Simulation study of torque ripple of an induction motor drive under thermal variations

Induction Motors are the major rotating device used in industrial applications, in which both torque and the speed precise control is achieved. After the existing of fast acting solid state switching devices the controlling of ac motor drives became simple, prior to that DC motors were dominated in industrial drive applications as the torque and speed would have controlled independently and was not possible earlier with Ac motor drives. There are many disadvantages of DC motor drive which are overcome with AC motor drives. There are various methods of controlling Induction motor drive but the best method is the Direct Torque Control the only drawback in this method is the torque ripple. From the basic equations of controlling the parameters it is noted that Stator resistance is one of the parameter on which the torque ripple depend, almost in all Induction motor drives this is considered as constant value, but stator resistance varies with the temperature. In this paper a clear study has been made on torque ripple variations with the variation in stator resistance. The study has been carried out in Using Matlab/Simulink software package.