Modelling embedded technologies in energy service networks - Modelling Distributed Energy Resources in Energy Service Networks - page 72

configurations and architectures; this diversity can affect key indicators such as cost,
efficiency and driveability of the units [26].
Presently, the most popular PHEV architecture options include [203]:

Electric coupling : Adds the power injections from the generator and the battery
system through a power converter, thus functioning as an electric coupler which
sends the power flows to an electric motor and eventually to the transmission
system; this configuration is also commonly referred to as series architecture;

●

Mechanic coupling : Uses a mechanical coupler to sum the ICE and electric
motor mechanical powers, this allows the vehicle to transmit power to their drive
wheels from two different sources; the configuration is also known as parallel
architecture;

●

Electro-mechanic coupling : Consists of electric and mechanic couplers that
combine the features from the previous architectures, thus offering more oper-
ation modes; the configuration is popular within industry and also referred to
as series-parallel.

●

Although various PHEV configuration alternatives exist, it is out of the scope of
this work to address hybrid vehicle design issues. Still, Figure 4.15 depicts the series-
parallel architecture for HEV and PHEV units to illustrate that the main difference
between the technologies is the addition of a charger to the PHEV configuration. This
element allows the plug-in charger to obtain electric power from the grid and store it
in its battery pack.
A set of indicators are common in the PHEV charging literature; however, in
this work only the indicators relevant in modelling the TCOPF tool are covered. This
set of indicators allows us to assess the power demands associated with groups of
this category, which in turn permits us to compare the impacts different degrees of
penetration can have on the networks. The approach employed, very similar to CHP
systems in subsection 4.3.1, is a generic model for energy conversion focusing on the
instantaneous input and output power flows, while considering the vehicle as a black
box characterised by its linear energy conversion efficiencies (its storage features are
ignored here and explained in detail later in subsection 4.4.3).
For the PHEV unit represented in Figure 4.16, all the power the vehicle obtains
from the electric grid will be eventually used either for transportation or for ancillary
services. However, in the incoming and outgoing paths from the energy storage, power
losses occur related to the efficiency of the system. In practical terms, these losses
are related to power electronics and electric motor characteristics (such mechanisms
are not modelled in this text), yielding the equations below.
The electrical power injection efficiency into the PHEV unit (G2V) can be
described as:

G 2 V
P phev
D

η G 2 V = (4.37)

where G 2 V is the net electric power injection into the battery system (W el )
P phev
D

is the electric power required by the PHEV from the grid (W el )