# Problem to resolve algebraic loop

조회 수: 11 (최근 30일)
razevedo 2011년 7월 20일
댓글: ahmed altaee 2017년 1월 27일
Hi Mathworkers.. I make a model and appear this error:
Simulink cannot solve the algebraic loop containing 'testestestes/Bateria/Subsystem/Simulink-PS Converter1/EVAL_KEY/SFUN' at time 2126.0 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('testestestes','AlgebraicLoopSolver','LineSearch')
b) reducing the ode23t solver RelTol parameter so that the solver takes smaller time steps.
If the error persists in spite of the above changes, then the model is likely ill-defined and requires modification.
I think that the problem is in connection of Simscape and SimPowerSystems, like the image... I know that i need use a tranfer function, but i doní know when i put this... My model is in the next picture: http://img151.imageshack.us/img151/1276/80572262.png
When i put Transfer Fcn?
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ahmed altaee 2017년 1월 27일
i have the same problem !!

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### 답변 (1개)

Arnaud Miege 2011년 7월 20일
Put the transfer function between the voltage measurement block and the Simulink - PS Converter block, or between the PS - Simulink Converter block and the current source. This will help break the algebraic loop. You might want to change the coefficients of the transfer function though to represent a low-pass filter with a cut-off frequency that is above the maximum frequency content that you want to capture.
HTH,
Arnaud
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razevedo 2011년 7월 20일
But I can not connect it... Like i show in the picture appear a red line...
Arnaud Miege 2011년 7월 20일
Yes, I know. I told you in my answer how to connect it. Read it again.

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