Research On Precise Control System Of Brushless DC Torque Motor

With the rapid development of science and technology and modern digital technology in China,automation,intelligence and modernization research in various industries and fields are developing rapidly.The commutation spark problem caused by brush structure of traditional DC motor limits its development.Brushless DC torque motor has attracted much attention because it retains the advantages of traditional DC motor and has no brush and commutation spark.It is favored in the field of automatic control and artificial intelligence robot.In recent years,the square wave control system commonly used in Brushless DC motor is limited in the field of precision instruments due to its disadvantages of large noise and torque ripple and low power utilization efficiency.Field oriented control technology can reduce the noise caused by square wave control.At the same time,the control of motor stator current is transformed into separate control of torque and magnetic flux through coordinate transformation,which greatly improves the accuracy of speed control and power utilization.Therefore,the precise control system of Brushless DC motor studied in this paper is based on the basic theory and principle research of field oriented control algorithm.The specific work is summarized as follows:(1)Firstly,this paper briefly describes the research status of Brushless DC motor and its drive system at home and abroad,and analyzes the basic structure,drive control principle and mathematical model of Brushless DC motor.This paper compares and introduces the control methods of Brushless DC motor and its advantages and disadvantages,and finally selects the field oriented control(FOC)technology as the theoretical basis to realize the separation control of torque and magnetic flux,so as to design a position sensor brushless DC motor control and drive system with speed accurate control with less noise and torque ripple and higher power utilization.(2)In view of the problems that the current mainstream drivers mostly use DSP chip design,integrated circuit,inconvenient secondary development and function expansion,this paper uses the modular design idea,divides the control system into the minimum system of the main control chip and the inductive brushless DC motor drive module,and gives the design scheme and schematic diagram of the drive control hardware system based on the in-depth analysis and understanding of the control principle of Brushless DC motor,And simplify the complexity of the system hardware circuit as much as possible.Aiming at the disadvantages of large noise and torque ripple of square wave control drive system,which is not conducive to accurate speed control,this paper compares and analyzes the advantages and disadvantages of various control algorithms,focuses on the theoretical basis of field oriented control algorithm,and compiles and realizes the core program of motor control,current sampling program and closed-loop control of field oriented control algorithm,The motor control system has less noise and torque ripple and higher power utilization.(3)For the hardware test board of the inductive brushless DC motor drive module designed in this paper,the stm32f407zgt6 development board with high-speed processing ability and the brushless DC motor with position sensor are used to build the hardware test environment,debug the programmed,set the PID closed-loop control parameters,and test the motor within the rated speed range of 3000 rpm.The test results show that the motor has more than 90% speed accuracy at each set speed,When the speed is set at 500 rpm,the system has a speed accuracy of more than98% after stability,which is in line with the expected goal of accurate speed control.Finally,the research on the application of field oriented control technology to the precise control system of Brushless DC motor with position sensor is completed.