UCC28070 THDi

"UCC28070 300-W Interleaved PFC Pre-Regulator Design Review" (SLUA479) on page 21 there is some limited test data on the 300Watts prototype.

Thanks

Steve,

I am in the same boat of you working on a low THD UCC28070 design. I just started on the PR779 demo board and havn't gone too far yet. I wonder do you have any suggestion on improving the THD on UCC28070 design?

Thanks

Terry Zhu

Hi Terry,

We have a 2kw pfc design and have under 3% THDi up to 160Vac in. Our initial application is for a customer requiring 115Vac in so we have not looked at ways to improving harmonics at the higher input voltages.

Where are you with THDi vs. input voltage? Do you need a THD less than 3% at the higher voltage range?

Steve

Terry,

My first post should have been 3% harmonics for a single frequency and 5% THDi under 160Vac in.

Steve

Hi Steve,

My application is for MIL which requires <3% induvidual current harmonic and < 5% current THD.  At the momemt, my goal is to get this for a 1.5kW PFC at 220VAC/60Hz input. I haven't got the 220VAC source yet. So I am playing with the TI 1.2kW demo board at 115VAC input. I got about 8% THD and seeing there was about 1mS flat spot in the current waveform after zero crossing as extacly you described in your other posts. I wonder is there any trick and area I should pay attention to get lower current distortion.

Update, I got the 220VAC source today. The initial test showed the current THD was 10% at 1.2kW load.

Thanks

Terry