Patent ID: 7068923

Claim:
A speed control apparatus of a motor comprising: a motor for driving a load, a current command generation unit which generates a source current command signal having a frequency component based on a difference between a speed command signal of the motor and a speed detection signal in which a speed of the motor is detected, a notch filter unit that both blocks a notch frequency having a predetermined frequency selected among continuous frequency band widths, and generates a compensating current command signal in which the notch frequency is eliminated from the source current command signal inputted, a notch filter adjustment unit which selects the notch frequency so that the compensating current command signal, in which a sustained vibration frequency component of the source current command signal is eliminated, is generated from the notch filter unit, a subtraction unit which generates an elimination portion current command signal resulting in a difference between the source current command signal and the compensating current command signal, an addition unit which adds the compensating current command signal and the elimination portion current command signal and generates a current command signal passed through the motor, and a current limit unit which limits a maximum value of the current command signal.