Menu

Discussion Forum

New Discussion
查找

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 The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Computation of coil induced magnetic field

Posted 2015年9月14日 GMT-4 05:49 Low-Frequency Electromagnetics, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.3 11 Replies

Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hullo everybody,

I need to simulate the magnetic field generated by an assembly of coils (geometry is 3D, not axisymmetric). To start with, I am just trying to simulate a single coil, which I model as a multi-turn coil domain, but I am not able to obtain the values of the B field which should be expected from analytical formulas. The far field is modeled as magnetic insulation.
If anyone can give me some hint it would be really welcome, thank you.

Alessandro
11 Replies Last Post 2015年9月17日 GMT-4 03:51
Ueli Hafner
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 07:49
Hi Alessandro,

in the Multi turn coil node there must be considered some settings:
1. set Coil-Type to circular
2. sub-node "coil geometry (maybe it a little bit different in version 4.3): choose an edge in the middle of the windings (ev. split the coil into two parts)
3. In the frequency domain peek values for the current are used.

I hope this hints can help you.

regards, Ueli
Hi Alessandro, in the Multi turn coil node there must be considered some settings: 1. set Coil-Type to circular 2. sub-node "coil geometry (maybe it a little bit different in version 4.3): choose an edge in the middle of the windings (ev. split the coil into two parts) 3. In the frequency domain peek values for the current are used. I hope this hints can help you. regards, Ueli
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 08:16

Hi Ueli,

thanks for your reply.
That's what I did: the coil is defined as circular, and I assign the value of the current circulating in it.
The reference edge is in the middle of the coil.
However, the values of B in the middle of the coil (on the symmetry axis) is approximately 50% lower that expected.

Regards,

Alessandro
Hi Ueli, thanks for your reply. That's what I did: the coil is defined as circular, and I assign the value of the current circulating in it. The reference edge is in the middle of the coil. However, the values of B in the middle of the coil (on the symmetry axis) is approximately 50% lower that expected. Regards, Alessandro
Ueli Hafner
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 08:31
Hi Alessandro,

can you post the geometrical values for the coil, the current and measured field or the model file?

regards, Ueli
Hi Alessandro, can you post the geometrical values for the coil, the current and measured field or the model file? regards, Ueli
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 09:03

Hi Ueli,

please find attached the model of the problem.

The expected value of the B field in the center of the coil along the axis is approximately 0.034T (the total current is 2697A, and the average radius is 0.05m; this is also confirmed by 2D axisymmetric analysis carried out with the FEMM software), but the value obtained is 0.02T.

Regards,

Alessandro
Hi Ueli, please find attached the model of the problem. The expected value of the B field in the center of the coil along the axis is approximately 0.034T (the total current is 2697A, and the average radius is 0.05m; this is also confirmed by 2D axisymmetric analysis carried out with the FEMM software), but the value obtained is 0.02T. Regards, Alessandro

Attachments:

Sergei Yushanov Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 09:12
Alessandro,

Attached is model file with comparison to analytic solution.

Regards,
Sergei
Alessandro, Attached is model file with comparison to analytic solution. Regards, Sergei
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 09:17

Hullo Sergei, unfortunately I'm using version 4.3a of Comsol, so I am not able to open your model...

Regards,

Alessandro
Hullo Sergei, unfortunately I'm using version 4.3a of Comsol, so I am not able to open your model... Regards, Alessandro
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 10:34


Ok, I've just verified that it actually works if I carry out a 2D (axisymmetric) solution; the value obtained at the center is 0.032T.

With the 3D solution though, the same value is 0.02T. The coil is defined exactly in the same manner as a multi-turn coil; the only difference is that in 3d I have to define a reference edge, but the values obtained are wrong no matter if I choose the inner or outer radius of the coil.

Regards,

Alessandro
Ok, I've just verified that it actually works if I carry out a 2D (axisymmetric) solution; the value obtained at the center is 0.032T. With the 3D solution though, the same value is 0.02T. The coil is defined exactly in the same manner as a multi-turn coil; the only difference is that in 3d I have to define a reference edge, but the values obtained are wrong no matter if I choose the inner or outer radius of the coil. Regards, Alessandro
Sergei Yushanov Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 10:47
Alessandro,

Make sure that mesh resolution is appropriate. The best way to do this is to draw coil axis line and set mesh size sub-node for this line. Refine mesh size and see how it changes the results.

Regards,
Sergei
Alessandro, Make sure that mesh resolution is appropriate. The best way to do this is to draw coil axis line and set mesh size sub-node for this line. Refine mesh size and see how it changes the results. Regards, Sergei
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 11:19

Alessandro,

Make sure that mesh resolution is appropriate. The best way to do this is to draw coil axis line and set mesh size sub-node for this line. Refine mesh size and see how it changes the results.

Regards,
Sergei


Hi Sergei,

yes I already tried mesh refinements, but with no substantial influence on the solution. I also tried what you suggest, by generating a very tiny cylinder along the axis line so as to control mesh size. Maximum value is still about 0.02T.

Regards,

Alessandro

[QUOTE] Alessandro, Make sure that mesh resolution is appropriate. The best way to do this is to draw coil axis line and set mesh size sub-node for this line. Refine mesh size and see how it changes the results. Regards, Sergei [/QUOTE] Hi Sergei, yes I already tried mesh refinements, but with no substantial influence on the solution. I also tried what you suggest, by generating a very tiny cylinder along the axis line so as to control mesh size. Maximum value is still about 0.02T. Regards, Alessandro
Sergei Yushanov Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月14日 GMT-4 12:02
Alessandro,

Attached is verification model in v.4.3.

Regards,
Sergei
Alessandro, Attached is verification model in v.4.3. Regards, Sergei
Alessandro Vicini
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年9月17日 GMT-4 03:51

Thank you very much Sergei.
Thank you very much Sergei.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content