Research On Reducing Torque Ripple Of Brushless Direct Current Motor

With the rapid development of micro-electronics and power electronic technology, Brushless DC motor as a new type motor is becoming more and more popular in recent years. But owing to the electromagnetic factors, the cogging effect, the armature reaction and due to the role of back emf and inductance current can't immediately commutate, it will generate large torque ripple. These torque ripples have made BLDC less suitable for high performance position applications. In this paper, torque ripple inhibition techniques have been reseached in details and some novel effective methods have been proposed.The objective of this dissertation is to minimize the torque ripple of BLDC motor. Begin with the dissertation introducing the base elements, working principle, operating characteristic and transfer function of the Brushless DC motor, then it briefly introducing the reason of brushless causes torque ripple of and the method to reducing it. According to the mathematical model of Brushless DC motor, we building the system simulation model and the simulation results are analyzed. Because of the cyclical features of torque ripple, we choose iterative learning control laws to reduce torque ripple of Brushless DC motor. Finally, two different compensation strategies with ILC implemented in speed loop and in torque loop are compared. The brushless DC motor is modeled by using MATLAB/Simulink to verify the validities of the proposed methods. Simulation results show that both ILC schemes are able to successfully compensate the torque ripples, but in practice the implementation requirements of these two schemes are very different. Simulink results validated the proposed methods are effective.