Variable rated speed control in partial load operation of a wind turbine

A system for operating a wind turbine during partial load operation, the system comprising:

• a controller comprising one or more processors, the one or more processors configured to perform one or more operations, the one or more operations comprising:
• providing a rated power for the wind turbine;
• comparing a power output of the wind turbine with the rated power;
• determining the power output is equal to the rated power and in response to the power output being equal to the rated power, maintaining a speed set point of the wind turbine equal to a rated speed set point;
• determining the wind turbine is operating in a partial load state corresponding to the power output being below the rated power and an operational space existing below system constraints of the wind turbine;
• and
• during operation of the wind turbine in the partial load state, varying, via the controller, the speed of the wind turbine based on a non-monotonic torque-speed relationship such that the speed during the partial load operation is higher than the speed at the rated power, wherein varying the speed of the wind turbine based on the non-monotonic torque-speed relationship further comprises operating the wind turbine to an increased speed set point that is greater than the rated speed set point at rated power as a function of torque until the system constraints or the rated power are reached.