Fuzzy-GA Multi-Objective Sizing of Wind-Solar-Flywheel-Battery Systems for Resilience-Constrained Islanded Microgrids

The use of renewable energy sources in islanded microgrids has been shown to complicate gridstability due to low system inertia, intermittent generation, and rapid load fluctuations. This studyuses a mathematical framework comprising power-balance modeling, flywheel dynamic energyrepresentation, battery state-of-charge (SOC) dynamics, and coordinated control strategies, allbased on a Fuzzy-Genetic Algorithm (GA) multi-objective sizing model. Simulations inMATLAB/Simulink were conducted using time-series data of renewable generation, load demand,and storage responses over a 10 s operating window in two scenarios: normal sizing of windsolar-flywheel-battery systems and Fuzzy-GA multi-objective sizing. Results show that the systemmitigated a 65 kW deficit at t = 6 s by coordinating the dispatch of 40 kW from the flywheel and25 kW from the battery. Frequency was stabilized between 49.78 Hz and 50.05 Hz, while voltagewas maintained between 0.93 p.u. and 1.02 p.u. The flywheel energy ranged from 17.4 to 18.7kWh, while battery SOC remained between 75% and 78%, indicating effective energymanagement. Also, the multi-method robustness test results were between -80 kW and 60 kW,proving excellent controller robustness during extreme load changes, thereby encouragingrenewable integration, resilient microgrid operation, and hybrid energy storage deployment fordecentralized power systems.