Performance evaluation of procedures used to correct measured I-V characteristics of photovoltaic modules for temperature and irradiance

Abstract

IEC 60891 ed.3 published in 2021 has defined four standard I-V characteristics correction procedures numbered 1 through 4. The aim of this work is to evaluate these four I-V translation methods. The results show that correction procedure 1 (CP1) and 2 (CP2) work well over a broad range of irradiances and temperatures. However, CP1 requires I-V curves being measured adequately down to negative current regime at low-irradiance levels and CP2 is not so suitable for low shunt-resistance modules; both also require a set of correction parameters. Based on our performance analysis, a new method based on CP2 is introduced to improve the correction performance for low shunt-resistance modules; the mean bias error (MBE) value of maximum power (P_MAX) improved from −10.26% to −1.32%. Correction procedure 3 (CP3) employs a drastically different correction procedure as compared with the other CPs. This work shows that CP3 works well over a broad range of irradiances and temperatures, but significant distortion of the corrected I-V curves may occur when extrapolation is required. Correction procedure 4 (CP4) requires only a single I-V curve and shows generally good results in short-circuit current (I_SC) but worse agreement in open-circuit voltage (V_OC) and P_MAX.