Computation and modeling of eddy currents in tape-wound square-loop cores

Eddy currents in tape-wound cores are classified into microscopic and macroscopic eddy currents. The latter, denoted by i
e
, exists during mode II among three switching modes. Inherent peak
\dot{\phi}
versus
F
for a high
F = F_{D}
drive is computed from measured
\dot{\phi}_{m}(F_{D})
and
\phi_{m}(F_{D})
, the
\dot{\phi}
and φ when
\dot{\phi}
is maximum. The expected line density of reversed-domain nucleation centers is computed from
\phi_{m}(F_{D})
. A switching tape-wound core is equivalent to one with "ferrite-core" characteristics that is loaded by a resistance
R_{e} = \dot{\phi}/i_{e}
. A special computer program was developed to compute
i_{e}(\phi,F_{D})
and
R_{e}(\phi,F_{D})
, the higher F
D
, the wider and lower the resulting U shaped
R_{e}(\phi)
. Domain-pattern models are proposed. Accordingly,
n_{p}(\phi,F_{D})
domains in which
\phi \cdot p(\phi,F_{D})
is generated are encircled by macroscopic eddy currents where
n_{p} \geq 0
and
1 \geq p \geq 0
. The semiempirical model
R_{e}(\phi,F_{D}) = R_{ez}(F_{D})/{1 - [\phi/\phi_{m}(F_{D})]}
, where R
ez
is R
e
at
\phi = 0
, is proposed. The functions describing
\phi_{m}(F_{D})
and
R_{ez}(F_{D})
include a total of five parameters besides.