Torque Ripple Minimization by Fuzzy-Logic Techniques on BLDC Motors

Recent developments in permanent magnet materials, power electronics and modern control technologies have significantly influenced the wide-spread use of BLDC motor drives. Torque ripple is one of the major problems in BLDC drives. Torque ripple exists due to several reasons like cogging, waveform imperfections, and supply current ripple resulting from PWM inverter and from phase current commutation. A wide variety of techniques have been proposed during the past few years for this problem. In this work, the comparision of 120° and 180° conduction mode switching scheme for PWM inverter is proposed to minimize the torque ripple in BLDC motor. On another hand Direct Torque Control technique (DTC) is applied to BLDC, for reducing torque ripple. Based on Direct Torque Control theory, a fuzzy controller which comprises of torque error, flux error and stator flux angle is designed to reduce the torque ripple in brushless dc motor. Then the results are compared on the simulation results with each other.