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Efficient finite element method to estimate eddy current loss due to random interlaminar contacts in electrical sheets
Author(s) -
Bikram Shah Sahas,
Rasilo Paavo,
Hakula Harri,
Arkkio Antero
Publication year - 2017
Publication title -
international journal of numerical modelling: electronic networks, devices and fields
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.249
H-Index - 30
eISSN - 1099-1204
pISSN - 0894-3370
DOI - 10.1002/jnm.2254
Subject(s) - eddy current , finite element method , polynomial chaos , random field , galerkin method , monte carlo method , materials science , computation , mathematical analysis , mechanics , mathematics , algorithm , structural engineering , physics , engineering , electrical engineering , statistics
Electrical sheets of electrical machines are laminated to reduce eddy current loss. However, a series of punching and pressing processes form random galvanic contacts at the edges of the sheets. These galvanic contacts are random in nature and cause an additional eddy current loss in the laminated cores. In this paper, a stochastic Galerkin finite element method is implemented to consider random interlaminar contacts in the magnetic vector potential formulation. The random interlaminar conductivities at the edges of the electrical sheets are approximated using a conductivity field and propagated through the finite element formulation. The spatial random variation of the conductivity causes the solution to be random, and hence, it is approximated by using a polynomial chaos expansion method. Finally, the additional eddy current losses due to the interlaminar contacts are estimated from a stochastic Galerkin method and compared with a Monte Carlo method. Accuracy and computation time of both models are discussed in the paper.