The Research Of Electronic Commutation Brushless DC Motor Control And Protection System

The brushless DC Motor(BLDCM)is a new style permanent magnet motor,which uses an electronic commutation circuit instead of a conventional mechanical commutation device.Compared with the traditional BLDCM with carbon,its advantages include high efficiency,large torque,small size and so on.So the BLDCM control system is widely used in the transmission field that must have high-speed performance and higher control precision,such as aerospace,household appliances,CNC machine tools and so on.This thesis will firstly introduce the basic structure of BLDCM and its working principle,studying preliminarily the mechanical properties,regulatory characteristics and mathematical model.In order to let the brushless DC motor has a high reliability and good robustness in the work,it takes two-phase conduction mode and three-phase inverter structure,incremental PID control algorithm,PWM modulation technology,completing the basic research of the control and protection system.Also,combining functional module with S-functions to construct current and speed dual close-loop control system of simulation model in MATLAB/Simulink,experiments were carried out under the different operating conditions,studied the system of the dynamic and steady-state performance,as well as output response.The experimentation results show the control algorithm can meet the requirements of BLDCM under the multiple operating conditions.Then,according to the BLDCM system index requirements: accuracy control,stability of operational principles and rapid dynamic response and so on.Taking advantage of high-speed computing capability of TMS320F28035 chips,designed the system hardware test platform.The structure of drive taking a new integrated DRV8301 drive circuit,the bridge inverter circuit,rotor position detection circuit,protection circuit of overvoltage and overcurrent,and so on.Under the environment of CCS5.5 simulation,programming the software control program to achieve the overall function of hardware system.Meanwhile,providing the main program flow chart and detailed functional description.Finally,120 W low-power motor as the controlled object in the thesis,through completing the BLDCM control and protection system of software and hardware joint debug,characteristic analysis carried out under the different operating conditions.The experimental results show that the hall sensor can accurately detect the motor rotor position,the inverter can achieve high efficiency commutation.During phase change,the pulsation torque is small and waveform smoothness is better.Verifying that the system can achieve high control accuracy and good output performance.