A Grid-Supportive Current Ramp-Rate Constrained (GS-CR2C) Control Strategy for a SST-Based Bidirectional Multi-Port Fast-Charging Station

Though a variety of control strategies have been proposed for electric-vehicle (EV) fast-charging stations (FCSs), their impact on the grid has been largely overlooked. In this paper, a Grid-Supportive Current Ramp-Rate Constrained (GS-CR
²
C) control strategy has been proposed for a bidirectional multi-port FCS, which prevents detrimental impact of high power ramps during fast charging/discharging on the interfacing utility-grid. A comprehensive theoretical derivation for the proposed GS-CR
²
C control strategy is provided along with realistic charging and discharging schedules of various types of connected EVs (heavy, medium and light) during grid-to-vehicle (G2V) and vehicle-to-grid (V2G) functionalities respectively. A thorough real-time validation of the proposed control scheme on a RTDS platform is also demonstrated for a 22 kV grid-connected, 1 MVA bidirectional FCS. An excellent adherence to the charging/discharging schedule, low DC bus ripple, along with superior utility-grid side power quality are observed.