Estudo de estratégias de sincronização para sistemas de geração distribuída utilizando Phase-Locked Loop (PLL)

Abstract

In recent years, concerns about the environmental impacts of electricity production and the scenario of increasing energy demand have led to the frequent adoption of renewable energy sources, aiming at sustainability. Since the self-sufficiency of isolated systems is still uncommon due to high implementation costs and technological bottlenecks related to battery efficiency for energy storage, the integration of these sources into the power grid has become a growing trend. In this context, DC-AC converters play a crucial role in connecting distributed generation systems to the electrical grid. This work focuses on analyzing the characteristics of four different control systems based on Phase-locked Loop (PLL) and their impact on the performance of three-phase voltage inverters connected to the grid. The study briefly addresses the fundamental concepts of PLL system design but primarily focuses on analyzing the behavior of a grid-connected DC-AC conversion system composed of a three-phase inverter and control circuits where the PLL is an essential part. The PLL acts as a subsystem that receives the grid's three-phase voltage signals and, by analyzing its frequency, produces a modulation signal used to control the inverter's output voltage. The behavior of the voltages at the output of the three-phase inverter is evaluated through computer simulations in Matlab software. Simulations were performed for the system controlled by four different PLL models, and to compare the performance of the systems, the IAE (Integral of Absolute Error) and ISE (Integral of Squared Error) criteria were used. This approach aims to understand the limitations and advantages of the different control techniques studied, providing insights to improve the integration of renewable energy sources into the grid while promoting greater safety and energy efficiency.