Hunan University of Technology
Natural Science Foundation of China (No.51807058); Natural Science Foundation of Hunan Province (No. 2020JJ6082)
To solve the problems of large current stress, difficult soft switching of all switches and slow dynamic response of dual active bridge convert-ers, a multi-objective unified optimal control strategy based on triple-phase-shift control is proposed. The forward power flow global mode of triple-phase-shift control is analyzed, and three high-efficiency modes are selected to establish the analytical models of current stress and soft switching. Combined with the model, the optimal phase-shift ratio combination and the minimum current stress in different modes are derived by using the cost function optimization equation, which makes switches operate within the zero-voltage-switching power constraint range. At the same time, the virtual power component is introduced in the process of efficiency optimization. The small-signal model is constructed and the influence of small disturbance of different state variables on the output voltage is clarified. The experimental results show that the proposed control strategy can not only reduce the current stress of the dual active bridge converter, make all switches zero-voltage-switching, but also improve the stability of the output voltage in the full power range.