The improvement of model predictive control based on three-level three phase inverter

Abstract

To improve the dynamic response of the inverter, the conventional proportional-integral controller and the modulation part are substituted by the finite-control step model predictive control (FCS-MPC) strategy. Unlike the two-level inverter, the drifted neutral point potential is the issue that cannot be neglected. To resolve this issue, the cost function is modified in this paper. Besides, as all of the voltage vectors are employed during optimal research progress in FCS-MPC, the switching frequency is variable, which burdens the filter. The complex calculation progress also burdens the microcontroller. According to the conventional modulation algorithm, the voltage vectors are divided into several groups and the optimal calculations are simplified with them. Based on that modification, the switching frequency is fixed. Finally, the simulation and the experimental results are demonstrated, they reveal the validity and the merits of the proposed algorithm.