On the experimental validation of an improved five-parameter model for silicon photovoltaic modules

This paper presents the experimental validation of a new five-parameter model capable of analytically describing the I–V characteristic of a silicon photovoltaic module for each generic condition of operative temperature and solar irradiance. The operating current calculated with the model was validated on the basis of a series of experimental measurements performed in the field on two commercial silicon photovoltaic panels connected to a set of nine constant values of the electrical load. In order to examine the panels working in almost steady-state conditions only the data-sets of the sunniest days from sunrise to sunset were used. Unfortunately the production spread of photovoltaic panels did not permit the consistent comparison between the measurements and the data calculated by the model on the basis of the electrical characteristics provided by the manufactures. To surmount such an obstacle the determination of the particular current–voltage characteristic of the tested photovoltaic panel specimens was successfully attempted by filtering the collected data. The results of comparison have shown that the model defined by the new electrical characteristics is able to evaluate the operating current with a high degree of accuracy, even during days perturbed by very variable conditions of solar irradiance.