The Research Of BLDCM Vector Control System

Brushless DC motor is a new type of motor which is developed with the rapid development of permanent magnetic materials and power electronics.Brushless DC motor adopts the electronic commutation instead of mechanical commutation and brush.So this kind of motor successfully avoid many problems such as the sparking on commutator,brush machinery wear,and electromagnetic jamming.Brushless DC motor not only inherits the characteristics of DC motor,but also has the advantages of simple structure and easy maintenance.This series of advantages contribute to its widely application in driving and servo system.By comparison with the square-wave control method,brushless DC motor driven by sinusoidal-wave control method outputs smaller torque ripple and lighter motor noise.In addition,brushless DC motor vector control system has good speed regulation performance.Therefore,the research on the vector control system of brushless DC motor has the practical significance.Firstly,this paper introduced the internal structure of brushless DC motor.The mathematical model and coordinate transformation matrix were also deduced in this paper.The principle of SVPWM modulation and its digital implementation method were both described in detail.The id=0 rotor field-oriented control method was used as the control strategy of BLDCM vector control system in this paper.Secondly,the brushless DC motor control system is a nonlinear,multi-parameter,strong coupling system.Aiming at the shortage of traditional PI controller,this paper designed a fuzzy PI controller for the speed control loop.Under the parameter self-tuning fuzzy PI speed regulator,the dynamic performance and the static accuracy of the control system got better.Using MATLAB/Simulink to build a brushless DC motor vector control system simulation model.The traditional PI controller and fuzzy PI controller of the control system are both simulated and analyzed.Finally,this paper designed the hardware experimental platform based on SH79F1611 microprocessor.At the same time the multi-flyback switching power supply system is also designed.The software program is designed by using the Keil uvision4 development environment.At last the experimental results are analyzed to verify the feasibility of the control system.