An improved fault-tolerant five-phase induction machine using a combined star/pentagon single layer stator winding connection

Ayman S Abdel-Khalik, Mohamed A. Elgenedy, Shehab Ahmed, Ahmed M Massoud

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)


One of the main merits offered by multiphase machines is their high fault-tolerant capability. Literature has demonstrated that the performance of multiphase induction machines under fault conditions is affected by the employed stator winding connection. In open-loop controlled five-phase machines, the star connection is favorable under healthy conditions while the pentagon connection is favorable and yields a lower derating factor under the open phase condition. In this paper, a new combined star/pentagon single layer winding layout that combines the advantages of both star and pentagon connections is proposed for a five-phase induction machine. Although the proposed winding is intrinsically an asymmetrical ten-phase machine, the proposed connection allows for only five-phase terminals. Moreover, the proposed winding not only yields better flux distribution compared to a conventional single layer winding, but also provides a complete cancellation of the third-order harmonic flux component caused by the induced third sequence currents due to the saturation effect and/or under unbalanced operation. Hence, the machine losses are decreased, which improves the overall machine efficiency. For the healthy case, the machine is similar to a conventional star connected five-phase machine. However, with one phase open, the proposed connection results in a lower derating factor compared to conventional connections for both open-loop and optimal current control techniques. A 1-kW prototype machine is used for experimental verification.
Original languageEnglish
Pages (from-to)618-628
Number of pages11
JournalIEEE Transactions on Industrial Electronics
Issue number1
Early online date27 Apr 2015
Publication statusPublished - Jan 2016


  • derating factors
  • fault tolerant
  • induction machine
  • multiphase machine
  • optimal current control
  • pentagon connection
  • star connection
  • star/pentagon connection
  • stator winding configuration


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