Advanced Asymmetrical Switching Sequences-Based Model Predictive Control with Minimum Current THD for Single-Phase NPC Rectifiers

A novel model predictive control (MPC) based on advanced asymmetrical switching sequences (A
²
SS-MPC) is proposed in this paper for single-phase NPC rectifiers. The design principles of the switching sequences (SSs) consider the optimization of the grid current quality, the semiconductor devices losses, and the capacitor voltage balancing performance. The proposed algorithm reduces the number of state transitions of the bridge arms per control cycle to two, which is half of the conventional MPC based on SSs. Additionally, an advanced voltage vector duty cycle calculation strategy for the advanced asymmetrical SSs is proposed to minimize the error area and the total harmonic distortion of the grid current. Finally, the simulation results of four MPC algorithms validate the effectiveness of the A
²
SS-MPC.