Patent ID: 7872435
Filing Date: 2011-01-18
Classification: H02P

Abstract:
1. A motor control apparatus, comprising: an inverter for successively commutating the current to a motor using a pulse width modulation signal; a pulse width modulation signal generating device for generating the pulse width modulation signal using a carrier signal of variable frequency and phase; a rotational state quantity sensor for detecting a rotational state quantity relating to a rotational period of the motor; a phase difference detecting device for detecting the phase difference between the carrier signal and the rotational period based on the rotational state quantity; a frequency setting device for setting a frequency of the carrier signal to a value in accordance with a multiplier for one period in terms of electrical angle of the rotational period of the motor, based on the multiplier which changes in accordance with revolutions of the motor, when the rotational frequency of the motor is equal to or greater than a specified frequency and the phase difference is equal to or less than a specified value; and a synchronizing device for synchronizing a control period of the carrier signal to the rotational period of the motor.