Desenvolvimento e validação de traçador de curva IxV para módulos fotovoltaicos usando o método de carga eletrônica

Abstract

IxV curve tracers for photovoltaic (PV) modules are used as a method of diagnosing problems in modules such as shadowing conditions, faulty connections and degradation conditions. There are several types and brands of tracers available commercially, but their costs are quite high. The present research deals with the development and validation of an IxV curve tracer for an PV module focusing on the simplicity of the device and its low cost. The tracer developed is based on the electronic load method using a MOSFET as a load for the module. By means of an adequate variation of the gate-source voltage signal of the MOSFET it is possible to acquire the points of intersection of the characteristic IxV curves of the PV module and the MOSFET. These points are registered through a data acquisition board, with PIC 18F2550, which is controlled via USB by a computer with a graphical user interface developed with MATLAB software guaranteeing greater flexibility and functionality to the device. The validation process was performed by comparing the results obtained by the developed tracer and by a commercial tracer on the same module under the same conditions of temperature and solar irradiance. The results showed that the curves of the developed tracer and the commercial tracer were very close, with average errors (between the values obtained with the tracer developed and the values obtained with the commercial tracer) of current, voltage and power lower than 4.2 %.