UCC28064A: UCC28064A

Stuart Linzer

Intellectual 260 points

Part Number: UCC28064A

Hi Power Group,

PFC input stage is running well but looking for methods to lower the 3rd current harmonic.

Fundamental current is 3.0Amp and 3rd harmonic is 150mA. My criteria calls for a limit of 160mA.

While the circuit is passing I would like to have a little more margin to insure certification testing goes smoothly.

Power Factor is 0.99.

Total Current Harmonics is 6.6%

Vac = 115VAC

Input Current = 3.1APFC Stage.pdf

Fline = 400Hz.

Regards,

Stuart

over 1 year ago

0 Ray DiCecco over 1 year ago

TI__Genius 10635 points

Hi Stuart,

Please give me a day or two to look at what you've provided and see if I can make a suggestion. Can you tell me what the frequency is at the 1st and 3rd harmonics?

Thank you,

Ray

+1 Stuart Linzer over 1 year ago in reply to Ray DiCecco

Intellectual 260 points

Hi Ray,

1st harmonic (fundamental) is 400Hz. The 3rd harmonic is 1200Hz.

Regards,

Stuart

0 Ray DiCecco over 1 year ago in reply to Stuart Linzer

TI__Genius 10635 points

Thanks Stuart. I see that now :)

When designing PFC for avionics, the most important thing is to minimize the crossover distortion (which is the lack, or plateau, of current drawn from the AC mains during zero crossing). This can be done by minimizing the capacitance placed just after the bridge (C4 + C5 + C6) as this adds non-linearity to the circuit. Some of these capacitors can be moved in parallel to C10 and C11 if they are needed.

It’s also important to reduce the contribution from the output ripple increasing the output capacitance (C7/C8/C9) to keep the ripple small.

Regards,

Ray

0 Stuart Linzer over 1 year ago in reply to Ray DiCecco

Intellectual 260 points

Hi Ray,

Thank you for the information. This resolved my issue.

Regards,

Stuart

0 Ray DiCecco over 1 year ago in reply to Stuart Linzer

TI__Genius 10635 points

I'm glad this helped Stuart. I'll close this thread.

Power management

Power management forum

UCC28064A: UCC28064A