Gentlemen:
First, please let me introduce my self. I'm a retired Philips Semiconductor field application engineer that worked in the Pacific Northwestern US. I currently live in rural Kenucky, am building a new house that'll have a respectable solar-backup capability.
I'm planning on using several LM46002's , one per cell as an "equaliser" for a multi cell solar energy storage system (16 cell LIFEPO4) so the topic of minimal " standby" power is very timely but I have several other questions. My concept is: replace the inductor with a " fly-back" transformer and bi directional switch to each cell effectively changing into a form of buck boost operation (the switch is simply a power mosfet with source connected to one side of the transformer secondary and gate to the other allowing the current to alternately be in phase and out of phase with the voltage finally a good use for the dam body diode. To illustrate the concept assume a transformer with a 3 turn primary and 1 turn secondary arranged to be in series adding. Cells are alternately charged and discharged as Vout is moved up or down and a 4 to one duty cycle sets Vout at the voltage on a single cell. This is a stock pulse engineering transformer with 21 uh primary and 2 secondary's rated at 2.2 amps each (PA 3855.005NL) . The cell modules will all have a common Vin, Vout and ground. They can be powered independently and remain "isolated" by the transformers or powered from the pack or some part of it ( 4 cells with this transformer). My questions are about feedback and I'm hoping there is a way for the Vout to be a defined fraction of Vin, ignoring or canceling the reference, absent that I see three choices: regulate to nominal cell voltage, regulate to maximum (useful tor charging from external power) or regulating to minimum allowable cell voltage to get the absolute most out of the "pack" by giving the greatest amount of "boost" to weaker cells.
Your thoughts?
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