Improved Model Predictive Control for Three-Phase Dual-Active-Bridge Converters with a Hybrid Modulation

In this paper, an improved moving discretized control-set model predictive control (MDCS-MPC) with a hybrid modulation is proposed for 3p-DAB. The main objectives of this paper are to improve the efficiency in partial-load and to enhance dynamic performance for output voltage tracking. Firstly, the hybrid modulation, which consisted of triangular modulation, trapezoidal modulation as well as phase-shift modulation, can extend the soft-switching range and improve the efficiency for 3p-DAB, especially in light load conditions. Meanwhile, the closed-form of analytic expression of the hybrid modulation is derived and presented in the form of a simple table. Next, the designed hybrid modulation is incorporated into the proposed MDCS-MPC methodology to enhance the transition response for output voltage tracking. Furthermore, a proportional-integral observer is utilized to estimate the load current for the cost-saving of the current sensor. The main contribution of the proposed methodology relies on the fact that the dynamic response for output voltage tracking can be improved, the current stress can be reduced in light load, and the cost of the system can be saved. Finally, comparison experiments on a laboratory prototype are carried out to confirm the theoretical analysis and the performance improvement of the developed approach.