Inverter Apparatus

摘要

An objective of the present invention is to improve current detection accuracy and to reduce noise of carrier frequency. A motor apparatus and a motor drive apparatus calculate motor currents Iu, Iv, and Iw using a DC bus current detected value Idc of an inverter and control a magnitude and a phase of an applied voltage of a motor to drive the motor. A carrier adjuster decreases a carrier frequency Fc of the inverter if a motor output is relatively larger and that increases the carrier frequency Fc of the inverter if the motor output is relatively smaller. A pulse shift adjuster shifts an interphase waveform of a PWM pulse according to the carrier frequency Fc.

主权项

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.