# One-Diode Model Temperature Correction

Given the 1-diode model parameters defined for the module under STC conditions (25 °C, 1000 W/m^{2}), compute the temperature and irradiance-corrected parameters at the actual module temperature *T _{m}* and the available solar energy

*G*. The default temperature correction of all 1-diode parameters is linear. If a non-linear temperature correction of the diode ideality factor is desired, the then a set of additional parameters (polynomial coefficients) is available to affect this correction.

_{T,Eff}This non-linear response is illustrated in **Figure 36** for a family of I(V) curves with a module temperature range of 8 °C to 75 °C. This data was measured in the laboratory using the module temperature control system and a Spire long-pulse solar simulator.

### Figure 36. Non-Linear Module Power Temperature Response using a Third-Order Polynomial Correction to the Diode Ideality Factor γ

## Inputs

## Outputs

## Algorithm

1.) Given the effective available insolation *G*_{T,Eff} and module temperature *T*_{m}, find the corrected 1-diode shunt and series resistance.

2.) If the linear correction to the diode ideality factor is desired, or all non-linear coefficients *a _{y},b_{y},c_{y},d_{y}* = 0, then correct it for the module temperature as follows:

*a*γ is referring to the y1 non-linear temperature coefficient in PlantPredict and

*b*γ is referring to y2,

*c*γ is referring to y3 and

*d*γ is referring to y4

*R*

_{s}. As a result, the junction still experiences a voltage bias and there are currents flowing through both the recombination path and through

*R*

_{sh}when the terminal voltage of the device is zero, i.e. the recombination term does not go to zero in the short circuit condition. Therefore the photocurrent,

*I*

_{ph}must be greater than

*I*

_{sc}in order to supply parasitic currents as well as the external current which has the rated

*I*

_{SC,ref}value. Find the actual

*I*

_{ph}as follows:

The temperature dependence on voltage is also computed, but not used elsewhere in the simulation. Note that μΙ_{sc} ≅ α_{Iph}, given in 1/°C.

## Reference

Schwieger, M., Michalksi, S., Non-Linearity of Temperature Coefficients, Equivalent Cell Temperature and Temperature Behaviour of Different PV-Module Technologies. TÜV Rheinland Energie und Umwelt, Cologne, Germany. Proceedings from the 28th EU PVSEC.