Scalable GaN-Based EV Charging Station with Energy Storage

Electric Vehicle (EV) charging stations with integrated energy storage are gaining increased attention because they reduce the negative impact of EV penetration on the electric grid. This work leverages the attractive flying capacitor multilevel (FCML) topology as a building unit referred to in this paper as a cell to develop a scalable DC-DC stage of an EV charging station that integrates energy storage (ES). It is scalable because it is constructed of points that interface EVs and ESs that can be increased for future upgrades. These points have two interfaces: one interface of each point is linked to the DC-link and the other interfaces are linked to respective EV or ES interfaces. Each point may contain a single cell (FCML) or several parallel cells to scale up the power rating of a point. This architecture has been verified by building a prototype using Gallium Nitride (GaN) switches consisting of a 2 kW single cell point for EV charging and a 2 kW single cell point for ES integration. Experimental results are provided in this paper, which shows the promising potential of this architecture thanks to the FCML coupled with the GaN switches.