Study on the Control Strategy of Sensorless Brushless DC Motor
|School||Changchun University of|
|Course||Control Theory and Control Engineering|
|Keywords||Brushless DC motor Back EMF 3rd harmonic method Fuzzy Control BP neural network DSP|
Brushless DC motor with the previous position sensor brushless DC motor compared with the advantages of simple structure, high efficiency , reliable operation and easy maintenance , defense, aerospace , robotics , automotive electronics and other fields a better application . However, there are some deficiencies in the speed control strategy , greatly limits its further application . Therefore, Brushless DC motor speed control strategy of great significance . In this paper, Brushless DC motor speed control system , in-depth study . 1 on the basis of the analysis on the structure and composition of the Brushless DC motor and its basic working principle , in accordance with the principles of the brushless DC motor speed control , the establishment of Brushless DC motor double-loop speed control system's overall design solutions. Design for the current loop , the current adaptive regulator . For the speed loop speed controller based on fuzzy PID controller is designed . Experimental results show that the control strategy used in this paper can effectively implement the smooth speed control of the brushless DC motor . (2) the characteristics of Brushless DC motor rotor position detection difficult , the third harmonic back EMF - based rotor position detection method , while the design of the back EMF detection circuit and a low pass filter circuit , low - pass filter circuit filter out high frequency harmonic signals , and finally to obtain the exact position of the rotor . Brushless DC motor commutation torque ripple suppression , the use of the BP neural network parameter self-learning PID commutation torque ripple suppression method . Experimental results show that the Ripple Rejection on commutation torque ripple ripple effectively suppressed . Using a digital signal processor TMS320LF2812 position sensorless the digital speed brushless DC motor control system design . Mainly to complete the PWM control , ADC sequential sampling mode , the signal capturing unit and I / O control and other aspects of the design ; They also design the current detecting circuit , a motor driving circuit , the phase voltage detecting circuit , a low pass filter circuit , and a power supply circuit or the like .