Improved Model Predictive Control for Vienna Rectifier Based on Sliding Mode Structure

Vienna rectifier has advantages of low switching stress and high power factor. Based on the Vienna rectifier nonlinear system, a double closed-loop control strategy is proposed, which adopts sequential optimization model predictive control (SOMPC) in the inner loop and sliding mode variable structure control (SMVSC) in the outer loop. Firstly, the mathematical model is established to get the prediction error of grid-connected current and midpoint potential of dc side. Then, the given values of dc voltage and load current of the system are obtained through the outer of sliding mode. Finally, through the model predictive control cost function optimization to get the cost function minimum switch combination, achieved through switching sequence optimization on the system output and the exchange of current and neutral voltage in dc side control swiftly and effectively, realize the Vienna rectifier unit power factor control, stable dc voltage output and neutral voltage balance. Simulation results show the effectiveness and feasibility of the proposed scheme.