Patent ID: 8278853

Claim:
A brushless motor control apparatus comprising: a power supply means for energizing each of a plurality of windings of a plurality of phases in a brushless motor at corresponding predetermined energization timing; a rotational position sensing means for sensing a rotational position of a rotor of the brushless motor and for outputting a rotational position measurement signal, which corresponds to the sensed rotational position of the rotor; a power supply control means for controlling the energization timing of the power supply means based on the sensed rotational position of the rotor; a correction means for obtaining an electrical angle of a period between timing, at which an induced voltage generated in the brushless motor becomes a predetermined value after turning off of the energization of the plurality of windings from the power supply means, and timing, at which an output level of the rotational position measurement signal is changed, and for correcting the sensed rotational position of the rotor, which is sensed by the rotational position sensing means, with reference to the obtained electrical angle; and a correction control means for controlling the correction means such that the correction means obtains the electrical angle of the period between the timing, at which the induced voltage becomes the predetermined value, and the timing, at which the output level of the rotational position measurement signal is changed, in a period of one complete rotation of the rotor after elapsing of one electrical cycle from the time of turning off of the energization of the plurality of windings from the power supply means.