System for driving brushless DC motor and method of driving same

Abstract

Disclosed is a brushless DC motor drive system comprising a pole-position detector for detecting respective pole positions of permanent magnets of a rotor of a brushless DC motor, a present speed computing means for computing present speed of the brushless DC motor on the basis of an output signal from the pole-position detector, a speed differential computing means for computing a difference between a speed command and the present speed, that is, a speed differential, an energization start time computing means for computing energization start time in a present instance on the basis of energization start time in a preceding instance, and the speed differential, an energization start instruction means for instructing energization start upon the elapse of the energization start time in the present instance from a phase changeover point in time, an energization completion time computing means for computing energization completion time by subtracting the energization start time in the present instance from preceding pulse time and an energization completion instruction means for instructing energization completion upon the elapse of the energization completion time from the phase changeover point in time.

Dependencies are inferred from the claim text.