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Calculation of inductance value (COMSOL Version 3.5a)
Posted Mar 3, 2010, 4:19 a.m. EST 3 Replies
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Hi..
I have simulated a simple generator. I have injected current in coil using the current density options in subdomain setting. After running the simulation, I view the result of magnetic energy density from postprocessing.
formula used for current density = current / area of coil (amps/m^2)
formula for magnetic energy density = W=1/2Li^2 (J)
In order to get my inductance value, I rearrange the formula to get L=(2 x W)/i^2
I select the whole generator using ctrl A to get my magnetic energy density value. My problem is, when i increase the current, i from 1A to 2A to 3A (Value of current density increases), I get the same value of calculated inductance.
Can anyone advice me what I have done wrong.
Your help is very much appreciated. Thank you in advance.
I attach the file for reference.
I have simulated a simple generator. I have injected current in coil using the current density options in subdomain setting. After running the simulation, I view the result of magnetic energy density from postprocessing.
formula used for current density = current / area of coil (amps/m^2)
formula for magnetic energy density = W=1/2Li^2 (J)
In order to get my inductance value, I rearrange the formula to get L=(2 x W)/i^2
I select the whole generator using ctrl A to get my magnetic energy density value. My problem is, when i increase the current, i from 1A to 2A to 3A (Value of current density increases), I get the same value of calculated inductance.
Can anyone advice me what I have done wrong.
Your help is very much appreciated. Thank you in advance.
I attach the file for reference.
3 Replies Last Post Mar 4, 2010, 1:33 a.m. EST
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Posted:
1 decade ago
nothing is wrong
inductance should remain constant if you dont have non linear material in your gnerator !
inductance should remain constant if you dont have non linear material in your gnerator !
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Posted:
1 decade ago
Thanks Jean..
All this while i was assuming my model is nonlinear..Maybe I misinterpret the ACDC module guide:
'For most of the standard application modes you can apply the following criterion: if any coefficient or material property contains a dependent variable the model is nonlinear.'
How do I know my model is linear or nonlinear? How do I set it to be nonlinear?
I really do appreaciate any feedback and advice from you! I am learning new things from all the feedbacks....
Thanks!
All this while i was assuming my model is nonlinear..Maybe I misinterpret the ACDC module guide:
'For most of the standard application modes you can apply the following criterion: if any coefficient or material property contains a dependent variable the model is nonlinear.'
How do I know my model is linear or nonlinear? How do I set it to be nonlinear?
I really do appreaciate any feedback and advice from you! I am learning new things from all the feedbacks....
Thanks!
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Posted:
1 decade ago
Hi
I believe for your case ACDC, so long you do not consider saturation in some iron cores or similar effects your model will remain linear.
If you have the material module you could find some examples of saturating materials.
If not, you would have to type in the saturatin as a specific material property taking examples from the litterature or your material suppliers data.
Good luck
Ivar
I believe for your case ACDC, so long you do not consider saturation in some iron cores or similar effects your model will remain linear.
If you have the material module you could find some examples of saturating materials.
If not, you would have to type in the saturatin as a specific material property taking examples from the litterature or your material suppliers data.
Good luck
Ivar