Simulation of direct torque speed control of three phase induction motor using simulink.

Ahmed Isa Mudher Al-Shawi
Dr. Muthana J. Al-Khishali

Abstract: In this thesis, the various aspects related to controlling induction motors are investigated. Different control strategies are explored. The direct torque control (DTC) strategy is studied in details and its relation to space vector modulation (SVM) is emphasized. A SVM-based DTC strategy is suggested and a controller design which is based on the strategy is presented. A Simulink model representing the controller is developed and verified through this of MATLAB work. The model exhibits high modularity which makes it suitable for use in different induction motor control systems simulation scenarios. Each block in the model is developed from the very basic capabilities of Simulink which makes the model very suitable for testing and debugging. A modular model for the induction motor based on Krause’s model is developed. This model is used in the simulation instead of the built-in Simulink induction motor block, in order to enable testing the various parts of the induction motor model and to gain a deep insight in machine’s operation. This model is tested separately and shown to be working properly through simulating direct ac startup in Simulink. The performance of control is evaluated through simulating the whole system in Simulink and the suggested SVM-based DTC controlling system is shown to be superior to other controlling strategies investigated in the literature. It also shows that the induction motor settle down faster when using the suggested strategy compared to other previously studied strategies.