check out the SEPIC design for a switchmode circuit ... the input and output voltages don't need to be related, so in periods of low wind speed, and your genny is only putting out 10v, your sepic circuit will boost that to 24v ... on a high wind day, your genny might put out 30v+ and the sepic will buck that down to 24v.
although I'm not sure this sort of setup is recommended by the wind generator folks... most of the computerized generator controllers I've read about have a cut-in speed and an over-speed limiter ... when the wind is low, the controller lets the genny spin freely (open circuit), trying to catch the wind... once the rpms come up, the controller switches in the charging circuit, which loads the generator down... if the winds are too strong, the controller switches in some diodes or a heavy resistive load to slow the generator down (regen braking), before applying mechanical brakes ... too much speed and the genny will self destruct since it's pretty big and heavy.