Torque and flux control of an induction machine fed by a matrix converter under unbalanced AC supply with reactive power minimization

A predictive control strategy applied to a matrix converter based induction machine drive is presented in this paper. The strategy features the advantages of the direct torque control (DTC) and the predictive control, verifying its robustness throughout its behavior analysis under an unbalanced AC supply. The predictive control approach is based on the 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 switching condition. The switching state that optimizes the value of a cost function, used as evaluation criterion, is selected and applied during the next discrete-time interval. Experimental results confirm the high quality control of torque, flux and power factor with a fast dynamic response, where the unbalance in the AC supply is naturally mitigated.