BRUSHLESS MOTOR DRIVE DEVICE AND DRIVE METHOD

摘要

The present invention pertains to a brushless motor drive device and drive method in which the phase at which a pulse voltage is applied is switched according to position information based on pulse-induced voltage induced in a de-energized phase. In the drive device and drive method according to the present invention, when it becomes impossible to reduce a motor rotation speed to a target rotation speed using a square wave drive method, a skipping control is switched to in which brushless motor position information detection is skipped for some pulses instead of being performed every time for each pulse. In the skipping control, in a period in which position information detection will not be performed, a duty ratio is set that is below the minimum value (Dmin) necessary for position information detection. Additionally, if the motor rotation speed cannot be reduced to the target rotation speed even through skipping control, the timing of the switching of the phase at which the pulse voltage is applied is advanced.