Research On Starting Control Of Sensorless Brushless DC Motor

In recent years,brushless DC motor has been widely used in UAV,3C manufacturing,smart home and other fields because of its simple structure and convenient maintenance.Compared with brushless DC motor,brushless DC motor solves the adverse effect caused by mechanical commutation.Among them,the position sensor brushless DC motor with simple structure,reliable operation and low price occupies most of the market in the middle and low-end field of motor.However,with the development of society,the position sensor brushless DC motor also exposes some disadvantages and can not meet the needs of people’s life and work.Once there is a problem with the position sensor,the motor can not continue to work,and the position sensor increases the volume and cost of the motor,which limits the application of Brushless DC motor to a certain extent.At present,the zero crossing detection method of back EMF is the most commonly used method in the control technology of Sensorless Brushless DC motor,but this method is difficult to detect because the back EMF is too low when the motor is started.Therefore,this paper studies the control method of Sensorless Brushless DC motor.Firstly,this paper expounds the research background and significance of this subject,introduces the development and Prospect of Brushless DC motor,compares the position sensor control technology and position sensor free control technology of Brushless DC motor,comprehensively analyzes the reasons why the position sensor free control technology has become a hot spot in the research field of Brushless DC motor,and reads a large number of documents,Reference to a large number of current sensorless brushless DC motor control methods and starting methods.Secondly,this paper introduces the basic structure and working principle of Brushless DC motor,and establishes the mathematical model of Brushless DC motor.On the basis of theory,this paper proposes and studies a "new threestage" starting method for Sensorless Brushless DC motor control strategy.For this method,the positioning segment,acceleration stage and switching stage are analyzed in detail,the specific implementation method is given,and the Matlab/Simulink simulation model is built for simulation verification.Finally,the sensorless brushless DC motor control system based on stm32f103zet6 chip of Italian French semiconductor company is adopted,and the experimental platform is built at the same time.The experimental results verify that the starting control strategy designed in this paper can well control the starting and stable operation of low-power brushless DC motor.