Hi,
You know developed control strategy for OC3-Hywind wind turbine model in ADAMS has got blade actuator model. How is it possible to exclude the actuator model from control strategy?
Suppose we use FAST to generate adm file, in this way, is there any option within fst file to divest the actuator impact from the model?
Regards,
Mehdi,
Dear Mehdi,
There is no way in ADAMS to model blade-pitch control without an actuator. To minimize the influence of the actuator, I suggest that you derive the equivalent actuator spring constant used in the FAST-to-ADAMS preprocessor (BPActrSpr) based on a high natural frequency of the second-order actuator (e.g., for the NREL 5-MW turbine, we’ve used 30 Hz, resulting in an actuator spring constant of BPActrSpr = 971350000 N*m/rad).
Best regards,
Dear Jonkman,
Could you tell me how to get the stiffness and damping of the pitch actuator in your 5MW model?
In fact, I have tried to get the stiffness and damping as yaw actuator defined in FAST, as the inertia of blade about pitch axis is unknown, so i try to get the inertia inversely through stiffness and damping, but the inertia got from stiffness and damping are not the same, so could you tell me how to get the equivalent value for the stiffness and damping of the pitch actuator?
The calculation process is as below:
f=30,ζ=0.02,k=971350000,c=206000
wn=2pif=188.5
m1=k/wn^2=971350000/188.5^2=27338.43
m2=c/(2ζwn)=206000/(20.02188.5)=27320.6
As you can see, the m1 and m2 are not exactly the same, so are the way to get stiffness and damping right?
Best regards,
Chenen
Dear Chenen,
I agree with your calculations. The difference in the pitch inertias between the two calculations is likely related to numerical round in some of the values. The pitch inertia I used in the original calculation of BPActrSpr and BPActrDmp for the NREL 5-MW baseline wind turbine was 27338.44 kg*m^2
Best regards,