Model predictive power control based on virtual flux for grid connected three-level neutral-point clamped inverter

摘要

The paper presents a detailed description of the prediction model for Predictive Power Control based on Virtual Flux (MPPC-VF) scheme for control grid connected three-level neutral-point clamped inverter (3L-NPC). The controller uses a model to calculate predictions of the future values of the virtual flux, grid currents and DC-link capacitor voltages for all possible voltage vectors. The active and reactive power can be estimated based on the virtual flux and the current. The cost function is defined to minimize the error between the active, reactive power and their references, balance the DC-link capacitor voltage and reduce the switching frequency. The optimal switching state that minimizes the cost function is selected and applied to the inverter. Simulation results under different conditions are presented and compared with conventional Direct Power Control and Space Vector Modulation (DPC-SVM). The obtained results show the better performances of the proposed control method.