Study of predictive direct power control for three-level NPC converter

Based on the theoretical model of three-level converters, a mathematical model of the predictive active power and reactive power control is deduced. Relationship of both active power and reactive power with voltage vectors is analyzed from an instantaneous power perspective. Influence and tendency caused by voltage space vectors on the active power and reactive power are described in detail. Because different voltage vectors have different effects on the neutral point potential, the cost function related to the power error and neutral point potential control is constructed. According to the cost function, the optimum voltage vector sequence is determined. Correctness and feasibility of the predictive direct power control is verified through simulation and experiments.