Patent ID: 7170247

Claim:
A method of control of magnetic sound of an alternating current rotating machine comprising: when designating an order of a basic frequency component of a multi-phase alternating current supplied to an armature of a multi-phase alternating current rotating machine as “1”; adding, to said multi-phase alternating current, an (n−1)-th order (n is a natural number) radial direction vibration control use harmonic current having an inverse phase sequence from said basic frequency component; so as to change, among radial direction vibration comprised of vibration radially generated about an axis of a shaft of said alternating current rotating machine due to vibrating force generated by said alternating current rotating machine or input to said alternating current rotating machine from the outside, n-th order harmonic radial direction vibration components in comparison with a case of not adding said radial direction vibration control use harmonic currents; detecting said harmonic current components supplied to said armature; and performing feedback control so that deviations of amplitude and phases between detected values of said harmonic current components and computed values of said radial direction vibration control use harmonic currents to be added to said multi-phase alternating current become 0 so as to obtain target values of said harmonic radial direction vibration components.