Implementation of a Fuzzy Logic Controller for Long-Term Energy Management in a Hybrid AC/DC Microgrid

Abstract

This paper presents the design and evaluation of a fuzzy logic controller (FLC) for long-term energy management in a hybrid AC/DC microgrid. The study is based on the Smart Energy Office Building (SEOB) system, which integrates photovoltaic (PV) generation, a lithium-ion battery, and a hydrogen-based energy storage system consisting of an electrolyzer, hydrogen tank, and fuel cell. Conventional rule-based state machine control (SMC) methods are limited by their rigidity and inability to adapt to dynamic operating conditions. To address this limitation, a Mamdani-type fuzzy inference system is developed using key system variables, including battery state of charge, power imbalance, and hydrogen storage level. The proposed FLC is implemented in a MATLAB/Simulink environment and evaluated through long-term simulations, including a full-year scenario, a summer week, and a winter week, using real measured data. The results demonstrate that the FLC achieves smoother control behavior, reduces switching frequency, and improves coordination between energy storage components compared with SMC. Specifically, it reduces battery cycling, extends continuous operation of the fuel cell, and enhances overall system stability. While slightly increasing grid interaction, the FLC enables a more balanced and efficient energy distribution within the microgrid. The findings confirm that fuzzy logic control provides a robust, computationally efficient, and interpretable solution for long-term energy management in hybrid microgrids, offering significant potential for improving system performance and component lifetime.