Mechanical Design of Rotors for Permanent Magnet High-Speed Electric Motors for Turbocharger Applications

Simon Barrans, Mahir Al-ani, Jeff Carter

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Realisation of electrically boosted turbochargers requires electric motors capable of operating at very high speeds. These motors often use a permanent magnet rotor with the magnets retained within an interference fit external sleeve. Whilst it is possible to model such systems numerically, these models are an inefficient tool for design optimisation. Current analytical models of rotors typically consider the stresses induced by the shrink fit of the sleeve separately from the stresses generated by centripetal forces due to rotation. However, such an approach ignores the frictional interaction between the components in the axial direction. This paper presents an analytical model that simultaneously accounts for interaction between the magnet and outer sleeve in both the radial and axial directions at designed interference and with the assembly subjected to centripetal and thermal loads. Numerical models presented show that with only moderate coefficients of friction and rotor lengths; axial load transfer between magnet and sleeve takes place over a short distance at the ends of the assembly. This paper then demonstrates how the analytical model aids definition of a feasible set of rotor designs and selection of an optimum design.
Original languageEnglish
Pages (from-to)278-286
JournalIET Electrical Systems in Transportation
Volume7
Issue number4
Early online date24 May 2017
DOIs
Publication statusPublished - Dec 2017

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Electric motors
Permanent magnets
Rotors
Magnets
Analytical models
Axial loads
Thermal load
Numerical models
Friction

Cite this

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title = "Mechanical Design of Rotors for Permanent Magnet High-Speed Electric Motors for Turbocharger Applications",
abstract = "Realisation of electrically boosted turbochargers requires electric motors capable of operating at very high speeds. These motors often use a permanent magnet rotor with the magnets retained within an interference fit external sleeve. Whilst it is possible to model such systems numerically, these models are an inefficient tool for design optimisation. Current analytical models of rotors typically consider the stresses induced by the shrink fit of the sleeve separately from the stresses generated by centripetal forces due to rotation. However, such an approach ignores the frictional interaction between the components in the axial direction. This paper presents an analytical model that simultaneously accounts for interaction between the magnet and outer sleeve in both the radial and axial directions at designed interference and with the assembly subjected to centripetal and thermal loads. Numerical models presented show that with only moderate coefficients of friction and rotor lengths; axial load transfer between magnet and sleeve takes place over a short distance at the ends of the assembly. This paper then demonstrates how the analytical model aids definition of a feasible set of rotor designs and selection of an optimum design.",
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Mechanical Design of Rotors for Permanent Magnet High-Speed Electric Motors for Turbocharger Applications. / Barrans, Simon; Al-ani, Mahir; Carter, Jeff.

In: IET Electrical Systems in Transportation, Vol. 7, No. 4, 12.2017, p. 278-286.

Research output: Contribution to journalArticle

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T1 - Mechanical Design of Rotors for Permanent Magnet High-Speed Electric Motors for Turbocharger Applications

AU - Barrans, Simon

AU - Al-ani, Mahir

AU - Carter, Jeff

PY - 2017/12

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N2 - Realisation of electrically boosted turbochargers requires electric motors capable of operating at very high speeds. These motors often use a permanent magnet rotor with the magnets retained within an interference fit external sleeve. Whilst it is possible to model such systems numerically, these models are an inefficient tool for design optimisation. Current analytical models of rotors typically consider the stresses induced by the shrink fit of the sleeve separately from the stresses generated by centripetal forces due to rotation. However, such an approach ignores the frictional interaction between the components in the axial direction. This paper presents an analytical model that simultaneously accounts for interaction between the magnet and outer sleeve in both the radial and axial directions at designed interference and with the assembly subjected to centripetal and thermal loads. Numerical models presented show that with only moderate coefficients of friction and rotor lengths; axial load transfer between magnet and sleeve takes place over a short distance at the ends of the assembly. This paper then demonstrates how the analytical model aids definition of a feasible set of rotor designs and selection of an optimum design.

AB - Realisation of electrically boosted turbochargers requires electric motors capable of operating at very high speeds. These motors often use a permanent magnet rotor with the magnets retained within an interference fit external sleeve. Whilst it is possible to model such systems numerically, these models are an inefficient tool for design optimisation. Current analytical models of rotors typically consider the stresses induced by the shrink fit of the sleeve separately from the stresses generated by centripetal forces due to rotation. However, such an approach ignores the frictional interaction between the components in the axial direction. This paper presents an analytical model that simultaneously accounts for interaction between the magnet and outer sleeve in both the radial and axial directions at designed interference and with the assembly subjected to centripetal and thermal loads. Numerical models presented show that with only moderate coefficients of friction and rotor lengths; axial load transfer between magnet and sleeve takes place over a short distance at the ends of the assembly. This paper then demonstrates how the analytical model aids definition of a feasible set of rotor designs and selection of an optimum design.

KW - Design engineering

KW - Compressors

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