Combining Identification and Translation Methods of the Single-Diode Model to Compute the Average Temperature of Photovoltaic Modules From the Open-Circuit Voltage

Abstract

A common method of measuring the temperature of a photovoltaic module is by attaching a sensor to its back surface. However, since this method of measurement is punctual, the temperature gradient along the module surface is not considered. In addition to that, the temperature of the sensor is usually considered equal to the temperature of the photovoltaic cells, thus ignoring the temperature drop along the materials in between. This paper focuses on the problem of computing the average cell temperature of photovoltaic modules, based on information available on their respective datasheets and on measurements of the open-circuit voltage and solar irradiance. For that, different methods regarding identification and translation of the single-diode model parameters are used in conjunction, aiming to establish a simple and accurate procedure for computing the average temperature. The best performing combinations are then compared with IEC-60904-5, which presents a procedure for calculating the equivalent cell temperature of a module. Such computing procedures for the average module temperature have been experimentally tested, presenting coherent results.