Passive Backstepping Control of Dual Active Bridge Converter in Modular Three-Port DC Converter

Abstract

A dual active bridge (DAB) converter in a modular three-port DC converter is the key equipment to connect distributed energy and energy storage units and realize its efficient and large-scale utilization. When a DAB converter with traditional control is disturbed by the input voltage of distributed energy sources, some problems occur, such as large fluctuation of load voltage and slow dynamic response. In order to address such problems, this paper firstly starts with the single-phase shift control of the DAB converter, establishes the dynamic mathematical model of the DAB converter according to the nonlinear characteristics of the converter, transforms it into the passive form of Euler–Lagrange (E-L) model and designs the passive controller based on the analysis of the passive nature and stability of the converter, in order to improve the energy dissipation rate and ensure the global stability of the system. Secondly, in conjunction with the backstepping control, a passive backstepping controller is designed with the goal of shifting the comparison to eliminate errors caused by input disturbances and achieve fast-tracking of the reference voltage. Finally, a DAB simulation model based on passive backstepping control is established in Matlab/Simulink. By selecting the appropriate injection damping value, it is compared with traditional PI control and passivity-based control strategy, and the effectiveness of forward and reverse power transmission modes of the DAB converter under passive backstepping control is verified. The results show that the DAB converter with passive backstepping control has better dynamic performance and stronger robustness after sudden changes in input voltage.