Transfer function

Wind & Water Computer-Aided Engineering Software Tools
1

Hello,

Currently, I am working on the pitch control, so I use this file : https://github.com/OpenFAST/r-test/blob/main/glue-codes/openfast/WP_VSP_ECD/pitch.ipt

And this option in NRELOffshrBsline5MW_Onshore_ServoDyn.dat : 3 PCMode - Pitch control mode

With this configuration I can control the coefficients of Tf :

1 Order of tf #1 (highest power of s), input=Rotor speed (RPM), output=Integral Pitch demand (deg)
2.22 0.0 Numerator coefficients (Order+1 values, ascending powers of s)
0.0 1.0 Denominator coefficients (Order+1 values, ascending powers of s)

0 Order of tf #2 (highest power of s), input=Rotor speed (RPM), output=PD Pitch demand (deg)
5.14 0.08 Numerator coefficients (Order+1 values, ascending powers of s)
1.0 0.02 Denominator coefficients (Order+1 values, ascending powers of s)

0 Order of tf #3, input=Tower accel, output=pitch (deg) (Use 0 to not include tower feedback cntrl)
9.64 1.4 Numerator coefficients (Order+1 values, ascending powers of s)
0.358 1.0 Denominator coefficients (Order+1 values, ascending powers of s)

2 Order of tf #4, input=Pitch demand(deg), output=pitch (deg)
85 0.0 0.0 Numerator coefficients (Order+1 values, ascending powers of s)
85 3.703 1.0 Denominator coefficients (Order+1 values, ascending powers of s)

So my first question is about the PCMode 5 : user-defined from Bladed-style DLL. Where can I find the coefficients for this mode ?

My second one is about the pitch.ipt, Where can I find the PID diagram ?

Best Regards

Hugo BONTEMPS

2

Dear @Hugo.Bontemps,

Just a few comments:

  • The pitch.ipt file is used by the example user-defined pitch controller implemented in PitchCntrl_ACH.f90 (https://github.com/OpenFAST/openfast/blob/main/modules/servodyn/src/PitchCntrl_ACH.f90) selected via PCMode = 3 in ServoDyn. This was the baseline pitch controller used in the old WindPACT studies and is documented in Appendix E of the following report: https://www.nrel.gov/docs/fy06osti/32495.pdf.
  • In the OpenFAST r-test, this example pitch controller is used by the WindPACT 1.5-MW baseline wind turbine models, but not the NREL 5-MW baseline wind turbine models.
  • The NREL 5-MW baseline wind turbine models make use of a pitch controller implemented as a Bladed-style DISCON controller (PCMode = 5 in ServoDyn). This controller does not make use of the Pitch.ipt file.

I hope that helps.

Best regards,

1 Like
3

Dear @Jason.Jonkman

Thank you for your fast answer.

Best Regards

Hugo