Single-Phase Three-Level PWM Rectifier Predictive Control With Fixed Switching Frequency Based on Current Convex Optimization

This article proposes a fixed switching frequency predictive control method for neutral point clamped (NPC) single-phase PWM rectifier to achieve global optimization of the current during the entire switching cycle. Through the optimization of the switching sequence, a three-stage switching sequence that can control the midpoint potential balance is obtained. The extreme point, the initial point, and the end point of the current error within the switching period are employed to establish an error matrix, and the error matrix l(2)-norm minimality is considered as the optimization objective. This optimization problem is a convex optimization problem, and the optimal duty cycle of the switching sequence can be obtained by solving the convex problem. The optimal duty cycle of each feasible switching sequence is obtained, and then the switching sequence that minimizes the error matrix l(2)-norm is selected as the system output among all feasible switching sequences. Finally, the experimental results show that the proposed control scheme has good performance.