The Research Of Torque Ripple Restraining Of BLDCM

Brushless DC motor has simple structure, long service life, high efficiency and otheradvantages, and it has been widely used in the defense, aerospace, robotics, industrial processcontrol, precision machine tools, automotive electronics, home appliances, office automation andother fields. However, brushless DC motor has large torque ripple which will reduces system’sservice life and stability. Thus, the research on the suppression method of brushless DC motor’storque ripple restraining has realistic significance on improving the equipment’s operatingquality and service life.The paper takes the brushless DC motor as research object based on relevant domestic andoverseas researches. And the paper studies the problem of torque ripple and presents the methodcombination of FIR filter and the double closed-loop control system based on the improved PIDcontrol algorithm to suppress the torque ripple. It is verified the feasibility and effectiveness byexperiments. The main content of the whole thesis are as follows:1. The paper analyzes the research status of brushless DC motor from motor controller andsuppressive method of torque ripple. The paper analyzes brushless DC motor’s basic structureand working principle. Besides, the paper establishes mathematical model of motor, and imitatesBLDC motor by Matlab to verify the correctness of the model.2. The paper introduces the composition of brushless DC motor’s torque ripple, and itanalyzes the cause of brushless DC motor’s torque ripple from the aspects of armature reaction,current commutation, electromagnetic factors, cogging factors, machining and material factors.3. The paper introduces the principle of FIR filter and PID, and it puts forward the improvedPID control algorithm and double closed-loop control system based on the improved PID controlalgorithm. Aiming at the shortcomings of general double-loop control system, it presents themethod combination of FIR filter and the double closed-loop control system based on theimproved PID control algorithm. And it will be more effective to suppress the BLDC motor’storque ripple. 4. The paper takes STM32F103VC singlechip as the core to complete the hardware designof BLDC motor’s closed loop control system, including voltage and current sampling circuit,inverter circuit, overvoltage and overcurrent protection circuit. And it writes the program of mainmodule, control module and drive module. Then it does the experimental verification. The resultshows that comparing with general double closed-loop control system, the adoption of newcontrol method can further inhibit brushless DC motor’s torque ripple and have better motorperformance.