Simulation of an offshore Wind turbine 5MW based DFIG

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Mon Aug 08, 2016 9:20 am

Dear Ali,

According to the error message you are receiving, it looks like your wind file stores 88.6 seconds of data, but your simulation is trying to access data at 88.611 seconds. You'll need to run TurbSim longer to run longer FAST simulations; normally, TurbSim is run for over 10-minutes in length.

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

Ali.Elyaakoubi
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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Sun Aug 14, 2016 7:30 am

Thank you so much for your response
Please I am wondering somes output parameters clarification :
Bending moments at the main bearing at 0° and 90° are respectively LSSTipMya and LSSTipMza
What means Rotating shear force at the main bearing, and what are the outputs in FAST related to the parameters at 0° and 90°.

Sinceerly yours

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Mon Aug 15, 2016 7:11 am

Dear Ali,

I'm sorry, but I'm not really sure I understand your question. A few comments:
  • Normally ElastoDyn input parameter ShftGagL is used to locate the main shaft bearing from the rotor apex. The outputs at the main bearing then have names starting with "LSSGag". The outputs with names starting with "LSSTip" are at the end (tip, rotor apex) of the low-speed shaft (LSS).
  • Normally "0° and 90°" refer to measurements normal to each other such as LSSGagMya and LSSGagMza, or LSSGagMys and LSSGagMzs.
  • "Rotating" and "nonrotating" refers to whether the output load is in a coordinate system that spins with the shaft or fixed in the nacelle. The shaft system ("s") does not spin with the shaft; the azimuth system ("a") does spin with the shaft.
  • E.g. output LSSGagMya is orthogonal to LSSGagMza and both are expressed in a coordinate system that spins with the shaft. Output LSSGagMys is orthogonal to LSSGagMzs and both are expressed in a coordinate system that is fixed in the nacelle.
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

Ali.Elyaakoubi
Posts: 94
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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Mon Aug 15, 2016 8:31 am

Thank you for your explication
These are the rotating and the non rotating bending moment at the shaft's strain gage, its right.
But I found in some paper the output "Rotating shear force at the main bearing" to quantify I think the loads at the main bearing
Tell me if I am wright and what is the output related to that

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Mon Aug 15, 2016 8:46 am

Dear Ali,

The rotating and nonrotation shear force outputs at the main bearing are named LSSGagFya and LSSGagFza (rotating) and LSSGagFys and LSSGagFzs (nonrotating).

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

Ali.Elyaakoubi
Posts: 94
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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Sat Nov 26, 2016 10:37 am

Dear Jason
I hope you are fine
Please i met a problem when i wanted to work with aeroDyn v15
In fact I have indicated the path in the test.18 to the file of the aeroDyn V15 rather that aeroDyn for v14, and i have changed compaero to 2 but the simulation doesn't run
I want to perform the time simulation in order to obtain an approachable value for TSR of the 5MW, elsewher how i can obtain the TSR with the v14

I wil appreciate your help
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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Mon Nov 28, 2016 7:12 am

Dear Ali,

It's hard to know what you are doing wrong without seeing your input files, but from the error message you are receiving, I suspect you having set CompAero to 2 in the FAST primary input file.

It appears that you are using a version of FAST v8 that is not quite the newest. FAST v8.16 was released in July. Unless you have a specific reason for using an older version, I suggest that you upgrade to the newest version, available from here: https://nwtc.nrel.gov/FAST8. In FAST v8.16, Test18 is already set up to use AeroDyn v15.

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

Ali.Elyaakoubi
Posts: 94
Joined: Wed Oct 21, 2015 8:43 am
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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Tue Mar 14, 2017 2:16 pm

Dear Mr janson
I want to extrait the rotating force at the main bearing LSSGagFza and LSSGagFya in Simulink (u(strmatch('LSSGagFza',OutList))). I have listed the parameters in the ElastoDyn output list but an error occured:
[url]The expression: u(strmatch('LSSGagFza',OutList))
in 'NREL5MW/Fcn6'
has a syntax error[/url]

Please a help

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Tue Mar 14, 2017 4:36 pm

Dear Ali,

From your description, I don't see anything wrong with what you've done. But I don't run Simulink often enough to know what would trigger this error. Hopefully another forum user can comment as to what could be the cause.

