A true mppt will look for the maximum power point at each wind speed and adjust its load to keep the prop on the peak of the power curve.
In theory the tsr should remain constant for a given prop and the mppt should keep the prop rotational speed directly proportional to wind speed. If for some reason the maximum power point of the prop doesn't track with wind speed exactly proportional to rotational speed it will set the rotational speed to a value to match the maximum power point. It should work for any mill.
Wind changes speed frequently and violently and in less than a second the power of the prop can double, it is a tall order to track things that are so unpredictable especially as at each point you nave to measure power then change the controller pulse width then look again to see if it is better or worse. If worse you go the other way. if better you try again until you go too far then you move back. With solar this is reasonably easy as things change slowly.
I am not sure how far this has been perfected for wind. I suspect most schemes are very slow and track the average maximum power not the true peak.
The alternative that works for a given machine is to measure prop speed and adjust your controller to produce a given load for each rotational speed and you set it up so that the alternator power curve loads the prop to its optimum point all the way up the range. It only works for a given machine that it is set to track and if other things change such as battery volts it may not be a perfect track of the peak power point.
This is the method I use, it is not as convenient or versatile as a true seeking mppt but it works well enough as the prop doesn't have a sharp peak at the peak of the power curve and a little variation in tsr has no real effect.
These controllers use a buck or other variable ratio dc converter and altering the pulse width lets it work in a similar way to a transformer. If the alternator speed is high, the voltage will be high and it will produce the same power into a low voltage battery ( the amps go up in the battery circuit to maintain the same power at low volts).
Because the voltage is rising with speed the alternator efficiency stays well up so heating is much reduced. When eventually you reach the alternator limit you are likely near the comfortable mechanical limit of the prop and furling will keep under control. There is no need to limit the converter current and with furling it is not advisable to do so as it will run away with reduced load.
A speed based pitch control can be let to run at a speed that the alternator can handle but in this case current limiting although a waste of power would cause no trouble.
Again in the ideal conditions where prop speed tracks wind speed the alternator volts will track wind speed and the power level will track wind speed cubed.
In a battery charging scheme where volts are effectively constant the battery current will track wind speed cubed for a perfect alternator. In real life the alternator inefficiency means that the track is nearer speed squared and I simply use a servo loop tracking the output current against a signal proportional to speed squared from a multiplier. By fiddling the loop gain it can be made to rise a bit above speed squared if the alternator is very efficient.
There you are nice and simple, so much easier to achieve than furling? Sadly no furling mills have been around for about a century, mppt is just around the corner?
You are new at this there is plenty left for you to perfect, it's not too late.
Flux
Flux