Sistema fotovoltaico com integração de um conversor elevador de tensão contínua a capacitor chaveado e um inversor de três níveis a diodo grampeado: utilização da sequência de fibonacci nas condições de sombreamento parcial

Abstract

Due to the increasing utilization of photovoltaic systems in the urban environment, mainly on the roofs of buildings, the operation of such systems under condition of partial shading became more frequent. This situation is provoked by neighborhood structures besides clouds. The characteristic curves of the photovoltaic modules/arrays have a nonlinear behavior. Because of this, when submitted to partial shading condition, di?erent points of power maximum may appear in the curves making di?cult the tracking the point of operation and resulting in generation losses. In order to minimize this problem, this paper deals with a technique of maximum power point tracking based on the Fibonacci sequence.TheFibonacciapproachisabletosearchtheoperationofthesystemattheglobal maximum point. The system consists of a dc-dc multilevel boost converter (MBC), and a multilevel NPC inverter. The MBC, which combines the conventional boost converter with a voltage switched capacitor structure, is responsible for tracking the point of maximum power, raise and regulate the voltage with high transformerless static gain. The NPC inverter, in turn, is used to process the energy generated by the photovoltaic system by feedingasingle-phaseloadwith vevoltagelevels.Inordertovalidatetheproposedsystem, simulation and experimental results are presented and discussed for uniform irradiance conditions and three di?erent partial shading conditions.