Three phase induction motor using direct torque control by Matlab Simulink

ABSTRACT Induction motors are widely used in industries due to their rugged structure, high maintainability and economy than DC motors. There has been constant development in the induction motor drive system and their implementation in industrial applications. Direct Torque Control (DTC) is one of the control strategies of torque control or speed control in induction machine. It is considered as an alternative to the field oriented control or vector control techniques. These two control strategies are different on the operation principle but their objectives are the same. In this method the stator voltage vectors is selected according to the differences between the reference and actual torque and stator flux linkage. Here only the stator current and voltages is needed to calculate the actual torque and the flux linkages. The status of the torque and flux linkages applied the optimal switching logic. This optimal switching logic is used for the switching of the three-phase inverter. The inverter output gives the controlled voltage vectors that is applied to the induction motor. By properly adjusting the inverter switching the speed of the motor is controlled. The performance of an induction motor under the classical Direct Torque Control method and improved scheme have been studied and confirmed by simulation using MATLAB.