Research On BLDCM System And Flux-weakening Control Based On DSP

The brushless DC motor(BLDCM) not only has the merit of the AC induction motor for simple structure, reliable operation and easy upholding but also has the merit of the DC Motor for high performance, no lose and easy control. It has been widely used in the various fields of the national economy. So, it is very significant to research a control system with high performance based on the DSP.Summarizing the development and application of BLDCM control system, this paper gives a deep research on basic structure, working principles, control performance and mathematical model of BLDCM in detail. The dynamic simulation model of control system is built and simulated in MATLAB/Simulink Environment. The simulation model of speed and current dual closed loop proved that the control system works well as it was expected,,On the basis of the theory design, the hardware and software design of the digital control system are dissertated in detail. The hardware of the controller is built by using the ADMC401 as the microprocessor. After a dissertation on the whole design of the hardware part, several chief circuits are expounded. For the software part, the procedure flow charts are made with the modularization design concept.Due to the fact that flux-weakening control of permanent magnet brushless DC motor is difficult to achieve brought by the difficulty of magnet adjustment, the effect caused by the armature reaction of the stator winding to the magnetic field of the permanent magnet rotor is analyzed in detail. Through demagnetizing action of armature reaction, a reversed magnetic field is added to obtain a weakened field to achieve an equivalent flux-weakening control method. A new control strategy over base-speed presented in this paper is analyzed. And experiment based on the designed control system is conducted.Finally, the experimental research is implemented on this BLDCM control system and the waves are given. Experimental results show that the design of the control system is reasonable and reliable. In conclusion, the BLCDM control system has high performance and high dependability. It has practicality in the field of engineering.