New voltage vector generation method for a MPC algorithm with constant switching frequency operation

This paper Introduces a novel voltage vector generation method for fixed switching frequency scheme of a finite-control set model predictive control (FS-MPC). The main feature of the proposed work is to search the optimum voltage vector responsible of minimizing the cost function. A novel algorithm based on two searching loops is introduced, the first loop optimizes the voltage vector angle while the second one defines its correspondent modulus. The optimal combination is then generated into a FS-MPC algorithm to control a 3L-NPC grid-tied inverter. A closed-loop space vector modulator takes in action of firing the switches and balancing the two DC capacitors of the inverter. The overall discrete model in (dq) frame is developed. The design of the proposed algorithm is then detailed. Simulation results verifies the effectiveness of the proposed method in fulfilling grid requirements during normal operation and against external disturbances.