The power control of the Turbowinds' wind turbines is based on the Active Stall Control (ASC) principle.

The ASC offers both the advantages of pitch-controlled blades and the stall effect, currently being used in the classic stall regulated wind turbines. Due to the pitch-controlled blades, the rated power level can be tuned precisely, eliminating effects of differences in air density, blade-surface contamination etc. This way, the uncertainties in the rated power level (typical for the passive stall control) can be avoided.

Consequently the ASC guarantees maximum power output for all environmental conditions without overloading the drive train of the turbine.

Besides providing power control, the blade pitch system is also used to accelerate the blades from idling to operational speed and bringing the rotor back to a safe idling situation in case of a grid loss or any other functional error (aero -braking).