The Controller Research And Develop Of Sensorless Brushless Dc Motor

Brushless DC motor(BLDC) has been used increasingly more widely in low power traction, speed control, torque control because its compact construction and excellent controllability. The research in sensorless control of Brushless DC(SLBLDC) motor is a hot topic. This thesis focous on developing low-cost industrial used controller of sensorless brushless DC motor, to prepare for market applications.The brushless DC motor without position sensor control theory was researched in this paper firstly. The mathematical model of BLDC was briefly analised. Electronic commutation modulation mode, Three-stage start method, Back EMF Theory and low pass filter-virtual neutral point theory was in-depth studied, and the cause of position signal phase delay error was obtained, and its compensation method was researched.Then the comparative study of sensored-control theory and Sensorless-control theory was expanded, and the feasibility of Sensorless-control theory was analised. The Matlab/Simulink simulation model was established both sensored-control theory and Sensorless-control theory, and motor start-up performance, speed adjustability, torque responsiveness were comparative analised. The analysis results show that the Sensorless-control theory is good for BLDC control.A full consideration to the controller cost was taken and the controller was designed based on the expected performance. The controller development was completed, which obtain digital control system building based on MC9S08MP, hardware system building and software system building. At the end, the controller experimental platform was built, and the experiment and test was taken to verify the peromance of the controller.