Problem running Test18.fst in Simulink by Changing TMax using FAST_8.16

Dear David,

I’m sorry, but I don’t understand your question. What output parameters are you seeking?

Best regards,

Hello Dear Jason,

I thank first for their quick reply. My goal is to implement in Simulink for Test18.fst an active tower-damping controller and Drive Train Damping Controller. But I’m having trouble and I can not find any papers that can help me. Please, maybe you have an idea or papers that could help me. I would be very grateful for that.

Best Regards,
David

Dear David

I would review the following journal article:

Bossanyi, E. A., “Wind Turbine Control for Load Reduction,” Wind Energy, Vol. 6, No. 3, June 2003, pp. 229–244.

Best regards,

Dear Jason,

Tkank you ever so much!. I try to find the journal article.

best regards

Dear Jason,

I found the document. Please how can I determine the paramter M, D, K and F of the second order system ?. You told me that it is not possible with FAST v8.
Is the output “TTDspFA” the tower fore-aft velocity?

best regards

Dear David,

As discussed in the following forum topic: http://forums.nrel.gov/t/how-to-find-the-paramter-of-the-first-bending-modal-mass-damping-and-stiffnees-coefficients/1594/2, FAST v8 returns the linearized model in first-order form. So, while you can’t get the second-order matrices M, D, K, and F, you can get the same terms normalized by the mass matrix i.e. I, [ M^-1 ]*D, [ M^-1 ]*K, and [ M^-1 ]*F through the FAST v8 linearization analysis. This first-order form should also be amendable for controls design.

See the OutListParameters.xlsx file provided in the FAST archive for the complete list of ElastoDyn output parameters. TTDspFA is the tower-top fore-aft deflection. As discussed in the following forum topic, while you can get the tower-tip deflections and accelerations, the tower-top translational velocities are not currently output parameters available from ElastoDyn: http://forums.nrel.gov/t/output-parameters-of-tower-top-yaw-bearing-motions/1591/2.

Best regards,

Dear Jason,

Please can you help me?. I have difficulties with the linearization to determine the Pamrater M, D, K and F.

I want only enalbel the DOF “Tower fore-aft mode”. For this I set following DOF in Elasto.Dyn:
---------------------- DEGREES OF FREEDOM --------------------------------------
True FlapDOF1 - First flapwise blade mode DOF (flag)
False FlapDOF2 - Second flapwise blade mode DOF (flag)
False EdgeDOF - First edgewise blade mode DOF (flag)
False TeetDOF - Rotor-teeter DOF (flag) [unused for 3 blades]
True DrTrDOF - Drivetrain rotational-flexibility DOF (flag)
True GenDOF - Generator DOF (flag)
False YawDOF - Yaw DOF (flag)
False TwFADOF1 - First fore-aft tower bending-mode DOF (flag)
False TwFADOF2 - Second fore-aft tower bending-mode DOF (flag)
False TwSSDOF1 - First side-to-side tower bending-mode DOF (flag)
False TwSSDOF2 - Second side-to-side tower bending-mode DOF (flag)
False PtfmSgDOF - Platform horizontal surge translation DOF (flag)
False PtfmSwDOF - Platform horizontal sway translation DOF (flag)
False PtfmHvDOF - Platform vertical heave translation DOF (flag)
False PtfmRDOF - Platform roll tilt rotation DOF (flag)
False PtfmPDOF - Platform pitch tilt rotation DOF (flag)
False PtfmYDOF - Platform yaw rotation DOF (flag)

RotSpeed = 12.1 rpm

In ServoDyn.dat I set:
PCMode = 0;
VSContrl = 1 and set the of SIMPLE VARIABLE-SPEED TORQUE CONTROL to the values extra from Document Definition of a 5-MW Reference.

I use a Windtype = 1 with Wind = 12 m/v

I run the Model and get the data “Test18.SFunc.1.lin” and “Test18.SFunc.2.lin”

After running the file “GetMats_f8.m”, I get the Matrix AMat (10x10).

  1. Are my procedures with this configuration correct?
  2. If yes, Please how can I convert this matrix to have the parameters M, D, K and F?
  3. If no, how can I proceed?

Thank you in advance,
Best regards, david

Dear David,

If you only want to enable the first tower fore-aft mode DOF, why haven’t you enabled it, and why did you enable other DOFs. Set FlapDOF1 = DrTrDOF = GenDOF = False and TwFADOF1 = True. The result will be A of size 2 x 2.

I don’t know what you mean when you say, “set the of SIMPLE VARIABLE-SPEED TORQUE CONTROL to the values extra from Document Definition of a 5-MW Reference”, but once you disable the generator DOF, the torque control models won’t have any effect anyway.

