Energy Management of a PV-Battery-Fuel Cell-Diesel Hybrid System for DC Microgrid Applications

Abstract

This paper presents the design and simulation of a hybrid energy management system incorporating photovoltaic (PV) panels, a battery energy storage system, a solid oxide fuel cell (SOFC), and a diesel generator to ensure a stable DC bus voltage under varying generation and load conditions. The system is modeled using MATLAB/Simulink, where the PV panel is connected to a boost converter controlled by a maximum power point tracking (MPPT) algorithm to optimize energy extraction. A bidirectional non-isolated DC-DC converter connects the battery to the DC bus, enabling both charging and discharging modes based on the state of charge (SoC) and load demand. The bus voltage is regulated at 48V using a Model Predictive Controller (MPC), ensuring fast dynamic response and reduced steady-state error. A fuel cell system supported by a PI-controlled boost converter and a diesel generator interfaced through a threephase controlled rectifier act as auxiliary power sources. These sources are prioritized based on real-time energy availability and storage conditions. Simulation results demonstrate the system’s ability to maintain voltage stability during PV fluctuations, and ensure uninterrupted power delivery through coordinated energy sharing. The proposed control strategy enhances system resilience, operational efficiency, and power quality in standalone or off-grid applications.