PV modules
Data used by the engine
| Data | Use |
|---|---|
| Peak power (Wp) | Nominal power; defines the kWp of the installation |
| Vmp, Imp, Voc, Isc | Electrical validation of strings |
| Efficiency | Informative |
| Temperature coefficients of Pmax, Voc and Isc | Thermal loss and voltage limits in cold and heat |
| Dimensions (length × width) | How many modules fit on each plane |
| Weight | Report |
| Technology and cell type (HC or FC) | Shading model |
| Bifaciality | Rear-side gain (see Bifacial) |
| Single-diode model parameters | See below |
| Warranties and price | Report and economics |
Single-diode model
The behaviour of the module with irradiance and temperature is calculated with the single-diode model using the PVsyst parameterisation. The parameters are:
- number of cells in series,
- series resistance (R_s),
- shunt resistance at reference (R_sh,ref) and at zero irradiance (R_sh,0),
- ideality factor (γ),
- temperature coefficient of the current (α_sc),
- and, optionally, μ_γ and the R_sh exponent.
If the module does not include them, they are estimated from the datasheet: the saturation current is fitted so that the STC Voc matches the datasheet, and μ_γ so that the model reproduces the declared Pmax temperature coefficient.
Physical details in Temperature and single-diode model.
Module curves
In the data sheet you can see the I-V and P-V curves at different irradiances and temperatures, and the efficiency curve against irradiance. They come from the same model used by the simulation.
Half-cell and full-cell
The cell type affects the shading model. It is inferred from the name and technology (HC, half-cut, shingled and MBB count as half-cell) and, if they say nothing, from the number of cells: 60/72 is full-cell and more than 96 is half-cell. You can force it.
Bifacial modules
If the module is bifacial, the bifaciality φ (ratio of the rear side to the front side at STC) comes from the datasheet; if missing, 0.70 is used.