An improved performance direct-drive permanent magnet wind generator using a novel single-layer winding layout

Ayman Abdel-Khalik, Shehab Ahmed, Ahmed M. Massoud, Ahmed A. Elserougi

Research output: Contribution to journalArticle

26 Citations (Scopus)


Direct-drive permanent magnet (PM) generators have become a strong contender in medium and large rating wind energy conversion systems as they not only provide higher efficiency and annual energy production, but also reduce the operational and maintenance cost. PM generators with nonoverlap single-layer windings provide a cost-effective design variation that eases manufacturing, reduces torque ripples, enhances voltage quality, and provides fault tolerant capability. The performance of such machines depends mainly on the proper selection of the pole and slot numbers, which results in negligible coupling between phases. The preferred slots per phase per pole (SPP) ratios eliminate the effect of low order harmonics in the stator magnetomotive force (MMF), and thereby the vibration and stray loss are reduced. This paper proposes a new three-phase winding configuration based on the 20 slots/18 poles five-phase PM machine. The proposed design is compared with the well-known 24 slots/20 poles three-phase PM machine. The comparison shows that the proposed generator offers reduced torque ripples, improved output voltage quality, and less core loss for the same machine volume.

Original languageEnglish
Article number6497625
Pages (from-to)5124-5134
Number of pages11
JournalIEEE Transactions on Magnetics
Issue number9
Publication statusPublished - 2013



  • Cogging torque
  • Permanent magnet (PM) machines
  • Single layer winding
  • Voltage quality
  • Wind energy generation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

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