The Research And Design Of Control System Of Sensorless Brushless DC Motor Based On DSP

Along with the increasing requirements of accuracy and robustness of brushless DC motors'speed adjustment system, intelligent control techniques win more and more intresting. In this thesis a DSP based intelligent control system is proposed for sensorless brushless DC motor. By introducing the line voltage difference rotor position detection algorithm and single-neural adaptive PID control algorithm into electric current loop and speed loop control, good performance is achieved.Firstly, the research background of the design of brushless DC motors'control system is introduced in brief, and the research content of the subject is presented also. The working principle and mathematical model of BLDCM is analyzed in detail. And then the line voltage difference rotor position detection method is deduced, also the intelligent control algorithm of single-neural adaptive PID is described thoroughly.Secondly, on basis of the electric schematic of BLDCM, and with the using of SIMULINK library module in Matlab, the simulation models of converter circuit module, motor module, rotor-site detector module, logic decoder and generator module, PWM generator module, electric current loop and speed loop are set up.which constitutes BLDCM's overall simulation model. And then the line voltage difference detection module is also established to observe the line voltage difference waveform and verify the theoretical results.Thirdly, this article has highlighted the design methods of hardware circuit, which is consisted of power driver circuit, DSP control circuit, line voltage difference detection circuit, isolate circuit, power supply circuit and speed control circuit. The design ideas and methods of software system are also presented, which is consisted of the initialization subroutine,starting subroutine,updating comparison value or commutation subroutine, AD interrupt service routine, and speed loop and electric current loop adjustment control program.Finally, the experimental results and waveforms are given and analyzed in detail.