Implementing variable speed and collective pitch control for NREL 5MW turbine

Wind & Water Controls
1

Dear all,

I want to implement variable speed and collective pitch control for NREL 5MW blade. My simulation is based on 5MW_Land_BD_DLL_WTurb.fst. Since I’m recently to OpenFAST, there is no DISCON.dll file in the 5MW_Baseline/ServoData folder, but only a DISCON.F90 file. I don’t want to make any modification to the controller so I don’t want to compile the .F90 file. Instead, I copied a DISCON_x64.dll file from the FAST V8 archive instead but got the following warning:

fast_solution:fast_advancestates:srvd_updatestates:dll_controller_call:bladedinterface option was designed for an explicit-loose coupling scheme. using last calculated values from dll on all subsequent calls until time is advanced. warning will not be displayed again.

The reason for my implementing the control model is that I want to see the influence on blade root flapwise bending moment with or without pitch control, especially when the 10-min wind speed is beyond the rated wind speed. However I didn’t see any dropdown for blade root flapwise bending moment when pitch control is enabled compared with totally diable ServoDyn. I totally don’t know the reason except for the warning message above.

Could anyone help me solve this problem? Thanks in advance.

2

Dear @Tongzhou.Zhang,

Precompiled DLL versions of the baseline controllers for the NREL 5-MW baseline wind turbine models are available with the OpenFAST releases–see: Releases · OpenFAST/openfast · GitHub (you don’t need to go back to the FAST v8 archive for those).

The baseline controllers for these models are not targeted at reducing blade loads; rather, they focus on generator speed control. Independent blade-pitch control could be added to reduce blade loads.

Best regards,

3

Dear Jason,

Thank you for your kindly reply. In your technical report “Definition of a 5-MW Reference Wind Turbine for Offshore System Development”, you mentioned the usage of variable speed and collective pitch. Does the Discon.dll file in the figure below include these features? If not, I wonder how I can obtain the dll file that contains variable speed and collective pitch control features?

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Best regards,

4

Dear @Tongzhou.Zhang,

Yes, all of these DISCON controllers support variable speed and collective pitch.

Best regards,

5

Thank you for your kindly reply!