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Issue with Single-Turn Boundary Feed in AC/DC

Posted 24.09.2014, 14:49 GMT-4 Low-Frequency Electromagnetics, Modeling Tools & Definitions Version 5.2 5 Replies

Jacob Sacks
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Hello,

I am trying to simulate a thin-film rectangular coil using the single-turn node in the AC/DC package. I've surrounded the coil with an infinite element sphere. Like many others, I can't seem to select the right boundaries for the boundary feed and ground. It tells me the boundaries are not applicable. The only way I can select them is if I set the geometry to an assembly instead of a union. And I can't seem to find a solution on the forum that works in my case. Is there any way I can select these boundaries while keeping my geometry a union? Links to an image and the model are below. Thanks so much!

Image: dl.dropboxusercontent.com/u/53647982/2014-09-24_1341.png
Model: dl.dropboxusercontent.com/u/53647982/Straight_Coil_v2.mph

Sincerely,
Jake
5 Replies Last Post 11.02.2016, 12:05 GMT-5
Nirmal Paudel COMSOL Employee

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Posted: 1 decade ago 30.09.2014, 09:24 GMT-4
Dear Jacob,

There are multiple ways to excite the coil that you have here. In either case, you would need to slightly modify the coil geometry to make it a close loop. The first approach is to use the Single Turn Coil and use the Boundary Feed feature similar to the following inductor_3d example:
www.comsol.com/model/modeling-of-a-3d-inductor-10299

Next approach is to use the lumped port and Impedance Boundary conditions, as done in the same inductor_3d example or the rf_coil example below:
www.comsol.com/model/modeling-of-an-rf-coil-6126

Best Regards,
Nirmal Paudel
------------------------------
COMSOL Employee
USA
Dear Jacob, There are multiple ways to excite the coil that you have here. In either case, you would need to slightly modify the coil geometry to make it a close loop. The first approach is to use the Single Turn Coil and use the Boundary Feed feature similar to the following inductor_3d example: http://www.comsol.com/model/modeling-of-a-3d-inductor-10299 Next approach is to use the lumped port and Impedance Boundary conditions, as done in the same inductor_3d example or the rf_coil example below: http://www.comsol.com/model/modeling-of-an-rf-coil-6126 Best Regards, Nirmal Paudel ------------------------------ COMSOL Employee USA
Jagadish Singh
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Posted: 9 years ago 08.12.2015, 01:24 GMT-5

Dear Jacob,

There are multiple ways to excite the coil that you have here. In either case, you would need to slightly modify the coil geometry to make it a close loop. The first approach is to use the Single Turn Coil and use the Boundary Feed feature similar to the following inductor_3d example:
www.comsol.com/model/modeling-of-a-3d-inductor-10299

Next approach is to use the lumped port and Impedance Boundary conditions, as done in the same inductor_3d example or the rf_coil example below:
www.comsol.com/model/modeling-of-an-rf-coil-6126

Best Regards,
Nirmal Paudel
------------------------------
COMSOL Employee
USA



Hi Nirmal,
I am using the 3D inductor example as is to understand the flow for a comsol simulation.
When I reach the assingning Boundary Feed and Ground step under the Single-turn Coil 1, I am not able to choose the suggested boundaries, it says not applicable. When I try paste, the item is not picked up. I am actually doing it manually where I choose all the boundaries and then remove those not required.

could someone at comsol try redoing this with the example file and the steps given in the accompanying pdf?

As described by Jacob, it is possible to choose the boundary as an assembly, but not as a union.
I'm not sure if solving the model as an assembly is right..

Thanks for your help.

regards,
Jagadish

[QUOTE] Dear Jacob, There are multiple ways to excite the coil that you have here. In either case, you would need to slightly modify the coil geometry to make it a close loop. The first approach is to use the Single Turn Coil and use the Boundary Feed feature similar to the following inductor_3d example: http://www.comsol.com/model/modeling-of-a-3d-inductor-10299 Next approach is to use the lumped port and Impedance Boundary conditions, as done in the same inductor_3d example or the rf_coil example below: http://www.comsol.com/model/modeling-of-an-rf-coil-6126 Best Regards, Nirmal Paudel ------------------------------ COMSOL Employee USA [/QUOTE] Hi Nirmal, I am using the 3D inductor example as is to understand the flow for a comsol simulation. When I reach the assingning Boundary Feed and Ground step under the Single-turn Coil 1, I am not able to choose the suggested boundaries, it says not applicable. When I try paste, the item is not picked up. I am actually doing it manually where I choose all the boundaries and then remove those not required. could someone at comsol try redoing this with the example file and the steps given in the accompanying pdf? As described by Jacob, it is possible to choose the boundary as an assembly, but not as a union. I'm not sure if solving the model as an assembly is right.. Thanks for your help. regards, Jagadish
Nirmal Paudel COMSOL Employee

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Posted: 9 years ago 08.12.2015, 08:58 GMT-5
Dear Jagadish,

The issue is most likely that you have the "Magnetic Fields" physics being solved in "all domains". You would first need to solve the "Magnetic Fields" only in domains "1-8 and 10-14". That is, you would have to remove Domain 9 from the "Magnetic Fields" physics to get access to these two Boundaries; "Boundary Feed" on 58 and "Ground" on 79.

Hope this helps.

Best Regards,
Nirmal Paudel
Dear Jagadish, The issue is most likely that you have the "Magnetic Fields" physics being solved in "all domains". You would first need to solve the "Magnetic Fields" only in domains "1-8 and 10-14". That is, you would have to remove Domain 9 from the "Magnetic Fields" physics to get access to these two Boundaries; "Boundary Feed" on 58 and "Ground" on 79. Hope this helps. Best Regards, Nirmal Paudel
Jagadish Singh
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Posted: 9 years ago 08.12.2015, 09:31 GMT-5
Thanks NIrmal. But this did not help.

Also the reference pdf for this application does not speak of this step at all.
I am working with the local AE to have this fixed. Will update when we have a resolution.
Thanks NIrmal. But this did not help. Also the reference pdf for this application does not speak of this step at all. I am working with the local AE to have this fixed. Will update when we have a resolution.
Kristian Rye Jensen COMSOL Employee

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Posted: 9 years ago 11.02.2016, 12:05 GMT-5
Hi,

I had a support case where someone experienced the same problem and refered to the discussion forum. That more people were experiencing this problem.

I've tried to go through the step-by-step one more time. If you don't disclude domain 9, which is written on page 26 on the top. I have attached the image, then you'll receive the Non-applicable for the boundary 58 and 79.

Furthermore I have attached the model until page 27, so you can continue from here.

Hope this helps.

Best regards
Kristian
COMSOL Denmark
Hi, I had a support case where someone experienced the same problem and refered to the discussion forum. That more people were experiencing this problem. I've tried to go through the step-by-step one more time. If you don't disclude domain 9, which is written on page 26 on the top. I have attached the image, then you'll receive the Non-applicable for the boundary 58 and 79. Furthermore I have attached the model until page 27, so you can continue from here. Hope this helps. Best regards Kristian COMSOL Denmark

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