Intercomparison of pulsed solar simulator measurements between the mobile flasher bus and stationary calibration laboratories

Abstract

The Swiss Mobile Flasher Bus (SMFB) is equipped with a standard high-quality flasher and a very high throughput of up to 200 PV modules per day could be reached direct at customer site. Recently an analysis of the SMFB’s measurement uncertainty budget was presented, resulted in an expanded combined uncertainty of ±3% at a 95% confidence level for standard crystalline Silicon modules. This uncertainty value is about 1% larger than values of the best stationary test labs but enables still very accurate measurements at ambient temperature conditions with the advantage to make more measurements directly on customer’s site. In this paper this uncertainty values were tested by intercomparison of measurement results of the SMFB and the stationary JRC ESTI laboratory on the same PV modules performed within the same hour to reduce uncertainty contributions by instability of the device under test DUT. The largest difference of nominal power measurements was found to be smaller 0.5% for polycrystalline standard modules including the precision measurement at Fraunhofer ISE on the same DUT performed 20 months before. Measurements on standard thin film CIS PV modules resulted in deviations up to 3.7% which are within the calculated SMFB overall uncertainty value of 4%. No light pre-conditioning was performed to the CIS modules and different flasher pulse length was used, 10ms for the SMFB and 1.2ms for the stationary laboratory flasher. In a second intercomparison run the spectral response measurement on module level of SMFB and the JRC ESTI was performed by the use of band pass filters of about 50nm width. The good correlation of the results show that the SMFB spectral response measurement is valuable to calculate the spectral mismatch factor to account for different spectral characteristics of measured PV module, the used monitor cell and the flashers spectra to optimise the overall measurement uncertainty of the SMFB