COMSOL Forums: sinusoidal voltage to time dependent solver

Re: sinusoidal voltage to time dependent solver

Mon, 04 Feb 2013 05:14:22 +0000

Hi

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

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Good luck
Ivar

Re: sinusoidal voltage to time dependent solver

Sun, 03 Feb 2013 21:46:33 +0000

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

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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,

Re: sinusoidal voltage to time dependent solver

Mon, 28 Jan 2013 19:42:23 +0000

Re: sinusoidal voltage to time dependent solver

Sun, 23 Dec 2012 23:09:02 +0000

Hi fellas

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,

Re: sinusoidal voltage to time dependent solver

Fri, 07 Dec 2012 15:55:11 +0000

Hi

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

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Good luck
Ivar

Re: sinusoidal voltage to time dependent solver

Fri, 07 Dec 2012 14:55:48 +0000

what a comprehensive answer. thanks.

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,

Re: sinusoidal voltage to time dependent solver

Thu, 06 Dec 2012 19:40:35 +0000

Hi

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

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Good luck
Ivar

Re: sinusoidal voltage to time dependent solver

Thu, 06 Dec 2012 18:41:55 +0000

thanks for the answer. the final question from is this: is there anyway to apply voltage and see magnetic field while using time dependent solver?

Thanks for support

Re: sinusoidal voltage to time dependent solver

Thu, 06 Dec 2012 15:30:37 +0000

Hi

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

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Good luck
Ivar

Re: sinusoidal voltage to time dependent solver

Thu, 06 Dec 2012 14:43:06 +0000

great answer. thank you very much. I don't know why there is no note about incompatibility of MEF with time dependent solver in manuals. Also thanks for your note. but one question rises now

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,

Re: sinusoidal voltage to time dependent solver

Thu, 06 Dec 2012 09:17:21 +0000

Hello,

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).

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Andrea Ferrario
Electromagnetics Group
COMSOL AB

sinusoidal voltage to time dependent solver

Wed, 05 Dec 2012 20:40:13 +0000

I am trying to apply sinusoidal voltage to a model with time dependent solver. I apply the voltage based on a function but it doesn't show anything. the model is attached.

thanks