Auto PFC? (And conclusion of Ballast Inductor) (And finished secondary)

["M Fabs" <the_machin_shin-at-hotmail-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I was wondering about automatic PFC.  I have a whole bunch of PFC caps, 
triacs, and zero-crossing-triac-out optocouplers.  Can I montitor the input 
current with a simple microcontroller, then tell that when to switch caps 
into and out of the circuit?  Would triacs be happy switching caps onto the 
line at zero crossings?  Any thoughts on this hair brained scheme would be 
welcomed.

I was thinking that I would average the rms current over several cycles 
before deciding to make a cap switch. I was also thinking of arranging the 
caps this way ...x*8, x*4, x*2, x*1, x*1/2... where x in my case is 15uF. I 
can just use a binary up/down counter to keep track of which total cap value 
I am at and to signal the optocouplers.  In the microcontroller I would 
probably just keep track of the last two switches to find out if I have 
reached a minimum...


About my ballast inductor (woefully underwound, and undersized), I have 
decided to wait indefinitely on that for any further modifications; I will 
probably just get a variac :)

(Max inductance != Max current)

Thanks for alllll the help!


I finished my secondary coil, I am pleased with how it looks.  4" SCH 40 PVC 
wound for x" with #22 wire.  I will measure it tonight, and measure it's 
inductance tomorrow.  The final poly coat is still drying. Bearings and 
threaded rod are your friends. (Motors help too...)

Pleased to say it is all coming together.  It's only been 2 years...
Michael.


I apologize if this message showed up twice....

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