In-Situ Performance characterization of photovoltaic modules during combined-accelerated stress testing

Current-voltage (IV) curve tracing and electroluminescence (EL) imaging have been developed for in-situ performance characterization of photovoltaic (PV) devices in a Xe lamp-based weathering chamber for combined-accelerated stress testing. The capability allows for progressive failure monitoring during accelerated ageing with dynamic control of the characterization environment (e.g. imaging at specific temperatures and mechanical stress levels). Both light and dark IV curve tracing are implemented with techniques to overcome light and temperature instability inherent to the chamber. A Raspberry Pi-connected camera with infra-red filter removed is used for EL imaging, providing a low-cost, small form-factor solution which is desirable for use in a harsh environment. The camera is installed within a thermally-isolated housing mounted within the climate chamber. Measurement and control are achieved via LabVIEW, where characterization is integrated as part of the test protocol and performed automatically.