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Thermal module

Hello everybody,

I'm using thermal module in PSIM 2023.1 and I want to use the equation option to define curve via formula.

I've tried several time but it didn't work and when I click on the button "verifiy" nothing happend with or without formula.

Could you supply the text format to respect or the protocol for using these features. Thank a lot.

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PSIM

v2023.1

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Rhonda_20369

Hi, Xavier.
The button "Verify" is to check the syntax of the equation. It does not check the correctness of the equation from engineering point of view.

This button is not functioning for now. I have passed this problem to the development team.

The syntax of the equation is similar to those in C code. There are a few pre-defined variable names:

i, id, ic: device current
Tj, T: junction temperature, in oC (T is also treated as Tj)
v: device voltage
RG_ON: gate resistance at turn-on
RG_OFF: gate resistance at turn-off

There are a few examples in the Device database: Wolfspeed's MOSFET_Eon

About your statement "it didn't work", would you please explain what did not work?

Did you created a new device using equations to define one or more curves?

Did you use this device in a PSIM schematic?

Did this device produce incorrect simulation results?

Xavier Fonteneau

Thanks for the fast answer. I've got several topics to discuss.

First, I want to use the VDS=f(ID) graph on a new device.

So, I open the VDS=f(ID) graf, I tick the equation button and I fill in the blank by the equation form with your pre-defined variable names.

When I close the windows, I see that the equation is taking into account (equation title on the graf) and I save the device model.

I closed the thermal editor and PSIM 2023. I relaunch the software but I observed that the device I have created doesn't contain the equation anymore.

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Concerning, what didn't work. First when I fill in the equation "0.01*i", graf is not plot. It would be useful to draw the curve in relation with the equation..

Then, When I used the model to check the equation, the simulation result doesn't match with the expected behaviour.

For example, I inject 100A in the MOSFET' channel to the model device through the thermal model (flag activated), I measure VDS at 1mV. Or I expected 1VDC.

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Other question, what about the temperature impact on the equation, is "Tj" taking into account and how ?