The use of fast spectroradiometers for pulsed solar simulator spectra measurements

In this paper a calibration procedure and good laboratory practice on the use of a commercial fast spectroradiometer for the measurements of the emission spectrum of a pulsed solar simulator at ESTI (European Solar Test Installation) is presented. Quantitative assessment of spectroradiometer calibration and spectra measurement uncertainties, together with their influence on the calculation of photovoltaic (PV) modules performance are also presented. A commercial fast spectroradiometer was used for solar simulator spectra measurements. The first part of the experimental work consisted in the instrument calibration by means of a calibrated FEL-type standard lamp. The spectroradiometer was then used for emission spectrum measurements of a class A simulator (according to IEC60904-9 standard), with 1.5 ms flash duration. A sensitivity analysis, varying spectroradiometer delay time (since flash start), integration time and angular tilt was performed. The behavior of fast spectroradiometer was also investigated, in particular focusing at NIR wavelength region (800-1100 nm). Finally, the measured spectral irradiance distribution of the flasher was used for spectral mismatch correction factor calculations, according to IEC60904-7. The I-V curves used for these calculations were measured indoor on polycrystalline silicon and thin film CIGS (copper indium gallium diselenide) photovoltaic modules at STC (standard test conditions: 1000 W/m², AM 1.5 and 25°C). Spectroradiometer calibration showed how much it can be influenced by a non optimal orientation toward the lamp source: a dedicated mechanical set-up for the device is therefore needed, for a reproducible angular tilt. Spectra measurements on the pulsed solar simulator show a good reproducibility. Furthermore, data analysis on PV modules I-V curves at STC suggests that emission spectrum of pulsed simulator can significantly influence the calculation of module electrical parameters. On the basis of all th- se results, a calibration routine of pulsed solar simulators emission is proposed by implementing periodical spectrum check using fast spectroradiometers.