Battery Energy Storage Systems for Mitigating Fluctuations Caused by Pulse Loads and Propulsion Motors in Shipboard Microgrids

In present times, the concerns over severe environmental pollution, fluctuations, and fossil-fuel consumption caused by immensely dynamic loads (pulsed loads) have captured attention in shipboard microgrids. In order to make such power system stable and reliable, presently, more generators are kept online that operate much below their efficient point. Therefore, in order to boost the fuel efficiency of shipboard microgrids, the minimum generator operation with N-1 safety can be considered as a possible solution, which is a trade off between reliability and fuel economy. For that, one of the efficient solution is to interface an energy storage system (ESS) by removing the backup generator or removing one of generator and operate rest of the generators close to their efficient point. Energy storage devices that have been frequently in use in different applications consist of batteries, flywheel, ultra-capacitor, and fuel cell. Lithium-ion among the different type of batteries is one of the most used battery in fully electric zero-emission commercial ferries that sails on shorter routes. This paper therefore presents Lithium-ion based Battery Energy Storage System (BESS) as a feasible solution to the prior mentioned concerns. At first, in order to cater with the fluctuation caused by the propulsion motor with the varying sea conditions, BESS is interfaced without the use of buck-boost converter in parallel with the DC-link capacitor. Secondly, the same BESS is interfaced with the point of common coupling (PCC) in order to cater with pulsed loads. The proposed methodology is simulated and verified using MATLAB/SIMULINK software environment.