The discussion revolves around the appropriate use of optical versus static dielectric constants in e-field simulations, particularly in the context of capacitor design and modeling. Participants explore the implications of different dielectric constants based on frequency and the specific requirements of their simulations.
Participants express differing views on the definitions and applications of static, DC, and electrostatic simulations, indicating that the discussion remains unresolved regarding the best practices for selecting dielectric constants in e-field simulations.
Participants highlight the variability of dielectric constants with frequency and the potential limitations of simulations, suggesting that assumptions made in modeling should be scrutinized. There is also mention of the need for clarity on the differences between simulation types and their implications for modeling outcomes.
This discussion may be useful for individuals involved in capacitor design, e-field simulations, or those interested in the effects of dielectric properties on electrical performance in various applications.
That strongly suggests DC or low frequency modelling.newengr said:
The values for a range of frequencies are always available - use Google. One shouldn't keep within the limitations of any simulation and rely on it whatever; there is a lot of real world information about these things. Simulations have a habit of making assumptions about what you want. This allows you to get an 'answer' out but it should always be scrutinised but there are pitfalls that you have to accept when you want too much 'help' in driving the software. (GIGO)tech99 said:
It is for use in DC so it seems the static value is suitable. There will be some high frequency content since there is switching in the converter, but DC is dominant.Baluncore said:
In your thread title and first post you used the words "optical vs. static", but now you changed to "DC or electrostatic". DC is analogous to static, but optical and electrostatic are completely different. Can you say more about what you are simulating?newengr said:
This kind of implies that you are simulating capacitors in switched mode power supplies (SMPS, using SPICE?)? If so, you need to take into account the equivalent series resistance (ESR) of the capacitors, since that is a major part of what causes ripple voltage in the output of SMPS.newengr said:
Sorry for jumping all over the place. I want to design a FEA simulation for a capacitor considering different dielectrics and other things like dielectric thickness and other geometries. I found static and optical dielectric constants which is what prompted this post. I wasn't sure what the difference was or when to use which. You mentioned DC or low frequency modeling so I just wanted to confirm that I am interested in DC. I just mentioned the high frequency switching content in case that added something else to the discussion. Looking back, I don't think it did. I'm not doing converter or component modeling considering electrical performance, but I'm more so considering material properties dependent and the physical geometry. So I think FEA is appropriate here.berkeman said:
What other parameters are available for dieletrics in that simulation environment? How can you model ESR, for example? And loss tangent?newengr said:
Through DC simulation I'm able to model the conductivity, permittivity, and permeability of the plates as well as the dielectric. ESR should be able to be modeled through conductivity. Loss tangent is a function of capacitive current and resistive current so I suppose you could determine the loss tangent from simulation. If I wanted add loss tangent as a parameter, I would I have to use the RF module which I'm not using here. I'm mainly considering parameters that effect e-field intensity.berkeman said:
