Desenvolvimento e validação de traçador de curva IxV para módulos fotovoltaicos

Abstract

IxV curve tracers for photovoltaic modules (PV) are used as a method of diagnosing problems with the modules as shadowing conditions, faulty connections and degradation conditions. There are several types and brands of tracers commercially available, but their costs are quite high. This research addresses the development and validation of a IxV curve tracer for a PV module focusing on the device's simplicity and low cost. The tracer developed is based on the electronic load method using a MOSFET as a load for the module; through a suitable variation of the gate-source of the MOSFET voltage signal is possible to acquire the points of intersection of the curves IxV characteristics of the PV module and the MOSFET. These points are acquired via a data acquisition board with PIC 18F2550, which is controlled via USB to a computer with a graphical user interface developed with MATLAB software, ensuring greater flexibility and functionality to the device. The validation process is performed by comparing results obtained from the developed and a commercial tracer on the same module under the same conditions of temperature and solar irradiance. The results show that the curves of the developed and the commercial tracer are very close to each other with errors of current, voltage and power lower than 3%.