In-depth analysis of photovoltaic module parameter estimation

Accurate knowledge of photovoltaic (PV) module model parameters plays an important role in PV power generation system. Therefore, in this study, the single-diode model of PV modules, physical meaning and solution methods of various parameters were introduced firstly. Then, the influence of various parameters on I-V characteristics was analyzed, and the parameter sensitivities of various parameters to the open circuit voltage and short circuit current were quantitatively discussed. Finally, different types of PV modules in a public dataset were used as objects, and different algorithms were employed to estimate the value of each parameter. Through simulation, some important points were provided: (i) the influence of photocurrent and parallel resistance on I-V characteristics is relatively independent, while the influence of reverse saturation current, series resistance, and ideality factor on I-V characteristics is highly coupled; (ii) the system degrees of freedom is totally different in case of considering the reverse saturation current as a dependent and independent variable. The improvement of the system degrees of freedom remarkably reduces the root mean square error of I-V characteristics; (iii) the estimated parameter resulted from meta-heuristic algorithms do not have the characteristic of uniqueness and may not represent the true values of the parameters.