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UCC28070

Jefferson Carlos Fischer
Prodigy 20 points
Other Parts Discussed in Thread: UCC28070

Hello,

I'm testing the PFC controller (UCC28070) on Power Simulator (PSIM). However, I still didn't understand how to proceed to represent the Voltage Feed-Forward (kVff) block (see document in attached: "Feed Forward KVff block").

In the same way, I'm using on my simulation one filter instead of the Voltage Feed-Forward (kVff) block. Is it correct? Please check the document "PFC Controller with filter_bridgeless converter". My simulation is not working.

Note: My objective is to simulate the controllers (voltage and current) on PSIM (designed according to SLUA479B from TI), similar to the UCC28070 architeture, because I do not have a ready circuit for the UCC28070 on PSIM. Therefore, I'm trying to represent the circuit of the UCC28070 on PSIM.

Best regards,

Fischer

  • 0
    TI__Mastermind 31580 points
    Hi Jefferson,

    Let me see if I can find soemone to help with your question.

    Regards

    Peter
  • 0 in reply to Peter Meaney
    Prodigy 20 points
    Hello Peter,

    Anyone can help me?

    Regards,

    Jefferson
  • 0 in reply to Jefferson Carlos Fischer
    TI__Mastermind 34465 points
    Hi Jefferson,
    Your analog feed-forward implementation will not reflect the step change nature of the UCC28070 and simulation will be false which may mask unwanted behavior in certain cases.
    You need to implement a PSIM block that provides the 8 levels of KVFF voltages depending on VINAC input.
    This is essentially the table in the datasheet with the thresholds and hysteresis specified.
    You should be able to do this with a series of comparators and references (with hysteresis)
    Each comparator output activates a voltage source that corresponds to the threshold level being exceeded.

    Hope this helps.
    Regards
    John Griffin
  • 0 in reply to John Griffin1
    Intellectual 450 points

    Hi Jefferson,

    Just saw your post, I am working on a psim model as well.

    Have you figured this out? I used a c block to set the correct value depending on the input voltage.

    Steve

  • 0
    TI__Genius 12990 points
    Hi Jefferson,

    Any update on simulating the FF circuit on UCC28070? If so what was your solution. I will close this thread if your issue have been solved.

    Thanks,
  • 0
    TI__Mastermind 22190 points

    Hi Jefferson,

    The provided models are for PSPICE(and TINA) and if you need to develop a different model for yourself for PSIM then

    datasheet and functional block diagram are the official materials you have to rely on   to build a model.

    I read through the replies and it seems John Griffin gave you the a good starting point in his post:

    "You need to implement a PSIM block that provides the 8 levels of KVFF voltages depending on VINAC input.
    This is essentially the table in the datasheet with the thresholds and hysteresis specified.
    You should be able to do this with a series of comparators and references (with hysteresis)
    Each comparator output activates a voltage source that corresponds to the threshold level being exceeded."

    Regards,

    Arash