pvlib.pvsystem.calcparams_desoto¶
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pvlib.pvsystem.
calcparams_desoto
(effective_irradiance, temp_cell, alpha_sc, a_ref, I_L_ref, I_o_ref, R_sh_ref, R_s, 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 De Soto et al. model described in [1]. The five values returned by calcparams_desoto 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.
- 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 [1]) 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.
See also
Notes
If the reference parameters in the ModuleParameters struct are read from a database or library of parameters (e.g. System Advisor Model), it is important to use the same EgRef and dEgdT values that were used to generate the reference parameters, regardless of the actual bandgap characteristics of the semiconductor. For example, in the case of the System Advisor Model library, created as described in [3], EgRef and dEgdT for all modules were 1.121 and -0.0002677, respectively.
This table of reference bandgap energies (EgRef), bandgap energy temperature dependence (dEgdT), and “typical” airmass response (M) is provided purely as reference to those who may generate their own reference module parameters (a_ref, IL_ref, I0_ref, etc.) based upon the various PV semiconductors. Again, we stress the importance of using identical EgRef and dEgdT when generation reference parameters and modifying the reference parameters (for irradiance, temperature, and airmass) per DeSoto’s equations.
- Crystalline Silicon (Si):
- EgRef = 1.121
- dEgdT = -0.0002677
>>> M = np.polyval([-1.26E-4, 2.816E-3, -0.024459, 0.086257, 0.9181], ... AMa) # doctest: +SKIP
Source: [1]
- Cadmium Telluride (CdTe):
- EgRef = 1.475
- dEgdT = -0.0003
>>> M = np.polyval([-2.46E-5, 9.607E-4, -0.0134, 0.0716, 0.9196], ... AMa) # doctest: +SKIP
Source: [4]
- Copper Indium diSelenide (CIS):
- EgRef = 1.010
- dEgdT = -0.00011
>>> M = np.polyval([-3.74E-5, 0.00125, -0.01462, 0.0718, 0.9210], ... AMa) # doctest: +SKIP
Source: [4]
- Copper Indium Gallium diSelenide (CIGS):
- EgRef = 1.15
- dEgdT = ????
>>> M = np.polyval([-9.07E-5, 0.0022, -0.0202, 0.0652, 0.9417], ... AMa) # doctest: +SKIP
Source: Wikipedia
- Gallium Arsenide (GaAs):
- EgRef = 1.424
- dEgdT = -0.000433
- M = unknown
Source: [4]
References
[1] W. De Soto et al., “Improvement and validation of a model for photovoltaic array performance”, Solar Energy, vol 80, pp. 78-88, 2006.
[2] System Advisor Model web page. https://sam.nrel.gov.
[3] A. Dobos, “An Improved Coefficient Calculator for the California Energy Commission 6 Parameter Photovoltaic Module Model”, Journal of Solar Energy Engineering, vol 134, 2012.
[4] O. Madelung, “Semiconductors: Data Handbook, 3rd ed.” ISBN 3-540-40488-0