I am working on a project where the wind turbine knows the wind FF data ahead of time (say by 2-3 seconds), so that it can react on feed forward measurements (rather than feedback measurements). The objective is to show that performance can be improved when you sense wind speed ahead of time.
I have a few questions regarding the same.
- Is it possible to model feed forward-based control on FAST_v7? Either using the executable (by modifying the code) or using Simulink?
I am assuming it is possible, since the wnd files are generated before running the fst files. So technically, FAST knows what wind is going to hit the turbine at every instant before simulation begins. If the present time is T, FAST can then access the wind data of time (T+t) from the wnd file and then use it in the control algorithm.
- If it is possible, which option would be better? Should I opt for creating my own control algorithm and link it to the executable (I’m not familiar with FORTRAN, so this might be harder) or would Simulink interface be able to provide the necessary features for feed forward control?
P.S. I just joined this forum; I started using FAST only a couple of weeks ago and I was amazed to see such great work being done in developing FAST and the support being provided on this forum. Kudos!
There has been quite a bit of work on feedforward controls using FAST in the past few years by NREL and CU Boulder (as well as others).
The short answer is that yes, FAST v7 can be modified to get wind speeds ahead of the turbine. Perhaps the group at CU Boulder would be willing to share some of their code for FAST v7; otherwise you’ll have to make some (small) code changes to get the wind speed you want.
If you use FAST v8, you don’t need to change or recompile the code. In the InflowWind input file, specify a location ahead of the turbine where you want the wind speed measurement (i.e., set variables WindVxiList, WindVyiList, and WindVziList to the position you want, then request the velocities as output in the “OutList” section of the same input file). The easiest way to take advantage of these outputs is to use them in Simulink, just like you would with any other measurements coming from FAST.
If you use Simulink with FAST v8, you also have the option to use the undocumented lidar module, which can simulate lidar measurements ahead of the turbine. Because that is undocumented, though, it will probably take a little more effort to figure out what it’s doing.
Thank you, I’ve decided to use FAST v8.
Is the desired feature (getting velocities ahead of turbine) available in the binary turbsim FF files?
This feature is available for all wind formats currently implemented in the InflowWind module (.bts. .wnd, uniform, steady, HAWC, etc.)
I need to know the wind speed at many points in the plane ( more than 9 ) a few seconds before it reaches the turbine.
The maximum value that NWindVel takes is 9.Using NWindVel and the WindVxi list method I am unable to output wind speeds at more than nine points at a given time instant.
Is there a way to increase this limit or some other method to know the wind speeds at many points a few seconds before ?
If you’d like to access the undistributed wind upwind of the turbine within a FAST simulation at more than the 9 points NWindVel is limited to, you’ll have to make a minor modification to InflowWind and recompile FAST.
Though not “officially” documented, the LIDAR module of FAST may also be of interest to you: http://forums.nrel.gov/t/linking-measured-wind-data-from-lidar-to-turbsim/1043/8.
Apart from the FAST simulation, the standalone InflowWind driver is also useful for analyzing wind data that will be used in a FAST simulation: nwtc.nrel.gov/InflowWind/. In the standalone InflowWind driver, wind data can be output at a set of user-specified points or in a gridded volume.
Thanks a lot for answering my questions so fast.
I will definitely look into the methods you suggested.
I was able to implement the LIDAR module but I still have a few problems with finding wind information in a plane before it hits the turbine.
I used the CW LIDAR option.
‘WindMeas1’ is the wind velocity in which direction and at which point?Is it at the set focus?
I need to know the velocity of the wind at various points in a plane before it hits the turbine at a given time instant.
I just need the wind speed in the x direction.
Please may you tell me as to how I can get the wind speeds at at least 20 to 30 points in a plane in the x direction at a given time instant using the LIDAR module.
In case I want to know the exact wind speeds at these planes as compared to the measured values what should I do?
Is there any major problem with the LIDAR module ( as its not documented) ?
Sorry, but I have no experience with the undocumented LIDAR module and cannot comment on it. Hopefully someone else on this forum can comment.
Thank you for replying fast.
I have also posted these questions in another thread.