Assessment of photovoltaic I–V curve translation methods in real-world situations

Abstract

The evaluation of performance of a photovoltaic array is effectively conducted through the analysis of its I–V curves. However, conducting these measurements under real-world field conditions introduces certain shortcomings in subsequent analysis and modeling. Therefore, it becomes imperative to translate the I–V curves from measured data points to conform to the standard test condition (STC). The approach presented in IEC 60891:2021 addresses this requirement. This study focuses on investigating the accuracy of the translation process using Procedure 4 from IEC 60891:2021 across a wide range of irradiance and temperature, and compares it with state-of-the-art alternatives (Hansen and metaheuristic methods). Experimental data and optimization methods were employed to assess errors and determine the optimal conditions utilizing a single-diode equivalent circuit, along with its parameters for temperature and irradiance correction. The results demonstrated that the metaheuristic method achieved the best results in terms of average RMSE, surpassing the IEC in all cases and the Hansen method in approx. 81% of outcomes. Moreover, the outcomes under real outdoor conditions significantly diverge from those observed in indoor measurements conducted using a flash solar simulator.