NREL 5MW baseline controller and Bladed Interface

Hallo,

I currently try to learn FAST to use it for a simulation of the DOWEC 6MW wind turbine. Therefore I had a closer look at the CertTest examples of the NREL 5MW baseline turbine and especially at the ServoDyn input file.

And as there is a bladed-style dll used to control the NREL 5MW in these examples, I tried to understand the Bladed Interface section of the ServoDyn input file. What’s clear so far is that in the first lines of that section the file name of the dll, the procedure name and the communication intervall have to be defined. However then there are a couple of parameters starting with BPCutoff and ending with GenPwr_Dem which seem to could be also defined. Then I had a look into the source code of the controller (DISCON.f90) and there I saw that some of these parameter like the Maximum pitch rate are hardcoded into that dll file.

So if I for example would like to change the maximum pitch rate is it sufficient to just change the corresponding parameter in the ServoDyn input file or do I have to change it in the dll and recompile the dll.

Thanks for your answers in advance.

Kind regards,
Paul

Dear Paul,

ServoDyn input parameters DLL_ProcName, DLL_InFile, DLL_DT, DLL_Ramp, and BPCutOff are described in the FAST v8 ReadMe file: wind.nrel.gov/nwtc/docs/README_FAST8.pdf. The remaining input parameters in the “BLADED INTERFACE” section of the ServoDyn input file (inputs NacYaw_North through GenPwr_Dem) are model-specific inputs available in the Bladed code, which are not otherwise available in ServoDyn, and are passed as parameters to the Bladed DLL in the interface. These inputs only need to be specified if the Bladed DLL you are using requires them. None of the Bladed DLLs that NREL has supplied for the NREL 5-MW turbine models require that these inputs be specified; instead, the parameters of the Bladed DLLs that NREL has supplied for the NREL 5-MW turbine models are hard-coded within the DLLs. You must recompile the DLL if you wish to change these parameters.

I hope that helps.

Best regards,

Dear Jason,

Thank you very much for your fast reply which clearly answered my question.

In fact, I already thougt that it should work just like you described it. However I felt not really certain with my idea of how it works, so it’s nice to get a confirmation for that. Thanks again.

Kind regards,
Paul