Transient initialization at time 1129.68252521012, solving for consistent states and modes, failed to converge. Nonlinear solver: failed to converge, residual norm too large.

Hey guys need your help, I am working 2RC ECM model coupled with thermal built using simscape components, i encountered an error which gives error for R1 component. I tried changing the max step time and relative tolerance even though it fails. Here we have lookup tables used for OCV_SOC which is function of SOC and RC parameters which are the function of SOC,temperature and current.

• Transient initialization at time 1129.68252521012, solving for consistent states and modes, failed to converge.
• Nonlinear solver: failed to converge, residual norm too large.

Answer 1

[Shivam Lahoti]

Hi,

The error message indicates that Simscape is unable to solve your system, which can happen for several reasons. Often, it's due to abrupt transitions within your model. Here are some steps to help you resolve the issue:

1) Examine Sudden Changes: Look for abrupt changes or unexpected events, like a sudden pressure drop, that coincide with the error. This MATLAB Answers post might offer further insights.

2) Adjust Solver Settings: Consider changing your solver and increasing tolerances. For instance, if using 'Variable Step Auto', try switching to 'ode23t', and adjust tolerances from 1e-5 to 1e-3.For more information on solver selection visit the following documentation page.

https://www.mathworks.com/help/releases/R2020b/simulink/ug/choose-a-solver.html

3) Utilize the Solver Profiler: Use the Solver Profiler to analyze solver behavior just before the error. In the step size tab, you may notice a graph with a step size spike near the error time. Zooming in can reveal more details, like zero crossings. The following link contains more information on the Solver Profiler:

https://www.mathworks.com/help/releases/R2020b/simulink/slref/solverprofiler.html

I hope this would help resolve the query.

Regards,

Shivam.