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UCD3138PFCEVM-026: UCD3138 single phase PFC

Mownika Gudupuru
Intellectual 330 points
Part Number: UCD3138PFCEVM-026
Other Parts Discussed in Thread: UCD3138

Hi Team,

I am designing UCD3138 Single phase PFC for 2KW power rating. The compensation is done and stable system is os obtained.

I want to know about the Gain margin of the system which makes it stable?? My current phase margin is nearly 60 degrees but Gain margin is infinite.

Can a stable system have infinite GM?? Attaching images for your reference. Please let me know whether my system is stable or not and whether can I proceed to next stage i.e firmware or not??

Current loopCurrent loop

  • 0
    TI__Genius 13570 points

    Hello,

    The gain margin is infinite in the tool, but it doesn't happen on the board. There are a couple of reasons. One is that on a digital control loop, double poles  induced from sampling frequency will roll down the gain very fast. This is not included in the tool; the second reason is parasitic caps form high frequency poles. I recommend to work on phase margin instead.