The power coefficient of wind turbine (ratio between useful mechanical power and the total wind power) varies when the tip-speed ratio varies. I know also that we tend to keep constant the power coefficient in tip-speed values of 8-10 (on average, considering a 3 blades turbine) wherein we reach the maximum power and later we tend to decrease Cp when the wind power becomes too high in order to keep constant the power (pitch control for example). My question is: how we keep constant the power coefficient Cp for tip-speed ratio of 8-10? Is this done with converters? And is this done with a MPPT algorithm? (MPPT is the maximum power point tracking). If yes, is it possible to keep constant Cp also with pitch control or active stall?