Menu

Discussion Forum

New Discussion
Filter

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 The information provided may be out of date.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.

Problems with ac-dc module frequency domain study

Posted Jun 3, 2014, 3:27 p.m. EDT Low-Frequency Electromagnetics Version 4.4 3 Replies

Wei Liang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hi All,

Just started to use Comsol for 3d inductor magnetic field simulation. I find the ac-dc module tutorial pretty helpful and I followed that for the stationary simulation.

However, when I started the frequency domain simulation and used both the impedance boundary condition and lumped port as it is said in the tutorial, I can never finish a single calculation. Not even on a simple single turn inductor. The error is always fluctuating in the convergence plot.

I attach my model here which is a simple single turn inductor and I am trying to simulate the magnetic field at 1MHz. So I am wondering if you guys can help me on this one.

Thanks,

Attachments:

3 Replies Last Post Jun 4, 2014, 1:42 a.m. EDT
Sergei Yushanov Certified Consultant
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 3, 2014, 4:08 p.m. EDT
Wei,

Increase air conductivity to 0.01[S/m]. Rule of thumb for conductivity scaling is sig_metal/sig_air~1e6 to 1e8.
In your model this ratio was set to ~1e13 which seems too high.

Regards,
Sergei

Wei, Increase air conductivity to 0.01[S/m]. Rule of thumb for conductivity scaling is sig_metal/sig_air~1e6 to 1e8. In your model this ratio was set to ~1e13 which seems too high. Regards, Sergei
Wei Liang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 3, 2014, 5:10 p.m. EDT
Sergei, Thanks so much.

I managed to finish the calculation. But when I evaluate the lumped port impedance at 100KHz and 1Mhz, the real parts are the same at 32605 and the imag parts are both negative. I am not sure if the problem is from the lumped port setup. So I am wondering if you can comment on that.
Sergei, Thanks so much. I managed to finish the calculation. But when I evaluate the lumped port impedance at 100KHz and 1Mhz, the real parts are the same at 32605 and the imag parts are both negative. I am not sure if the problem is from the lumped port setup. So I am wondering if you can comment on that.
Wei Liang
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Jun 4, 2014, 1:42 a.m. EDT
I shrink the size of the gap domain in the model and make sure it is well inside the gap of the coil. And I got impedance like positive number+i*positive number. But it doesn't make sense for the imaginary part.

And I changed the height and the width of my user defined lumped port, I got totally different values. When I referred to the ac dc module tutorial, I am confused about the setup of the user defined lumped port dimension. In the tutorial, the height seems reasonable but the width comes from nowhere. Then I changed the width of the lumped port, the impedance also changes.

Can anyone comment how to setup the dimension of the user defined lumped port in magnetic field study?

Thank you so much
I shrink the size of the gap domain in the model and make sure it is well inside the gap of the coil. And I got impedance like positive number+i*positive number. But it doesn't make sense for the imaginary part. And I changed the height and the width of my user defined lumped port, I got totally different values. When I referred to the ac dc module tutorial, I am confused about the setup of the user defined lumped port dimension. In the tutorial, the height seems reasonable but the width comes from nowhere. Then I changed the width of the lumped port, the impedance also changes. Can anyone comment how to setup the dimension of the user defined lumped port in magnetic field study? Thank you so much

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