Just my two cents worth,
In an ordinary wind turbine alternator the output voltage is linearly proportional to the rotational speed. Your controller appears to have a feature in it to protect the wind turbine against run away over speeding in that when the input voltage rises above a certain amount, an indicator that it is at a higher rotational speed, it applies the brakes to protect the turbine. It appears that there is a mismatch between the controllers input voltages and the turbines output voltages.
Check the literature with your controller as this may - or may not - be an adjustable setting. If it is not adjustable, then the next way around it may be to see how your wind turbine is wired. It may be possible to make some wiring changes on your generator to change the output voltage for a given wind speed. For example on a three phase alternator it may be possible to rewire it from a star wiring to a delta which would have a lower output voltage and more current at a given wind speed, or even to wire and rectify each phase individually. Rich
