Fuzzy Logic Control of an Induction Motor Compared with PI Contro

Abstract

In this work, a model of fuzzy logic controller (FLC) was designed to regulate the speed of a 3-phase squirrel cage induction motor. The model was created in Simulink and simulated in MATLAB environment. The motor was tested at speeds of 120 rad/sec and 140 rad/sec under no-load condition
and simulation results were obtained. The speed of the motor was tested under the same condition but using Proportional + Integral (PI) controller. The results show that the PI controller could be replaced with the fuzzy logic controller due to the advantages of relatively short settling time and small overshoot. The settling time for the speed and torque for the FLC were 0.7s and 1.0s, while that of the PI controller were 1.0s and 2.1s respectively. Similarly, the overshoot was higher in the simulation results obtained for the torque and speed curves when the motor was tested with the PI controller than with the FLC. Finally, for the motor considered, it was found that the PI controller introduces nonminimum phase behavior in the system while the FLC does not.

Keywords: Induction motor, Simulink model, fuzzy logic control, proportional + integral control, nonminimum phase.