Research on Hybrid Control Strategy of SHEPWM and MPC Based on 3-Order Harmonic Optimization

Resolve the insufficient dynamic response involved in SHEPWM control of three-level inverters, this research proposed a hybrid control method that simulated the switching angle of SHEPWM through model predictive control, and verified that this method had lower switching frequency and better harmonic performance under steady-state conditions, as well as excellent dynamic response under dynamic conditions. However, the discreteness of MPC caused quantization errors in the switching angle of SHEPWM, resulting in certain low-frequency harmonic. To minimize quantization errors, this research utilized the third harmonic control to suppress the neutral point potential fluctuation and conducted Simulink simulation validation. The simulation results showed that the low-order harmonic content of the SHEPWM and MPC hybrid control method based on the third harmonic control was lower than that of the traditional hybrid control method under steady-state conditions.