Help me understand this warning message

2 views (last 30 days)
Nuno
Nuno on 7 Jul 2011
Is this an important warning?
Warning: Block diagram 'mesmotestesSoBatTerra' contains 1 algebraic loop(s). To see
more details about the loops use the command line Simulink debugger by typing "sldebug
mesmotestesSoBatTerra" in the MATLAB command window. To eliminate this message, set
the Algebraic loop option in the Diagnostics page of the Simulation Parameters Dialog
to "None"
Found algebraic loop containing:
'mesmotestesSoBatTerra/Subsystem/Simulink-PS Converter1/EVAL_KEY/SFUN'
'mesmotestesSoBatTerra/Subsystem1/Solver Configuration/EVAL_KEY/SFUN' (discontinuity)
'mesmotestesSoBatTerra/Subsystem/PS-Simulink Converter/EVAL_KEY/SFUN'
'mesmotestesSoBatTerra/powergui/EquivalentModel1/State-Space' (discontinuity)
'mesmotestesSoBatTerra/Subsystem/Voltage Measurement/do not delete this gain' (algebraic variable)
Warning: Discontinuities detected within algebraic loop(s), may have trouble solving
  1 Comment
Walter Roberson
Walter Roberson on 14 Jul 2011
Please do not create new Questions to "bump" existing topics. Duplication of questions results mostly in duplication of efforts.

Sign in to comment.

Answers (4)

Laura Proctor
Laura Proctor on 7 Jul 2011
You have an algebraic loop in your diagram which will slow-down your computation time and may not converge to a solution. You can identify which loop it is by setting the Algebraic Loop option (Simulation --> Configuration Parameters --> Diagnostics) to ERROR.
Generally it is due to a feedback loop that contains a sequence of direct feedthrough blocks. This algebraic loop can often be modeled without using feedback, if you do the math.

Kaustubha Govind
Kaustubha Govind on 7 Jul 2011

Nuno
Nuno on 8 Jul 2011
And said this: Block diagram 'mesmotestesSoBatTerra' contains an algebraic loop. The algebraic loop solver is disabled because of the current setting for Algebraic loop option in the Diagnostics page of the Configuration Parameters Dialog
Why i resolved this?
  2 Comments
Kaustubha Govind
Kaustubha Govind on 8 Jul 2011
It's not clear what you question is. Please explain what you mean by "Why i resolved this?" - it doesn't seem like you have resolved the algebraic loops from the above message.
Arnaud Miege
Arnaud Miege on 8 Jul 2011
Have a look at the answers and comments I gave to one of your previous questions:
http://www.mathworks.co.uk/matlabcentral/answers/9053-doubt-in-circuit-of-battery
I explain that interfacing Simscape to SimPowerSystems "will likely introduce an algebraic loop in your model, that you may need to break with, say, a low-pass filter (transfer function) with an appropriately chosen cut-off frequency."

Sign in to comment.


Nuno
Nuno on 12 Jul 2011
How i put the low-pass filter?
  4 Comments
Arnaud Miege
Arnaud Miege on 15 Jul 2011
Use your engineering knowledge. What is the highest frequency component you'd expect? Set your cut-off frequency to be higher than that. Set a gain of 1.
http://en.wikipedia.org/wiki/Low-pass_filter#Laplace_notation
Nuno
Nuno on 18 Jul 2011
But i don´t understand where i put a tranfer function?

Sign in to comment.

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Products

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!