IEEE Wireless Communications - April 2017 - page 68

IEEE Wireless Communications • April 2017
66
1536-1284/17/$25.00 © 2017 IEEE
A
bstract
Unlike traditional ICEVs, the introduction
of EVs is a significant step toward green envi-
ronment. Public CSs are essential for providing
charging services for on-the-move EVs (e.g., EVs
moving on the road during their journeys). Key
technologies herein involve intelligent selection of
CSs to coordinate EV drivers’ charging plans, and
provisioning of cost-efficient and scalable commu-
nication infrastructure for information exchange
between power grid and EVs. In this article, we
propose an efficient and scalable P/S commu-
nication framework, in line with a coordinated
on-the-move EV charging management scheme.
The case study under the Helsinki city scenario
shows the advantage of the proposed CS selec-
tion scheme, in terms of reduced charging waiting
time and increased number of charged EVs, as
charging performance metrics at EV and CS sides.
Besides, the proposed P/S communication frame-
work shows its low communication cost (in terms
of signalings involved for charging management),
at the same time great scalability for supporting
increasing EVs’ charging demands.
I
ntroduction
In smart grids, the application of electric vehicles
(EVs) [1] has been recognized as a significant
transportation option to reduce CO
2
emissions.
However, due to the limited battery capacity
and long trip distance in urban cities, EVs on the
move are more likely to run out of energy and
thus need to recharge batteries during their jour-
neys. How to manage the charging processes to
improve EV drivers’ comfort is vital to the success
and long-term viability of the EV industry.
Research efforts of literature works on EV
charging management focus on two use cases:
The
parking mode
addresses the use case where
EVs are parking at homes/charging stations (CSs),
with the concern of when/whether EVs should be
charged (i.e., charging scheduling). The
on-the-
move mode
addresses the use case where EVs are
on the move, with the concern of where/which
CSs they should plan for charging (i.e., CS selec-
tion).
Enabling mobile and communication technolo-
gies [2, 3] are important in smart grids, particular-
ly for the on-the-move mode use case. Here, the
decision on where/which CSs to charge involves
interaction across a number of entities in the net-
work, for example, on-the-move EVs, CSs, and the
global controller (GC), which implements the sole
charging management.
As such, there is a necessity to design the
communication infrastructure with efficiency
and scalability in mind, concerning the long-term
introduction of EVs. Nevertheless, the majority of
recent literature works rely on ubiquitous cellular
network communication [4], which is an expen-
sive solution.
Envisioning an urban city charging scenario
(by selecting a geographically deployed CS as the
charging plan), we aim to answer the following
three questions:
•How can state-of-the-art intelligent transportation
system (ITS) techniques be utilized for on-the-move
EV charging management? These include roadside
unit (RSUs), the Global Position System (GPS), and
standardization of vehicle-to-infrastructure (V2I)
communications. We propose a publish/subscribe
(P/S) [5] communication framework to facilitate fast
charging service, where necessary information (e.g.,
charging availability of CSs and charging reservations
of EV drivers) are shared among network entities.
Also, we enable lightweight computation at RSUs to
aggregate information for the purpose of communi-
cation cost reduction.
•Which CS should be selected by the EV driv-
er to achieve the best driving experience (e.g.,
minimized charging wait time), and how should
EV drivers’ charging reservations be utilized (e.g.,
arrival time and expected charging time at their
selected CSs) to coordinate charging manage-
ment? We develop a distributed charging man-
agement scheme concerning EV drivers’ charging
reservations to coordinate their charging plans.
•How does the provisioned communication
framework affect the actual charging performance
(e.g., charging wait time for EV drivers and num-
ber of charged EVs at CSs), and is the provisioned
ITS-enabled communication framework efficient
and scalable? We study the influence of informa-
tion publication interval, and RSU and EV densi-
ties on the system-level performance.
Y
ue
C
ao
, O
mprakash
K
aiwartya
, R
an
W
ang
, T
ao
J
iang
, Y
ang
C
ao
,
N
auman
A
slam
,
and
G
raham
S
exton
T
oward
E
fficient
, S
calable
,
and
C
oordinated
O
n
-
the
-M
ove
EV C
harging
M
anagement
S
mart
G
rids
Yue Cao, Nauman Aslam, and
Graham Sexton are with
Northumbria University.
Omprakash Kaiwartya is with
Universiti Teknologi Malaysia.
Ran Wang (corresponding
author) is with Nanjing
University of Aeronautics and
Astronautics, and the Collab-
orative Innovation Center of
Novel Software Technology
and Industrialization.
Tao Jiang and Yang Cao are
with Huazhong University of
Science and Technology.
Digital Object Identifier:
10.1109/MWC.2017.1600254WC
1...,58,59,60,61,62,63,64,65,66,67 69,70,71,72,73,74,75,76,77,78,...132
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