Questions regarding the Kp gains of ROSCO in Region 2

Dear Jason, Bonnie, or Nikhar,

I am working on the ROSCO control tuning but I have a question regarding the Kp gain in Region 2. The paper (Nikhar et al 2019) mentions that the A is parameterized by wind velocity, but I only found a single Kp in the ROSCO controller for NREL5MW, DTU10MW, and IEC15MW. I read the ROSCO code and Simulink model and there is no scheduling process for Kp(v). Recently, I found there is an option in the ROSCO_toolbox (, which scheduled the Kp based on the wind velocity vector below the rated wind speed and also has an option to specify a wind speed to interpolate the Kp gain at this point.

Does this mean the single Kp_vs in the ROSCO DISCON.IN is interpolated at a fixed wind speed? If so, what is this specific wind speed? If else, what is the condition? Thank you

Abbas, N.J., A. Wright, and L. Pao. An Update to the National Renewable Energy Laboratory Baseline Wind Turbine Controller. in Journal of Physics: Conference Series. 2020.

Hi Xianping,

This is admittedly not very clear - sorry about that!

The region two gain schedule is, technically, scheduled by v and calculated at each wind speed. In the ROSCO toolbox, this happens here: …

When the DISCON.IN file is written, the last value in the vs_gain_schedule is used: …

So, this corresponds to, basically, rated wind speed, as it is the wind speed coresponding to the last value in v_below_rated as defined here: …

I hope this clears things up for you.


Hi Nikhar,

Thank you for your reply. Yes, I also found this operation in writing DISCON.IN. Have a good evening!