Caracterização Experimental das Placas Fotovoltaicas

Abstract

Two small commercial photovoltaic panels, advertised with nominal specifications of 5 V and 5 W, will subsequently be employed to compare the energy produced by a fixed system and a solar-tracking system. However, the absence of a complete datasheet and the possibility of differences between the panels and the measuring instruments require prior experimental characterization. This study aims to characterize the electrical behavior of both panels and evaluate the reliability of the acquisition system based on two INA219 modules. Open-circuit voltage, controlled short-circuit current, and voltage and current responses under different resistive loads will be determined, allowing the construction of I–V and P–V curves and the estimation of the maximum power point. The power of each sample will be calculated as the product of simultaneously measured voltage and current, while electrical energy will be determined through trapezoidal integration of the instantaneous power values over the actual acquisition intervals. The observed electrical resistance will be estimated from voltage and current measurements and compared with load resistance values measured using multimeters. The influence of the instrumentation will be investigated through crossed measurements in the M1 and M2 configurations, alternating the association of the panels with the two INA219 modules. The system uses two ESP32 boards: a primary board responsible for measurements, processing, microSD card storage, and data transmission to a remote database with a retransmission mechanism; and a controller board responsible for automatically switching the panels between the measurement channels. Panel temperature, ambient temperature and humidity, and relative variations in illumination will be recorded as supporting variables. The study is expected to distinguish differences associated with the panels from those introduced by the measurement channels and to establish experimental parameters and reference uncertainties for the future comparison between the fixed and solar-tracking systems.

Keywords: Photovoltaic characterization; I–V and P–V curves; crossed measurements; INA219; measurement uncertainty.