Speed control apparatus of motor

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.