A predictive Direct Torque Control of Induction Machines

In this paper, a predictive direct torque control (DTC) of induction motor (IM) drive is presented. The control uses stator flux and current vectors as state variables. Predicted torque variation, with reference to its unforced response during each sampling time interval, is imposed with the aim of determining the pulse widths of the chain voltages of the supply inverter. The existence domain of the state variables in each sampling time interval is determined and depicted graphically. Inverter voltage saturation and current limitation constraints are also taken into account and shown graphically. The proposed control technique is employed in simulating a DTC IM drive by the Matlab Simulink tool. The simulation results, which are compared with those obtained by the traditional constant switching frequency DTC, highlight the good performance of the drive, especially referring to torque ripple and low-speed operation.