Driver for Snow Thrower headlight conversion

I guess this question would go here. I just put together a 3 x XM-L emitter, reflector and heatsink for my Snowthrower. The machine is equipped with a 14 volt halogen bulb now but I want to convert it to LED for better visibility. The machine generates an AC voltage which varies from about 6 volts at idle to 17 or so at full throttle. I’ve installed a bridge rectifier to convert the output to DC.

What sort of driver should i be looking for to the LED setup? Seems like sometimes at low rpms it might need boost and but mostly buck depending on engine speed. Has anyone here put something like this together before? Any guidance would be appreciated.

I think garrybunk did something similar as well as something else with his snowblower.

No, I was thinking of his riding mower project.

But for something different.