Problems with Test01_SIG model

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Organization: University of Cordoba (UCO)
Location: Córdoba (Spain)

Problems with Test01_SIG model

Postby Moises.Tellez » Mon Aug 26, 2013 1:35 pm

Hello everybody.

I am Moses Tellez, from Spain. I am working on a project about wind generators in Simulink and FAST, and I am a beginner in FAST.
I want to simulate the Generator VS Speed control, and I have simulated the Test01 file in FAST with VSContrl=1 and the others parameters activated, according to the FAST´s manual. Results appears consistent (I attached the file Test01.fst and the output file Test01.out). I calculated the VS_RGn2K with the formula offered by the Alan Wright´s technical report "Advanced Control Design for Wind Turbines", in page 21.

But I have a problem when I try to simulate the Test01_SIG.mdl in Simulink. First, Simulink gives an error (I´m using Matlab R2012a):

"Simulink cannot solve the algebraic loop containing 'Test01_SIG/Simple Induction Generator/SIG_Slop' at time 0.0 using the TrustRegion-based algorithm due to one of the following reasons: the model is ill-defined i.e., the system equations do not have a solution; or the nonlinear equation solver failed to converge due to numerical issues.
To rule out solver convergence as the cause of this error, either
a) switch to LineSearch-based algorithm using
b) reducing the fixed step size.
If the error persists in spite of the above changes, then the model is likely ill-defined and requires modification."

I have the entire forum and found a solution here:


I have placed a delay block in the model (I attached the mdl file). Alan Wright also uses a delay block in his models, in the technical report. I tested with different delays and different integration steps (smaller, larger), but the results aren´t the same as the .out file with FAST. I have also tested with a memory block. Moreover, the results are not consistent (for example, assumes that the GenPwr value should increase over time, but it oscillates). Also I attached the Simulink out file.

Thank you very much and sorry for my english level.

Moses Tellez
Here are all the files
(85.65 KiB) Downloaded 3710 times

Posts: 5
Joined: Sun Aug 25, 2013 4:00 pm
Organization: University of Cordoba (UCO)
Location: Córdoba (Spain)

Re: Problems with Test01_SIG model

Postby Moises.Tellez » Wed Sep 04, 2013 3:22 pm

Hello! Can anyone answer me? Which is better value for the delay block?


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