Wind turbine control to maximise power production with a thrust limit

A controller for a wind turbine having a rotor and a plurality of pitch-adjustable rotor blades mounted to the rotor, the controller comprising one or more processors configured to:

• retrieve a predefined power coefficient data structure comprising a plurality of power coefficient values, each power coefficient value corresponding to a respective combination of a pitch angle of the rotor blades and a tip speed ratio of the wind turbine;
• retrieve a predefined thrust coefficient data structure comprising a plurality of thrust coefficient values, each thrust coefficient value corresponding to a respective combination of the pitch angle of the rotor blades and the tip speed ratio of the wind turbine;
• determine, from the predefined power coefficient data structure, a combination of a value of the pitch angle and a value of the tip speed ratio at which the power coefficient value is maximized, subject to a thrust coefficient constraint that a thrust coefficient value of the predefined thrust coefficient data structure, corresponding to the combination of the value of the pitch angle and the value of the tip speed ratio, does not exceed a maximum threshold thrust coefficient value that is based on a current wind speed in the vicinity of the wind turbine;
• and
• control the wind turbine based on the determined combination of the value of the pitch angle and the value of the tip speed ratio, and on the current wind speed.

A wind turbine, comprising:

• a tower;
• a nacelle disposed on the tower;
• a rotor extending from the nacelle and having a plurality of pitch-adjustable rotor blades disposed on a distal end thereof;
• and
• a controller configured to:
• retrieve a predefined power coefficient data structure comprising a plurality of power coefficient values, each power coefficient value corresponding to a respective combination of a pitch angle of the rotor blades and a tip speed ratio of the wind turbine;
• retrieve a predefined thrust coefficient data structure comprising a plurality of thrust coefficient values, each thrust coefficient value corresponding to a respective combination of the pitch angle of the rotor blades and the tip speed ratio of the wind turbine;
• determine, from the predefined power coefficient data structure, a combination of a value of the pitch angle and a value of the tip speed ratio at which the power coefficient value is maximized, subject to a thrust coefficient constraint that a thrust coefficient value of the predefined thrust coefficient data structure, corresponding to the combination of the value of the pitch angle and the value of the tip speed ratio, does not exceed a maximum threshold thrust coefficient value that is based on a current wind speed in the vicinity of the wind turbine;
• and
• control the wind turbine based on the determined combination of the value of the pitch angle and the value of the tip speed ratio, and on the current wind speed.