Distributed bus signaling control for a DC charging station with multi paralleled flywheel energy storage system

Fast charging stations (FCS) will become an essential part of future transportation systems with an increasing number of electrical vehicles. However, since these FCS plugs have power ratings of up to 100 kW, serious stress caused by large number of FCS could threaten the stability of the main power grid. To overcome the possible adverse impacts, this paper applies a dedicated paralleled flywheels energy storage system (ESS) in FCS, to balance the power by the method of ramping the initial power peak. Distributed DC-bus signaling (DBS) method is employed in the power coordination of grid and flywheel converters, and the two flywheels are able to share the power peak through the voltage vs speed droop control. Furthermore, a reduced small-signal model has been built for the purpose of stability analysis and parameter optimization. Finally, real-time simulation results performed on a reduced scale model corresponding to experimental setup parameters have been reported in order to verify the validity of proposed approach.