Direct Torque Control Based Induction Machines for Speed-Torque Regulation

The state of the art of Direct Torque Control (DTC) is that its control architecture is less subtle for variations in machine parameters. It is a direct type control strategy in which no PWM technique is implemented and the voltage vector sequences are directly applied to the switches of inverter. This work presents the study of SQIM in two cases; first effect of variation in electromagnetic torque on motor speed and the effect of speed variation on load torque. The DTC controller also regulates the DC-bus voltage so that for the varying condition of rotor speed and motor torque, system voltage does not deviate. The DC-bus voltage is kept constant. The control strategy is also regulates the grid voltage to a constant value even though load is varying continuously. The converter controller mitigates the grid voltage harmonics and improves the power quality of the system.