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I recently succeeded in creating a powerful buck PFC with a value almost equal to 1 (0.999)

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As you know there are always problems when dealing with real life circuits. I mean, the PFC value is real, however, I am wondering if it is OK to have current harmonics (I am not really sure that "current harmonics" is the proper name) back to the AC source.

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You can see in the picture that the AC voltage signal (in blue) is clean (yes it is), but the current signal (in yellow) is distorted.

This is my EMI filter:

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Is it a problem to have distortion in the current signal?

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  • \$\begingroup\$ It depends- Which PFC regulations are you trying to meet? \$\endgroup\$
    – John D
    Commented Jan 9, 2023 at 22:24
  • \$\begingroup\$ Ah, interesting. Can you zoom on a section of the current waveform and resolve the rising/falling edges or ringing, as well as a few cycles of the switching frequency (likely in the 50ns to 5µs/div range)? Also, can you move the probe to the other side of the current shunt (so it will seemingly be measuring GND) and show the waveform if any? \$\endgroup\$
    – Tim Williams
    Commented Jan 9, 2023 at 23:20
  • \$\begingroup\$ What does simulation show for the current signal? \$\endgroup\$
    – Andy aka
    Commented Jan 9, 2023 at 23:28
  • \$\begingroup\$ Do you know the frequency range of your PFC meter ? \$\endgroup\$
    – tobalt
    Commented Jan 10, 2023 at 4:59
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    \$\begingroup\$ I see more an awfully-noisy current information than a distorted one. I suspect the measurement method is to blame. You should use a current probe for measuring the ac input current and not a series shunt where you need to bring the scope ground (which can be dangerous by the way). If you can post an updated result with a current probe, it would help, thanks. \$\endgroup\$
    – Verbal Kint
    Commented Jan 10, 2023 at 12:09

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I think I have the answer to my question: "yes"

Yes , it is a problem to have a distortion in the current signal, it is called THD (Total Harmonic Distortion) In my case this THD is caused by the high frequency current pulses.

So, to avoid this problem, we need some sort of filter to smooth the current waveform. Exactly like solar inverter output filters

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After I applied the filter, I got very nice current graph except some common noise related to the poor probing and exposed wires and the component's selection, but in the end it works very well.

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