Investigation of Asymmetric and Unbalanced Winding Structures for 3-Phase Permanent Magnet Synchronous Machines

Demir Y., El-Refaie A., AYDIN M.

45th Annual Conference of the IEEE Industrial Electronics Society (IECON), Lisbon, Portugal, 14 - 17 October 2019, pp.1132-1137 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume:
  • Doi Number: 10.1109/iecon.2019.8927327
  • City: Lisbon
  • Country: Portugal
  • Page Numbers: pp.1132-1137
  • Keywords: unbalanced winding, permanent magnet machine, fractional-slot motor, unbalanced winding PM motor, PM MOTORS, DESIGN
  • Kocaeli University Affiliated: Yes


In this study, an investigation of winding structures is performed for 3-phase unbalanced and asymmetric winding permanent magnet (PM) machines including different slot-pole combinations. There are two different cases for unbalanced winding (UBW) structure: 1) Stator slot number of the machine is divisible by three, 2) Stator slot number of the machine is not divisible by three. Only the first case is examined in this paper. The unbalanced winding layouts are created for minimum unbalance and maximum winding factor. Total magneto motive force (MMF) distributions for nine different slot-pole combinations and their harmonic contents are presented. Variation of the amount of unbalance for different slot-pole combinations is also provided in the paper. A prototype motor with 39-slots and 12-poles has been manufactured for experimental verification. A comparison between the finite element analysis (FEA) results and experimental results is presented for the prototype motor for both no-load and on-load conditions.