Since we're dealing with actual engineering here, I'm just going to point out that there's technically no such thing as a bicycle dynamo. Dynamos produce direct current, and all bike generators produce alternating current. "Dynamo" has become accepted terminology in the cycling world for any bike-mounted generator, but I'd assume an engineer would be required to call it an alternator. An actual dynamo would probably have quite a lot more drag due to the brushes, so your best bet is likely to be an alternator even if you don't buy something off the shelf.

Throwing out another technical point, the frequency of the AC produced by a bike generator varies a lot with the speed of the bike, so your conversion electronics will need to be able to deal with that.

Not sure what else to add...