一种复合谐振型DAB变换器的研究

Research on a Compound Resonant DAB Converter

针对能量双向流动的隔离型DC-DC变换电路,在考虑高频隔离型变压器励磁电感条件下,以一种对称型复合谐振LLC-DAB双有源桥变换器为研究对象,首先采用傅里叶变换和基波分析法建立该直流变换器的近似等效电路模型,基于双重移相控制方式,推导其功率特性和谐振电感峰值电流、谐振电容峰值电压特点;然后介绍LLC-DAB变换器原副边实现软开关的约束条件,并选择合理的移相区域,保证软开关实现的同时使有功功率得以连续调节;最后通过MATLAB搭建仿真电路模型,仿真结果验证在一定功率范围内,双重移相控制能保证软开关的灵活性且能实现电流应力最小。

For the isolated DC-DC converter circuit with two-way energy flow,under the condition of high frequency isolation transformer excitation inductance,a kind of symmetric composite resonance LLC-DAB dual active bridge converter(LLC-dual active bridge)is taken as the research object.Firstly,the approximate equivalent circuit model of the DC-DC converter is established by Fourier transform and fundamental analysis.Based on the dual phase-shifting control mode,the power characteristics,peak current of resonant inductor and peak voltage of resonant capacitor are deduced.Then,the constraints of soft switching in the primary and secondary sides of LLC-DAD converter are introduced,and a reasonable phase shifting region is selected to ensure the soft switching and the continuous adjustment of active power.Finally,the simulation circuit model is built by MATLAB,and the simulation results verify that the dual phase-shifting control can ensure the flexibility of soft switching and achieve the minimum current stress in a certain power range.