System and method for controlling pitch angle of a wind turbine rotor blade

A system for controlling a pitch angle of a rotor blade of a wind turbine, the system comprising:

• a rotor including a hub and a rotor blade;
• an actuator that adjusts the pitch angle of the rotor blade by rotating the rotor blade about a pitch axis relative to the hub;
• and
• a controller communicatively coupled to the actuator, the controller configured to:
• control the actuator to adjust the pitch angle of the rotor blade to move the rotor blade during a start-up sequence of the wind turbine;
• determine a minimum pitch angle threshold of the rotor blade based on a tip speed ratio of the rotor blade;
• compare a current pitch angle of the rotor blade to the minimum pitch angle threshold;
• and
• control, when the pitch angle meets the minimum pitch angle threshold, the actuator to prevent the pitch angle of the rotor blade from exceeding the minimum pitch angle threshold.

A wind turbine, comprising:

• a tower;
• a nacelle mounted on the tower;
• a rotor coupled to the nacelle, the rotor comprising a hub and at least one rotor blade extending from the hub;
• an actuator that adjusts the pitch angle of the rotor blade by rotating the rotor blade about a pitch axis relative to the hub;
• and
• a controller communicatively coupled to the actuator, the controller configured to:
• control the actuator to adjust the pitch angle of the rotor blade during a start-up sequence of the wind turbine;
• determine a minimum pitch angle threshold of the rotor blade based on a tip speed ratio of the rotor blade;
• compare a current pitch angle of the rotor blade to the minimum pitch angle threshold;
• and
• when the pitch angle meets the minimum pitch angle threshold, control the actuator to prevent the pitch angle of the rotor blade from exceeding the minimum pitch angle threshold.