Power rating of photovoltaic modules from outdoor measurements

Power rating of PV (photovoltaic) modules is realized at standard test conditions (1000 W/m/sup 2/ total irradiance, AM 1.5 spectral distribution in the plane of module, and 25 degrees C cell temperature). Design, monitoring, and check of specifications of PV modules and systems require prediction of module characteristics (maximum power, efficiency, V/sub mpp/, V/sub oc/, and I/sub sc/) under various conditions. A procedure for transformation of outdoor measurements or data sheet specifications of crystalline silicon modules to other conditions is proposed. With this procedure, improvement of power rating can be achieved through accurate checks of outdoor measurements, comparisons of different module measurements, and predictions of power output under various conditions. >