Vehicle traffic has increased dramatically, resulting in real problems such as increased greenhouse gas emissions and fossil fuel reliance. To overcome this issue, the world started to take a huge step towards electric mobility.
When thinking of an electric vehicle (EV), one of the most important things that should be taken into account is its charging system. There are three levels of charging for electric vehicles: level 1,2 and 3. Level 1 charging (120 V) works well for plug-in hybrid electric vehicles as they have smaller batteries (less than 25 kWh). Level 2 (220/240 V) which are commonly used for daily EV charging and can be installed anywhere. Finally, level 3 (400+ V) which is broken into DC Charging and (Tesla) Super Charging. (The higher the power, the faster the charging)
After introducing the three levels of EV charging levels, it is now critical to talk about On-board and Off-board Charging Systems. An on-board charger is connected to the power grid through a single-phase interphase and has two stages: the first is to convert the AC power from the grid to DC power and this allows bidirectional operation which will be discussed later on in this article and the second stage uses a DC-to-DC converter that provides a wide variety of DC to charge the battery. On the other hand, an off-board charging system (i.e., charging stations) takes incoming DC power (PV systems) or AC power (Generator) and converts it to DC power needed for the battery.
As mentioned in a previous article, converting to smart grids is one of the future goals and that is where bidirectional operation in EVs is taken into account; it is when a battery discharges power and gives it back to the grid or supports households in the case of blackouts, usually in the context of vehicle-to-grid (V2G), and this operation is what makes EVs not only environmentally friendly, but also an integral part of the future of power systems.
Afonso, J.L.; Cardoso, L.A.L.; Pedrosa, D.; Sousa, T.J.C.; Machado, L.; Tanta, M.; Monteiro, V. A Review on Power Electronics Technologies for Electric Mobility. Energies2020, 13, 6343. https://doi.org/10.3390/en13236343