Analytical expressions that include arbitrarily directed fields on all laminate boundaries can be used for calculation of the fields inside the laminate when the boundary fields are known from, e.g., measurements. A linear laminate block could be used in non-destructive testing for comparisons between different laminates. This article contains derivation of Fourier series of harmonically time varying, traveling electromagnetic fields in homogeneous, anisotropic approximations of laminates. The component of the magnetic field strength in the stacking direction is used as a source term in twodimensional Poisson equations for the magnetic field strength in other directions. This approximation is here used in three dimensions under the precondition that the conductivity is much smaller in the laminate stacking direction than in the other directions. Sine interpolation and different choices of types of boundary conditions are discussed. Different alternative subdivisions of the Poisson boundary value problems are treated. Shorted derivations of simple analytical expressions are given for both traveling and standing waves in two dimensions. Results from Fourier series in the three-dimensional case are compared with results from finite element calculations.
2. Reece, A. B. J. and T. W. Preston, Finite Element Methods in Electrical Power Engineering, Oxford University Press, 2000.
3. Lin, D., P. Zhou, Z. Badics, W. Fu, Q. Chen, and Z. Cendes, "A new nonlinear anisotropic model for soft magnetic materials," IEEE Transactions on Magnetics, Vol. 42, No. 4, 963-966, Apr. 2006.
doi:10.1109/TMAG.2006.871380
4. Bermudez, A., D. Gomez, and P. Salgado, "Eddy-current losses in laminated cores and the computation of an equivalent conductivity," IEEE Transactions on Magnetics, Vol. 44, No. 12, 4730-4738, Dec. 2008.
doi:10.1109/TMAG.2008.2005118
5. Lin, R., A. Haavisto, and A. Arkkio, "Axial flux and eddy-current loss in active region of a large-sized squirrel-cage induction motor," IEEE Transactions on Magnetics, Vol. 46, No. 11, 3933-3938, Nov. 2010.
doi:10.1109/TMAG.2010.2064782
6. Marcusson, B. and U. Lundin, "Axial magnetic fields, axial force, and losses in the stator core and clamping structure of a synchronous generator with axially displaced stator," Electric Power Components and Systems, Vol. 45, No. 4, 410-419, 2017 [Online], Available: http://dx.doi.org/10.1080/15325008.2016.1266062.
doi:10.1080/15325008.2016.1266062
7. Marcusson, B. and U. Lundin, "Harmonically time varying, traveling electromagnetic fields along a plate and a laminate with a rectangular cross section, isotropic materials and infinite length," Progress In Electromagnetics Research B, Vol. 77, 117-136, 2017.
doi:10.2528/PIERB17061909
8. Brander, O., "Partiella Differentialekvationer-en kurs i fysikens matematiska metoder, del B,", Studentlitteratur, 1973.
9. Griffiths, D. J., Introduction to Electrodynamics, 3rd Ed., Pearson, Addison Wesley, 1999.
10., "Matweb website,", http://matweb.com/search/AdvancedSearch.aspx, accessed Feb. 16, 2017.
11., "Trigonometric interpolation,", [Online], Available: http://www.math.vt.edu/people/embree/math5466/lecture7.pdf.
12., "Trigonometric interpolation and the fft,", [Online], Available: http://math.gmu.edu/ tsauer/na/ch10.pdf.