Research On Brushless DC Motor Control System

As an electromechanical energy conversion device,the motor is widely used.In this paper,brushless dc motor is selected as the research object.Brushless dc motor has the advantages of small size,low noise,small electromagnetic interference,wide range of speed regulation,etc,and has a wide range of applications in various fields,such as: robotics,medical,aerospace,and household appliances.Therefore,it is of great significance to study the brushless dc motor control system and improve the stability of the system.This paper first introduces the basic principle and mathematical model of brushless dc motor,describes several working characteristics of brushless dc motor,and analyzes the classical double closed loop control of brushless dc motor.Secondly,since the brushless dc motor is susceptible to external disturbances and internal parameter changes,the traditional PID control cannot adapt to the changes of system parameters.Therefore,the strategy of using sliding mode variable structure control algorithm to control the brushless dc motor is proposed.In this paper,on the basis of double closed-loop control strategy,through the derivation of the motion equation of brushless dc motor,the sliding mode variable structure control algorithm is used to design a scheme to improve the speed loop control,and the algorithm is verified by Maltlab/Simulink simulation software.Simulation results show that,compared with the traditional PID control,the variable structure has stronger robustness to the brushless dc motor control system with time variation.Finally,the drive circuit of brushless dc motor with STM32 as control chip is designed,including main circuit,optocoupler isolation protection circuit,hall position detection circuit,current sampling circuit,bus voltage and temperature sampling circuit,and the experimental platform of the system is built.Through the debugging of software and hardware,the feasibility of the designed drive circuit is proved,and the relevant experimental results are illustrated.