Measurement of Photovoltaic Current-Voltage Characteristics According to IEC60904-1

IV characteristics of PV module are measured under standard test conditions (STC) including spectral mismatch correction based on spectral response measurement on cell or module level. The minimum uncertainty of measured power for precision measurement is ± 1.5%, for standard measurement the minimum uncertainty is ±1.8 %. For every module measurement, three consecutive measurements are carried out as hysteresis measurements, where the I-V curve is swept twice for each measurement: from short circuit (Isc) to open circuit (Voc) during the first flash, and from open circuit (Voc) to short circuit (Isc) during the second flash. Due to capacitive effects, which vary between module technologies, a difference (hysteresis) between these two I-V curve sweeps can be observed. Whenever this difference is not negligible, the I-V curve sweeps are divided into multiple sections which are swept during multiple flashes, thus reducing the voltage slew rate and, in consequence, the capacitive effects and the entailed hysteresis between the two I-V curve sweeps.