Based On Dsp Digital Brushless Dc Motor Speed Control System

This paper describes a control system of sensorless permanent magnet brushless DC motor (BLDC) based on digital signal processor (DSP) after analyses and summarize the problem of the existing control system of sensorless permanent magnet BLDC, Based on study of the all the running method of sensorless permanent magnet BLDC, The principle and method of Back-EMF zero-crossing detection, phase judgement and phase-delay compensation are presented. The digital close-loop control technique is used to improve rotation speed characteristic wide scope of speed adjustment. This system used TMS320F2812, a DSP that made by TI, as the microprocessor. Thus it can easily output 6 PWM signals, Implement 12 bit A/D convertion, detect the position of rotor, compensate the phase-delay, switch smoothly between inner and outer synchronization and implement the speed close-loop control.The system is designed for the compressor of refrigeratory. On the view of the result of experiment, the motor started stably and quickly with small toque pulsant and had wide scope of speed adjustment. It can content all of the request of the compressor of refrigeratory. It also have the characteristic of simplicity, good adaptability and security, tc. So it would have wide scope of application.