AC ROTARY ELECTRIC MACHINE MAGNETIC NOISE REDUCTION METHOD, MOTOR CONTROL DEVICE AND AC ROTARY ELECTRIC MACHINE USING THE SAME

摘要

There is provided a technique for reducing or modifying magnetic noise of an AC rotary electric machine. By using as a reference the basic frequency component of multi-phase AC current flowing to an armature of a multi-phase AC rotary electric machine, higher harmonic current for magnetic noise reduction of n-dimensional frequency is superimposed over multi-phase AC current, thereby reducing or modifying the higher harmonic component of the basic frequency component multiplied by n-1 among the radius-direction magnetic excitation force generated in the radius direction of the iron core of the AC rotary electric machine. Magnetic noise is generated by synthesized vibration of circumferential-direction vibration and radius-direction vibration of the iron core generated by the magnetomotive force of the rotor. Modification of the radius-direction vibration is especially effective for magnetic noise modification. The magnetomotive force or the rotor has frequency equal to the basic frequency multiplied by 3, 5, 7, and 13. The higher harmonic component of the radius-direction magnetic excitation force caused by the higher harmonic component has a frequency equal to the basic frequency multiplied by 6 or 12. Accordingly, it is possible to obtain preferable reduction or modification by superimposing the current of frequency equal to the basic frequency multiplied by 7 and 13 on the stator current.