Investigation of Different Winding Configurations and Displacements of a 9-Phase Permanent Magnet Synchronous Motor with Unbalanced AC Winding Structure

摘要

Nine-phase permanent magnet motors are starting to be used in various applications. One of the key benefits is redundancy. Integral-slot electrical machines require modifications and optimization of both stator and rotor to maximize machine performance. In addition, sub-harmonics in magneto-motive force distributions is an important issue in motors with fractional-slot concentrated windings. These additional sub- and super-harmonics increase iron losses which becomes an even bigger challenge in high speed/frequency applications. A PM motor with unbalanced winding and unconventional slot numbers may be a good option for many applications thanks to the inherent advantages. In this paper, different winding configurations and displacements of an unconventional nine-phase PM motor with both balanced fractional-slot winding (FSW) and unbalanced winding (UBW) structure have been investigated. The focus has been on 117-slot with 12-pole and 36-pole combinations. A prototype motor with a suitable winding configuration has been manufactured. The FEA results have been validated with the experimental results and it is shown that such unconventional slot/pole combinations can be a good option for some high power applications.