while using the fit_desoto function to estimate parameters for further solar module calculations, I received the following error:
RuntimeError: Parameter estimation failed: The iteration is not making good progress, as measured by the improvement from the last five Jacobian evaluations.
The error comes from the optimize.root function of the SciPy library, which is used within the fit_desoto function.
Even if I use only 1s for the initial values of the fit_desoto function, I get this error.
The code for the function call in the main programm:
self.mp_desoto_fit = pvlib.ivtools.sdm.fit_desoto(v_mp=module['Vmpo'], i_mp=module['Impo'],
v_oc=module['Voco'], i_sc=module['Isco'], alpha_sc=module['Aisc'], beta_voc=module['Bvoco'],
cells_in_series=module['Cells_in_Series'], EgRef=1.121, dEgdT=-0.0002677, temp_ref=25, irrad_ref=1000,
root_kwargs={'options': {'col_deriv': 0, 'xtol': 1.49012e-05, 'maxfev': 0, 'band': None, 'eps': None, 'factor': 100, 'diag': None}})
The root_kwargs in the function call of the fit_desoto function influence the solver of the root function, but different properties for the solver don't fix the problem.
Do you have any ideas on this issue?
What I already tried:
- Checked all types of initial values for the fit_desoto function.
- Choosed different options for the root function solver
- Code debugged and checked the variables inside the root_function. No NaN values or similar while the function is calculating
Thanks in advance
The Problem within the function isn't solved, but it can be bypassed by using the fit_cec_sam function which is quite similar to the fit desoto function.
The problem within the fit desoto function occurs by the initial guess.
Check out the answers on Git Hub for details.
https://github.com/pvlib/pvlib-python/issues/1226