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

Brushless DC motor is one kind of motor that not only with a number ofadvantages of AC motor, such as simple structure, reliable operation, easymaintenance, but also retained the wide and smooth high speed performance oftraditional DC motor, and its high efficiency and many other features, and overcome aseries of shortcomings of the traditional DC motor caused by mechanical reversing.Therefore, brushless DC motor has a very broad application prospects in the industrialareas. The research of control system that powered by a brushless DC motor core iswith great significance.In order to build a low-cost practical experiments targeted platform, with thebreakthrough point of sensorless control, theoretical and experimental research ofsensorless brushless DC motor is studied on this subject.On the basis of reading a large number of documents, this article first describesthe current three major hot spots of brushless DC motor: sensorless control ofbrushless DC motor, speed control of brushless DC motor and torque ripplesuppression of brushless DC motor. After that, according to the basic structure andworking principle of brushless DC motor, the mathematical model of brushless DCmotor is described, and its dynamic model is derived. Then the key technology ofsensorless control is discussed, and a direct torque control scheme is proposed, whichthe inverter circuit commutation logic is acquired by the measurement and calculationof current, voltage, and other measurable physical quantity of motor. And simulationmodel of the direct torque control of brushless DC motor system is built on theMatlab/Simulink platform. The simulation experiment of no-load starting, startingwith load and load disturbance is carried out by using this model. On the basis oftheoretical analysis, the hardware platform of the control system for sensorlessbrushless DC motor is built by using Microchip’s16-bit motor control chipDSPIC30F3010. Then this article introduced the major software algorithms andflowcharts, and given some experimental results. The experimental results show thatthe design of this article is with good system performance. Finally, this articlesummarized the system designed on this article, required the problems which needingfurther study and resolve, and prospected on the proposals in this article.