The Research Of Control System For Brushless DC Motor Using DSP Technology

Brushless DC motor is a new motor and the integration of power semiconductors and permanent magnet materials. It has the excellent speed control performance of DC motors, and many such advantages of AC motors as simple structure, easily controlled, high reliability, high efficiency, and easy maintenance. At present, in the field of industrial control, it has been widely used.This paper introduces the brushless DC motor control system design based on DSP and the design process.First, the paper analyzes the basic configuration and the fundamental principle of the brushless DC motor control system, and then a brushless DC motor mathematical model is built. The commutation process and the distribution of the PWM signal of a brushless DC motor are analyzed.Secondly, the fuzzy self-tuning PID controller is designed, according to the characteristics of the system, and the simulation model of the brushless DC motors is established, based on the fuzzy self-tuning PID controller. Simulation studies of the starting process, operation process, switch-in and switch-out of load, are carried out. Curves of Rotation speed, torque, current and back-EMF, are got in accordance with Fuzzy self-tuning PID control and PID control, respectively, and these curves are compared to make analyses. Meanwhile, curves of rotation speed, which are got with fuzzy self-tuning PID and normal PID, respectively, are analyzed. The results of simulation prove the feasibility of the control system.Finally, the software and hardware design of the system are presented. As for the part of hardware design, first an overall design of the whole system is presented, and then several main circuit designs such as DSP interface circuit, drive circuit, three-phase inverter circuit, logic control circuits and circuit protection are given. Electromagnetic interference (EMI) of the circuit, and solutions to the problem of electromagnetic interference, are also discussed. As for the part of software design, the overall design and the main flow chart are given as well. Then several problems of the software implementation such as activated module, interrupt module, position detection module, the module for phase control, the speed control module current regulator module are discussed in detail. At last, the reliability of the software is designed.