Novel Control Strategy based on Differential Flatness Theory and Model Predictive Control for Dual-Active-Bridge DC-DC converter

The renewable energy is becoming prevalent in environmental problems. In order to transform energy steadily, the Dual-Active-Bridge (DAB) DC-DC converters are commonly installed in the renewable energy co-generation systems. Moreover, these converters often need to have fast dynamics, robustness against disturbance, voltage transformation abilities and so on. In order to address these issues, a novel control strategy combined Differential Flatness Theory (DFT) and Model Predictive Control (MPC) is proposed in the paper and applied on a DAB DC-DC converter. The proposed strategy can transform the voltage to reference value accurately with fast dynamics as well as the excellent robustness. The contradiction between heavy computational burden and fast dynamics is managed by the applied discretized control set and the adaptive step. Besides, adaptive step contributes to smaller overshoot. Assessments on the performance of the proposed novel control strategy are conducted comparing with PI control and ordinary MPC. Simulation under MATLAB/Simulink are carried out to prove the theoretical allegations.