Physically-consistent parameterization in the modeling of solar photovoltaic devices

This research tests the standard one-diode model of a crystalline-Si photovoltaic cell, focusing on the physical accuracy. In particular, the (apparent) shunt resistance and the diode ideality factor are studied. Current-voltage characteristics of illuminated crystalline-Si photovoltaic modules are analyzed, and some limits of applicability of the standard model are given. Typical values of the ideality factor for crystalline-Si devices are derived from own experimental data as well as from recently published literature. It is shown that the contribution of the apparent shunt resistance is only significant for cell voltages below about 0.45 V, and depends on irradiance. This result is consistent with earlier research. Some reference books on Photovoltaics give a wrong shape of the electrical characteristic based on a non-physical interpretation of the shunt resistance. This paper may be particularly useful for power electronics engineers designing inverters and maximum-power-point tracking algorithms.