A method for operating first, second and third rotor blades of a wind turbine comprising:
- a nacelle and a hub both arranged on a top of a tower, said hub is configured to rotate around an axis, and first, second and third rotor blades each pivotably mounted on the hub;
- a processor;
- the first rotor blade having an associated first electrical pitch drive system disposed inside the hub, the first electrical pitch drive system is connected to the processor, and the first electrical pitch drive system comprising a first gyroscope configured to register a first angle value of a longitudinal axis of the first rotor blade with respect to earth gravity, the first angle value is an angle between a first gravity vector and a first perpendicular vector that is perpendicular to the first gyroscope, wherein the first perpendicular vector is aligned with a center axis of the first rotor blade;
- a first electrical pitch motor configured to adjust a pitch of the first rotor blade;
- the second rotor blade having an associated second electrical pitch drive system disposed inside the hub, the second electrical pitch drive system is connected to the processor, and the second electrical pitch drive system comprising a second gyroscope configured to register a second angle value of a longitudinal axis of the second rotor blade with respect to earth gravity, the second angle value is an angle between a second gravity vector and a second perpendicular vector that is perpendicular to the second gyroscope, wherein the second perpendicular vector is aligned with a center axis of the second rotor blade;
- a second electrical pitch motor configured to adjust a pitch of the second rotor blade;
- the third rotor blade having an associated third electrical pitch drive system disposed inside the hub, the third electrical pitch drive system is connected to the processor, and the third electrical pitch drive system comprising a third gyroscope configured to register a third angle value of a longitudinal axis of the third rotor blade with respect to earth gravity, the third angle value is an angle between a third gravity vector and a third perpendicular vector that is perpendicular to the third gyroscope, wherein the third perpendicular vector is aligned with a center axis of the third rotor blade;
- and
- a third electrical pitch motor configured to adjust the pitch of the third rotor blade,
- wherein the first gyroscope is immovable in relation to the first electrical pitch drive system, the first electrical pitch drive system is immovable in relation to the hub and rotates with rotation of the hub around the axis so that deflection of the first blade is not detected by the first gyroscope, the second gyroscope is immovable in relation to the second electrical pitch drive system, the second electrical pitch drive system is immovable in relation to the hub and rotates with rotation of the hub around the axis so that deflection of the second blade is not detected by the second gyroscope, the third gyroscope is immovable in relation to the third electrical pitch drive system, the third electrical pitch drive system is immovable in relation to the hub and rotates with rotation of the hub around the axis so that deflection of the third blade is not detected by the third gyroscope, and the first, second and third gyroscopes are each in a fixed distance from the axis of rotation of the hub, the method comprising:
- calculating by the processor a rotational velocity of the hub based on the first, second and third angle values and adjust the rotational velocity of the hub by adjusting pitches of the first, second and third rotor blades using the first, second and third motors.