Hybrid Energy Storage System in Naval Vessel with 2-Stage Power-sharing Algorithm

Short duration and power intensive load such as pulse load weapon system can result in severe voltage and frequency variation in the naval vessel if it is handled alone by the generators. Hence, it is meaningful to design a hybrid energy storage system (HESS) with a lithium-ion battery (LiBatt) and an ultracapacitor (UC) which can handle both high energy and power density events while mitigating the impacts of pulse load. In this paper, the impact on the system frequency and voltage by the pulse load with and without HESS are investigated. 2-stage power-sharing algorithm for HESS with frequency decoupling and the fuzzy logic controller (FLC) is designed. State of charge (SOC) observer is incorporated to ensure that the HESS SOC is within the user-defined limits. The proposed strategy resulted in lower voltage and frequency variation of the system and it is verified using MATLAB/Simulink model for various scenarios.