Three vector modulation model predictive control of grid-connected inverter

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. (C) 2021 The Author(s). Published by Elsevier Ltd.