Uncertainty budget assessment of temperature coefficient measurements performed via intra-laboratory comparison between various facilities for PV device calibration

The performance of PV devices at different operating temperatures is important for determining the energy they produce once deployed. Therefore current-voltage characteristics are measured over a range of typical operating temperatures and the temperature coefficients of the main electrical performance parameters are extracted. They are the temperature coefficient α of short-circuit current, β of open-circuit voltage and δ of maximum power. The European Solar Test Installation has recently upgraded its capability to determine these temperature coefficients. The existing two setups were improved to be able to cover extended temperature ranges and two further setups and respective measurement procedures were made operational. For all setups revised uncertainty estimates were calculated. Here the setups and procedures are presented, together with the measurement uncertainty for the three temperature coefficients. Measurements were made on seven PV devices and their consistency compared based on uncertainties. It was found that all setups are fully consistent. The advantages of the different setups are also discussed.