If you search this board for Classic, or Midnight Solar Classic you'll find quite a few articles. You can also check their site.
The short, the Classic allows you to program into the controller a user adjustable power curve of an alternator. The controller then allows the voltage to be decoupled from the nominal battery voltage, attempting to follow the curve based on available wind for maximum output. It is similar to MPPT for PV but also different in how it accomplishes it.
The Classic also has upgradeable firmware, data logging, local app, web-hosting, load diversion, etc., ...some nice features.
There are also some folks who've successfully built their own MPPT controllers for wind, but this is probably the most common commercially available.
~ks