Brushless DC Motor Control System Based On STM32

Brushless DC motor has the advantages of small size, large output, excellent torque performance, wide speed control range, strongly overload capacity and high operating efficiency. At the same time, it retains the excellent performance of the DC motor about speed control, it has a simple structure and reliable operation. The control of motor is one of the most important technologies in the research of electric vehicle. How to design a good dynamic performance, strong stability, low noise, simple structure and low price of the control system has become the focal and difficult problem.This paper uses the brushless DC motor has a quasi sine wave, this type of motor has a feature that the flat form width of back EMF waveform is less than 30° or the back EMF waveform is sine wave. Firstly, the basic structure and operation principle of the brushless DC motor control system are introduced in this paper. Then, the mathematical model of the brushless DC motor is established in the three-phase static coordinate system. The Clark transform, Park transform and its inverse transform are described in this paper. Besides that, the mathematical model of the motor in the synchronous rotating coordinate system is presented.Because of the traditional sensorless control scheme has the defects of weak anti-interference ability, poor stability, high cost and large volume. This paper proposes a sensorless rotor position and speed estimation scheme based on a new sliding mode observer. Uses the hyperbolic tangent function with continuous smooth property as switching function instead of the sign function. The estimated back EMF value of the current sliding mode observer is estimated the second time, constructs a back EMF observer, further filter out the high frequency chattering signal. Finally, get the information of rotor position and speed. In order to verify the reliability of the proposed scheme, analysis the estimated back EMF based on a new sliding mode observer, and compared with the traditional program. The results show that the proposed scheme has obvious advantages, the estimated back EMF is basically consistent with the actual back EMF of the motor, and the chattering is effectively suppressed.In the actual manufacturing process, in order to suppress the cogging torque ripple, some special process is used, cause the non ideal back EMF waveform of the motor. For the quasi sine wave brushless DC motor. A vector control scheme of Brushless DC motor based on space vector pulse width modulation is proposed. Makes the id= 0. The vector control system of Brushless DC motor is designed and the simulation model of MATLAB/SIMULINK is built, the result shows that the control system of the brushless DC motor based on vector control has good dynamic and static performance, low torque ripple can be realized when the vector control is completed under different load, this system has the characteristics of fast response, smooth movement, stable and reliable.Lastly, completes the hardware and software design of Brushless DC motor control system based on STM32, sets up the experimental platform and the test and analysis are completed in the laboratory. The experimental results show that the design of sensorless vector control system has excellent control performance and certain value for practical applications.