A novel virtual admittance droop based inertial coordination control for medium-voltage direct current ship with hybrid energy storage

In the Medium-Voltage DC (MVDC) ships, pulse load will cause great disturbance to DC bus voltage. Hybrid energy storage (HESS) including Supercapacitor, Lithium batteries and Flywheel will bring significant improvement to the energy regulation ability of the ship integrated power system (IPS). A novel virtual admittance droop control based on the traditional virtual resistor and capacitor droop (VRCD) control is proposed. Through the design of specific virtual admittance structure and parameters, the generator and the HESS can bear the high, medium and low frequency part of the transient power fluctuation according to their own characteristics. Moreover, the State of Charge (SOC) recovery control of energy storage does not depend on the secondary controller, which simplifies the control structure. Simulation and experiment verify the effectiveness of the proposed control strategy.