# Problems with Test01\_SIG model

**URL:** <https://forums.nlr.gov/t/problems-with-test01-sig-model/753>\
**Category:** Computer-Aided Engineering Software Tools\
**Created:** [August 26, 2013, 7:35pm UTC](https://forums.nlr.gov/t/problems-with-test01-sig-model/753 "2013-08-26T19:35:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Moises.Tellez](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Moises.Tellez](https://forums.nlr.gov/u/Moises.Tellez)\
**Post date:** [August 26, 2013, 7:35pm UTC](https://forums.nlr.gov/t/problems-with-test01-sig-model/753/1 "2013-08-26T19:35:27Z")

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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  
set\_param(‘Test01\_SIG’,‘AlgebraicLoopSolver’,‘LineSearch’)  
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:

> [@Error Running Test01\_SIG](http://forums.nlr.gov/t/error-running-test01-sig/493/1):
>
> Good morning, I have been successful running the OpenLoop simulink model but I receive the following error when I try to run the Test01\_SIG model: Trouble solving algebraic loop containing ‘Test01\_SIG/Simple Induction Generator/SIG\_Slop’ at time 0. Stopping simulation. There may be a singularity in the solution. If the model is correct, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances) Can anyone offer suggestions? Thanks, Ryan Neahr

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  
[Test01\_SIG.rar](https://forums.nlr.gov/uploads/short-url/wt5eHuZ4cp23cqYRC2Bkm8GKDro.rar) (85.6 KB)

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**Author:** ![Moises.Tellez](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Moises.Tellez](https://forums.nlr.gov/u/Moises.Tellez)\
**Post date:** [September 4, 2013, 9:22pm UTC](https://forums.nlr.gov/t/problems-with-test01-sig-model/753/2 "2013-09-04T21:22:23Z")

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

Thanks.