Estimating rotor resistance of wound rotor induction motor by look-up table and fuzzy logic approach

Abstract

Wound rotor induction motors are commonly used in high torque, adjustable speed industrial applications. The provision to add external resistances to the rotor offers high starting torque and smooth starting at a low starting current. In this paper, the look-up table method and fuzzy logic methods are introduced to estimate the rotor resistance value. This is achieved by controlling the firing angle of the thyristor converter circuit connected to the rotor. The smooth variation in speed with constant starting current and high torque is achieved for various reference values. The performance of the look-up table method and fuzzy logic controller method are compared with the traditional external resistance method. The results show that the speed error in the look-up table method is higher than in the fuzzy logic method but less than the traditional external resistance method. The performance of the fuzzy logic method is closer to the traditional external resistance method with less speed error and settling time.