| Abstract |
For electronic circuit simulation in SMPS design, especially the equivalent circuit of the magnetic
components such as the hf-transformers has to be known. For determination of proximity losses as
well as main- and leakage-inductances of hf-transformers, the magnetic field distribution inside the
winding area might be determined by solving a boundary value problem [1]. The proposed method is
not applicable, if the transformer geometry is non-rotational, as i.e. an E-core. In [8], the problems of
only determining the inductance of a choke on a simple gapped ferrite P-core have been discussed.
In this report, a novel approach for determination of hf-transformer main- and leakage-inductances,
based on a ferrite core equivalent layout will be presented. Therefore the ferrite core will be replaced
by surface current loops driving a surface current distribution m K &
, which has to be determined from
the core’s magnetization. The magnetization may be estimated from the magnetic flux inside the core
using the inductor’s magnetic circuit model. Finally, for an arbitrary transformer an analytical
inductance determination will be presented, using the previously gained equivalent core layout. The
proposed method is also applicable for EFD- and ETD-cores. Inductance-measurements for twowinding
transformers on E-cores prove the quality of analytical simulations. |
