TECHNICAL FIELD

The present invention relates to an inverter control device.

BACKGROUND ART

Conventionally, there is a known current control method for reducing vibration or noise caused by an electromagnetic excitation force deriving from a magnetic circuit structure of a motor in an alternating current motor which is driven by using an alternating current generated by PWM modulation of an inverter. PTL 1 discloses a method for attenuating a harmonic component of a radial magnetic excitation force by superimposing a magnetic sound reduction harmonic current including an n−1th order frequency in a reverse phase order and an m+1th order frequency in the same reverse phase order based on a fundamental frequency component of an alternating current distributed to the motor.

CITATION LIST

Patent Literature

PTL 1: JP 2005-304238 A

SUMMARY OF INVENTION

Technical Problem

The alternating current flowing to the motor is used to control driving of the motor, and includes a fundamental harmonic current component such as a sine wave whose frequency is converted according to a rotational speed of the motor, and a harmonic current component of a switching operation of the inverter. The frequency of the harmonic current is determined based on the frequency of the fundamental harmonic current and the frequency of a carrier wave used for PWM modulation. Hence, depending on the rotational speed of the motor, an electromagnetic excitation force produced in the motor by the fundamental harmonic current, and the electromagnetic excitation force produced in the motor by the harmonic current are superimposed, and cause significant vibration and noise. The method disclosed in PTL 1 cannot effectively improve this point.

Solution to Problem

An inverter control device according to the present invention is an inverter control device which controls an inverter which generates an alternating current from a direct current by using a plurality of switching elements, supplies the generated alternating current to a motor and drives the motor, and the alternating current includes a fundamental harmonic current corresponding to a rotational speed of the motor, and a harmonic current of a switching operation of the switching elements, and a second phase is controlled such that a first phase and the second phase are not superimposed on each other at a predetermined motor rotational speed, the first phase being a phase of an excitation force cyclically produced in the motor by the fundamental harmonic current, and the second phase being a phase of an excitation force cyclically produced in the motor by the harmonic current.

Advantageous Effects of Invention

According to the present invention, it is possible to effectively reduce vibration and noise caused by a motor.

