Page 39 - Power Electronics News - December 2020

Design Design

ing and discharging of the vehicle based on
vehicles remain stationary for 90% of their time.

In Figure 1 there is also a reference to the OCPP real-time energy production, local power
data exchange protocol (OCPP stands for Open consumption and information on the state of
Charge Point Protocol): it is a standard proto- charge of the EVs.
col that defines the communication between
EV, charging station and a central management UMC can be implemented through unidirection-
system and is a reference for implementing EV al control of vehicle, whereas SMC necessarily
smart charging solutions. requires bidirectional flow of power and controls
(the so called V2G technology).
We can identify five main benefits of Smart

Charging:

1. efficient and optimal use of the power
grid;

2. it is a solution able to avoid the conges-
tion of the power network; Figure 3: V2G block diagram.

Actually, this picture refers to a more gener- Power Sharing, also known as levelling or load
3. it is capable of smoothing peaks in power al case, the so called V2X (Vehicle to Anything) balancing. This feature allows power grid opera-
demand; technology, since both Vehicle to Grid and Vehi- tors to distribute the available energy proportion-
cle to Home are shown. ally (which means, equally) on all active charging
4. it can produce electricity directly on site stations. Therefore, Power Sharing allows an
(that is, in the charging stations) exploit- optimal distribution of the available energy with-
ing renewable energy sources such as SMART CHARGING FEATURES out requiring any upgrade to the existing network
solar panels, wind energy, and other; The first important feature of Smart Charging is infrastructure. Figure 4 shows three use cases

Figure 2: Smart charging classes.
5. investments in grid infrastructure can be
reduced. VEHICLE TO GRID TECHNOLOGY
An overall view of what V2G technology means is
shown in Figure 3. We can see there are:
SMART CHARGING CLASSES

According to Figure 2, Smart Charging solutions ▶ a control unit on the vehicle (ECU) which
can be grouped in two classes: interacts with a control unit on the charging

station;
▶ UMC (User Managed Charging) class, where it
is the owner of the vehicle who chooses the ▶ inside the EV there are some high voltage
charging time based on the price of energy batteries (HVB), which are charged and dis-
and his or her needs; charged through DC high voltage;

▶ SMC (Supplier Managed Charging) class, ▶ a charging station, which interacts with the
where it is the energy supplier who direct- grid and the “intelligence” on the cloud.
ly manages, via V2G technology, the charg-

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