Performance Improvement of a Field-Oriented Induction Motor Drive via Fuzzy Control

Abstract

This paper presents a fuzzy slip angular speed estimator for improving the efficiency of an indirect field-oriented (IFO) induction motor drive. The proposed estimator consists of a fuzzy detuning correction controller (FDCC) and a fuzzy excitation controller (FEC). At heavy load, the rated flux excitation of motor is set and the nominal slip angular speed is augmented by a tuning signal generated by the proposed FDCC such that the motor drawn line current is significantly reduced, and thus the field-orientation characteristics can also be much improved. At steady-state of light load, for reducing the line drawn current more effectively, the nominal slip angular speed is set and the flux current command is reduced from its rated value by the FEC. As the transient due to command or load change occurs, the flux current command is restored to its rated value to increase the torque generating capability. Finally, a simple reference model following controller is designed to further yield good rotor speed dynamic response. The design methodology of the proposed controller is detailedly described, and the performance of the resulted motor drive is demonstrated experimentally.