A brushless DC motor speed control device and speed control method

Abstract

The invention discloses a brush-less direct current motor speed regulating method and a speed regulating device using the same. The brush-less direct current motor speed regulating method includes steps that capturing PWM waveform output from a comparison module; connecting the PWM waveform with an interrupt signal, entering interrupt immediately when a high level is detected in the PWM waveform, and enabling a current sampling module to immediately sample the current which flows through a bus resistor; sending the sampled current to a current regulator, and enabling the current regulator to output a duty ratio according to a preset current and the sampled current; using the duty ratio to control the on and off of a bridge power tube in a three-phase bridge type inverter, and controlling the effective voltage exerted to the brush-less direct current motor to regulate the rotating speed thereof. The brush-less direct current motor speed regulating method is capable of solving the problems of high cost and low reliability of the existing phase current sampling, the motor torque pulsation of the direct current bus sampling and the like.

Description

technical field

[0001] The invention belongs to the field of speed control of brushless direct current motors, in particular to a brushless direct current motor speed regulating device and speed regulating method based on direct current bus current sampling. Background technique

[0002] Brushless DC motor speed control system is a new type of speed control system. Its speed and current double closed-loop digital control system can be divided into hysteresis control and PI control according to different current control strategies. The current hysteresis control makes the motor work in the conduction mode. By comparing the given current value with the feedback current value in real time, the power tube is controlled to be turned on or off within one cycle to realize the regulation of the current. The current PI control makes the motor work in the 120° conduction mode, and the current regulator generates an appropriate duty cycle, and according to the position of the permanent...

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