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Inductances AC vs DC
Posted Mar 20, 2017, 9:51 a.m. EDT Low-Frequency Electromagnetics, Modeling Tools & Definitions, Parameters, Variables, & Functions 1 Reply
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Hello everybody!
I've discovered that coil with iron core has different inductance values depending on a study type.
Stationary study produces higher inductance value compared to frequency domain one. Field distribution is also different. DC has more homogeneous magnetic field within iron core while AC has all the field concentrated in a thin surface layer.
So now I have 2 questions:
1. Which of the two inductances is the correct one?
2. As far as I know, maximum achievable magnetic field in iron core lies around 2 T. In AC model I got magnetic flux density up to 5 T within iron core. Since inductance is derived from total magnetic energy and that energy is calculated by integrating all those flux density values, does it mean that I'm getting incorrect inductance values as well?
I've discovered that coil with iron core has different inductance values depending on a study type.
Stationary study produces higher inductance value compared to frequency domain one. Field distribution is also different. DC has more homogeneous magnetic field within iron core while AC has all the field concentrated in a thin surface layer.
So now I have 2 questions:
1. Which of the two inductances is the correct one?
2. As far as I know, maximum achievable magnetic field in iron core lies around 2 T. In AC model I got magnetic flux density up to 5 T within iron core. Since inductance is derived from total magnetic energy and that energy is calculated by integrating all those flux density values, does it mean that I'm getting incorrect inductance values as well?
1 Reply Last Post Mar 21, 2017, 3:29 a.m. EDT
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Posted:
8 years ago
Are you representing the iron core with a value for relative permeability, or are you using an actual BH (or HB) curve? The fact that your field has gone to 5T in the iron suggests you are using a relative permeability value, which of course provides no way to include saturation of the iron.
Mark
Mark