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3D Inductor modeling

Posted Mar 1, 2011, 5:39 a.m. EST Version 3.5a 4 Replies

Matteo Di Cosmo
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Hi,
I'm a newbie in Comsol but I'm trying to simulate and modeling an inductor using the AC/DC module. I want to study the total current distribution (focusing on skin and proximity effect) and the the resistance and inductance behaviour respect to the frequency. For this I choose in the model navigator the AC/DC module/ Quasi-static Electromagnetic/Time-Harmonic Analysis.

I already follow the "Inductance in a Coil" and the "Integrated square spiral inductor" and I tried to use both of them to solve this problem.

The applied voltage is called Vin and I make a parametric variation respect to the frequency. To calculate the inductance and resistance I use some scalar expressions "adapting" these of the "Inductance in a coil" model but it doesn't work. The error is "R_c is not a vald global expression".

Where I'm making mistake?

Thank you very much,
Matteo

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4 Replies Last Post Apr 1, 2011, 1:52 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 1, 2011, 9:08 a.m. EST
Hi

have you checked your units there ? and where do you define Jphi_emqa in 3D ?

Internal variable names change depending on the 2D-axi, 2D or 3D set-up in COMSOL ;)

current densities are per m^2 and you integrate over a domain in m^3 the result is a current A*m ?

check the equations in the Physics Equation Systems ... view

Finally, for me to be correct in ACDC you should loop your currents fully, you have current entering from above and exciting below, but the arrive and dissapear in "thin air"


--
Good luck
Ivar
Hi have you checked your units there ? and where do you define Jphi_emqa in 3D ? Internal variable names change depending on the 2D-axi, 2D or 3D set-up in COMSOL ;) current densities are per m^2 and you integrate over a domain in m^3 the result is a current A*m ? check the equations in the Physics Equation Systems ... view Finally, for me to be correct in ACDC you should loop your currents fully, you have current entering from above and exciting below, but the arrive and dissapear in "thin air" -- Good luck Ivar
Matteo Di Cosmo
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Posted: 1 decade ago Mar 1, 2011, 1:13 p.m. EST
Thank you very much for your helpfullness.

Actually I pretended to start solving a complex problem after done two simple tutorial in two hours without focus on what really is COMSOL and what is the phylosophy behind.

Anyway your words are more useful than the tutorial I done, I understood much more now (The complexity of COMSOL, too :) ).

I think I will work much more on the models avaibles.

Thank you.

Matteo
Thank you very much for your helpfullness. Actually I pretended to start solving a complex problem after done two simple tutorial in two hours without focus on what really is COMSOL and what is the phylosophy behind. Anyway your words are more useful than the tutorial I done, I understood much more now (The complexity of COMSOL, too :) ). I think I will work much more on the models avaibles. Thank you. Matteo
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 1, 2011, 3:49 p.m. EST
Hi

we all get burned by trying out our nice "complex" models, it takes some time to get used to COMSOL. But by training on the exercices, and then trying out simple cases, i.e and helping people here on the Forum, you learn a lot, I bet you will soon be a COMSOL pro. And it's so fun to use it to see how physics and the underlaying equations finally behaves

--
Good luck
Ivar
Hi we all get burned by trying out our nice "complex" models, it takes some time to get used to COMSOL. But by training on the exercices, and then trying out simple cases, i.e and helping people here on the Forum, you learn a lot, I bet you will soon be a COMSOL pro. And it's so fun to use it to see how physics and the underlaying equations finally behaves -- Good luck Ivar
Brian Schneider
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Posted: 1 decade ago Apr 1, 2011, 1:52 p.m. EDT
Hey Matteo,

I'm also a newbie here in COMSOL and I'm also having an error like "R_c is not a vald global expression", but it seems it doesn't relate to the value I have determined for this after noticing the error. How did you solve it?

Thanks,

Brian
Hey Matteo, I'm also a newbie here in COMSOL and I'm also having an error like "R_c is not a vald global expression", but it seems it doesn't relate to the value I have determined for this after noticing the error. How did you solve it? Thanks, Brian

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