。为此提出一种输入输出电流连续且可实现软开关的Boost型双向桥式变换器,该变换器具有结构对称、电气隔离和控制简单等优点,适用于输入输出电流脉动较小的应用场合。介绍该变换器的工作原理,且详细分析开关管电压和电流在开关过程中的变化情况,并据此推导出在考虑结电容影响时开关管实现零电压开关的条件。最后通过一台1 kW的原理样机对理论分析进行验证。

The conventional dual active bridge（DAB） dc/dc converter can be appropriate for the systems with bidirectional power flow,but its output and input currents are discontinuous.Therefore,a boost-integrated DAB converter of which output and input currents are continuous was proposed in this paper.The proposed converter has the advantages of symmetrical structure,galvanic isolation and simple control strategy,and it is suitable for the applications with low current ripple requirement.This paper described the operation principle and zero-voltage-switching（ZVS） condition of the converter in detail.Specially,the ZVS condition was deduced on the basis of particular calculation of the resonant interval that occurs at the moment of switching,which is in consideration of the junction capacitors of switches.Finally,a 1kW prototype converter had been built to verify the theoretical analysis.