How calculate fit_cec_sam parametrs?

[JBreidaks]

from pvlib.ivtools.sdm import fit_cec_sam

#https://www.jasolar.com/uploadfile/2022/0511/20220511060835815.pdf
#Model "JA Solar JAM72S30-530/MR"

Panel specifications

celltype = "monoSi"
v_mp = 41.31 # in volts
i_mp = 12.83 # in amperes
v_oc = 49.3 # in volts
i_sc = 13.72 # in amperes
alpha_sc = 0.65 # in %/C (assuming the same as in the previous example)
beta_voc = -0.286 # in %/C (assuming the same as in the previous example)
gamma_pmp = -0.35 # in %/C
cells_in_series = 144
temp_ref = 25 # in degrees Celsius

Calculate coefficients

coefficients = fit_cec_sam(celltype, v_mp, i_mp, v_oc,
i_sc, alpha_sc, beta_voc,
gamma_pmp, cells_in_series)
print(coefficients)

I am trying fit coefficients for CEC SAM, but I get error.

6parsolve simulation error
: Could not solve, sanity check failed (-33): abs((P - Pmp) / Pmp) > 0.015

RuntimeError: Parameter estimation failed

[cwhanse]

alpha_sc = 0.65 # in %/C (assuming the same as in the previous example)
beta_voc = -0.286 # in %/C (assuming the same as in the previous example)

These temperature coefficients need to be in A/C and V/C, respectively. See the docstring here.

[cwhanse]

What is the "previous example" you mention?

[JBreidaks]

perc_alpha_sc = 0.045
perc_beta_voc = -0.275 # in %/C
alpha_sc = (perc_alpha_sc / 100) * i_sc
beta_voc = (perc_beta_voc / 100) * v_oc

Is this transformation correct?

[cwhanse]

Yes