Problem about baseline controller of NREL 5MW wind turbine

This forum if for discussing controls. Questions about how to implement controls in FAST are more appropriate to the CAE Tools forum.

Moderator: Bonnie.Jonkman

Yanhua.Liu
Posts: 34
Joined: Mon Feb 29, 2016 5:22 am
Organization: University of Hull
Location: HULL,UK

Problem about baseline controller of NREL 5MW wind turbine

Postby Yanhua.Liu » Tue Jul 05, 2016 3:49 pm

Hi all,

I am trying to design baseline torque controller and pitch controller as the description of Chapter 7.2 and 7.3 of this Pdf " http://www.nrel.gov/docs/fy09osti/38060.pdf" .Now I have some confusion about the baseline torque controller. The curve between generator torque and generator speed is like the blue one in Figure 1
Figure 1.jpg
Figure 1.jpg (79.25 KiB) Viewed 1757 times
. I set the wind speed is a constant 18m/s and results are obtained like in Figure 2. You can see the generator power and torque both have some fluctuation at near 11s -16s which is caused by the little fluctuation of the rotor speed. I found this is because when the generator speed vibrates lightly between region 2 1/2 and region 3, the output torque and power have a big fluctuation showed in Figure 2
Figure 2.jpg
Figure 2.jpg (74.01 KiB) Viewed 1757 times
. I think the fluctuation of generator power like in Figure 2 is caused by the region 2 1/2. What's the purpose of the region 2 1/2?

Because the above problem, when I set the wind speed as changing, the generator power fluctuated too much like in Figure 3
Figure 3.jpg
Figure 3.jpg (87.74 KiB) Viewed 1757 times
. Can anyone help me to explain or solve this problem? It drives me crazy. Thank you so much!

All the best.

Yanhua

Jason.Jonkman
Posts: 3753
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: Problem about baseline controller of NREL 5MW wind turbi

Postby Jason.Jonkman » Wed Jul 06, 2016 1:39 pm

Dear Yanhua,

Region 2 1/2 exists to limit tip speed (and hence noise emissions) at rated power i.e. without it, rated power would not be reached until a much higher speed.

To eliminate the drastic drops of torque and power in Region 3, the NREL 5-MW baseline controller places uses a conditional statement so that the torque is computed as if it were in Region 3--regardless of the generator speed--whenever the blade-pitch-angle command exceeds 1 deg, as explained in Section 7.2 of the NREL 5-MW specifications report that you referenced.

I hope that helps.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov


Return to “Controls”

Who is online

Users browsing this forum: No registered users and 1 guest