Diseño y construcción de un trazador de curvas I-V para analizar paneles solares fotovoltaicos

Abstract

The great increase in the photovoltaic solar energy industry has led to the development of tools that make it possible to periodically evaluate the state of photovoltaic generation systems. Among these tools, the I-V curve tracers stand out, which allow evaluating the state of photovoltaic plants, providing precise information about possible failures or deterioration that may be affecting the operation of the installation. In this context, the present work shows the design and construction of an I-V curve tracer based on the capacitive charging method, which is used to obtain the current-voltage characteristics of photovoltaic modules or strings in order to evaluate their performance. The entire design process of the I-V curve tracer is described in detail in this work, which specifies all the materials used, the electronic diagram of the control and force stages, and the program developed in Python to control the entire operation of the I-V curve tracer. A simulation carried out in PSIM allows to exemplify the operation of the equipment. Once the design was completed, the equipment construction process was proceeded, resulting in a portable and scalable equipment capable of obtaining the current-voltage characteristics of photovoltaic systems with short-circuit currents lower than 16 A and with open-circuit voltages lower than 500 V, this in times below 1 second. In addition, the document provides a bibliographic review of the most relevant information regarding the I-V curves and their analysis; as well as information related to the different methods that I-V curve tracers can use. Finally, experimental tests were carried out on the photovoltaic panels of the Microgrid laboratory of the University of Cuenca in order to evaluate their status and validate the operation of the constructed I-V curve tracer. The results of the experimental tests showed that four of the six photovoltaic panels analyzed present failures or deterioration, which is consistent with the expected results. In addition, the results obtained were compared with those obtained from a commercial I-V curve tracer, obtaining similar results in both cases, thus verifying that the equipment built is adequate to analyze the state of photovoltaic generation systems.