STUDY OF VARIABLE SPEED RANGE OF INDUCTION MOTOR

Abstract

Induction motors (IM) are the most widely used electrical motors due to their reliability, low cost and robustness. The need for variable speed of an induction motor arises in certain industrial applications and this is often difficult to achieve because induction motors are of fixed speed. The objective of this thesis to study the methods of improving speed range and characteristics of an induction motor. In this study, firstly the electric statics of IM, which affect characteristics and linearity, have been studied. Secondly,the characteristics for several methods of speed control of an induction motor such as , variable rotor resistance, variable stator voltage, constant V/f control methods was represented using MATLAB programming. Finally, the results of closed loop constant v/f control with variable speed drive and proportional–integral controller was obtained by MATLAB/SIMULINK, and dynamic IV response was represented and analyzed, which was found to match the characteristics available in literature of speed control of induction motors.