Is it realistic to use the thermal module Mosfet (Eon) to get the Power losses within ZVS to ON operation?

Carlos Revert
Carlos Revert New Altair Community Member
edited October 2023 in Community Q&A

The converter I am currently simulating has ZVS to ON. The issue is that because of that, the switch just sees the diode  forward voltage drop (Vfw) so the losses are significally reduced. The thing is that I assume that the curves provided by the manufacturers (e.g. Eon vs Id ) for specific drain-to source voltages are within Hard switching operation and looking to the PSIM manual it seems that the current (for a given junction temperature) is the only variable taking into account to interpolate the curves.

Therefore, the resulting switching losses depends on just the current seen by the thermal module switches at the switching moment and that seems weird to me since the losses not only depend on the current but also on the voltage.

Is it clear my doubt?

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Answers

  • Albert_Dunford
    Albert_Dunford
    Altair Employee
    edited October 2023

    The voltage drop across the switch is part of the test conditions and curve parameters for Eon vs Id. There were some bug fixes release in 2023 to ensure the proper turn on losses are calculated. Also, ensure that your data set includes losses to Eon vs Id at 0 amps. You might need to insert a 0,0 point.

    But yes, the losses will scale with Vds properly. In fact there are now multiple curves used to scale properly with changing Vds for this model. Here we see a device with the loss curves defined at a constant temp and at different Vds, PSIM will use these to scale the losses.

    image

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