Solar Irradiance measuring using PV module and PIC microcontroller based Electronic assembly

In this paper, a simple and low cost method based on a mathematical equation is used to calculate the solar irradiance (G). It is based on the short circuit currents output and the currents at the maximum power point (MPP) of the PV module at both Standard test conditions (STC) and Actual conditions of irradiation & temperature (G,T). The values of currents at $(STC)\{I_{sc}(STC); I_{mp}(STC)\}$ are read directly on the PV module datasheet, while the other value of currents at ( $G, T$ ) conditions $\{I_{sc}(G, T); I_{mp}(G, T)\}$ are measured via a data acquisition card equipped with a PIC microcontroller and voltage and current sensors. The used equation with the four currents is programmed using LabView interface. Several irradiances deduced from these four data are displayed on the graphical interface. Three different PV modules have been tested and the obtained solar irradiances have been compared to those displayed by a first class pyranometer. The error calculation confirms the accuracy of the proposed method.