Best regards,

Hello Dera Jason,

after the Linearization with: TwFADOF1 = True, DrTrDOF = True, RotSpeed =12.1, PCMode = 0, VSContrl=1; Windtype = 1 with HWindSpeed=12m/s.
I get the following Matrix:

AMat =

        0            0               1            0
        0            0                0            1
   -4.234      0.03072      -0.3436       0.8568

-0.0006466 0.0007049 -0.02692 -0.06755

From AMat:
-[M^1]*K = [-4.234, 0.03072; -0.0006466, 0.0007049]
-[M^1]*C = [-0.3436, 0.8568; -0.02692, -0.06755
I =[1, 0; 0, 1]

Please, is it possible to calculate M, K, C and F from this matrix?. I find no way

Thank you in advance,
Best regards

Dear David,

As I said before, you can’t directly get M, C, K, and F because FAST v8 linearization does not output M, but you can get I, [ M^-1 ]*C, [ M^-1 ]*K, and [ M^-1 ]*F. The latter, [ M^-1 ]*F, is available in the B matrix instead of the A matrix. This first-order form should also be amendable for controls design.

Best regards,

Dear Jason,

Thank you for your answer.

Best regards

Hello Jason,

Please I have quetion about the simulation of IPC 2P. I use a Swith Block to turn my IPC
When I simulate the IPC, must IPC also be active? I mean IPC 1P On and IPC 2P on for the IPC 2p

Because when I turn: I IPC 1P off and IPC 2P on, CPC on, I don’t get the The right plots
and When I IPC 1P on and IPC 2P on, CPC on, I can get the load reduction

For example:
For example, in the image of Yaw Moment (left), IPC 1P and 2P were on
And right was simulate when only IPC 2P on and IPC 1P off

My question is: To simulate IPC 2P, must IPC 1P be active?

Thank you in advance,

Best Regards

Hello Dear Jason,

Please, for the implementation of a Tower for-aft movement damping controller, I find the in OutListParemeters the Parameter YawBrTAxp, YawBrTAyp and YawBrTAzp and all this three Parameters are for the Tower fore-alt acceleration.

My question: Which parameter can I use als Output in ElastoDyn for the Tower fore-alt acceleration?. I use YawBrTAxp, but I’ m not sure

Thank you in advance,

best regards.

Dear David,

From the OutListParameters.xlsx spreadsheet provided in the FAST archive:

YawBrTAxp; Tower-top / yaw bearing fore-aft (translational) acceleration (absolute); Directed along the xp-axis; (m/s^2)
YawBrTAyp; Tower-top / yaw bearing side-to-side (translational) acceleration (absolute); Directed along the yp-axis; (m/s^2)
YawBrTAzp; Tower-top / yaw bearing axial (translational) acceleration (absolute); Directed along the zp-axis; (m/s^2)

I’m not sure why you say these three all tower fore-aft acceleration, but you are correct that YawBrTAxp is the one you want.

Best regards,

Dear Jason,

Thank you for your quick response

Best regards

Hello Dear Jason,

For the simulation of a Tower for-aft movement damping controller, are the file “NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat” and “NRELOffshrBsline5MW_Onshore_AeroDyn_Tower.dat” to be inserted in inputfile “Test18.fst”? Or do not you need it?

thank you in advance,

Best regards

Dear David,

The file “NRELOffshrBsline5MW_Onshore_ElastoDyn_Tower.dat” is already used by Test18–but it is referenced from “NRELOffshrBsline5MW_Onshore_ElastoDyn.dat”, rather than from “Test18.fst”.

The file “NRELOffshreBsline5MW_Onshore_AeroDyn_Tower.dat” is only used with AeroDyn v14. Test 18 uses AeroDyn v15, and so, “NRELOffshreBsline5MW_Onshore_AeroDyn_Tower.dat” is not needed unless Test 18 is changed to use AeroDyn v14. Even then, “NRELOffshreBsline5MW_Onshore_AeroDyn_Tower.dat” is referenced from the AeroDyn v14 primary input file (“NRELOffshrBsline5MW_Onshore_AeroDyn.dat”), rather than from “Test18.fst”.

Best regards,

Hello Dear Jason,

please, I have questions about the Tower fore-aft controller.
Which parameters represents the he tower fore-aft bending moment? I use the Parameter YawBrTAxp as the fore-aft acceleration.

I want to use a second-order filter between the fore-aft acceleration and the Loop Gain, Please do you have an idea how I can find the parameters of the filter?

thank you in advance
best regards

Dear Jason,

It was indicated in one of your responses that “alternatively, you could also output the nonrotating bending moments in the low-speed shaft i.e. LSSTipMzs (yaw) and LSSTipMys (tilt)” to establish a feedback for individual pitch control. I have performed modeling of the 5 MW wind turbine using a modified version of FAST that enables teetering about the Y and Z axes. Results show values of LSSTipMzs and LSSTipMys are almost zero for the teetering hub, indicating that teetering achieves a balanced out-of-plane loading across the rotor disk. Hence, teetering and IPC can be considered alternate approaches to achieving the goal of balancing the out-of-plane loading and thus reducing the cyclic loading on various components of the wind turbine.

For this reason, I would like to compare IPC with teetering using identical wind profiles and hopefully publish the results. I would like to know if you (or any members of the FORUM) know of a modified version of FAST that is available for download and that allows for IPC. Ideally, this would use an algorithm that is recognized as providing the optimal results.

Best regards,
Arnold Ramsland

Dear Arnold,

I don’t personally have a sample controller compatible with FAST that employs independent blade-pitch control (IPC), but I’ve seen many papers in the past with IPC, so, I"m sure there are appropriate controllers around. Hopefully someone else following this forum can respond.

Best regards,