| The aim of the thesis is to develop an DSP based experiment platform of the brushless DC motor (BLDC) control system, and its value lies in that research of different control methods can be experimented on the platform, and an alternative choice with low cost and sufficient functions for engineering application is also supplied.Firstly, the mathematic model of the brushless DC motor and its control system was established, and emulation of the control system was made by using Matlab simulink tools, which supplied basis for the design and debug of the practical system.DSP TMS320LF 2407A of Texas Instrument has been employed to construct the digital controller. Control arithmetic of position loop and velocity loop has been realize in the digital controller, whose output is PWM signal with adjustable occupy rate which is put in the driving circuit to realize motor's position and velocity control.The driving circuit is mainly consist of brushless DC motor control chip Si9979Cs of Vishay Siliconix company and 6 MOSFETs form the 3 bridges. Si9979Cs can directly transform the motor rotor magnetic poles'displacements detected by HALL groupware into the on-off signals of the 6 MOSFETs to realize electronical switch. PWM signals output by the digital controller were amplified to realize motor's torque and velocity control. To prevent the control disturbance in the process of MOSFETs on-offs, Optoisolator circuit has been used to realize the isolation of the driving circuit and the control circuit.C was used to write all of the control program, and the program has been modularized to have openness for further expansion of the future research.Finally, signal waves of every part of the system were tested and adjustment of the position loop and velocity loop control parameters were finished.Experiment results showed that the developed system can meet expected design requirements to be studied as research platform for further research and put into practical project after some improvement. |
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