Provision of Synthetic Inertia via Energy Storage VSC for a Ship AC/DC Microgrid

Hybrid microgrids are increasingly being considered for application in ships, as part of current trends in the electrification of transportation, where power systems are standalone under normal operations. This paper focuses on the development of a model-based synthetic inertia provider through a power controlled VSC-based battery energy storage system within a ship AC/DC microgrid, configured for operation when the ship is in port. A new electromechanical power-speed model, representing the interaction between the ship rotating generators and the VSC AC/DC sides, has been derived. A linearized form of the model has been utilized for power system small-signal analysis, in addition to deriving the model-based synthetic inertia method. Also, the paper introduces a switching function that offers an extra advantage as it only activates the synthetic inertia provider when needed for stabilizing the generator speed or frequency. A detailed system simulation has been carried out which has generated speed-response results, demonstrating that the proposed SI method outperformed the existing standard and frequency-events methods in terms of performance and minimum utilization of the available VSC power.