Active Power Control of Wind Turbines for Ancillary Services: A Comparison of Pitch and Torque Control Methodologies

Paul Fleming, Jake Aho, Lucy Pao

Research output: Contribution to conferencePaperpeer-review

39 Scopus Citations


As wind energy generation becomes more prevalent in some regions, there is increased demand for wind power plants to provide ancillary services, which are essential for grid reliability. This paper compares two different wind turbine control methodologies to provide active power control (APC) ancillary services, which include derating or curtailing power generation, providing automatic generation control (AGC), and providing primary frequency control (PFC). The torque APC controller provides all power control through the power electronics whereas the pitch APC controller uses the blade pitch actuators as the primary means of power control. These controllers are simulated under various wind conditions with different derating set points and AGC participation levels. The metrics used to compare their performance are the damage equivalent loads (DELs) induced on the structural components and AGC performance metrics, which are used to determine the payments for AGC services by system operators in the United States. The simulation results show that derating the turbine reduces structural loads for both control methods, with the APC pitch control providing larger reductions in DELs, lower AGC performance scores, and higher root-mean-square pitch rates. Providing AGC increases the structural loads when compared to only derating the turbine, but even the AGC DELs are generally lower than those of the baseline control system. The torque APC control methodology also allows for more sustained PFC responses under certain derating conditions.

Original languageAmerican English
Number of pages6
StatePublished - 2016
Event2016 American Control Conference, ACC 2016 - Boston, United States
Duration: 6 Jul 20168 Jul 2016


Conference2016 American Control Conference, ACC 2016
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2016 American Automatic Control Council (AACC).

NREL Publication Number

  • NREL/CP-5000-66074


  • active power control
  • ancillary services
  • damage equivalent loads
  • pitch APC
  • torque APC
  • wind power


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