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 The information provided may be out of date.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.

## sinusoidal voltage to time dependent solver

Posted Dec 5, 2012, 4:40 PM EST AC/DC & Electromagnetics Version 4.3a 11 Replies

thanks

Attachments:

The Magnetic and Electric fields physics does not support Time-dependent studies, only Stationary and Frequency. You can see it in the Time Dependent step (the yellow sign near the physics's name in the table).

Depending on what you want to do, you need to use another physics, for example Electric Currents.

Note that your model as it is now cannot be solved with a Magnetic interface since it does not respect current conservation (current is "created" on one boundary and "destroyed" on another).

--

Andrea Ferrario

Electromagnetics Group

COMSOL AB

if magnetic and electric interface doesn't work for this, how can we see magnetic field while we apply voltage to the model. another question is " Is it OK to use parametric solver with the time as variable instead of time dependent one with magnetic and electric solver?"

Regards,

there is in the doc if you get to the right page ;), but you should also check the solver proposed when you enter the physics, there you see which are "set-up" by default, and also by looking to the equations , if you have d/dt 's your time response will work if you have w omega's, the frequency response too, but if none appear, when you switch your selected solvers then no luck.

Also ACDC is assuming instantaneous time response on the magnet fields, else you are in wave propagation mode = RF

--

Good luck

Ivar

Thanks for support

check www.comsol.eu/community/forums/general/thread/33429/#p91817 and see if that can inspire you ;)

--

Good luck

Ivar

you mentioned " you run time solving in EC and a parametric sweep in MF based on the current domain mapping" . would you mention the details or refer to a document about this coupling?

Regards,

if you are studying a steady state sinus, it often far easier and quicker to use the frequency domain solver than a true transient, transient behaviour and sustained sinus excitation is not fully the same, because you have all the transient effects from your inperfect BC's in the time solver

--

Good luck

Ivar

I finally could have time-dependent analysis with magnetic field solution. however it has a serious problem. I used MF solver with multi turn coil for each phase of my machine. the problem is working for just a single phase and when I enable the boundary for the second and/or third phase, the solver doesn't work. I tried many modification but no progress. I would appreciate if you would help me. the file is attached (the solution is removed because of the large size: 800MB)

Regards,

have you got your model running ?

At least you could reduce the overall air size to some diam 0.4 ad somewhat longer than you imported model, then add some 4 cm of infinite elements and set them up for cylindrical coordinates. But I'm not sure what you expect to see ?

then you define the ima,b,c over all the domains, but they have some sense only locally, I would rather use the formula directly in the multi-Turn Coil BCs

Anyhow for continuous AC you should use the frequency sweep mode at a fixed frequency of 60 Hz and then give the amplitudes as complex values (physors) for the phase instead of the wv1,2,3(t) approach. The time domain is only useful for a transient turn on, and in MF you do not get any ringing as the 2nd time derivative physics is ignored

--

Good luck

Ivar

Hi

have you got your model running ?

At least you could reduce the overall air size to some diam 0.4 ad somewhat longer than you imported model, then add some 4 cm of infinite elements and set them up for cylindrical coordinates. But I'm not sure what you expect to see ?

then you define the ima,b,c over all the domains, but they have some sense only locally, I would rather use the formula directly in the multi-Turn Coil BCs

Anyhow for continuous AC you should use the frequency sweep mode at a fixed frequency of 60 Hz and then give the amplitudes as complex values (physors) for the phase instead of the wv1,2,3(t) approach. The time domain is only useful for a transient turn on, and in MF you do not get any ringing as the 2nd time derivative physics is ignored

--

Good luck

Ivar

thanks. I think I have to give up using time dependent analysis with this model. But the problem is phase shift. How can I consider Ib=120<-240deg (i.e. 120 amplitude and -240degree of phase angle). I can define this in time dependent but I don't know how to define it in frequency sweep. please help

Regards,

the phasor approach (complex amplitudes), should work check the the doc

--

Good luck

Ivar

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.