SOC-based Hybrid Energy Storage System Dynamical and Coordinated Control for Vessel DC Microgrid

-A piecewise linearized power distribution control strategy of Hybrid Energy Storage System (HESS) for the DC vessel microgrid is proposed in this paper. It not only can stabilize the DC bus voltage well but also can optimize the charge/discharge operation of storage units according to their current state-of-charge (SOC) level. The high power density energy storages (e.g. supercapacitor) response quickly to compensate the instantaneous load variation and keep the bus voltage stabilization, the high energy density energy storages (e.g. lithium battery) supply the continuous energy, moreover, the charge/discharge power of the lithium battery is closely related to the current SOC level of the supercapacitor. Simulation results indicate that the control strategy can automatically adjust the working state and output of the supercapacitor and lithium battery, and maintain the DC bus voltage within a reasonable range when the load demand suddenly change.