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Coil Node: Using different expressions for Coil current (pre-computation)
Posted 8 apr 2020, 17:09 CEST Parameters, Variables, & Functions, Studies & Solvers, Equation-Based Modeling Version 5.4 3 Replies
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Dear all,
I'm currently looking for a solution for the problem described in the title. The idea is, that a specific coil geometry (e.g. nTurns, nLayers, conductor radius, ...) leads to different coil parameters (i.e. coil resistance mf.RCoil_1 and coil inductance mf.LCoil_1). I can precompute those values with a stationary study using an arbitrary current (Idc) in the coil excitation field.
For a time-dependent study (in this case frequency transient combining MF and heat transfer) I'd like to use those general parameters. In this case I'd like to assign a time dependent current to the coil excitation: i(t) = u0/mf.RCoil_1 * (1 - exp(t/(mf.LCoil_1/mf.RCoil_1))).
I know that I could e.g. use the withsol operator and rewrite the coil exitation field with the expression for i(t). But as soon as I for exampel to start to change the geometry (add some turns, take away some layers, change conductor radius), the first study would have to be conducted again and I get's cumbersome not forgetting all the steps to get the right result.
Is there any way to solve this? Would it somehow be possible to dublicated the the Coil Node and assign each of the nodes to another studie / studie step?
Thank you very much for your help.
Best,
Stefan
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Update: Duplicating the complete mf physics node and assigning each node to either the transient or the stationary study should do the trick, right? Or is there a (maybe more clean way) to do so?
Best,
Stefan
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Stefan,
you can also have multiple coils in one physics and activate them selectively in the study steps. You need to check the box "Modify model configuration ..." in the study step to get access to all the physics nodes.
One more option is to use parametric switches in the coil current expression, such as:
I(t) = switch1 * f1(t) + switch2 * f2(t) + ....
The switchn need to be defined as parameters and are either 0 or 1. This way you can control the expression in a parametric sweep.
Cheers Edgar
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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Dear Edgar,
Thank you very much for your two suggestions. I haven't noticed this "modify model configuration" checkbox, I will try this. Also the switch method with those parameterised booleans is a good idea.
Thank you again for the quick and helpful response.
Best,
Stefan