One load, many sources?

[LM21]

I want to load several power sources so that they all contribute. All sources come and go randomly. Power is probably  from  watts to  tens of watts. What I know now, power  sources are small windmills. They give AC.

I was thinking about unregulated fly back regulators, one for each source.

[mariush]

My first thought was that the easiest solution would be for each output to power some kind of water pump filling a water tank, then at the bottom a generator can generate power at a continuous rate from the water pouring out from the reservoir.
Waste of energy, lose efficiency, but would be simple.

Next thought was converting everything to DC at a fixed voltage like 48v for example, and then using a bunch of dc-dc controllers connected together, like LTC7871  : https://www.analog.com/media/en/technical-documentation/data-sheets/ltc7871.pdf

The IC supports up to 24 phases (connecting 6 chips to each other, 6 phases on each chip) and you supply each phase with up to 100v (48v in my example) from one input or another ...  and boost that or buck that to whatever voltage you want (example 14v or 28v to charge up a LifePo4 battery / Lead Acid battery) or just buck-boost to 48v to power things.

The problem is making sure each phase would receive the enough current based on the output current draw ... I'd probably have some p-channel mosfets or something to disconnect an input if the current is too low... for example if there's one source that can do 48v 0.5A and one that can do only 48v 0.1A ,  maybe it's better disconnect the second and connect the first to the second phase as well, and have  2 48v 0.25A phases.

[NiHaoMike]

I would say a separate boost converter from each input to a common rail, then (if needed) a buck converter to the final voltage.

[LM21]

Good suggestions. I  remember how smooth a rectified 3-phase voltage is. More phases may work also here. But each phase may come and go, depending on the wind.

[jbb]

This sounds like an interesting problem. Could you maybe sketch what you’re interested in doing?

Are you interested in maximising energy capture? If so, you would want a controller for each windmill.

How far apart is everything? A 48V DC common bus may not be the best solution (eg if distances are short 24 V or even 12 V may be OK). Likewise, is this going to be indoors or outdoors?