Dynamic Modeling and Control of Hybrid Electric Vessels with a Super-Capacitor and a Lithium Battery

This paper presents a dynamic model of a dual-motor vessel powered by an integrated energy system consisting of a supercapacitor (SC) and lithium battery. The SC manages high-power demands, reducing the load on the lithium battery to enhance its lifespan and improve overall system efficiency. MATLAB/Simulink was used to simulate this model, integrating energy sources, transmission systems, traction motors, propellers, and vessel body dynamics. A rule-based control strategy (RBCS) with specific operational modes—Supercapacitor Mode, Hybrid Mode I, Hybrid Mode II, and Hybrid Mode III—was developed to effectively manage energy distribution, improving energy flow and extending battery life, which lowers maintenance costs and enhances performance. Additionally, a fuzzy control method was implemented and compared to RBCS. Results indicate that fuzzy control improves velocity stabilization by 3.8% between 750 and 1200 seconds, and reduces energy consumption by approximately 5.7% compared to RBCS, highlighting its potential for greater efficiency and control in vessel propulsion energy management.