Prototype for the characterization of photovoltaic panels based on a SEPIC converter

This paper presents the design and implementation of a prototype based on a SEPIC (Single-Ended Primary Inductance Converter) used to measure the characteristic curves of photovoltaic (PV) panels. The SEPIC is controlled to emulate a variable resistance at the output of the PV panel in order to obtain a set of values (voltages and currents) for different operating points at the output of the panel. The set of voltages and currents are stored and sent to a computer in order to display the characteristic curves in real-time. The performance of the prototype is firstly evaluated though simulations in PSIM and subsequently by experimental results. The results show the outstanding performance of the SEPIC converter and its suitable use for this kind of applications due to its low input current ripple and its operation as a buck-boost converter. The resulting prototype allows the characterization of PV panels up to 500 W.