A new method to obtain I-V characteristics curves of photovoltaic modules based on SEPIC and Cuk converters

The basic operation of a solar cell, module or photovoltaic generator under different irradiation and temperature conditions is characterized by its I-V characteristic curve. Only the experimental measurement of the I-V curve allows us to know with precision the electrical parameters of a photovoltaic cell, module or array. This measure provides very relevant information for the design, installation and maintenance of photovoltaic systems. Currently, the I-V characteristic curve is obtained by connecting a variable charge to the panel terminals in order to achieve that the current of the terminals ranges from zero to the short circuit current. In this paper we propose a new experimental way to measure this characteristic curve by using Buck-Boost-Derived DC-DC converters. It has been proved that the optimal topologies for this purpose are the SEPIC (Single-Ended Primary Inductance Converter) and Cuk converters. The theoretical analysis performed has been validated by means of simulation and experimentally. Additionally, a comparison between three known conventional methods and the proposed one is provided.