V/f-based speed controllers for an induction motor using AI techniques: A comparative analysis

Abstract

This paper presents a comparative analysis of speed controllers for threephase induction-motor scalar speed control. The control strategy consists in keeping constant the voltage and frequency ratio of the induction-motor supply source. First, a conventional control loop including a PI controller is realized. Then a fuzzycontrol system is built on a MATLAB platform, which uses speed and difference in speed variation to change both the fundamental voltage amplitude and frequency of a sinusoidal pulse width modulated inverter. An alternative optimized method using Genetic Algorithm is also proposed. The controller performance, in relation to reference speed and step change of speed variations with constant load-torque, is evaluated by simulating it on a MATLAB platform. A comparative analysis of these with conventional proportional-integral controller is also presented.