Experimental system for current-voltage curve measurement of photovoltaic modules under outdoor conditions

This paper describes an experimental system developed in the photovoltaic laboratory at the University of Málaga (Spain) to measure the current-voltage curve of photovoltaic modules under outdoor conditions. The measurement is performed in an automated way by employing commercial instruments controlled by a computer using the GPIB standard. Several modules, selected sequentially through a set of relays, are biased by a four-quadrant power supply while a function generator synchronizes two multimeters in order to acquire voltage and current values. The measurement uncertainties were also estimated. The proposed method for synchronizing the voltage and current measurements ensures that these measurements are performed simultaneously; this means that the estimated uncertainty is lower than those obtained using other previously proposed methods. The main electrical parameters are estimated. A user-friendly application allows the user to configure several parameters, such as bias rate, voltage, and current limits and the number of points of the curve. Copyright © 2011 John Wiley & Sons, Ltd.