Questions about simulation results of 5MW by FAST

Dear Jason.Jonkman,
A test of 5MW Reference wind turbine is simulated.But i have some questions about the results
Simulation conditions: 18m/s Turbulent Wind
For Initial conditions,i set BlPitch(1)/(2)/(3)=14.92°, RotSpeed=12.1rpm
In my pitch control strategy , i set : if rotor speed >rated rotor speed, then generation torque= rated torque
but FAST’s results of previous 100 simulation steps are not same as theory. since 100 steps ,The simulation results by FAST are very consistent with the theoretical results.
The results of first 34 step(each step= 0.015s) are as follows:

From the figure , when wind speed is about 15m/s, greater than rated wind speed, rotor speed is greater than rated speed.
But the generation torque(0~16kN) is far less than the rated torque(43kN) ?
and pitch angle is 0 degree?

Look forward to your help,Thank you!

jucy leo

Dear Jucy Leo,

I agree that the torque and pitch results do not look correct for the NREL 5-MW turbine.

From your post, it sounds like you have developed your own control strategy. The problem seems to be related to this controller, so, I think you’ll need to debug the problem yourself.

If you’d rather use the controller NREL has developed for the 5-MW reference turbine, please see the post found here:

I hope that helps.

Best regards,

Dear Jason Jonkman,
Thank you for your help and fast answer. i think i have fond the reason. Because i add a low pass filter and notch filter for feedback speed Signal(GenSpeed). If i remove the filters, generation torque is right. That’s why after 100 steps, simulation results are normal.
Now i simulate 5MW model By FAST and Simulink. you suggest me to use your controller, that’s a good idea. But if i add new control strategy such as Tower vibration control, so i must add new code in your cotroller, i must make a new DLL-file, is this understanding right?
For Dll-file Compiling,should i install a software named “Fortran90” as you described in FAST manual?

Jucy Leo

Dear Jucy Leo,

The answer to both of your questions is “yes.” You must recompile the DLL if you want to modify the baseline NREL 5-MW controller. You will need a Fortran compiler for this.

Best regards,