Learizing Baseline 5MW Wind Turbine with FAST


I’ve a question regarding getting a linearized model of the 5MW wind turbine.
I want to get a linearized model of the wind turbine in Region 3. and I’ve used the 5MW baseline wind turbine model, with the settings as indicated in FAST user manual. here is a summary of these settings

Linearization works fine, FAST converge after 65 steps (time=322 secs).
As I don’t have any rotating states, I’ve used the “cce.m” code to get the Average natural frequencies. and I get the following results.

Now my Question is: I know that the first two natural frequencies (0.32616, 0.32143) are related to tower first fore-aft and side-to-side modes, as I get similar values if I run the same Linearization but this time setting GenDOF to false so I get (0.32665, 0.31636). but what about the other two natural frequencies, and their corresponding damping ratios and mode shapes. how could I interpret them.

Best Regards
Rannam Chaaban.

Dear Rannam,

The generator DOF results in a rigid-body mode, which in MBC3 shows up as a pair of zero-valued (or near-zero-valued) frequencies with +/- inf damping.

See the following post for more guidance on how to interpret the full-system mode shapes resulting from application of a FAST linearization and MBC3: http://forums.nrel.gov/t/eigenanalysis-fast/362/1.

I hope that helps.

Best regards,

Dear prof Jonkman
I am enter to linearize the 5MW Baseline wind turbine, I afollow all the steps on the post Fri Apr 27, 2012 3:38 pm and i named the file"Test30.fst" and the User guide of FAST
When i run the script “open loop.m” an error occur
Attempted to access CertTest_TMax(30); index out of bounds because numel(CertTest_TMax)=26.

Error in Run_OpenLoop (line 29)
TMax = CertTest_TMax(iTest);

If you can help me pleaze if i do somethings wrong or what

Bets regards

Dear Ali,

I’m not sure what you are trying to do. Run_OpenLoop.m is a MATLAB script for running the complete FAST CertTest using the interface between FAST v8 and Simulink. However, if you want to linearize a model, you should not be using FAST v8 and you should not be using Simulink. The linearization functionality of FAST is available in the standard (executable) version of FAST v7.02, available from here: nwtc.nrel.gov/FAST7. We are working to add linearization functionality into FAST v8, but it will be a while before this is available.

Best regards,

Than kou very much for your reply Mr
I have used the vesrion the vesrion 7 to do the linearization of 5 MW Baseline wind turbine
After i did the modification necessay in the file and when i run ths simulink, an error occur
NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis.

Running NWTC Subroutine Library (v1.07.00b-mlb, 10-Jan-2013).

Running FAST (v7.02.00d-bjj, 20-Feb-2013)-Compiled as S-Function for Simulink.

Heading of the FAST input file: NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis.
FAST can’t linearize the model when interfaced with Simulink or Labview. Set AnalMode to 1 or
use the standard version of FAST.

Aborting FAST.

If you can please tell me what means this error

Best regards

Dear Ali,

The error message is quite descriptive. You can’t run a FAST v7 linearization analysis using the Simulink interface. Either use the executable version of FAST v7 or disable linearization. The Simulink interface to FAST v7 is only useful for running time-marching analyses.

Best regards,

Thank very much
If you can tell me what i do exctelly
Really i am stoped at this stage

Dear Ali,

I’m sorry, but I don’t know what your problem is. Can you run the FAST.exe from a command prompt?

Best regards,

Yes I run the FAST.ex in the command prompt of windows 7
This what it gives:
Runing FAST < V7.02.00d-bjj, 20-Feb-2013>
Input File,“primary.fst” not foud
Aborting FAST

Dear Ali,

To run FAST from a Windows command prompt, the syntax is:

To start, it easiest to open up your command window in the directory in which your FAST primary input file and FAST executable are stored. For example, if you have an input file named “Input.fst”, along with “FAST.exe”, stored in “C:\FileLocation”, you should type:

C:>cd FileLocation
C:\FileLocation> FAST Input.fst

The syntax is the same for different input files. Simply change “Input.fst” to whatever input file you want.

Best regards,

Thank you very much Mr for your reply
I did what you tell me , but now an error occur
In valid numerical input for file: NRELOffshrBsline5MW_Tower_Onshore.dat
The error is occured while tryong to read TwrFADmp(1)
Aborting FAST
Really i am sorry for this lot of question, but i would like to work with this great tool

Dear Ali,

A complete FAST v7 model of the onshore NREL 5-MW turbine is available here: wind.nrel.gov/public/jjonkman/NR … nshore.zip. Did you modify these input files in some way?

Best regards,

I have tested with this file
It gives me somethings, an error is given at the wind profile not found
I have used a step, and “90m_12mps_twr”
an error is occured: No file extension found. Assuming.\WinData\9M_12mps_twr is a binary FF file …
The input file \WinData\9M_12mps_twr was not found Could not initialize Aerodyn
Aborting FAST

Dear Ali,

The error message in your text doesn’t seem to match the error message in your attachment. Regardless, I didn’t include the wind data file in the NREL 5-MW archive I linked to in my prior post and I’m not sure what wind file you are trying to use. I’ve attached a wind data file containing steady 12-m/s wind suitable for model linearization in FAST v7, which is in AeroDyn’s so-called “hub-height” format. Download this file and enter the name (optionally including path) as WindFile on line 10 of the AeroDyn primary input file.

Best regards,
12ms.txt (232 Bytes)

Thank you very much it works well
The wind profile depndends on the operation point where we want to linearize the system I think Mr JONSON
It gives me somethings as this image if you can tell me what means this


The 5MW model uses a Bladed-style DLL controller, which is a special recompiled version of FAST v7. The executable you need should be in the zip file Jason linked to on Nov 13. The error message comes because it is trying to use a different controller.

The DISCON.ddl?
I run it directely on prompt comman or there is another way to use it


You need to use the FAST executable that is in the zip file (not the FAST executable that is in the standard FAST archive on our web site). It will call the DISCON.dll. You cannot just call the dll from a command line.

Dear JOnkmann
The zip file :wind.nrel.gov/public/jjonkman/NRELOffshrBsline5MW/NRELOffshrBsline5MW_Onshore.zip, dont contain any FAST.
Only one executable FAST vesrion I found it in the FAST Archive
Can you explain plus about that

In fact i have used a FAST executable found in the archive"NRELOffshrBsline5MW_OC3Hywind.zip" and another error occur if you have an idea about when comes this error tell me please


Dear Ali,

A suitable executable of FAST v7 with the standard interface to Bladed-style DLL controllers is available here: wind.nrel.gov/public/jjonkman/NR … nshore.zip.)

However, I believe you are trying to linearize the NREL 5-MW FAST v7 model, correct? To linearize a model, you’ll have to disable active pitch and torque control from the DLL i.e. set PCMode = 0 and VSContrl = 0 or 1, depending on what type of trim case you are considering (with TrimCase = 3, set VSContrl = 1 and VS_RtTq to the desired constant generator torque – see the “Linearization” section of the old FAST User’s Guide for more information: nwtc.nrel.gov/system/files/FAST.pdf.) Once you disable active pitch and torque control from the DLL, you can use the standard executable of FAST v7 provided in the FAST v7 archive.

Best regards,