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

Because BLDCM(Brushless DC motor,BLDCM)has a series of advantages,such as a long using life,simple structure,no commutation spark,light weight,high power density and high efficiency of excitation losses,etc.Coupled with its control algorithm is simple and hardware implementation cost is very low,only a small workshop to complete all of the work of production and equipment.Besides,it can be comparable to traditional brush DC motors in terms of speed characteristics,in addition,it doesn’t require carbon brushes and commutators etc.devices.It has been highly concerned from the domestic and foreign researchers.BLDCM has been widely used in the aerospace,automotive electronics,process control,electronic equipment,underground mine operations,automation,home appliances and public places after extensive research and efforts.Thus,It has an extremely important significance to meet the basic requirements of BLDCM’s control and improve the reliability of the work of the control system.The design start from no position sensorless BLDCM,based on low cost,simple structure and good practicality as a starting point,focusing on sensorless BLDCM control algorithm,and the corresponding simulation and experimental verification,in parallel with the principle of verification also has a certain practicality.First of all,this paper introduces the main direction about the current domestic and foreign experts and scholars focus on BLDCM,that is BLDCM without position sensor(sensorless)control,speed control studies,research and torque ripple suppression and the integrated circuit chip research,etc;Moreover,combined with previous research found that the use in the modulation PWM_ON_PWM between two conduction mode can be effectively suppressed when the torque fluctuation commutation current,three-phase conduction mode can further improve the utilization of the motor windings,greatly reduced small torque ripple caused by current commutation.And according to the composition and operation control unit and the principle of BLDCM,describes the mathematical models and equations of motion of the motorNext,introduced the sensorless control of BLDCM for various start-up method,and proposed a secondary positioning of 3-step start-up as the startup method;Using line-to-line back-EMF method control without position sensor works with the working process of the brushless DC motor discussed study,by observing the line-to-line back-EMF signal and specific rotor location can be obtained by integrating in speed,which is line back-EMF waveform processing and filtering,takes its maximum value is divided by back-EMF coefficient.This article still built BLDCM system simulation model under simulink platform,using the model for the corresponding simulation.Lastly,making use of ds PIC33FJ16MC304,that’s MCU of Microchip,built a Sensorless BLDCM hardware control system platform after finishing theoretical analysis and Simulation verification,and details the ways in which software algorithms,specific flow chart and the corresponding hardware circuit,etc.Also gives some experimental results of the hardware platform.In this paper,the design of the system are summarized,also made in the future need to continue research and solved the problem of the application,and the proposed scheme are discussed.