Method of controlling a wind turbine and controller for a wind turbine

A method of controlling a wind turbine, wherein a minimum required hydraulic pressure represents a hydraulic pressure of at least one accumulator of the wind turbine which is required to pitch at least one blade of the wind turbine which is associated with the at least one accumulator into a stop position of the wind turbine, wherein a pitch angle represents a pitch angle of a normal of the at least one blade of the wind turbine relative to an incoming wind direction, the method comprising:

• determining a minimum requirement function of the minimum required hydraulic pressure dependent on the pitch angle;
• determining an offset minimum requirement function being offset to the minimum requirement function by a predetermined positive offset and representing a function of an offset minimum required hydraulic pressure dependent on the pitch angle;
• detecting a current hydraulic pressure in the at least one accumulator at a current pitch angle of the at least one blade;
• determining that the current hydraulic pressure is higher than the minimum required hydraulic pressure at the current pitch angle and lower than the offset minimum required hydraulic pressure at the current pitch angle;
• controlling the wind turbine such that the current hydraulic pressure is above the minimum required hydraulic pressure at the current pitch angle;
• and
• controlling the wind turbine such that the current hydraulic pressure is above the offset minimum required hydraulic pressure at the current pitch angle.