The Research Of Sensorless Brushless DC Motor Drive System

Brushless DC motor (BLDCM) is a kind of electromechanical integration machinery, and its technique has been rapidly developed in recent years with the help of the development of power electronic technique and the appearance of new type of permanent magnet materials. As BLDCM has being widely used in many fields, the sensorless BLDCM attract more attention and become more active research field. In this paper, some pivotal techniques which surround sensorless brushless DC motor drive system were researched.Firstly, the model of sensorless BLDCM drive system is established based MATLAB. The different kinds of methods for detecting of rotor position, the methods of motor starting and the control algorithm were analyzed and simulated .Secondly, a sensorless BLDCM system is designed with the TMS320F2812 as microprocessor. Four kinds of rotor position detect circuits based on back-EMF; current sampling and over-current protection circuit were designed simultaneously.Finally, software of the system was programmed based the CCS2000. The software involves five main parts: rotor pre-orientation part, starting part, rotor position calculating part, speed calculating part and speed adjusting part.In conclusion, the sensorless BLDCM drive system is designed in this paper, all parts of the system were emulated and analyzed. The experimental system is implemented. The results of experiment and simulation show that the scheme of the system and circuit presented and designed in this paper is feasible.