Research Of Brushless DC Motor Control System

Brushless DC motor is a new type of DC motor which uses electronic commutation directly instead of the mechanical structure of commutating brush.It mainly includes three parts,the body of the motor,position detection,and a power conversion circuit.It has the characteristics of high torque current ratio,good dynamic performance,excellent speed control performance,reliability and simple structure.It has been widely used in various fields.Firstly,the background and significance of the research are briefly introduced.Research status of Brushless DC motor control system is summarized and analyzed.The working principle,structure,mechanical characteristics and mathematical model of Brushless DC motor are described.On the basis of this,the modeling and simulation analysis is carried out.Secondly,according to the control system of the brushless DC motor,the traditional PWM control method has the problem of large torque ripple,So a new control circuit based on buck is proposed to restrain the torque ripple.The influence of traditional PWM control mode of torque ripple is analyzed.And the principle of torque ripple suppression based on the new control circuit for Buck is expatiated at the same time.According to the modeling and simulation which is conducted,the new control circuit can suppress torque ripple of the brushless DC motor efficiently.At the same time,aiming at the problems existing in the traditional PID control algorithm,the improved fuzzy PID algorithm is adopted in the system,and carries on the modeling and simulation.The results of co-simulation of fuzzy PID control show: The fuzzy PID control system has advantages of quick response,fast response time,small overshoot,strong robustness.On this foundation,The design based on buck converter with fuzzy PID control is mainly contains the design of hardware and software.The design of hardware part is mainly including the power converter circuit,protection circuit and power circuit.And the design of software part is mainly including the project of fuzzy PID program.After the design of system software and hardware,the experiment is carried out,and the experimental result are analyzed.The experimental result show that the system has small torque ripple and good control performance.