Affiliations: Institute of Electrodynamics, Microwave and Circuit Engineering (EMCE), University of Technology, Vienna, Austria
Correspondence:
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Corresponding author: Helmut Pfützner, Institute of Electrodynamics, Microwave and Circuit Engineering (EMCE), University of Technology, Vienna, Austria. Tel.: +43 664 39 02 103; E-mail:pfutzner@tuwien.ac.at
Abstract: This paper puts a novel methodology of
``multi-directionally non-linear magnetic equivalent-circuit calculation''
(MACC) for discussion. It models transformer cores of Goss texture through
local elements that are represented by non-linear magnetic resistances. From
its concept, it allows for 2D or 3D distributions of induction components,
considering arbitrary degrees of non-linearity and anisotropy. The present
work describes modelling of rotational magnetization by means of a network
of elements for flux in three different directions, the rolling direction
(RD), the transverse direction (TD) and the diagonal direction (DD) in
overlaps. Other directions are assumed to be ``hard'', thus being neglected.
A 3-phase core package is modelled by 41 elements, assuming two main flux
paths. Three sets of nonlinear permeability functions are attributed to the
individual elements, starting with roughly estimated induction
distributions. The corresponding system of Kirchhoff equations is solved in
well known ways. Step-wise approximations of the set of induction components
are performed until they correspond with the set of permeability values in
acceptable grades. The resulting local distribution of induction components
indicates maximum values of TD-components in the T-joint region and the
adjoining yoke regions corresponding to maximum rotational magnetization. In
comparison with experimental findings, the results of modelling show similar
tendencies. However, as a specific advantage of MACC-modelling, it allows
flexible and rapid checks of consequences of changes of material parameters
and geometric parameters, respectively.
Keywords: Numerical magnetic modelling, electric equivalence circuits, transformer cores, induction distribution, rotational magnetization, non-linear systems
