Simulation and Comparative Analysis of Speed Control of Induction Motor Using Fuzzy Logic, PI Controller and PID Controller

This paper presents simulation of closed loop scalar speed control of three-phase induction motor. A Fuzzy logic controller with two input and one output is used in the controller. Speed of the motor is adjusted by Fuzzy logic controller (FLC) with the help of predefined rules for input and output of fuzzy controller. Two inputs to the FLC are speed error and change in speed error. Its output is frequency of AC input of the motor. The frequency is determined from rules of the FLC under different conditions. The control strategy keeps Voltage-Frequency ratio of induction motor constant. Three phase induction motor is fed by PWM based inverter. The speed control system for 3-phase induction motor is implemented using FLC in conjunction with Sinusoidal PWM generator. The performance analysis of this closed loop speed control system is carried out in MATLAB/Simulink. It is found that the motor speed can be kept constant when load is varied. Performance of Fuzzy controller is compared with PID and PI controller using parameters like overshoot, rise time and settling time. Keywords- Fuzzy Logic Controller(FLC), Induction Motor, MATLAB/Simulink, Scalar Speed Control, V/f Control.f