quasi-dynamic simulation

[royclh]

Hi,

I wonder if someone could explain me what is meant by the quasi-dynamic and quasi steady state simulation? I was reading through some papers from the internet about these and still have not been able to understand how this methodology is formed. Can we consider it a statistical approach or AI approach. I know it has been used to simulate dynamic voltage response. I appreciate if someone could tell me or give me some basic information about this. Many thanks.

 

[electricpete]

Quasi-static means some aspect of the dynamics is being neglected for purposes of simplifying the analysis (the error may or may not be negligible depending on the problem). Often there is a single d/dt term that is neglected as long as the frequency is low enough.

One typical context of quasi-static is Maxwell’s equations. The full equations have coupling between electric and magnetic fields in the 3rd and 4 equations below.
1 - Del dot D = rho
2 - Del dot B = 0
3 - Del cross E = -d/dt(B)
4 - Del cross H = J + d/dt(D)

If you should describe a time-varying continuous system and choose to assume induced voltage d/dt(B) is negligible, that is often called electro quasi-static analysis. The H is decoupled from the E (no wave behavior) and we can analyse the E fields on their own.

If you should describe a time-varying continuous system and choose to assume maxwell’s displacement current d/dt(D) is negligible, that is often called electro quasi-static analysis. The B is decoupled from the E (no wave behavior) and we can analyse the H fields on their own.

Another interesting example – if you should choose to analyse the DOL startup transient of an induction motor using the steady state torque speed curve – that is quasi-static analysis. There are transients present which modify the transient torque curve so it is not soley a function of speed. The error can be surprisingly large for a DOL start of a low inertia load.

There are many other examples. Perhaps you have a context in mind?

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[electricpete]

One correction in bold:

If you should describe a time-varying continuous system and choose to assume maxwell’s displacement current d/dt(D) is negligible, that is often called magneto-quasi-static analysis. The B is decoupled from the E (no wave behavior) and we can analyse the H fields on their own.

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