Parameter estimation technique for double-diode model of photovoltaic modules

This paper proposes a parameter estimation technique for the double-diode electrical model based on the physical behavior of the photovoltaic (PV) module with respect to variations of the environmental conditions. There are several different techniques for PV parameter estimation. However, most of them identify the parameters for a specific irradiance and temperature. This means that different sets of parameters are found for each environmental condition, providing results that do not represent I-V curves correctly. Thus, the parameters provide only a mathematical representation with lack of physical meaning. In the proposed technique, it is necessary to execute the parameter estimation only once, because the model is valid for all range of values of the environmental conditions available on datasheets or experimental curves. Moreover, the restrictions imposed on each parameter makes the model capable of emulating the physical behavior of the PV module, particularly useful in fault diagnosis and predictive and corrective maintenance of PV systems. Comparison results based on datasheet and experimental curves are presented to verify the effectiveness of the proposed parameter estimation technique.