The Research Of Sensorless Blushless DC Motor Control Based On PLD

As a newly designed product, Brushless DC motor (BLDCM) has gained a great development in recent years. BLDCM which possesses the merits of both AC and DC motor has been widely used. However, traditional BLDCM drive must relies on the position sensor to obtain the rotor location, which brings on some inevitable drawbacks, such as complex installation, low reliability and so on. Thus methods of sensorless BLDCM control are receiving increased concern by the research staffs at home and abroad recently.The method of back electromotive force(EMF) crossing zero, as the basic control measure, is presented for the sensorless control system of BLDCM. There exist the start problem and commutation deviation in this method, the paper proposes three-stage rising frequency and rising voltage software starting and software phase compensation respectively.Based on the dynamic mathematical equation and equivalent circuit of the BLDCM, the PWM closed-loop speed control method is selected and the paper finally establishes the MATLAB/SIMULINK model of BLDCM body and control system. The simulation results show that the model of BLDCM and its control system has good dynamic and static properties. This provides a theoretical foundation for the design and manufacture of the BLDCM and the control system debugging.This paper presents a high-performance PIC microcontroller with Programmable Logic Device (PLD) as the core of the control system of the sensorless BLDCM, with the help of PLD digital logic function to complete the motor commutation logic operations in order to share the PIC microcontroller logic operation pressure. This strategy makes the PIC and PLD function all obtained greatest degree display. On this basis, the design of system software and hardware is completed.Experimental results show that the designed control program can realize motor right commutation and stable operation, and achieve the desired results.