How to solve algebraic loop error??

Hii....I came across this error while making a model..

Simulink cannot solve the algebraic loop containing 'trial_3/PV panel/PV module' 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('trial_3','AlgebraicLoopSolver','LineSearch') b) reducing the VariableStepDiscrete 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 am using coding to make photovoltaic panel and MPPT P&O algorithm.

Please help me to solve this error.

[ahmed altaee]

i have the same problem!! :(

[Rajesh Laguri]

Have you done this, can you please suggest how you solved this issue.I am also coding for same.

[Jim Riggs]

It's true that you can break algebraic loops using a unit delay as Azzi Abdelmalek says, but judging by the comments, people are not reviewing the link provided by Walter Roberson, below. This article contains some important information and considerations on the effect of using a unit delay and provides an alternative solution.

[Malaiyappan M]

in MPPT Buck/Boost Converer try adjust the Inductor Value to resolve this error

Answer 1

[Azzi Abdelmalek]

Algebraic loop occurs often, when you have a feedback through a constant block or equivalent, which means your signal y(t0)=constant * y(t0) , you should have y(t0+1)=constant*y(t0) which you can get with a unit delay block

[billel madridi]

it's useful your answer, i just added a unit delay and it works thanks

[Walter Roberson]

Divyasri Venkat commented, "Thanks sir even i got the same error"

[Ahmed Badie]

It works, thanks

[[e-mail]]

thank you , after all this time , its works finally by your answer

[Ibrahim Banat]

where can I add this block in my system?

[Azzi Abdelmalek]

just before the feedback

[Ibrahim Banat]

firstly, thanks for reply. but I don't know the exact location to insert the block.. my system consists of 72 cells PV panel and I'm studying the shading effect and the same problem appear every time. Can I send you my system to see whats I mean?

[Ibrahim Banat]

Any help Mr. Azzi Abdelmalek

[lukemya fabien]

I have the same error but in the PV array block, I don't see where I can place the unity delay. Please help me to solve this problem. Thanks.

[Mohamed Yousry]

Thanks Dear Azzi, this answer surely solved my problem.

[Om Krishan]

Thanks@VAzzi Abdelmalek it works

[Praveen Kumar]

Same issue. Where should I place the unit delay? Someone, please comment. Thank you.

[Lukas Kretzschmar Waeny]

Same issue, thanks for helping ...

[Sudhanshu Telrandhe]

thanks for helping ...

[NING XUE]

Simulink cannot solve the algebraic loop containing 'partial_shading_conditions2/PV_SERIES2/Subsystem/Divide2' at time 0.039814999999999996 using the LineSearch-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 TrustRegion-based algorithm using set_param('partial_shading_conditions2','AlgebraicLoopSolver','TrustRegion') b) reducing the VariableStepDiscrete 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.

The same issue,but I have place the unit delay before the feedback,can't solve this problem

can you help me?

Answer 2

[Walter Roberson]

Please read http://blogs.mathworks.com/simulink/2015/07/18/why-you-should-never-break-an-algebraic-loop-with-with-a-memory-block/

[Jim Riggs]

Good tip. Thanks.

Answer 3

[Kalyani Dhawad]

I have same problem in pv system

Answer 4

[Ahmed]

I've faced the same problem before, it can be solved by adding a unit delay block and type "set_param('trial_3','AlgebraicLoopSolver','LineSearch') " in the command prombit window of MATLAB.

[matham kiran kumar]

Thank you. Its working for me too.

[Akash maheshwari]

can you pleasse explain set_param('trial_3','AlgebraicLoopSolver','LineSearch'). i did that in my matlab command window but window show me that algebraic loop parameter did not found.

Answer 5

[Gert Kruger]

PV panel model with fixed algebraic loop: https://www.mathworks.com/matlabcentral/fileexchange/71682-pv-array-with-algebraic-loop-broken

[PIRC]

same problem. you model not helpful.

[Malaiyappan M]

Inductor is not designed properly

Answer 6

[ayachi amor]

Click on the PV panel itself, go to ' Advanced', then click on 'Break algebaic loop in internal model'.

hope to be solved.

[Zachary Naidoo]

Hi, I have tried this by my displays for voltage and current show nan when for this. However if I don't click it then it displays the result with an error