US Patent 10240580 Adjusting a rotor blade pitch angle

A method of adjusting a pitch angle of a rotor blade of a rotor of a wind turbine is provided. The method comprises varying the pitch angle of the rotor blade during wind operation of the wind turbine from a starting angle to reach a limit angle (α1, α2) at which the rotor blade and/or an operational value (P) of the wind turbine reaches a predefined threshold limit (P1/2; α1, α2), deriving a safe angle (α3, α4) dependent on the limit angle (α1, α2), operating the rotor blade at the safe angle (α3, α4) or an angle from the safe angle (α3, α4) away from the limit angle (α1, α2). A pitch angle adjustment system is also provided for the same purpose.