IEC 60904-1:2020 pdf free.Photovoltaic devices-Measurement of photovoltaic current-voltage characteristics.
The l-V characteristic for the device under test shall be measured such that it reflects, as closelyas possible, the performance of the device under steady-state conditions, i.e. where there is noinfluence due to drifts in irradiance or device temperature or the voltage sweep rate.Sweeprate effects occur when the voltage bias is stepped or swept too rapidly for the device responseto equilibrate for each measurement of the current.This effect can be due to device capacitance,as is the case for some crystalline silicon PV devices,or it can be due to a more complex deviceresponse,as is frequently observed in some thin-film devices such as perovskite cells,seeIECTR63228.
Errors due to PV device capacitance are related to the combination of the PV technology andl-V curve measurement parameters (sweep direction，time delay per measurement point,number of pulses (in multiple-pulse method) and rate of change of applied voltage,current orirradiance).The errors due to PV device capacitance are normally most pronounced for themaximum-power point and the open-circuit voltage of the l-V curve,whereas errors in short-circuit current due to capacitance are in general minimal. More guidance on ensuring that themeasurement approximates steady-state conditions is provided in Annex B.
The contribution of transient effects to the overall measurement uncertainty shall be considered.
ln general, test results are reported for various conditions.The three main parameters that shallbe reported together with any test result are:
a) Total in-plane irradiance.
b) Spectral irradiance in the test plane (graph or table), if spectral mismatch corrections are required.
c) Cell junction temperature of the device under test.
The test procedure is as follows:
a) Mount the reference device as near as possible to the device under test.For PV calibration or power rating by use of solar tracker, both shall be normal to the direct solar beam within ±5°. For the alignment between reference device and device under test refer to 4.2 c).Connect to the necessary in strumentation.
b) lf the device under test and reference device are equipped with temperature controllers, set them at the desired level.The temperature of the reference device should be brought andkept as close as possible to the temperature at which it was calibrated and the temperatureof the device under test to the desired reporting temperature. lf active temperaturecontrollers are not available, the latter may be achieved by bringing the device under testto a point below the target temperature and letting it warm up naturally under the naturalsunlight in combination with temporary shading. In general, there can be differencesbetween average device temperature and average sensor temperature during warming up.Therefore,either correction or proper accounting for it in the uncertainty calculation shall be done.IEC 60904-1 pdf download.