  Electric Vehicles (EVs) are projected to be one of the major contributors to
energy transition in the global transportation due to their rapid expansion.
The EVs will play a vital role in achieving a sustainable transportation system
by reducing fossil fuel dependency and greenhouse gas (GHG) emissions. However,
high level of EVs integration into the distribution grid has introduced many
challenges for the power grid operation, safety, and network planning due to
the increase in load demand, power quality impacts and power losses. An
increasing fleet of electric mobility requires the advanced charging systems to
enhance charging efficiency and utility grid support. Innovative EV charging
technologies are obtaining much attention in recent research studies aimed at
strengthening EV adoption while providing ancillary services. Therefore,
analysis of the status of EV charging technologies is significant to accelerate
EV adoption with advanced control strategies to discover a remedial solution
for negative grid impacts, enhance desired charging efficiency and grid
support. This paper presents a comprehensive review of the current deployment
of EV charging systems, international standards, charging configurations, EV
battery technologies, architecture of EV charging stations, and emerging
technical challenges. The charging systems require a dedicated converter
topology, a control strategy and international standards for charging and grid
interconnection to ensure optimum operation and enhance grid support. An
overview of different charging systems in terms of onboard and off-board
chargers, AC-DC and DC-DC converter topologies, and AC and DC-based charging
station architectures are evaluated.
