Driving And Speed Controlling System Of Permanent Magnet Brushless DC Motor Based On MCU

Nowadays permanent magnet DC motor is widely used in all aspects of production, industry and agriculture. It has high power density, high efficiency, stable performance, high torque output and so on. With the development of the technology, the application of permanent magnet DC motor will be more. In recent years, the application of permanent magnet DC motor in electric vehicle is more and more, and the sensorless control technology can not only reduce the cost and the volume, but also improve the reliability of the system. Therefore, on-line detection of motor performance and identification of important parameters are important to the research on motor control and diagnosis.One problem we are very care about is the torque ripple of BLDC motor in the process of commutation.The existence of the stator tooth groove to make a change in the air gap reluctance rotor rotates, produce the magnetic resistance torque, bring extra pulse armature effect.On the one hand, make the rotor spinning process continuously give play to the role of magnetic and demagnetization, air-gap magnetic field distortion is on the other hand, will bring the torque ripple of BLDC motor work in three phase six state, the stator magnetic field is not a continuous rotation, but by electricity from leaping step rotation Angle, thus produces the commutation torque ripple.In addition to the motor structure factors, torque ripple caused by commutation current is the main cause of torque noisel.In order to reduce the torque ripple of the phase current in the commutation process, in the process of software design, this paper use the stm8 s series specially designed for motor control chip commutation events(COM) function, to a large extent inhibiting the current noise.The full text mainly for the following research work:The first part is the development status of permanent magnet DC motor at home and abroad, and overview of the advantages and disadvantages.The second part first introduces the structure of the brushless dc motor and its control system’s overall structure, then the work principle of brushless dc motor are introduced in details.The third part focuses on the mathematical model of brushless dc motor, providing theory basis for motor control On the basis of mathematical model, this paper introduces the operation of the brushless dc motor and features, operating characteristics is refers to the motor is started, under the condition of normal work and speed, motor external relations between the measurable physical variables.The final part of the brushless DC motor control system is hardware and software design, including hardware control circuit of the control circuit,the design of the power conversion circuit, the design of the software system based on MCU. and some of the waveform test in the motor running.Test shows that the STmicroelectronics company stm8 series MCU about controling brushless DC motor can suppress the phase noise in the very great degree.