The Research Of Brushless DC Motor Commutation Torque Ripple Suppression Technique And Application

The permanent magnetic brushless DC motor (BLDCM) has been widely used in medical, aerospace and other fields due to its excellent performance. However, the BLDCM has the disadvantage of torque ripple in running process, which limits its application in some occasions requiring high performance. Therefore, it is necessary to study the electromagnetic torque ripple suppression techniques in order to improve the static and dynamic performance of BLDCM and improve its application level.This thesis briefly analyzes the basic structure and working principle of the BLDCM, established the accurate mathematical model, and then discussed the suppression mechanism of commutation torque ripple. After analyzing the torque ripple suppression strategies from both of the PWM modulation and control modes, the thesis proposes a double closed-loop control system of BLDCM, which consists of an outside speed loop with PID controller and an inside current loop with fuzzy controller based on torque.A detailed design schedule for specific modules of the proposed control system is proposed in the thesis, and a simulation model based on MATLAB/Simulink is established. Through comparing and analyzing the simulation experimental results of the direct torque control system, PID control system and the control system which contains fuzzy controller based on torque, the proposed control system of BLDCM shows a better static and dynamic performance.The proposed torque ripple suppression strategy is applied to the drive system of high-speed sewing machine which based on BLDCM. By analyzing the experimental data during the process of speed adjusting and motor braking, it show that the proposed torque ripple suppression strategy can achieve the higher requirements of stability and positioning accuracy of high-speed sewing machine.