Induction motor slip control with efficiency optimization using fuzzy logic techniques

Abstract

This paper describes a fuzzy logic based slip controller for an induction motor, with efficiency optimization for steady state operation. The speed control is accomplished through a Mandani type fuzzy controller, with 11 rules, taking speed error (built with 5 Membership Functions - M.F.) and speed error variation (3 M.F.) as inputs, to produce the slip increment (5 M.F.). The average motor input power is computed and used to decrement the motor voltage until minimum input power is found, optimizing the efficiency. A Mandani type fuzzy controller, with 5 rules, was devised for this purpose using the input power variation (5 M.F.) as input, to produce the voltage decrement (5 M.F.). Matlab/Simulink and its Fuzzy Logic Toolbox were used to design the controllers under simulation environment. Simulation results are presented comparing the fuzzy logic controller with a traditional approach, using a PI with antiwindup mechanism for slip control. Experimental results obtained with standard hardware are also shown.