pvlib.pvsystem.calcparams_cec

pvlib.pvsystem.calcparams_cec(effective_irradiance, temp_cell, alpha_sc, a_ref, I_L_ref, I_o_ref, R_sh_ref, R_s, Adjust, EgRef=1.121, dEgdT=-0.0002677, irrad_ref=1000, temp_ref=25)[source]

Calculates five parameter values for the single diode equation at effective irradiance and cell temperature using the CEC model described in [1]. The CEC model differs from the De soto et al. model [3] by the parameter Adjust. The five values returned by calcparams_cec can be used by singlediode to calculate an IV curve.

Parameters:
effective_irradiance : numeric

The irradiance (W/m2) that is converted to photocurrent.

temp_cell : numeric

The average cell temperature of cells within a module in C.

alpha_sc : float

The short-circuit current temperature coefficient of the module in units of A/C.

a_ref : float

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

I_L_ref : float

The light-generated current (or photocurrent) at reference conditions, in amperes.

I_o_ref : float

The dark or diode reverse saturation current at reference conditions, in amperes.

R_sh_ref : float

The shunt resistance at reference conditions, in ohms.

R_s : float

The series resistance at reference conditions, in ohms.

Adjust : float

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

EgRef : float

The energy bandgap at reference temperature in units of eV. 1.121 eV for crystalline silicon. EgRef must be >0. For parameters from the SAM CEC module database, EgRef=1.121 is implicit for all cell types in the parameter estimation algorithm used by NREL.

dEgdT : float

The temperature dependence of the energy bandgap at reference conditions in units of 1/K. May be either a scalar value (e.g. -0.0002677 as in [3]) or a DataFrame (this may be useful if dEgdT is a modeled as a function of temperature). For parameters from the SAM CEC module database, dEgdT=-0.0002677 is implicit for all cell types in the parameter estimation algorithm used by NREL.

irrad_ref : float (optional, default=1000)

Reference irradiance in W/m^2.

temp_ref : float (optional, default=25)

Reference cell temperature in C.

Returns:
Tuple of the following results:
photocurrent : numeric

Light-generated current in amperes

saturation_current : numeric

Diode saturation curent in amperes

resistance_series : float

Series resistance in ohms

resistance_shunt : numeric

Shunt resistance in ohms

nNsVth : numeric

The product of the usual diode ideality factor (n, unitless), number of cells in series (Ns), and cell thermal voltage at specified effective irradiance and cell temperature.

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.

[2] System Advisor Model web page. https://sam.nrel.gov.

[3] W. De Soto et al., “Improvement and validation of a model for photovoltaic array performance”, Solar Energy, vol 80, pp. 78-88, 2006.