Hybrid Energy Storage System for Voltage Stability in DC Microgrid using Fuzzy Logic Controller

Abstract

This paper presents a comprehensive Hybrid Energy Storage System (HESS) integrating lithium iron phosphate (LFP) batteries and supercapacitors (SC), governed by a 49-rule Mamdani Fuzzy Logic Controller (FLC), to enhance voltage stability in a 48V DC microgrid. Intermittent generation from solar PV and wind sources causes bus voltage deviations that degrade load performance and shorten storage life. The HESS exploits the high energy density of batteries for sustained power delivery and the high power density of supercapacitors for transient compensation. The FLC dynamically allocates power without requiring an exact plant model. MATLAB/Simulink validation under three disturbance scenarios confirms voltage regulation within ±1.2%, battery peak current reduction of 38%, and a 2.6× improvement in estimated battery cycle life over single-battery ESS. The FLC-HESS outperforms conventional PI-based configurations across all evaluated metrics including transient response, steady-state error, and storage component longevity.