Yaw control

Wind & Water Controls
1

Hello you all. I need to do the yaw control with YCMode 4 (Simulink/Labview) and to activate it I set True the YawDOF on ElastoDyn.

------- ELASTODYN v1.03.* INPUT FILE ------------------------------------------- NREL 5.0 MW Baseline Wind Turbine for Use in Offshore Analysis. Properties from Dutch Offshore Wind Energy Converter (DOWEC) 6MW Pre-Design (10046_009.pdf) and REpower 5M 5MW (5m_uk.pdf) ---------------------- SIMULATION CONTROL -------------------------------------- True Echo - Echo input data to "<RootName>.ech" (flag) 3 Method - Integration method: {1: RK4, 2: AB4, or 3: ABM4} (-) 0.0001 DT - Integration time step (s) ---------------------- ENVIRONMENTAL CONDITION --------------------------------- 9.80665 Gravity - Gravitational acceleration (m/s^2) ---------------------- DEGREES OF FREEDOM -------------------------------------- False 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] False DrTrDOF - Drivetrain rotational-flexibility DOF (flag) False GenDOF - Generator DOF (flag) True 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)

But I have this error on the S-Function:

Error:An error occurred while running the simulation and the simulation was terminated
Caused by:
Error reported by S-function ‘FAST_SFunc’ in ‘fast_sim_actyaw/FAST Nonlinear Wind Turbine/S-Function’:
FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates(node 2, blade 1):BEMT_UnCoupledSolve:DeterminePhiBounds:There is no valid value of phi for these operating conditions! Vx = NaN, Vy = NaN, rlocal = NaN, theta = 0.19784.

Thanks in advance

2

Dear Ylenia,

As discussed several times on this forum, with the AeroDyn updated in OpenFAST v1.0.0 or newer, OpenFAST/AeroDyn will no longer abort if there is “no valid value of phi”. A warning message is displayed when this happens (although the situation should happen much less frequently), but the software is now robust enough to choose a suitable phi and continue without aborting. So, I would recommend upgrading to OpenFAST.

Regardless, though, I see NaNs in your solution, which points to a more serious problem with your simulation set up. How far into the simulation are you receiving this error? Does the solution appear to be unstable (e.g. the displacements growing without bound) for some reason?

Best regards,

3

Thank you Jason for your quick response. Now after setting 2 CompElast (the last time was setted to 1), 1 CompInflow, 2 CompAero, 1 CompServo I don’have NaNs but the problem persist and it’s shown up after 0.014s of 0.1 simulation seconds:

An error occurred while running the simulation and the simulation was terminated
Caused by:
Error reported by S-function ‘FAST_SFunc’ in ‘fast_sim_actyaw/FAST Nonlinear Wind Turbine/S-Function’:
FAST_Solution:FAST_AdvanceStates:AD_UpdateStates:BEMT_UpdateStates(node 36, blade 3):BEMT_UnCoupledSolve:DeterminePhiBounds:There is no valid value of phi for these operating conditions! Vx = -9.11774E-02, Vy = 19.529, rlocal = 0.21591, theta = 0.15896

I can see just this error. Should I run the BeamDyn in stand-alone mode to see if the model is unstable?
Best regards

4

Dear Ylenia,

As I stated before, upgrading to OpenFAST v1.0.0 or newer will eliminate any errors triggered by “no valid value of phi”. Until recently, the Simulink-FAST interface was not functional in OpenFAST, but this has since been resolved–see: github.com/OpenFAST/openfast/pull/204. However, there may be other things wrong with your model.

Is this a FAST model provided by NREL or a model you made yourself?

Best regards,