sapm(effective_irradiance, temp_cell, module)¶
The Sandia PV Array Performance Model (SAPM) generates 5 points on a PV module’s I-V curve (Voc, Isc, Ix, Ixx, Vmp/Imp) according to SAND2004-3535. Assumes a reference cell temperature of 25 C.
effective_irradiance (numeric) – Effective irradiance (suns).
temp_cell (numeric) – The cell temperature (degrees C).
module (dict-like) – A dict, Series, or DataFrame defining the SAPM performance parameters. See the notes section for more details.
A DataFrame with the columns –
i_sc : Short-circuit current (A)
i_mp : Current at the maximum-power point (A)
v_oc : Open-circuit voltage (V)
v_mp : Voltage at maximum-power point (V)
p_mp : Power at maximum-power point (W)
i_x : Current at module V = 0.5Voc, defines 4th point on I-V curve for modeling curve shape
i_xx : Current at module V = 0.5(Voc+Vmp), defines 5th point on I-V curve for modeling curve shape
The coefficients from SAPM which are required in
moduleare listed in the following table.
The modules in the Sandia module database contain these coefficients, but the modules in the CEC module database do not. Both databases can be accessed using
The airmass coefficients used in calculating effective irradiance
The angle of incidence coefficients used in calculating effective irradiance
The empirically determined coefficients relating Imp, Vmp, Ix, and Ixx to effective irradiance
Short circuit current at reference condition (amps)
Maximum power current at reference condition (amps)
Short circuit current temperature coefficient at reference condition (1/C)
Maximum power current temperature coefficient at reference condition (1/C)
Open circuit voltage temperature coefficient at reference condition (V/C)
Coefficient providing the irradiance dependence for the BetaVoc temperature coefficient at reference irradiance (V/C)
Maximum power voltage temperature coefficient at reference condition
Coefficient providing the irradiance dependence for the BetaVmp temperature coefficient at reference irradiance (V/C)
Empirically determined “diode factor” (dimensionless)
Number of cells in series in a module’s cell string(s)
Ix at reference conditions
Ixx at reference conditions
Fraction of diffuse irradiance used by module
 King, D. et al, 2004, “Sandia Photovoltaic Array Performance Model”, SAND Report 3535, Sandia National Laboratories, Albuquerque, NM.