Software

Solar Cells I-V Curve Tracer software is developed by PV Test Solutions. It is distributed as an executable program. License to use PV Test Solutions' custom software is part of the system. Software allows for a large number of different configurations and has numerous integrated extended analysis options. The PC software automatically calculates key properties of solar cells from the measured I-V curves.

View of the main screen.

The main screen is divided into several areas allowing user to either perform some actions or to gain some specific information. These areas are as follow:

• Actual light intensity (continuously measured and monitored),
• Actual temperature of measuring table (continuously measured and monitored),
• Main “keys” provided to start and stop measurements,
• Setting parameters for either light or dark measurements from the main window,
• Setting plot options and graph features,
• Essential information about current file where measured I-V data are to be stored,
• Essential information about solar cell which is currently measured,
• Basic cell parameters as determined after last I-V measurement,
• Measurement conditions,
• Measurement results,
• Small graphics window provided to show current changes of measuring table temperature versus time (visable on "Info" tab),
• Information on correction to light fluctuations and translation status of measured I-V curve.

Analytical features:

• Advanced signal filtering procedure enabling I-V measurement even under strongly fluctuating light sources,
• Calculating cell series resistance according to IEC 60891 standard,
• Three procedures (IEC 60891) allowing to correct measured I-V curve to Standard Test Conditions (STC),
• Implemented numerical procedures enabling fitting of measured I-V curve (light and dark) to either of four equivalent diode models (SEM, DEM, VDEM, VDDEM*),
• Fast routine determination of thermal coefficients of basic parameters of a solar cell,
• Correction of measured I-V curve to any other conditions than those recorded during the test,
• Calculation Rectification Ratio,
• Long term instability indicator,
• Implemented advanced sorting procedures according to user defined criteria (binning function).

* VDDEM - Two Variables Double Diode Exponential Model (for dark I-V curves require finding six independent parameters, implement on request)

Examples of measurements:

Example of "light" measurement.

Example of "dark" measurement plotted in both lin-lin as well as in lin-log scales, showing extreme voltage (-10 V) and current (15 A) ranges, respectively.

Example of cell’s series resistance determination according to IEC-60891 standard	Example of cell’s I-V curve fitting to Double Diode equivalent electrical model (red points – measured, green line – calculated)