Patent ID: 9531305
Filing Date: 2016-12-27
CPC Classification: H02P

Claim Text:
1. A motor drive apparatus that detects an electric current flowing as a DC bus current of an inverter to calculate a motor current detected value and that controls a magnitude and a phase of an applied voltage of a motor according to the motor current detected value, comprising: a carrier adjuster that decreases a carrier frequency if an average value of the DC bus current or an instantaneous value of the DC bus current is at or above a predetermined value and that increases the carrier frequency if the average value of the DC bus current or the instantaneous value of the DC bus current is at or below the predetermined value; and a pulse shift adjuster that changes an interphase waveform of a PWM pulse according to the carrier frequency; wherein the carrier adjuster switches the carrier frequency using a hysteresis provided in the predetermined value, and wherein the predetermined value is proportional to a motor output calculated from a rotational velocity of the motor and a motor torque.