I was reading about power factor in electronic devices and I found charts showing that usually the power factor varies (usually decreases) with the load. So if you have a device that either works with 0% or 100% of load it's somehow easy to develop a power factor corrector (passive) but if your device varies the load from 0% to 100% it gets more complicated.
My question is: the device can be seen as a Z load. This Z (impedance) load is composed by a R (resistance) part with a X (reactance) part. So if my device varies the load by changing the relation between X and R (for example keeping same capacitors and inductors values but varying the resistance somehow), of course we then have a different final Z value so we have a different PF. But is it possible that in some cases the X varies like R so the resultant Z (and therefore the PF) remains the same for every load?
Furthermore, is it possible to map the device PF x Load curve and create a PFC that follows the same curve (even though if you change something in the device you have to do it again and considering simple devices where there's just a single dial to vary the load)?
Best Answer
It is already what active (continuously tracking the complex power) compensation systems do.
It is possible, why not, and also a good idea for few states. If you have a machine with 2 power states, then you need 2 pre-calculated reactance exclusively selected by a simple reactive power detection logic. Or it can even somehow be commutated by the dials on the machine itself.