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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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mutual inductance in 3D

Posted 2014年1月27日 GMT-5 07:47 Low-Frequency Electromagnetics Version 4.4 7 Replies

David Segal
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Hi

There have been some posts on this issue but no clear resolution to the problem.
Say we have 2 randomly shaped coils at random 3D orientation. Find mutual inductance with 1% accuracy.
One method would be to inject a current in one coil and find voltage in the other.
If you try the Magnetic fields model as in the Comsol 2D example you find it is not easy defining
the terminals on the 3D boundaries (especially if you include the infinite boundary feature).
The terminals can only be defined on an external boundary.
Question is also how heavy the mesh must be to achieve desired accuracy.
thanks for any advice
David
7 Replies Last Post 2014年1月29日 GMT-5 10:31
kishore naik
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Posted: 1 decade ago 2014年1月27日 GMT-5 08:50

Dear david,
You can use multi turn coil domain feature in 3D also . And you can find mutual inductance by mf.VCoil_2/mf.ICoil_1/mf.iomega
--
kishore Naik Mude
Dear david, You can use multi turn coil domain feature in 3D also . And you can find mutual inductance by mf.VCoil_2/mf.ICoil_1/mf.iomega -- kishore Naik Mude
David Segal
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Posted: 1 decade ago 2014年1月27日 GMT-5 09:59
Hi

thanks. My problem is with a pair of planar spiral inductors . multiturn coil will not work here
Hi thanks. My problem is with a pair of planar spiral inductors . multiturn coil will not work here
Dennis Brown
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Posted: 1 decade ago 2014年1月27日 GMT-5 15:15

Question is also how heavy the mesh must be to achieve desired accuracy.
thanks for any advice
David


I would start with a coarser mesh and then tighten it up and see how the results change. This is called a mesh study. Just a way to see how fine you have to make a mesh before you see diminishing returns on the results.
[QUOTE] Question is also how heavy the mesh must be to achieve desired accuracy. thanks for any advice David [/QUOTE] I would start with a coarser mesh and then tighten it up and see how the results change. This is called a mesh study. Just a way to see how fine you have to make a mesh before you see diminishing returns on the results.
David Segal
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Posted: 1 decade ago 2014年1月27日 GMT-5 16:43
Hi

thanks the meshing is actually a minor issue. The main question is how to set up the model
Hi thanks the meshing is actually a minor issue. The main question is how to set up the model
Dennis Brown
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Posted: 1 decade ago 2014年1月28日 GMT-5 08:34
It would be better if you posted the actual model or something close to it (if it is proprietary in nature) but in generic terms, you will most likely have to place the coils inside an airbox. The airbox sides will be "ground" so you have see to it that you can place lumped ports at coil input. Make the airbox big enough but not too big as a first cut. There is a model in the comsol model gallery of a 3D inductor. That one is in enclosed in an airbox and could serve as a good kickoff/reference point. Take a look at the online models, see what does/doesn't make sense, and if you have other questions please post them.
It would be better if you posted the actual model or something close to it (if it is proprietary in nature) but in generic terms, you will most likely have to place the coils inside an airbox. The airbox sides will be "ground" so you have see to it that you can place lumped ports at coil input. Make the airbox big enough but not too big as a first cut. There is a model in the comsol model gallery of a 3D inductor. That one is in enclosed in an airbox and could serve as a good kickoff/reference point. Take a look at the online models, see what does/doesn't make sense, and if you have other questions please post them.
kishore naik
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Posted: 1 decade ago 2014年1月29日 GMT-5 10:31
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest

--
kishore Naik Mude
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest -- kishore Naik Mude
kishore naik
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Posted: 1 decade ago 2014年1月29日 GMT-5 10:31
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest

--
kishore Naik Mude
I am having same issue with spiral coils, I applied a external current density on the coils, i can find inductance by energy method , but mutual inductance i am not able to. Please suggest -- kishore Naik Mude

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