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Generalized slip transformations and air-gap harmonics in field models of electrical machines

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Original languageEnglish
Article number8107708
JournalIEEE Transactions on Magnetics
Issue number9
Publication statusPublished - 1 Sep 2016
Publication typeA1 Journal article-refereed


In numerical field analysis of steady states of electrical machines, frequency-domain methods are often much faster than time-domain methods. Frequency-domain techniques often involve simplifications that impact their accuracy on harmonic effects due to slotting, saturation, and time harmonics in winding currents. The nature of these inaccuracies and their relationship to air-gap field harmonics is not that well covered in the literature. Correct prediction of air-gap field harmonics can be based on careful use of spectral Dirichlet-to-Neumann mappings and generalized slip transformations. We show how nonzero harmonics in the air-gap fields can be reliably predicted and explain the nature of inaccuracies in certain common steady-state solution techniques.


  • Boundary value problems, Fourier series, harmonics, rotating machines

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