Analysis of key performance parameter extraction from current voltage measurements of photovoltaic devices

The accuracy of the characterisation of photovoltaic devices may be affected by the method of extraction of the performance parameters. This paper investigates potential uncertainties in extracted short circuit current (I_sc), open circuit voltage (V_oc) and maximum power (P_mpp) from current-voltage (I-V) data of a photovoltaic (PV) device. Different interpolation methods are compared. Linear interpolation, straight line regression and polynomial regression methods are compared in different scenarios in which the curve point density and point selection for extraction are varied. The comparison shows that regression approaches can produce more accurate results when appropriate curve point density and point selection are selected. When attempting to extract I_sc. V_oc and P_mpp from noisy or irregular I-V data, linear interpolation is less robust than regression because of the irregular point distribution on the I-V curve.