Search found 47 matches

by Cheng.Zhang
Thu Mar 14, 2019 9:16 am
Forum: Controls
Topic: Pitch and Torque Cntrl (Region 3)
Replies: 22
Views: 3260

Re: Pitch and Torque Cntrl (Region 3)

Dear Jason,

I have a controller that reduced the platform roll by -20% and platform pitch rate by -25% comparing with GSPI.
But the DEL of tower base side-to-side and fore-aft moment almost same as GSPI. Is it normal?

best regards,
Cheng
by Cheng.Zhang
Thu Mar 14, 2019 6:33 am
Forum: Controls
Topic: Pitch and Torque Cntrl (Region 3)
Replies: 22
Views: 3260

Re: Pitch and Torque Cntrl (Region 3)

Dear Jason,

Thank you!
Now, it is clear to me.

Best regards,
Cheng
by Cheng.Zhang
Thu Mar 14, 2019 4:48 am
Forum: Controls
Topic: Pitch and Torque Cntrl (Region 3)
Replies: 22
Views: 3260

Re: Pitch and Torque Cntrl (Region 3)

Dear Jason, Thank you! I'm confused that, 1). Do a high vibration of the drivetrain-torsion means a high variation of the rotor speed? 2). In my opinion, performance is highly related to the control algorithm. If I introduce additional control input (generator torque), the control is different from ...
by Cheng.Zhang
Wed Mar 13, 2019 1:28 pm
Forum: Controls
Topic: Pitch and Torque Cntrl (Region 3)
Replies: 22
Views: 3260

Re: Pitch and Torque Cntrl (Region 3)

Dear Jason, If I am well understood, there are 2 methods to get generator torque, (considering the turbine working in region 3) first, constant torque: fix it at its rated value; second, constant power: get the generator torque by calculating T = P_rated/Omega; And I'm working on the floating wind t...
by Cheng.Zhang
Thu Jul 12, 2018 3:24 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, I want to use mlife to calculate the Damage Equivalent Load (DEL) as a performance index for my controller, and I read the topic concerning the Mlife and the Mlife_user, but I still don't understand how to calculate it. For example. If I want to calculate the DEL of blade flap-wise bendi...
by Cheng.Zhang
Wed Jun 13, 2018 1:29 pm
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, Yes, you are right, I applied MBC transform. So the MBC just transfer the 3 blade pitch angles outputs to BldPitch_collective, Bld_Pitch_cosine, and Bld_Pitch_sine. It does not affect the input. That is to say, the linear model I got from FAST is right? Even the output blade pitch angles...
by Cheng.Zhang
Wed Jun 13, 2018 9:34 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, 1. I used mbc3.m got matrix MBC_AvgA, MBC_AvgB, MBC_AvgC, and MBC_AvgD. 2. The input is CBP angle. (a step signal) 3. Output including BldPitch1, BldPitch2, BldPitch3... Then, BldPitch1 shoud = BldPitch2 = BldPitch3 = input. but the result shows that input = BldPitch1. BldPitch2 and BldP...
by Cheng.Zhang
Wed Jun 13, 2018 9:16 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, First, the outputs including rotating DOFs. I agree that xdot and x should apply MBC, but the input u is CBP control command, it is in no rotating frame. What I confused is how to apply MBC on state alone, and does not affect the input. Do you think it's right to apply MBC to get A_nr=MB...
by Cheng.Zhang
Wed Jun 13, 2018 8:54 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, Thank you for your fast reply. I'm not sure but do you think whether it's right like this: Apply MBC to blade DOFs, but not the collective-blade control input. That is to say, the state space model is like this, delta_Xdot_nr = A_nr *delta_X_nr + B*delta_u delta_Y_nr = C_nr*delta_X _nr+ ...
by Cheng.Zhang
Wed Jun 13, 2018 7:48 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, Recently, I met a problem about linearization. First, I used CBP control, and I used 2 DOFs(GenDOF, PtfmPDOF) linearized model before. Now, I want to activate more DOFs and carry out a more precise linear model by FAST. But, I found that when activating the DOFs on blades (e.g. FlapDOF1,...
by Cheng.Zhang
Wed May 23, 2018 10:22 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason,

Thank you for your response.

Could you tell me that when activating all the DOFs in FAST, is there a big impact on the controller performance?
And, can the blade pitch angle be negative? Are there saturations on the blade pitch angle?

Best regards,
Cheng
by Cheng.Zhang
Wed May 23, 2018 7:25 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, I have some questions concerning the FAST. I designed a pitch controller and applied it on FAST v7 with 2 activated DOFs (GenDOF and PtfmPDOF), it works well on the SIMULINK. But when I activated ALL DOFs on FAST, the SIMULINK cannot run. The errors are as the figure following. Could you...
by Cheng.Zhang
Fri May 04, 2018 11:01 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, Yes, my example has something wrong, the platform pitch should decrease with increasing wind speed in region 3. What I want to express is just like what you said, in different wind condition, the objective is to reduce the oscillations of platform pitch about the mean, rather than mean v...
by Cheng.Zhang
Fri May 04, 2018 9:56 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, I'm not sure I understand well. If my controller is successfully adding the damping of platform pitch. Does it mean the platform pitch acceleration is decreased? For example, suppose that, 1. in a condition of 14m/s stochastic wind, apply a controller makes rotor speed at rated, and make...
by Cheng.Zhang
Fri May 04, 2018 9:28 am
Forum: Controls
Topic: questions about reference control input
Replies: 50
Views: 10543

Re: questions about reference control input

Dear Jason, Yes, the controller does not work well. As far as I know, a lot of papers' control objective including reducing platform pitch, the control problem of FOWT is the platform pitch motion. I can't understand you said it is not common for the FOWT controller to regulate platform pitch. Could...

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