| The research on the energy conservation,new type of high efficiency motor drive technique is becoming the hotspots in the field of motor research,by the reason of the austere situation of energy shortage and the requirement of energy saving and environmental protection.Permanent magnetic brushless DC(BLDC)motor has several advantages,for instance,simply structure,high efficiency and high reliability.Due to these advantages,as a drive motor,BLDC motor is also wide applied in the field of aerospace,electric motor,household appliances and industry.The rotor position of BLDC motor is mostly measured by rotor position sensors,whereas due to the devise applications and the complex operation environments,the application of rotor position sensors results in the limitation of volume and weight as well as the decrease of motor operation reliability.Therefore,sensorless control method for BLDC motor possess of theory research significance and engineering application value.This thesis mainly develops the BLDC motor drive system using digital signal processer.With the analysis on BLDC motor and the control system,the control system simulation models which includes system models and the sub-modules.The proposed simulation models which contain sensor and sensorless BLDC motor control system are analyzed and modeled.The speed,torque,back-EMF and phase current response curve are gained by system simulation.The sensor control system simulation indicates that the motor speed reduced1.33%when t=0.05s adding T_m=1.5N.m load;the speed restore to steady state again after0.08s.The sensorless control system simulation shows that the motor speed reduced 4.6%when t=0.07s adding T_m=1.5N.m load,;the speed restore to steady state again after 0.08s.The latter method has more speed decreasing because of the lack of the internal current control for the phase current,and decreases the ability to resist load changing which is within the allowable range.The drive control system based on DSP of BLDC motor is designed.The system consists of TMS320F2812 processor main control circuit,DC bus voltage and current detection circuit,rotor poles position back-EMF zero crossing detection circuit,PWM power drive circuit,isolation circuit and keyboard circuit.The rotor poles position signal is detected by the back-EMF zero crossing circuit,then voltage is divided and filtered.The signals are sent to the two capture units of TMS320F2812 time manager.The software of system includes main program and subprogram module in which the subprogram module includes motor stop,rotating and speed setup,three steps starting,interrupt capture speed calculation,sampling interrupt and keyboard subprogram.Finally,the current response curve,steady state current curve and the phase voltages of BLDC motor three steps starting phase are gained by the control system experiment.The experiment results shows that BLDC motor phase current is 5A,the motor speed is 600r/min after 5ms,the motor speed control switches to close loop control,motor operates steadily.The experiment shows that the hardware and software system achieve the control requirements,the system parameters meet the requirements. |
