Three-vector Model Predictive Control without Weight Coefficient based on Three-phase Neutral Point Clamped Inverter

Three-phase three-level neutral point clamped inverters are widely used in new energy fields such as photovoltaic power generation and wind power generation by virtue of their multilevel topology. The traditional three-vector model predictive control can solve the problems of current harmonics and unfixed switching frequency that exist in the single-vector model predictive control, but the traditional three-vector model predictive control still has the problems of large computation and difficult design of weighting factors. Based on this, this paper proposes a three-vector model predictive current control without weighting factors. The method firstly selects the voltage vectors by dividing the sectors to eliminate the weighting factors, secondly adopts the principle of non-differential beat control to obtain the reference voltage and the optimal sectors, and finally calculates the action time of each vector and designs the switching sequences by means of the cost function. The experimental results show that the proposed control strategy can quickly regulate the midpoint potential balance, and the current harmonic content is reduced to 3.5%.