Advanced energy management for RES integrated multiport EV charging station with efficient ancillary service to distribution network

Driven by environmental concerns and advances in energy storage technologies, the deployment of electrified transportation networks (ETNs) has gained significant momentum in recent years. However, the rapid expansion of multiport fast-charging infrastructure has begun to exert significant stress on existing power distribution grids and raises concerns regarding grid stability and power quality. This paper presents a bidirectional multiport charging station (MPCS) architecture integrated with photovoltaic (PV) generation, a battery energy storage system (BESS), and a weak AC grid, coordinated by a supervisory control (SC) layer and local controllers (LCs) to realize islanded, hybrid, grid-connected, and ancillary-service operating modes. Detailed coordinated dynamic models of all subsystems are developed in MATLAB/Simulink, and their performance is evaluated through time-domain simulations under highly intermittent solar insolation and time-varying MPCS and AC-grid load profiles. Under CHAdeMO fast-charging operation with individual electric-vehicle charging currents reaching 250 A at each DC interface, the proposed energy-management scheme limits DC-bus and point of common coupling (PCC) voltage excursions to within ±5% of nominal despite severe PV intermittency and load variability. During peak hours and disturbance conditions, the same framework provides ancillary services consisting of reactive-power/voltage support at the PCC, targeted active-power support to the weak feeder, and EV-assisted V2G compensation support. The findings demonstrate that the coordinated SC and LCs structure effectively mitigates MPCS-induced grid disturbances, improves dynamic power allocation, and preserves transient stability, enabling decentralized distribution networks to accommodate increasing fast-charging demand without immediate infrastructure upgrades.