Model type definition and main STC parameters, + summary of all the parameters involved in the model, + Tool showing the main results of the model, for any Irradiance and temperature conditions
+/- tolerances specified for the Nominal power. Only used in PVsyst for establishing the default value of the "Module quality loss" factor (fixed at Low tol + a quarter of the difference (High-Low)).
Technology
Gives choice for the main technologies of PV modules available on the market. Acts on the model.
GRef
Reference irradiance for the (Isc, Voc, Impp, Vmpp) specifications. Usually STC = 1000 W/m².
TRef
Reference temperature for the (Isc, Voc, Impp, Vmpp) specifications. Usually STC = 25°C,
Isc
Short circuit current at (GRef, TRef) conditions,
Voc
Open circuit voltage at (GRef, TRef) conditions,
Impp
Max. power point current at (GRef, TRef) conditions,
Vmpp
Max. power point voltage at (GRef, TRef) conditions,
muIsc
Temperature coefficient on Isc [mA/K] or [%/K]
Additional data > Secondary parameters
LID loss
Sometimes specified by the manufacturer Specified muVoc Normally muVoc is a result of the model. An alternative value may be specified here according to the datasheets. This value may eventually be used during the sizing (choice in the project's parameter definitions)
Absorptivity
Light absorptivity for the temperature evaluation through the thermal balance. Please let at default value.
Nb of bypass diodes
Useful for the electrical shading calculations in the Module Layout part. Normally 3 diodes for 60 and 72 cells, 4 diodes for 96 cells in series.
BRev
Special parameter for reverse voltage behavior; negligible influence in the shading calculations. Please let at default value.
Model parameters
Parameters of the "standard" one-diode model
Rshunt
Shunt resistance at GRef. Measured as the inverse of the slope of the I/V characteristics around Isc at STC. If not specified, you can keep the value proposed by PVsyst.
Rsh (G=0)
Intercept at G=0 of the exponential behaviour of Rsh according to irradiance,
RshExp
Parameter of the exponential. Without very reliable determination, let it at its default value of 5.5.
Rseries, model
Series resistance involved in the one-diode model. For crystalline modules, you can keep the proposed value, which may be determined either according to a pre-defined gamma value, or low-light performances.
Rserie max
Maximum possible value of Rserie. A higher value would not allow the I/V characteristics to pass through the 3 reference points.
Rserie app
Apparent series resistance, as measured on the I/V curve as the inverse of the slope around Vco at (GRef, TRef). This slope is the sum of the Rserie (model) and the exponential effects.
Gamma
Diode Quality Factor, involved in the "one-diode" model.
muGamma
Thermal (linear) correction factor on Gamma, modification of the "standard" model for obtaining a specified muPmpp if necessary.
IoRef
Diode saturation current, involved in the "one-diode" model.
muVoc
Thermal behaviour of the Voc. Related to Rserie, but the manufacturer data is usually not attainable with reasonable other parameters. This value is a result of the model, and will usually not be compatible with the manufacturer's data.
muVocSpec
Specified manufacturer's data, may eventually be used during the sizing if the PVsyst model is not suited.
muPmpp
Normally a result of the model. May be forced to a specified value by acting on the muGamma parameter.
muPmppReq
Specified value for muPmpp if required.
Parameters for the modifications of the one-diode model for amorphous and CdTe technologies
d²mutau
Specific parameter for the contribution of the recombination loss parameter. The validity domain of this value for finding a solution to the non-linear equations is strongly correlated with Rshunt and Rserie. It has implications on the thermal behaviour, especially of Vco. To our experience with the long-term measurements of several amorphous modules, the value of d²mutau parameter should be rather near to its maximum possible (about 80 to 90%).
Spectral corr
Parametrized correction according to Air mass and Kt. Fixed correlation (from University of Loughborough), may be activated or not. Not suited for CdTe technology.
Sizes and technology
NCell serie
Number of cells in series, necessary for the determination of the model, for one cell.
NCells parall
Number of cells in parallel, not really used by the model.
Cell Area
Area of one cell, will give sensitive area of the module, and allow the definition of a "cell" efficiency; Not necessary.
Module Length
Total length of the module. Necessary for the calculation of the module efficiency,
Module Width
Total width of the module. Necessary for the calculation of the module efficiency,
Apparent length
Tile modules or BIPV: if defined, will be used for the efficiency instead of total length,
Apparent width
Tile modules or BIPV: if defined, will be used for the efficiency instead of total width,
Max voltage IEC
Max. voltage allowed for the array in worst conditions Voc(low temp) - i.e. insulation voltage acc. to IEC standard (usually 1000 V),
Max voltage UL
Max. voltage allowed for the array in worst conditions Voc(low temp) - i.e. insulation voltage acc. to US standards (usually 600 V),