Permanent Magnet Brushless DC Motor Design And Drive Control Research

Brushless DC motor(BLDCM), a novel motor without mechanical brush is widely used because of its simple structure, good reliability, high efficiency, etc. In recent years, because of the appearance of sensorless brushless DC motor, the motor structure becomes simpler, further enhances the reliability of the motor, and expands the range of applications. The main research content of this paper is the design of the permanent magnet brushless dc motor and its drive system including the rotor position detection, initial start-up method and control method.Firstly, this paper briefly introduces the background and application of BLDCM, analyzes the research status at home and abroad, and makes the work arrangement. According to the analysis of the BLDC motor's component part and the operating principle, the mathematical model of the motor is established.Then two sets of preliminary design of the 12 V, 22 W BLDC motor are presented. Using the electromagnetic FEM software, the performance and curves of the motor are obtained to prove the correction of the design. At the same time, the better design is chosen.Secondly, the paper focuses on the rotor position detection, and finally uses the most mature Back-EMF zero-crossing detection technology after comparing different rotor position detection technology. Based on the Back-EMF method, the zero-crossing detecting circuit are introduced and analyzed in detail,then compensation method in software are proposed. It needs another starting method when the motor is starting,because running is not stable now.Finally, this paper sets up the corresponding hardware experiment platform based on STM8S103, the whole control system software is under the use of the IAR software platform. The test results which is from conducting a series of testing performance of different motor parameters are analyzed and summarized. And then, test of the controller is on basis of the specified control method and the debugging results are analyzed. In the end, on the whole summary work, this paper analyzes the problems encountered in debugging, and makes prospect for the next step of work.