Open AccessMechanical design of rotors for permanent magnet high‐speed electric motors for turbocharger applications
Author(s) -
Barrans Simon M.,
AlAni Mahir M. J.,
Carter Jeff
Publication year - 2017
Publication title -
iet electrical systems in transportation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.588
H-Index - 26
eISSN - 2042-9746
pISSN - 2042-9738
DOI - 10.1049/iet-est.2016.0081
Subject(s) - magnet , turbocharger , interference fit , rotor (electric) , mechanical engineering , centripetal force , electric motor , engineering , torque , rotation (mathematics) , electric machine , mechanics , automotive engineering , physics , computer science , turbine , stator , artificial intelligence , thermodynamics
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.