Well, I would forget the micro and worry about the basics. What about control power? Is there an AC source that you plan on using for that? If so, the split, isolated supply is mostly a function of using a transformer with good isolation. If not, you need to strap a switching supply that can handle the entire output range, to the turbine output. That would probably mandate a minimum speed at which your system would work.
From a safety standpoint, it wouldn't be prudent to reference all of your supplies to the emitter or source of your switch unless it was at or near earth potential.
Joe
