Modeling and Experimental Studies of the Photovoltaic System Performance in Climate Conditions of Poland

Abstract

The polycrystalline silicon photovoltaic system located in Poland has been investigated from a modeling and an experimental perspective. The five-parameter single-diode (SD) model was used to compute the current–voltage (I-V) characteristics of the PV modules for weather conditions measured during one year (2022) of PV system operation. Based on the I-V curves, the PV power output, monthly energy yields, and performance were simulated. Besides the single-diode method, the Osterwald model (OM) was used to estimate the power output of the PV system under scrutiny. The modeling results were compared to the experimental data. The determination coefficient (R2), root mean square error (RMSE), mean bias error (MBE), and relative error (RE) were utilized to quantify the quality of both models. The highest R2 value of 0.983 (power output) was found for March, a relatively cold and sunny month in the analyzed period. The lowest values of the RMSE and the MBE were found to be 5% and 1%, respectively. A high correlation between the modeled and the experimental daily yield was noticed in June, which was the sunniest month of the year. Median values were found to be 5.88 kWh/kW (measurement), 5.87 kWh/kW (SD), and 5.87 kWh/kW (OM). The RE of the monthly array yield was found to be below 1% (summer half-year) in terms of the single-diode method. The strong correlation between the simulated and the experimental findings was also noticed for the medians of the DC performance ratio (PRDC). The median values of the PRDC from May to July were found to be in the range between 0.88 and 0.94.