Improved Model Predictive Control to Eliminate Common-mode Voltage and Balance the Neutral-point Potential for 3L-NPC Rectifier

In this paper, improved model predictive control (MPC) algorithm with fast computation is proposed to eliminate the common-mode voltage (CMV) and balance the neutral-point potential for three-level three-phase neutral-point diode clamped (NPC) rectifier. First, the switching states that generate high CMV and NP unbalance are eliminated when designing MPC schemes. Then, four voltage vectors are preselected as candidate voltage vectors depend on the location of the reference voltage vector. Compared with the conventional MPC, the number of voltage vectors involved in the MPC algorithm can be reduced from 7 to 4, which effectively improves the computation time. The results on Matlab/Simulink simulation have proved the validity of the proposed method.