Effects of the variations of inductance and resistance of rotating induction motors on vector control

Inverter circuits which are used to drive and control electric motors has been developed recently with the help of electronic power switches and microprocessors having better performance, speed and capacity with rapid developements in technology. These developements result in easier and better applications in control methods of speed and torque of induction motors. In classical control methods used for induction motors, it is seen that speed and torque are coupled together. But it has been shown that, this problem is eliminated by vector control methods. By these methods, speed and torque can be controlled as two independent components. However, in control of speed and torque, it has great importance to determine the machine parameters correctly. It is very difficult to determine the parameters of an induction machine. The parameters can be changed by frequency, magnitude of current and temperature in working conditions. In this thesis, vector control simulation of three phase induction motors has been made with the method of Indirect Rotor Flux Field Orientation, and the effects of change in parameters on this method has been investigated. For this purpose, rotor field equations of Indirect Rotor Flux Field Orientation Method has been obtained and simulated on computer. Two different motors and inverters has been used and the results obtained from simulations has been compared and discussed. A brief explaination has been made on how the changes in parametersVI affect the Direct Field Orientation Methods. Finally, the methods proposed for correction of parameter changes has been presented.