A set of algorithms to estimate MPP of a solar PV system in partial shading condition

Abstract

From the careful observation of the reported work, it is found that there is no mathematical model available to estimate the performance degradation of a total cross-tied connected (TCT) photovoltaic (PV) array due to partial shading conditions (PSC). Inthis work, a set of algorithms is established to estimate the performance degradation of a TCT connected PV system at different PSC which will enable the PV installers to estimate MPP of the PV system. By employing these algorithms, it will be easier to estimate the performance degradation of a TCT connected PV systems due to PSC without using any measuring instrument except the measurement of irradiance and temperature. To achieve this goal, a study has been performed to estimate the unknown parameters of a PV module, whose values are not provided in the manufacturer s datasheet. To estimate five unknown parameters such as diode ideality factor, series resistance, shunt resistance, diode saturation current, and photo generated current of a single diode model newlinePV module, a simplified algorithm is developed, neglecting the less significant terms, which reduces the number of non-linear exponential terms. As a result, the computational complexity of the algorithm is minimized. Substituting the estimated values of the unknown parameters, the PV module output power is calculated for different temperature and irradiance conditions, which shows very good matching with the manufacturer s datasheet values. The output of the proposed algorithm is compared with some of the existing works, which shows better performance compared to the existing literature. For better accuracy in estimating the output of the PV module, the nominal operating cell temperature (NOCT) is considered. The proposed model output is verified with the simulated and laboratory-scale experimental results of a 315 Wp PV module, which shows better accuracy with the proposed model considering NOCT. The uncertainty in measurement is not more than 6.88%. In the existing PV modules, cells are connected in series