Reduction of 12th Radial Force in Double Inverter Fed Permanent-Magnet Motors

Abstract

This paper proposes a control method to suppress vibrations in a double-star winding permanent-magnet synchronous motor (PMSM). The double-star winding PMSM, which has two three-phase windings, can be used to improve reliability and torque ripple cancelation. A 6th order torque ripple is canceled by providing a phase angle of 30° to the mechanical angle between the two windings. A temporal 12th order radial force vibration causes a breathing mode vibration, which uniformly deforms the stator core in a double-star winding PMSM. The breathing mode vibration is suppressed by superimposing the 6th order current. In this study, the temporal 12th order and spatial 0th order radial force, which causes the breathing mode vibration, was reduced by 86.3% by superimposing the 6th harmonic current via simulations. The radial acceleration was experimentally measured on the surface of a motor. The temporal 12th order radial acceleration on the motor surface exhibited a reduction of 66.5%.