The Research Of Sensorless Control Method Of The Bldc Motors

The BLDC Motor with its superior performance, has been applied in each realm broadly. For the control method of brushless DC Motor, it is very important to check that passing turns sub-position. But the usage position sensor of brushless DC motor spread the corrupt practice increasingly. For the sake of better in the industrial realm application, the sensorless brushless DC Motor is put forward, and carried on an extensive and thorough research. This dissertation will carry on a related research of the problem which current research has meet.First, it will analyze structure and the work principle of brushless DC motor ,then study the essence structure and the work principle of sensorless brushless DC motor, and based on the model of dynamic state mathematics subsequently, according to Matlab/simulink, set up the independent function model. By carrying on the organic integration of the model, it will simulate brushless DC motor really. This approaches actual system more, speeding a design and adjusting to debugging, also for the follow-up research laying foundation. Second, as currently study of hot point ,back—EMF, it will discuss the principle of the sub- position examination in detail. Based on the principle, it put forward a kind of improving back-EMF method of crossing-zero checking turns position .But this didn't resolve to the root problem that the speed scope is very narrow and it need an in expiation of speed error and so on .Thus it put forward a new improvement method at next chapter. At last, it deduced a new improvement method from the theories, and make use of a new physical concept—the independent of speed function for accuracy checking up the turns sub-position and the communication point so as to control sensorless brushless DC motor with the breadth regulating-speed scope from zero to high speed. Based on the function, it will research the new control method. Then based on Matlab/simulink, it will simulate brushless DC motor and study the state characteristic and analyse and discuss the result. Finally, it will set up the experimentation flat to prove the possibility and the rationality of its theories.