| 摘要 |
<P>PROBLEM TO BE SOLVED: To preliminarily detect the rotation speed of a brushless DC motor already rotated for some reason without use of an accurate motor current detecting means and a position detector. <P>SOLUTION: A motor driving controller drives and controls the three-phase brushless DC motor connected to the output of a three-phase bridge constitution of switching elements from a DC power supply. The controller is provided with a means for detecting a current flowing between the DC power supply and the bridge circuit, a means for generating a pseudo three-phase AC voltage from the three-phase bridge circuit before the motor is driven and maintaining a peak value of information obtained from the current detecting means, a filter means for passing through a frequency lower than the frequency of the pseudo three-phase AC voltage in a maintained result from the maintaining means, and a means for checking the frequency of an output result from the filter means with a rotation frequency of the motor as a frequency sum or a frequency difference of the obtained frequency information and the frequency of the pseudo three-phase AC voltage to activate the motor. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
