| 摘要 |
PURPOSE: A duty ratio control apparatus and method is provided to achieve an improved operating reliability of the motor by compensating for the ripple voltage caused due to load driving, through the duty ratio control, and maintaining constant rotational frequency and torque. CONSTITUTION: A duty ratio control apparatus comprises a rectifying unit(21) for rectifying commercial AC power into a DC power of a predetermined level; a motor(22); a switching unit(23) for receiving the DC power from the rectifying unit, and supplying the power to the motor in pulse form corresponding to a predetermined duty ratio; a voltage sensing unit(24) for sensing the voltage level of the DC power; and a micro computer(25) for maintaining the rotational frequency and torque of the motor at a preset level by controlling the switching unit in such a manner that the duty ratio varies in accordance with the ratio of the set level of the voltage applied to the motor during no load, to the level of the voltage output from the voltage sensing unit during load driving.
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