Predictive control of two parallel induction machines fed by a six-leg indirect matrix converter under an unbalanced ac-supply

This paper proposes a predictive torque and flux control for a multi-motor drive system. The scheme is based on a six-leg indirect matrix converter used to drive two induction machines operating at the same speed even under different load torque conditions. By using the mathematical model of the converter and machines, the proposed control scheme selects the switching state that minimizes error in the torque, flux and reactive power predictions, according to their reference values. Through simulation results it is shown that the predictive approach can be simply implemented with a good tracking of the controlled variables to their respective references. The results verify the fast dynamic response of the torque in both machines and demonstrate effective compensation of reactive power in transient and steady state under an unbalanced ac-supply.