Abstract:
The main aim of the thesis dealt with the concept of speed control of a three-phase induction motor in pumping application.In recent years, a major issue that effects the electricity generation in Roseires hydro-power station is sedimentation. Dredge Pumps are frequently used there to remove sand and gravel in front of the intakes of the turbines. Three-phase induction motor is the most widely used electric motors in this processto drive these pumps.It runs at essentially constant speed-which is frequency dependant- from no-load to full-load.However, controlling the motor speed is required for optimizing the dredging process by controlling the flow, increasing bearing and pumps seal life and Pump energy savings.
Variable frequency electronics drives are being used to control the speed of induction motor. Direct torque control is a one of the latest drive technology describes the way in which the control of torque and speed are directly based on the electromagnetic state of the motor. It is the first technology to control the real motor control variables of torque and flux.
In this thesis a system of three phase induction motor with Adjustable Speed Drives (ASD) is used to drive heavy-duty dredge pumpusing direct torque control method. MATLAB/SIMULINK tool is used for simulating the whole system. The results are then obtained in speed and torque control modes to fulfill the requirements of controlling the speed and achieving the objectives.
