Electrical modelling and experimental validation of a photovoltaic module using different models

The source of solar energy is the electromagnetic and thermal energy released due to the fusion reaction within the core of the star located at the centre of our solar system. The average value of this energy originating from the Sun out of the atmosphere of the earth is approximately 1367 W/m² and its called "solar constant". A certain amount of this energy is reflected back to the space by the atmosphere of the earth. Within the atmosphere of the earth, the value of solar energy is in the range 0-1100 W/m² due to the reflection, absorbance, accentuation and other obstructions. Photovoltaic cells are energy conversion devices made of semiconductor structures, converting the electromagnetic energy coming from sun to electrical energy. In the present study, an experimental system has been set up consisting of a polycrystalline type of photovoltaic panel made up by 36 cells, at the Faculty of Engineering of Bolu Abant İzzet Baysal University, in Bolu province. As well as the photovoltaic panel, the experimental system consists of sensors to measure system characteristics, data logger, battery and an electronic control unit. A validation of the system characteristics obtained by the solution of analytical equations has been made, measuring solar radiation (G), temperature (T), voltage (V) and current (A) at 10 minute intervals on this experimental system, for a total of 6 days. Based on these 6 days, using a total of 4 different analytical I-V curve model namely, 4-parameter, improved 4-parameter, 5-parameter and 2-diode models, the current and voltage values have been determined and compared to the values measured. The results of these solutions have been analysed based on the statistical indicators RMSE and R². Based on these measurements, solutions and the statistical indicators, it has been shown that amongst these 4 different models, the 4-parameter model has proved to be the most accurate model, leading to the most favourable statistical results.