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Convergence problem ( PID heater controller)
Posted 17 apr 2014, 05:26 GMT-4 Fluid & Heat, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD), Studies & Solvers Version 4.4 1 Reply
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Hi,
I have a problem with the convergence of my model. I have this message d'error
""
there are 876 degrees of freedom returning NaN / Inf in the matrix rows for the variable comp1.T.
the coordinates (0.021,0.00055) (0.0212876,0.00055) (0.0215991,0.00055) (0.0219364,0.00055) (0.0223016,0.00055) ...
and for the same degrees of freedom, NaN Inf in columns of the matrix.
The linear solver has sent an error message.
The relative residual (6th 051) is larger than the tolerance.
The returned solution has not converged correctly"""
When I consider the power of heater as a consatnt my model ( MOCVD Chamber) converges. Unfortunately,
when I want to control the power of heater( P_adjustable) I had always the same message d'error.
I defined in EDO et EAD global equations P_adjustable=T_consigne-intop1(T)
intop1(T) is temperature in the control point
T_consigne is desired temperature in the control point
I defined T_consigne in parameters
I used a refined mesh, and a resolution with auxilary sweep kappa.
Should i change values of PID Coeffecients ?
I attach my model version 4.
Any idea, help ? Thanks in advance !
Regards,
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Try with only the Proportionnal value, sometimes I and value are not needed and give instabilities
Best regards