Generator Speed

Wind & Water Computer-Aided Engineering Software Tools
1

Hi,

I want to simulate my model under the wind condition of 12 m/s EOG. After some changes of the model, I found that the generator speed can not reach the limit value at EOG maximum speed 16.6 m/s. The turbine should be shut down when the EOG happens at the maximum wind speed due to the controller’s protection. But now the turbine is not shut down because the generator speed is below the limit value. I do not know which parameters influence the generator speed. I have simulated the shut down situation before. Now I can not simulate this case any more. Maybe some parameters changed cause this problem.

Thanks

Best regards

Yinping Yang

2

Dear Yinping Yang,

The generator speed is primary influenced by the balance between aerodynamic torque and the generator torque. The aerodynamic torque, in turn, is influenced by the wind speed, blade-pitch angle, turbine deflections, etc. The generator torque is influenced by the generator speed and/or more sophisticated control actions–depending on what torque controller you’ve implemented.

Best regards,

3

Hi,

Thanks. Finally I found the reason of this difference. When I use " DYNIN " method to model the aerodynamics, the machine will not shut down during the gust. If " EQUIL " is chosen, the machine will be shut down. The generator speed calculated by " DYNIN " is lower than that of " EQUIL ", and is below the limit value.

The pitch angle comparison reveals FAST does not have pitch actuator effects. I found this also in the control chapter of FAST’s theory manual. I want to add some actuator dynamics effects in the subroutine PitchCntrl() inside BladeDLLInterface.f90. After " Call BladedDLLInterface(…BlPitchCom…)" , I add something like:

IF ( BlPitchCom(NumBl)-BlPitch(NumBl) > 20 ) THEN
BlPitchCom(NumBl)=BlPitch(NumBl)+4
ENDIF

Is this correct ? Will it influence the results of normal calculations? Maybe you can give me some advice?

Thanks a lot

Best regards

Yinping Yang

Ptch.jpg
Ptch.jpg1280×692 63.1 KB

4

Dear Yinping Yang,

You can add blade-pitch-actuator dynamics inside routine PitchCntrl() as you wish. But the logic you listed in your post makes no sense to me. “BlPitch” is an array containing the current pitch-angle values of each blade when routine PitchCntrl() is called at each time step. “BlPitchCom” is an array containing the pitch-angle values of each blade that you want to command (these become the new pitch angles because FAST has no internal pitch-actuator dynamics). Both arrays contain the angles in the units of radians.

Best regards,

5

Hi,

Thanks. Have you ever realized the pitch actuator before? Maybe you can suggest me some papers or books that I can refer to. I want to add a basic primitive pitch actuator. I have not done this before.

Best regards

Yinping Yang

6

Dear Yinping Yang,

I have not implemented an actuator dynamics model into FAST myself, but you can find examples of this in Alan Wright’s controls design report: nrel.gov/docs/fy08osti/42437.pdf.

Best regards,