pvlib.ivtools.fit_sdm_cec_sam

pvlib.ivtools.fit_sdm_cec_sam(celltype, v_mp, i_mp, v_oc, i_sc, alpha_sc, beta_voc, gamma_pmp, cells_in_series, temp_ref=25)[source]

Estimates parameters for the CEC single diode model (SDM) using the SAM SDK.

Parameters

  • celltype (str) – Value is one of ‘monoSi’, ‘multiSi’, ‘polySi’, ‘cis’, ‘cigs’, ‘cdte’, ‘amorphous’

  • v_mp (float) – Voltage at maximum power point [V]

  • i_mp (float) – Current at maximum power point [A]

  • v_oc (float) – Open circuit voltage [V]

  • i_sc (float) – Short circuit current [A]

  • alpha_sc (float) – Temperature coefficient of short circuit current [A/C]

  • beta_voc (float) – Temperature coefficient of open circuit voltage [V/C]

  • gamma_pmp (float) – Temperature coefficient of power at maximum point point [%/C]

  • cells_in_series (int) – Number of cells in series

  • temp_ref (float, default 25) – Reference temperature condition [C]

Returns

tuple of the following elements –

  • I_L_reffloat

    The light-generated current (or photocurrent) at reference conditions [A]

  • I_o_reffloat

    The dark or diode reverse saturation current at reference conditions [A]

  • R_sh_reffloat

    The shunt resistance at reference conditions, in ohms.

  • R_sfloat

    The series resistance at reference conditions, in ohms.

  • a_reffloat

    The product of the usual diode ideality factor n (unitless), number of cells in series Ns, and cell thermal voltage at reference conditions [V]

  • Adjustfloat

    The adjustment to the temperature coefficient for short circuit current, in percent.

Raises

  • ImportError if NREL-PySAM is not installed. –

  • RuntimeError if parameter extraction is not successful. –

Notes

Inputs v_mp, v_oc, i_mp and i_sc are assumed to be from a single IV curve at constant irradiance and cell temperature. Irradiance is not explicitly used by the fitting procedure. The irradiance level at which the input IV curve is determined and the specified cell temperature temp_ref are the reference conditions for the output parameters I_L_ref, I_o_ref, R_sh_ref, R_s, a_ref and Adjust.

References

[1] A. Dobos, “An Improved Coefficient Calculator for the California Energy Commission 6 Parameter Photovoltaic Module Model”, Journal of Solar Energy Engineering, vol 134, 2012.