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I have the circuit in this figure:

enter image description here

I get the following error: Initial conditions solve failed to converge. Nonlinear solver: Linear Algebra error. Failed to solve using iteration matrix. The model may not give enough information to make it possible to solve for values of some of its variables. Specific advice is given below.

all components and nodal across variables involved Tie variable x to a definite value, for example by connecting an appropriate domain reference block.

I have looked at the other questions on this on MATLAB answers (did not see any on here) and these solutions did not work:

  • Changing the S-PS block to filter input.
  • One question was missing ground but I have that.

Any idea what is wrong?

am304
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mrsB2013
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  • Could it be because the output of your op-amp is not connected to anything? You need something physical other than just a voltage sensor block. – am304 Sep 24 '18 at 08:24
  • Hm... adding an RL doesn't seem to fix it either. – mrsB2013 Sep 24 '18 at 13:56
  • So one end of the resistor is connected to the output of the op-amp and the other? To ground? Also, what's in Vin? – am304 Sep 24 '18 at 14:25
  • RL is 10k, It is connected to the op-amp at one end and ground at the other. Vin is a sensor (I'd based my circuit off the of the example ssc_opamp_inverting but that was scrictly physical components). But your question piqued my interest so I tried removing it. I then got an error that a solver is needed. So I tried with a "Solver Configuration" block, which also didn't help. – mrsB2013 Sep 24 '18 at 14:43
  • OK so the solver configuration block must be somewhere inside Vin. Not sure what else to suggest. Maybe use a ramp rather than a step input? What solver & solver configuration are you using? – am304 Sep 24 '18 at 15:06

1 Answers1

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Hi I had the same problem and I managed to solve mine.

I have a Solve Configuration block in the model.

I was able to run my model initially but I ran into the LA convergence issue when I modified my model.

Once I increased the Nonlinear iterations count the solver managed to complete.

Dharman
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Kevin Goh Seng Tak
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