双有源桥DC-DC变换器（DAB）在三重移相（TPS）控制下拥有3个独立的控制自由度，通过移相自由度的合理组合可以减小DAB的电流应力，然而软开关分析表明，当DAB的电流应力处于最优状态时，系统的效率并不一定是最优的。该文在电流应力优化控制的基础上，提出一种同时考虑电流应力和效率的DAB性能综合优化方法。首先，基于DAB的开关组合规律建立了TPS控制下DAB的损耗模型，通过换流回路分析，对任意开关组合下功率半导体器件的通态损耗、开关损耗，磁性元件的铜耗和铁耗分别进行计算。在此基础上，引入效率优化权重，构建综合考虑电流应力和效率的优化目标函数，采用二维遍历算法寻优获得DAB综合性能最佳时的工作点。实验对比了单独优化电流应力或者效率时DAB的性能差异，通过合理选择效率优化权重，使得实验样机在传输6 kW功率时的效率绝对增加了0.83%，而电流应力只增加了0.5 A。该方法可以在基本不增加电流应力的前提下，有效提高DAB的效率。
There are three independent control degrees of freedom in dual active bridge DC-DC converters (DAB) with triple phase shift (TPS) control. The current stress in a DAB can be reduced by a reasonable combination of changes in the phase shift degrees of freedom. However, soft switching analyses show that the system efficiency is not necessarily optimized when the DAB current stress is optimized. This paper presents a performance comprehensive optimization method that considers both the current stress and the efficiency based on current stress optimization control. Firstly, a DAB loss model for TPS control is developed based on the switching combination laws. A commutation loop analysis is used to separately predict the on-state losses and switching losses of the semiconductor devices and the copper losses and iron losses of the magnetic component for any combination of switches. Then, an efficiency optimization weight is introduced to construct the optimal objective function balancing the current stress and efficiency. A two-dimensional traversal algorithm is then used to optimize the DAB working point. The DAB performance is compared to measurements when the current stress or efficiency is optimized separately. Proper selection of the weight increased the prototype efficiency when transmitting 6 kW by 0.83% with the current stress only increased by 0.5 A. Thus, this method effectively improves the system efficiency without substantially increasing the current stress.
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