Integração de sistemas fotovoltaicos na rede elétrica por meio do conversor de quatro braços e controle preditivo de corrente

Abstract

The Brazilian electrical system, characterized by an extensive transmission and distribution network, faces growing challenges, especially in residential areas, which are supplied by distribution transformers connected in delta/star configuration. These systems form a three-phase four-wire network, which encounters difficulties due to the coexistence of three-phase and single-phase loads connected to the distribution grid. The presence of these single-phase loads can lead to imbalances, resulting in significant currents in the neutral conductor, overloading it and degrading power quality. Therefore, this work proposes the use of a four-arm three-phase inverter with Finite Control Set Model Predictive Control (FCS-MPC) to mitigate neutral current and optimize power quality in low-voltage electrical networks. Additionally, to optimize the photovoltaic system's performance, the study also investigates two Maximum Power Point Tracking (MPPT) techniques: the Perturb and Observe (P&O) method and a hybrid strategy that combines P&O with predictive control. Finally, the study focuses on analyzing losses in the semiconductor switches of the converter. To validate the proposed control strategies, simulations were conducted using PSIM® software, and experiments were carried out in the System Optimization Laboratory (LOSE) at UFPB. The obtained results demonstrate the feasibility and effectiveness of the proposed approaches, contributing to the improvement of power quality in low-voltage distribution systems.