Re: [femm] what frequency range can FEMM be used in?

[David Meeker <dmeeker@xxxxxxxxxxxxxxxxx>]

corneliuspaul@xxxxxx wrote:

> the only reason i need an electromagnetic field FEM software right now is
> that i
> have to do a research on different concepts for a high voltage transformer.
> the device will be operated at 50kHz, maybe later the frequency range will
> be extended to about 200kHz.
> i need to compute the following parameters:
> - main and leakage inductance (good accuracy needed)
> - rms, skin and proximity losses (average accuracy needed)
> - core losses (average accuracy needed)
> (sinusoidal currents will do fine as a first approach, arbitrary current
> waveforms would be great.)
>
> the manual says the FEMM software is to be used for "low frequency
> applications" but i have not found what frequency range is meant
> by "low"
>
> so my question to the experienced group is:
> is the FEMM package suitable for the given frequency range and needed
> computations?
>

"Low frequency" means problems that can be described by a diffusion equation
rather than by a wave equation. There are some metrics that you can look
at--basically the wavelength at the frequency of interest must be much longer
than some characteristic lengths of your problem. For some details, check out
http://web.mit.edu/6.013_book/www/chapter15/15.3.html. At the frequencies that
you are looking at in a transformer-sized domain, the low-frequency formulation
ought to be ok.

Dave Meeker


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