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.