Research That Based On STM8 Controlled Brushless DC Motor

Speed control of Brushless DC motor is an important part of the brushless DC motor drive system, directly affect the operating characteristics, determines a motor can play a maximum performance and a mechanical system can meet to the problem under a certain environment etc.. Brushless DC motor speed control system and design of science, is an important premise to improve productivity. The brushless DC motor is more and more used in precision regulator of automobile and home appliances, industrial, medical and other fields, through better design of Brushless DC motor speed control system, ensure the stability and the accuracy of the motor output. At the same time, to further improve the motor efficiency, this has great significance on promoting labor. So through the study of the brushless DC motor speed control system to further improve the system performance is of great significance to the liberation and development of productive forces.STM8 is a new kind of specially suitable for brushless DC motor control of the microprocessor, the PWM channel has six complementary output function with dead zone, is a kind of special for motor control and design of control chip with excellent performance. At the same time, the price is only 1/5 of the price of the ordinary motor driven processor. In summary, the brushless DC motor control system which is composed of the cost is greatly reduced, so the price is low, and have a lot of equipment condition, especially to meet the needs of the development of agricultural equipment in china.At present, the control strategy of Brushless DC motor rotor position detection method to calculate the rotor position is to use the Holzer component signal. This way, in addition to the motor transducer additional outside, but also consider the decrease caused by vibration, overheating phenomenon motor work such as accuracy, slow response of dynamic. In view of the above problems, this paper designed a brushless DC motor without speed sensor detection hardware platform, mainly by the control circuit, power circuit, signal processing components, using N+N MOS framework, the establishment of core power control circuit. First of all, the design of the three stage start, greatly reducing the brushless DC motor at low speed signal blind detection process, improves the performance of motor starting. Secondly, by detecting the free phase winding back EMF zero crossing method to detect the rotor position, the best time for obtaining more accurate and improve the stability of motor running stage. Third, adjust the way through the PI, the design speed and current double closed loop control, the dynamic response time is shortened, and improve the system of rapid response and control precision. In the MATLAB simulation software, by starting the motor running speed test, PI regulation, to calculate the dynamic regulation characteristic curve. From the simulation results, the accuracy and stability of double closed loop PI control of output speed and maximum dynamic adjustment process to shorten the time. Finally, write each module control software control system, realize the whole function of the control system.In order to realize the control system easy to operate, added on a computer program written in C++, realize the visualization of the operating system.Experimental results show that the operation reliability and control accuracy, strong STM8 brushless DC motor speed control system based on high, laid the foundation for further development of the speed control of Brushless DC motor, has the very high application value.