Conversor modular multinível para usinas solares fotovoltaicas: implementação e validação experimental

Abstract

The increasing demand for electricity and the discussions on environmental paradigms have led in recent decades to a diversication of the energy matrix. Among the renewable energies, photovoltaic solar energy (PV) has emerged with an accelerated growth in installed capacity in the world, reaching the mark of 303 GW in 2016. The photovoltaic solar plants are characterized by the arrangement of a large number of panels associated in series and/or parallel connected to a converter. The most commercially used to pologyisthe centralized one, where a large number of panels are connected to a converter with only a MPPT (Maximum Power Point Tracker) algorithm, responsible for tracking the maximum power point, which is dependent on solar irradiance and temperature. However, this high number of panels per MPPT is not ecient, because under partial shadowing conditions it is not possible to maximize the energy available individually by each panel. Due to the low eciency of these systems, their feasibility requires the maximum utilization of the available energy. The greater the number of MPPT trackers, the better the use. The decentralizedtopology,ormulti-string,allowsagreaternumberofMPPTtrackers.Modular multilevel converters have interesting advantages for large-scale photovoltaic applications due to the multiple inputs of direct current with MPPT, modularity and reduction of the volume of sinusoidal lters. The use in these converters of electronic transformers (SST), which operate at high switching frequencies using semiconductors of Silicon Carbide (SiC), is presented as an alternative to ensure galvanic isolation between the panels and the electrical network, dispensing a bulky and voluminous low-frequency transformer, and thus, improving converter compaction. In this work, the implementation and experimental validation of a multilevel modular converter for applications in photovoltaic solar plants are presented