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Breakdown voltage of parallel capacitor.
Posted 6 nov. 2012, 06:26 UTC−5 Version 4.3 7 Replies
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I am designing a simulation of the breakdown voltage of a parallel capacitor. So what I'm trying to figure out is, how the easiest way to to this is. For starters I guess it could be interesting to plot an I-V curve for the current between the two plates and then see where the current spikes. However, I am quite new at Comsol and I'm at a loss at how to make such a plot. I've designed the geometry and so forth, but how would I design the plot?
Anything helps.
Thank you
Tore.
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I don't think there is a straightforward way to model dielectric breakdown in COMSOL. You would need to implement the set of equations describing this extremly nonlinear process.
However you can model the electric field in the dielectric and see where it exceeds the break down field strenght of the material. However this doesn't give you a I-V curve.
Cheers
Edgar
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I have more or less concluded that you are right. I think I can live with the solution with the electric field, and then do parametric sweeps on the voltage and the gap to get me an indication of where the breakdown is exceeded.
Thank you
Tore.
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and even then you must pay a lot of attention to the edges and corners in the model because of the field enhancements there.
So, try to avoid sharp corners and edges and take care to mesh fine enough. However, you will probably gain some insight into your problem even without directly modeling the breakdown.
Cheers
Edgar
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Thank you for your answer again.
I am aware of the issues in terms of the corner and I will delve into the issues. I'll let you know what I find out.
Best regards
Tore
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Tore,
and even then you must pay a lot of attention to the edges and corners in the model because of the field enhancements there.
So, try to avoid sharp corners and edges and take care to mesh fine enough. However, you will probably gain some insight into your problem even without directly modeling the breakdown.
Cheers
Edgar
Hi agan Edgar.
I'm trying to do a 2D simulation of the problem at the moment. But while I'm trying to use fillets for smoothening the corners, I still can't completely optimize the issue of localized concentrated charge. If you see the model I've uploaded, you'll notice that for the fillet on the left hand side of the model, there still is a large concentration of charge because the fillet still amounts to a 90 degree angle onto the substrate. How can I best solve this?
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to my taste it doesn't look too bad. You can try to use a finer mesh,
Cheers
Edgar
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Tore,
to my taste it doesn't look too bad. You can try to use a finer mesh,
Cheers
Edgar
I actually tried with a finer mesh, but for some reason it actually only seems to make it worse. Something tells me a more coarse grid will be better, but I'm yet to look into it.