A Nine-Phase Six-Terminal Concentrated Single-Layer Winding Layout for High-Power Medium-Voltage Induction Machines

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

Research output: Contribution to journalArticle

14 Citations (Scopus)


This paper proposes a new winding layout for high-power medium-voltage nine-phase induction machines (IMs) based on a single-layer concentrated winding layout having a unity winding factor. The machine is fundamentally an asymmetrical nine-phase IM, where phases are connected in such a way as to provide six terminals that are fed from two three-phase inverters. Compared to a conventional asymmetrical six-phase IM with the same stator and copper volumes, it provides improved torque density, a higher torque/current ratio, and a simpler winding layout. Finite-element simulation is used to compare the proposed winding layout with a conventional split-phase six-phase IM to assess the claimed merits. A 1.5-hp prototype IM is also used for experimental verification. The experimental results are given under both healthy and fault conditions, where the faulty converter is completely disabled. The achievable derating factors under this case are then given and compared with those of conventional six-phase IMs.

Original languageEnglish
Article number7738399
Pages (from-to)1796-1806
Number of pages11
JournalIEEE Transactions on Industrial Electronics
Issue number3
Publication statusPublished - 1 Mar 2017



  • Asymmetrical winding
  • fault tolerant
  • induction machine (IM)
  • multiphase machines
  • nine-phase machine
  • single-layer winding
  • six-phase machine
  • stator winding configuration

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering

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