I'm interested in building, or at least learning about building, a DC power supply with active power factor correction. I'm sure someone will ask "why the heck do you want to do that?" so I'll give a brief explanation. I'm working on a project where I will be driving a large number of high power LEDs. I have a DC-DC constant current regulator circuit I will be using to drive the LEDs, but it needs a DC power source. I'd need in the neighborhood of 48v and 6 - 10A to drive the LED array. First thought would be to buy a cheap power supply such as can be found on eBay for maybe $40. However, none of these cheap supplies have active PFC, which is something I'm interested in given the outrageous power factor and inrush current of a typical budget power supply in this power range, and the fact that I might have several of these large LED arrays running simultaneously. There are supplies out there with active power factor correction, but they're vastly more expensive and hard to find (I can find a few units in the $200+ price range).
So, I'm curious about what exactly it is that provides the power factor correction, at least from an educational standpoint - if not from a "gee, I can build that myself" perspective. Unfortunately, it seems a murky subject. I've spent hours googling and trying to read on forums, but it seems like every time you find something discussing DIY power factor correction, it's a complete hoax where someone's shoving a few huge caps in a project box and attaching it to the mains lines in their home. Clearly not what I'm looking for.
Have you measured the power factor of your circuit? I am a little bit curious as from what you described, it doesn't seem that you are using any inductive or capacitance load so your PFC should be pretty close to 1.
Why on earth do you want to have a power factor corrected power supply. All that power factor correction does for you is make you pay for the power you are using. With a poor power factor you get the power much cheaper because your meter only records the power vector projected onto the real axis. In an industrial context the power companies will penalise you for a poor power factor by charging you more per unit to compensate for the fact that it doesn't show up on the meter. But in a domestic context they can't monitor it and so don't know you are doing it.
Have you measured the power factor of your circuit? I am a little bit curious as from what you described, it doesn't seem that you are using any inductive or capacitance load so your PFC should be pretty close to 1.
I have not measured the power factor of the "current implementation," but I know it's bad, because I can look it up. The current implementation uses several large DC power supplies. I can look up the power factor in the datasheets for those supplies and confirm that it's terrible.
Why on earth do you want to have a power factor corrected power supply.
To avoid having to upsize the infrastructure (read: electrical circuits in my home) supplying the LED arrays to deal with the current spikes that occur with a poor power factor. As I'm sure you're aware, a load with a poor power factor (such as the DC supplies I'm using with passive rectifiers in them) pulls a very high current for a short portion of the AC cycle. This current spike means that I need to severely de-rate the wiring, breaker, and other infrastructure supplying the circuit.
In the end, this is also partially academic. I've built the entire rest of this project from scratch, so I understand it thoroughly. The concept of active power factor correction is the only (potential) part of this project that I don't know enough about to build myself, hence the question. I'm frustrated that I cannot research this easily on my own, due to the vast amount of meaningless noise that's out there on this subject, so I'm wondering if anyone can point me in the direction of some meaningful material on the subject.