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Hi everybody,
I'm trying to calculate transformer leakage
inductance and stray capacitances. Thanks to Cornelius H. Paul's notes on
'Calculating Transformer Inductances with Femm' and Jim Bloor's valuable
favour, Femm gave some results for leakage inductance. Now I have two
questions:
1) What is the effect of frequency on the leakage
inductance? When I change the frequency, flux lines and magnetic energy
integral changes. Is this logical?
2) What about stray capacitances? I think
making the secondary current zero (open circuit the secondary winding) and
applying the nominal voltage to primary winding and calculating the stored
energy in the electric field may help us. After obtaining the stored energy, by
using W=0.5*C*V^2 (half of the product of the capacitance and the square of
applied voltage is equal to the energy stored in the electric field. ) we can
obtain capacitance value. But how can we apply voltage to primary and how can we
integrate the electric field over the volume (of course an area in 2D) by using
FEMM? And if I manage to calculate this, what is the dependency of capacitance
to frequency? Is there any relation between the frequency and the stored energy
in the electric field ? ( Like the relation in the leakage inductance
calculations) ? Thanks.
Erdal Bizkevelci
Middle East Technical University Tubitak Bilten 06531 Ankara/TURKEY |