The basic measurement setup is shown in the picture 1. Current voltage characteristics of a solar module/cell are measured using a Xenon flash as an irradiation source. During a single flash QuickSun electronics unit records the voltage and current signals while the module is swept from short circuit into open circuit. 4-wire measurement principle is essential in order not to measure any voltage losses due to parasitic resistances in cables and connectors.

Irradiance signal is recorded using a monitor cell and the voltage and current signals are corrected accordingly following the procedure in the standard IEC60891.

Two temperatures are measured in order to perform the necessary correction calculations to the desired target temperatures, typically 25 ºC. Module is assumed to be at ambient temperature and monitor cell temperature is used for correcting the irradiance signal

Picture 1: Measurement setup

The measurement is initiated by triggering a flash. When the tail of the flash pulse has reached the preset level, typically 1200 W/m², an electronic load, field effect transistor, is triggered in order to sweep the voltage linearly from zero to open circuit. Because of the decaying flash pulse the maximum power point will be measured very close to the typical target irradiance level, 1000 W/m² minimizing irradiance correction effects.

Picture 2: Measurement principle

The recorded signals, voltage, current and irradiance, are transferred to a PC and exhibited by QuickSun software as shown on the left in the window below. With this data the typical IV graph with key statistics is calculated using the procedure of the standard IEC60891 shown in the right hand window.

Picture 3: Measurement