Re: [femm] [Resistance and Inductance as a function of frequnecy]

["you se-ho" <sxy28@xxxxxxxxxxx>]

To Dear Dr. Meeker, Hang and all:

How are you ? I am in disk drive industry. I study and research on 
interconnect from preamp side to head.

I used main Dr. Konrad's papaer to implement FEM.
[1] IEEE transactions on magnetics, vol. Mag-17, no.1 January 1981.
[2] IEEE transactions on magnetics, vol. Mag-18, no.1 January 1982.
[3] IEEE transactions on power apparatus and systems, Vol. PAS-101, no 10 
OCt, 1982. (Interestingly, in this paper, Dr. Csendes argues with Dr. 
Konrad. Even though to me, there is no (not much) difference each other's 
method.)

In paper [2] equation (23), source current I_s can be obtained from the 
total current I by using I_s = I - I_e (where I_e is induced eddy current 
term.)
Instead, I used I = I_s + I_e putting known source current (+1A for one 
conductor and -1A to the other conductor.) Moreover, there is (induced) 
current on the ground that has not any current source.

To calculate inductance, I use energy relation since now I have total 
(indeced) current (which is not 1A.)

I used triangle.exe to generate mesh like FEMM. I used -r option (triangle 
-r) to refine mesh. So, I terminte simulation when abs(L - L_old) / L is 
less than, for example, 1% or 2%. Interestingly, my program usually stop 
around 3000-6000 triangles when Maxwell 2D program stops between 600-3000 
triangles.

what is the field smoothing ? I use energy relation to calculate 
capacitance. The result is pretty much same as that of Maxwell. Is there
any particular reason that energy without field smoothing causes error (to 
inductance and resistance) ?

Thanks.
Any comments will be appreciated.
Sincerely,
SE-HO YOU






> >
> > I implemented FEM to calculate resistance and inductance with published
> > paper. If I see the resistance value, it is always smaller than that of
> > Ansoft's Maxwell. This is more outstanding at higher frequency. If I use
> > much more triangles, then clearly it took much more time, nevertheless 
> the
> > resistance value is always smaller than Maxwell's. When I calculate
> > inductance and resistance, I use same mesh data. I calculate inductance
> > first, then calculate current and resistance. I now feel that I need to 
> some
> > special algorithm to get convergence fast. has somebody any idea ?
> >
>
> Well, maybe Maxwell's result is just dead wrong : ) Seriously, can you 
> give
> more details about what example you are trying to reproduce (e.g. a 
> reference to
> the paper that you were talking about)? It's hard to say much without 
> knowing
> more.
>
> Dave Meeker
>
> << dmeeker.vcf >>

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