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

Ali.Elyaakoubi
Posts: 94
Joined: Wed Oct 21, 2015 8:43 am
Organization: abdelmalek Essaadi University
Location: MOROCCO

Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Thu Mar 16, 2017 1:18 pm

Dear jason
Tell me if I am right
To calculate the PI parameters of the pitch controller the 5MW WT, we can use the relation rather than the lineraization:
Kp=kp(theta=0)*GK(theta)

Ki=ki(theta=0)*GK(theta), where GK(theta)=1/(1+theta/theta_k) (theta_k=6.30°)
For example at the wind speed v=15 m/s, Ω=12.1 rpm, theta=10.45°, then we replace in the previous equation and we can obtain the PI parameters at the defined point: Kp= 0.0071, Ki= 0.0030 (wind =15 m/s)

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Thu Mar 16, 2017 2:39 pm

Dear Ali,

Yes, your understanding is correct. Of course, the gains at theta=0 and theta_k depend on the turbine design, derivable from through FAST linearization.

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

Ali.Elyaakoubi
Posts: 94
Joined: Wed Oct 21, 2015 8:43 am
Organization: abdelmalek Essaadi University
Location: MOROCCO

Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Thu Mar 16, 2017 4:31 pm

Thank you very much Jonson for your reply
When I have implemented the Pi pitch controller with the calculated parameters( Kp= 0.0071, Ki= 0.0030), there is a large divergence from the gain scheduling controller. My simulation have been done by a turbulence wind speed of 15 m/s mean value, i.e around the point of linearization where the controller is acted on the generator error. I expected that the result don't coincide with that of the baseline controller due the changes of the wind speed and therefore the operating point, but in my simulation there s a large divergence. Can you please tell me what causes be to that divergence.

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Thu Mar 16, 2017 4:51 pm

Dear Ali,

I don't know enough about the details of what you have done to know why your controller yields different results than the baseline controller, but of course, the gain scheduling in the baseline controller will certainly have some influence--more so for higher levels of turbulence. Are you using the torque-speed curve in your controller that the baseline controller is using?

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

Ali.Elyaakoubi
Posts: 94
Joined: Wed Oct 21, 2015 8:43 am
Organization: abdelmalek Essaadi University
Location: MOROCCO

Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Ali.Elyaakoubi » Thu Mar 16, 2017 5:29 pm

I don't understood well what you mean by "the torque-speed curve in your controller that the baseline controller". But I writ you some details about the simulation
My simulation was done in the region 3 of wind turbine operation, so the torque is kept fixed at the optimal value, and the turbine is controlled to regulate its produced by means of the pitch controller. I have simulated the gain scheduling controller, that i have called baseline controller, for comparison purposes and the controller worked well. My aim now is to design a linear controller (PI), so a linearization of the wind turbine must be given to derive the system parameters. I am using the relations to calculate the parameters PI around wind=15 based on the report of the 5 MW WT:
Kp=kp(theta=0)*GK(theta)

Ki=ki(theta=0)*GK(theta)
So implemented the PI so my problem is that the results are farm from that of the gain scheduling

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Re: Simulation of an offshore Wind turbine 5MW based DFIG

Postby Jason.Jonkman » Thu Mar 16, 2017 8:21 pm

Dear Ali,

The baseline controller for the NREL 5-MW turbine does not keep torque fixed in Region 3; instead, power is kept fixed in Region 3 by deriving the torque as inversely proportional to generator speed. Using constant power will yield additional variation of the rotor speed (and resulting blade pitch) than using constant torque would.

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


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