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algebraic loop problem in PV array block

Hello everyone,
I tried to upload my simulink code on PV panel tracking into the texas instruement control card (defino F28355), but I found problem from algebraic loop. I tried use debugger (ashow command) and it shows algebraic loop inside the PV block inside the diode.
I think the parameter Vd inside needs to have something done with it. I've found out using delay block to solve but not sure where to put in the model.
Any suggestion for me? Thank you in advance.


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1 Answer

Answer by Gert Kruger on 28 Jun 2019
 Accepted Answer

The reason why there is an algebraic loop:
The V-Filter and I-Filter in the model, for the computation of Vd, is supposed to break the algbraic loop. Vd which is dependent on the model output is fed-back to the model inputs which would have caused an algebraic loop if the filters were not present. The presence of the algebraic loop indicates that the V-Filter and I-Filter implementation probably has an unintended direct feed-through at some point during the simulation.
Some suggest to add a unit delay, but this forces the model to be a mixed simulation problem, even if the rest of the model consist out of continuous state models. Secondly, what is an appropriate sample time for the unit delay?
Download a PV panel model with the algebraic loop fixed at:
The proposed solution has been tested.
Kind regards,

  1 Comment

Dear Gert
Thank you so much for your answer, I will try using your model to simulate my work

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