Three vector modulation model predictive control of grid-connected inverter

Abstract

Aimed at the issues of the fixed range of vector selection, fixed amplitude, and fixed direction in the conventional single and double vector model predictive control for grid-connected inverters, such as the large current pulsation and poor steady-state performance of the system, a three-vector model predictive control strategy is proposed. Firstly, the desired voltage vector is equivalent to the combination of two adjacent non-zero voltage vectors and one zero voltage vector in a control period. Secondly, Choose the best vector combination by optimizing the objective function twice. The output optimal voltage vector combination is modulated to generate a PWM wave, which acts on the grid-connected inverter. Finally, the proposed three-vector model predictive control and the traditional single and double vector model predictive control are simulated and compared. From the simulation results, when the grid-connected reference current is 10 A, the harmonic current content of the grid-connected inverter is 2.98%, 2.48%, 1.13% under the single-vector, double-vector and three-vector model predictive control, respectively. combined with the results of the dynamic simulation experiments, the results show that under the three-vector control, the results show that the three-vector model predictive control grid-connected inverter enjoys less harmonic content, lower loss, more efficient operation, and stronger robustness.