Investigation of winding topologies for permanent magnet in‐wheel motors

• Yang Tang ^[1] ; Johannes J.H. Paulides ^[1] ; Evgeny Kazmin ^[1] ; Elena A. Lomonova ^[1]
  1. [1] Eindhoven University of Technology

     Eindhoven University of Technology

     Países Bajos

     
• Localización: Compel: International journal for computation and mathematics in electrical and electronic engineering, ISSN 0332-1649, Vol. 31, Nº 1 (Special Issue: Electric machines and systems), 2012, págs. 88-107
• Idioma: inglés
• Enlaces
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• Resumen

  • Purpose – This paper aims to find the optimal winding topology for a 14‐pole permanent magnet synchronous motor (PMSM) to be used as an in‐wheel motor in automotive applications.

    Design/methodology/approach – Comparison is first performed among lap windings with different combinations of slot numbers and pole numbers. A general method for calculating the winding factors using only these numbers is proposed, thus the preferable slot numbers resulting in relatively large winding factors for this 14‐pole PMSM are found. With these slot numbers, the Joule losses of armature windings are further investigated, where the impacts of different end‐winding lengths are considered. By this means, the optimal slot number that causes the least Joule loss is obtained. On the other hand, as a competitor to lap windings, toroidal windings are also discussed. The thermal performances of these two types of windings are compared by performing a finite element analysis (FEA) on their 2‐D thermal models.

    Findings – For the 14‐pole in‐wheel PMSM discussed in this paper, the preferable slot numbers leading to relatively large winding factors are 12, 15 and 18. However, with the specified geometry constraints, the optimal choice of slot number is 15, which results in the least Joule loss and thus the highest efficiency. On the other hand, by implementing the toroidal winding topology, the armature windings of this machine can be effectively cooled and thus allow a larger electrical loading than the lap windings do.

    Research limitations/implications – This work can be continued with investigating the impacts of different combinations of slot number and pole number on harmonics and cogging torques.

    Originality/value – This paper proposes a general method for calculating the winding factor of PMSMs using only the phase number, the slot number, and the pole number. With this method, the calculation procedure can be easily programmed and repeated.