Simulation and verification of a hybrid ferry propulsion system for maritime operation in Saudi Arabia

Hybrid marine propulsion systems are becoming increasingly indispensable to support the analysis of energy management performance and system-level control behavior, especially of small vessels under variable load conditions. Nevertheless, a significant percentage of existing simulation research is based on simplified operational profiles or subsystem-level validations and thus limits their applicability to realistic maritime environments and full energy management assessments. The present investigation is aimed at developing and evaluating a modular hybrid propulsion system model, which is able to effectively synchronize the propulsion dynamics, power distribution, and energy storage performance under controlled simulation conditions representative of typical maritime operating profiles. A comprehensive hybrid power system is formulated and simulated in MATLAB/Simulink. It consists of a synchronous reluctance assisted permanent magnet generator (SRPM), a lithium-ion battery, and an SRPM propulsion motor. A hierarchical energy management architecture, based on state of charge (SOC) droop control and proportional-integral (PI) current control, is used to coordinate generator-battery power sharing and maintain DC-bus stability during dynamic operating situations. Simulation results indicate consistent system-level behavior under the considered operating conditions of the model in terms of propulsion speed tracking error of about 0.7%, torque tracking error of about 2%, DC-link voltage transient deviations of + 4.9% and - 3.6% with tighter regulation during steady-state operation, d-q axis current tracking error of 1% and 2%, total power tracking error of 3%, and battery SOC tracking errors of about ± 1% within the safe operating envelope of battery SOC of 20-80%. The proposed framework is a scalable and forward-compatible simulation platform for hybrid marine propulsion analysis. It enables the assessment of energy management strategies and opens the door for the integration of hydrogen fuel cells and renewable energy sources in the future to support the development and system-level evaluation of hybrid maritime propulsion systems aligned with Saudi Arabia's Vision 2030.