Secondary voltage and frequency restoration control of drop controlled inverter based microgrids with Type-3 fuzzy logic

This text focuses on the changing dynamics in the energy sector and the disadvantages of traditional energy sources and how to overcome these disadvantages with renewable energy sources. The limited and environmentally unfriendly structure of traditional energy sources has created threats to energy security and environmental sustainability. It emphasizes that renewable energy sources are an important solution to overcome these challenges. These sources enable cleaner and more sustainable energy production by obtaining from natural resources such as solar, wind, hydroelectric. The integration of renewable energy sources into the grid highlights the advantages of microgrids. Microgrids offer a distributed structure that integrates local energy production, storage and consumption. However, along with the advantages brought by these structures, some technical challenges also arise. This thesis addresses the role of microgrids, which are a fundamental component of modern energy systems, in depth, emphasizing the critical importance of voltage and frequency control in microgrids in particular. Microgrids offer flexible structures that can operate in an isolated manner as well as connect to other microgrids or the main grid. Thanks to advanced control techniques, automation, energy storage technologies, communication infrastructure and high computing capacity, microgrids provide significant advantages over traditional centralized grids by increasing energy efficiency and reliability. Voltage and frequency control in microgrids plays a vital role in ensuring the stability and reliability of these systems. Especially in islanded microgrids, factors such as lack of backup power and sudden load changes can cause voltage and frequency fluctuations. Minimizing the effects of these fluctuations and maintaining system stability is critical to ensure the efficient operation of microgrids and increase energy efficiency. This thesis focuses on improving voltage and frequency control in microgrids, explaining the potential of Type-3 fuzzy control strategy. Type-3 fuzzy control offers an effective control structure that allows parallel operation in microgrids with highly distributed generation. This strategy can work independently of the structure of the microgrid and adapt to different operating conditions. Simulations performed on the MATLAB-Simulink software platform demonstrate the effectiveness of Type-3 fuzzy control strategy in voltage and frequency control.