To alleviate the imbalance and fluctuation issues when adopting traditional finite control set model prediction (FCS-MPC), a fast low-computation sequential model prediction control (S-MPC) for optimizing midpoint voltage balance is proposed. The method establishes the mathematical models of system output current and midpoint voltage separately and performs the optimization prediction of the cost functions constructed by the two models according to a certain priority. The S-MPC method is effective in controlling the midpoint voltage of the DC bus. Meanwhile, compared with the traditional model predictive control based on midpoint voltage balance (M-MPC), the S-MPC shows better results under the condition of unbalanced DC bus capacitance. Under the capacitance imbalance condition, the THD of the output current of S-MPC is reduced by 7.54% compared to that of FCS-MPC, while S-MPC is reduced by 1.96% compared to the conventional M-MPC.

Model Prediction Control,ANPC,Mid-Point Voltage Balance