Behavior of the Predictive DTC Based Matrix Converter Under Unbalanced AC Supply

A novel time discrete control strategy applied to a Matrix Converter that drives an AC machine is presented. The strategy features the advantages of the Direct Torque Control and the Predictive Control, verifying its robustness through out the analysis of its behavior under an unbalanced AC supply. The high performance of the predictive control is based on the deterministic model of the converter-machine system. Such model is used to predict at any given sampling time the future values of the electrical variables as a function of the switch status. A functional is then optimized and the optimum switch status is thus selected. The optimum selection ensures unitary input power factor and zero steady state error in the flux and torque of the AC machine. The speed is adjusted by a closed loop scheme and the unbalance is naturally mitigated. Several simulations showing the transient and steady state behavior of the proposed scheme are presented.