The Study And Realization Of The Sensorless Brushless DC Motor Control System

As the features of simple structure,high efficiency and easily controlled,brushless DC motor(BLDCM)is widely used in aerospace,household appliances and electric drive and other aspects.It not only has advantages of traditional DC motor,such as easily controlled,high speed performance and high efficiency,and so on,but also has advantages of traditional AC motor,such as brushless and conveniently repaired,and so on.It becomes a hot topic in field of model motor.However,rotor position sensor of BLDCM has heavily increased motor's volume and cost,and greatly limits the applications of BLDCM.Therefore,sensorless control,which has wide significance,has becomes one of the hot control methods of BLDCM.This paper introduces the development of brushless DC motor and a systematic analysis of its working principle,also discussed the future development of brushless DC motor direction and trends,and highlights the main principle of position sensor and control technology rotor position detection method.On the basis of analysis of brushless DC motor structure and basic working principle of the mathematical model and made according to the application requirements and the technical maturity of the back EMF zero crossing detection method as a brushless DC motor without position sensor rotor position control system detection method.On the basis of theoretical analysis and mathematical model established on Matlab / Simulink simulation model,simulation model of EMF position detection method proposed for research and validation,and ultimately determine its reliability.Finally,according to the design requirements and technical specifications designed brushless DC motor without position sensor control system hardware circuit boards,and use it to verify the feasibility of the control system.The main control board hardware using Microchip 's dedicated control chip dsPIC33FJ16MC304 motor control chip,the counter electromotive force detecting circuit,current,voltage protection circuit and other control circuits by the main control chip and the peripheral circuit and software components.And describes the major software algorithms and flow charts,and gives some experimental results.The experimental results show that the design of this article is with good system performance.Finally,this article summarized the system designed on this article,required the problems which needing further study and resolve,and prospected on the proposals in this article.