Unsteady controller at high (>23m/s) steady wind speeds

[MSaraber]

I am running simulations of the IEA 22MW turbine for steady wind speeds in range 3-25 m/s. For wind speeds larger than 23m/s I see the rotor speed fluctuates between 5.5rmp and 8.5rpm. Looking at the blade pitch large deviations can also be concluded. Am I doing something wrong is something happening in the tuning at these high wind speeds? I am no control expert, but these figures don't look correct.

I am using ROSCO version 2.9.0 controller.

Look forward to a reply.

[ptrbortolotti]

I suppose you are using BeamDyn, am I right? If so, I'm aware of the issue, which I've investigated at length. So far I've concluded that the model is unstable at high winds (>22m/s). However a paper will appear at TORQUE 2024 showing that HAWC2, Bladed, and QBlade do not experience this instability. I'm still working on it and I'll share more updates as I get them

[MSaraber]

Hi Pietro, Thanks for your quick reply. To answer your question: I am using ElastoDyn and not using BeamDyn for the blades. Do you expect the same to happen using ElastoDyn or are you unaware of this instability?

[ptrbortolotti]

@dzalkind I haven't run much of ElastoDyn for the blades. Have you seen this happening?

[dzalkind]

@MSaraber, thanks for making us aware of this! There were issues with the gains, which I have addressed in #74. I tested locally and it seemed to work fine at cut-out wind speeds.

[MSaraber]

Its also working for me now. Thanks for the help!