Prior to the abundance of power supplies made by rectifying and filtering AC, "power factor" was pretty much universally thought of as sinusoidal voltage and current that were not in phase with each other. This, of course, is what you get with linear reactive loads. If you have an excess of inductive loading you can correct the power factor by adding capacitive reactance (perhaps with "synchronous condensers" that are big machines that pretend to be capacitors). You can't use linear reactance to compensate for the very non-linear behavior of a capacitively filtered rectifier circuit. The peak of current is temporally very close to the peak of voltage, but for most of the half-cycle the current is zero. There are passive techniques that can improve power factor, but not at the dangling end of the power cord.
Active power factor correction, or active harmonic filtering as it is often called in Europe, generally is done using a boost switch mode converter designed so that the instantaneous input current is directly proportional to the instantaneous input voltage but inversely proportional to the average input voltage. - which is a little tricky. A typical single-phase APF converter will boost to about 385-400 volts DC and to do a good job it needs to accomplish that boost for the entire AC cycle - big boost near zero crossings, small boosts at peak. The last time I designed such a beast, 100 kHz was a fairly popular switching frequency, being a reasonable compromise of the usual "everything is in conflict with everything else" nature of switchers. It is APF that makes lots of higher power switchers "universal input" - accepting anything form about 85 to 265 VAC (actual, not nominal) or equivalent DC.
A moderator might like to move this and a bunch of previous posts off to another thread, since they are non-responsive with regard to the original topic.
Active power factor correction, or active harmonic filtering as it is often called in Europe, generally is done using a boost switch mode converter designed so that the instantaneous input current is directly proportional to the instantaneous input voltage but inversely proportional to the average input voltage. - which is a little tricky. A typical single-phase APF converter will boost to about 385-400 volts DC and to do a good job it needs to accomplish that boost for the entire AC cycle - big boost near zero crossings, small boosts at peak. The last time I designed such a beast, 100 kHz was a fairly popular switching frequency, being a reasonable compromise of the usual "everything is in conflict with everything else" nature of switchers. It is APF that makes lots of higher power switchers "universal input" - accepting anything form about 85 to 265 VAC (actual, not nominal) or equivalent DC.
A moderator might like to move this and a bunch of previous posts off to another thread, since they are non-responsive with regard to the original topic.