Control method and control system of fan

摘要

A control method of a fan comprises steps of: detecting a rotational speed of a blade and a rotor position of the blade; generating a control signal according to the rotational speed and a predetermined rotational speed; obtaining a Back-EMF waveform according to the control signal, the rotational speed, the rotor position and a waveform; adjusting the phase of the Back-EMF waveform; and outputting a switch control signal.

主权项

1. A control method of a fan, comprising steps of:
detecting a rotational speed of a blade and a rotor position of the blade; generating a control signal according to the rotational speed and a predetermined rotational speed; obtaining a Back-EMF waveform according to the control signal, the rotational speed, the rotor position and a waveform, wherein the waveform is derived from an induced electromotive force of a coil of a motor of the fan is measured by an oscilloscope and digitalized to be a prototype for the Back-EMF waveform; adjusting the phase of the Back-EMF waveform; and outputting a switch control signal where the switch control signal is used to control a switch for the blade, wherein the motor generates a first sine-like wave signal, which is a Back-EMF of the motor, and the control method further comprises steps of:
a voltage-transforming unit receiving and adjusting the first sine-like wave signal to output a second sine-like wave signal;an analog-to-digital converting unit generating a plurality of sampling signals according to the second sine-like wave signal;the analog-to-digital converting unit storing the sampling signals in a data table; andreading out the waveform according to the sampling signals from the data table.