This article describes the various causes of thermal solver convergence issues in simulation models, such as warning 6209 and situations where the conjugate solver fails to converge, or an invalid temperature distribution is detected. It provides detailed methods for diagnosing and resolving these issues.
The following are general steps to take when addressing convergence issues:
If you encounter WARNING 6209 during thermal analysis, the following steps may help resolve the issue.
If you encounter the message indicating that the Conjugate - Gradient solver didn't converge, take the following steps.
For models where the thermal temperature difference doesn’t decrease:
If you have issues with accuracy of temperature distribution, for example problematic situations or spots in temperature for some particular elements, e.g. with low aspect ratios, which are caused by negative conductivities and capacitance distribution coefficients combined with high temperature gradients in certain directions: