One issue with power factor corrected power supplies is that in the short term (as a minimum, at the line frequency), they do behave like resistors (current goes up when voltage goes up) but as they have a slow voltage regulation loop to provide regulated output, they do behave like constant power loads to the grid in the long term. The transition between the two modes of operation is not always smooth and can lead to instabilities when combined with the generator's response and the line impedance. I had this particular problem with a 5kW PFC corrected power supply that was working fine by itself but caused line oscillations when 16 of them were running in parallel.
On Feb 11, 2017 4:04 AM, "David" <davidwh...@gmail.com> wrote: > On Thu, 9 Feb 2017 19:06:51 -0500, you wrote: > > >One simplistic way to look at all this is that a switcher presents a > “negative > >resistance” load. If you drop voltage, current goes up. OCXO’s happen > >to share this issue. Negative resistances are *not* what most power source > >guys want in their control loop. > > > >Bob > > People working with emitter/source followers do not like it either and > I cannot see the folks using inverters wanting to pay to put big > resistive heaters across the grid to compensate. > > Adding power factor correction to switching power supplies was cheap > compared adding "negative resistance" correction. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.