pvlib.ivtools.sdm.fit_pvsyst_iec61853_sandia_2025#

pvlib.ivtools.sdm.fit_pvsyst_iec61853_sandia_2025(effective_irradiance, temp_cell, i_sc, v_oc, i_mp, v_mp, cells_in_series, EgRef=1.121, alpha_sc=None, beta_mp=None, R_s=None, r_sh_coeff=0.12, min_Rsh_irradiance=None, irradiance_tolerance=20, temperature_tolerance=1)[source]#

Estimate parameters for the PVsyst module performance model using IEC 61853-1 matrix measurements.

Parameters:

  • effective_irradiance (array) – Effective irradiance for each test condition [W/m²]

  • temp_cell (array) – Cell temperature for each test condition [C]

  • i_sc (array) – Short circuit current for each test condition [A]

  • v_oc (array) – Open circuit voltage for each test condition [V]

  • i_mp (array) – Current at maximum power point for each test condition [A]

  • v_mp (array) – Voltage at maximum power point for each test condition [V]

  • cells_in_series (int) – The number of cells connected in series.

  • EgRef (float, optional) – The energy bandgap at reference temperature in units of eV. 1.121 eV for crystalline silicon. EgRef must be >0.

  • alpha_sc (float, optional) – Temperature coefficient of short circuit current. If not specified, it will be estimated using the i_sc values at irradiance of 1000 W/m2. [A/K]

  • beta_mp (float, optional) – Temperature coefficient of maximum power voltage. If not specified, it will be estimated using the v_mp values at irradiance of 1000 W/m2. [1/K]

  • R_s (float, optional) – Series resistance value. If not provided, a value will be estimated from the input measurements. [ohm]

  • r_sh_coeff (float, default 0.12) – Shunt resistance fitting coefficient. The default value is taken from [1].

  • min_Rsh_irradiance (float, optional) – Irradiance threshold below which values are excluded when estimating shunt resistance parameter values. May be useful for modules with problematic low-light measurements. [W/m²]

  • irradiance_tolerance (float, default 20) – Tolerance for irradiance variation around the STC value. The default value corresponds to a +/- 2% interval around the STC value of 1000 W/m². [W/m²]

  • temperature_tolerance (float, default 1) – Tolerance for temperature variation around the STC value. The default value corresponds to a +/- 1 degree interval around the STC value of 25 degrees. [C]

Returns:

dict –

alpha_scfloat

short circuit current temperature coefficient [A/K]

gamma_reffloat

diode (ideality) factor at STC [unitless]

mu_gammafloat

temperature coefficient for diode (ideality) factor [1/K]

I_L_reffloat

light current at STC [A]

I_o_reffloat

dark current at STC [A]

R_sh_reffloat

shunt resistance at STC [ohm]

R_sh_0float

shunt resistance at zero irradiance [ohm]

R_sh_expfloat

exponential factor defining decrease in shunt resistance with increasing effective irradiance

R_sfloat

series resistance at STC [ohm]

cells_in_seriesint

number of cells in series

EgReffloat

effective band gap at STC [eV]

See also

pvlib.pvsystem.calcparams_pvsyst, pvlib.ivtools.sdm.fit_pvsyst_sandia

Notes

Input arrays of operating conditions and electrical measurements must be 1-D with equal lengths.

Values supplied for alpha_sc, beta_mp, and R_s must be consistent with the matrix data, as these values are used when estimating other model parameters.

This method is non-iterative. In some cases, it may be desirable to refine the estimated parameter values using a numerical optimizer such as the default method in scipy.optimize.minimize.

References

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