Abstractâ Dynamic charging of electric vehicle technology aims to deploy the use of electric vehicle on a large scale. In order to realize and achieve an effective ...
2015 Euromicro Conference on Digital System Design
Information and communication technology research opportunities in dynamic charging for electric vehicle Oussama Smiai1, Francesco Bellotti1, Alessandro De Gloria1, Riccardo Berta1, Angelos Amditis2, Yannis Damousis2, Andrew Winder3 1 DITEN, University of Genoa, Via Opera Pia 11A, 16145 Genoa, Italy, 2 Institute of Communications and Computer Systems (ICCS), Athens, Greece 3 ERTICO, Brussels, Belgium
approaching the charging pad will be based on a set of software, hardware and protocols. While charging, the EV should not exceed a speed limit and its receiving coil should be aligned with the charging pad of the lane to ensure maximum energy transfer. The EV should inform other EVs using the lane about its status to avoid collision and inform about the potential problems of the charging infrastructure. This paper reports a state of the art analysis of the most relevant ICT solutions related to dynamic charging of EV and provides the indications for future research in the field.
Abstract— Dynamic charging of electric vehicle technology aims to deploy the use of electric vehicle on a large scale. In order to realize and achieve an effective and reliable system, the information and communication solutions (ICT) need to be developed. The ICT solutions look particularly to assess areas such as routing, booking of the charging lane, billing, vehicle identification, guidance to charging lane and assistance while charging. In this paper, we review the state of the art of ICT solutions and provide indications for the future research. Keywords—dynamic on-road charging; information technology solutions; electric vehicle; wireless charging; routing; charging lane; EV identification; lane keeping
The remainder of this paper is organized in several sections addressing the following topics: • EV identification: The charging infrastructure needs to identify the EV approaching the charging lane before authorizing it for charging.
I. INTRODUCTION Electric vehicle (EV) is a promising technology for new transportation system. The number of sold electric vehicles is still small because the costs of electric vehicles are more compared to internal combustion engine (ICE) vehicles. This high cost is due to the fact that cost of the battery is still high, another reason is the limited driving range of the electric vehicle and this problem is known as the “range anxiety”. The “range anxiety” limits the use of EV to urban trips. One solution to the limited driving range is to increase the size of the EV battery, which will increase the cost of the EV and makes it less accessible to the public. Another obstacle to the adaptation of the EV is the recharging time, where the EV needs several hours to do a full recharge.
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• Guidance to charging lane: Notifying the EV driver in the highway about the location of the charging lane. • Driving assistance while charging: The driver needs to maintain a speed limit and align with the charging pad in order to maximize the efficiency of the energy transfer. • Dynamic routing: A navigation device routes the driver to his destination, plan the charging actions and inform the driver about the availability of the charging lanes.
Researchers proposed the dynamic wireless charging on the move to extend the driving range of the EV [1], the following is a scenario consisted of a trip done by an EV: in a highway connecting two cities, one of the lanes will be a charging lane. This lane will contain many charging pads underneath the road. When an EV approaches a charging pad, the charging pad will deliver a wireless energy to the charging coil of the EV. Some research projects are assessing the feasibility of the electric dynamic charging, and it is foreseen that ICT will play an important role in this context. The charging infrastructure needs the ICT system to manage the lane users, process booking requests and issue bills. Guiding the EVs to the charging lanes will be supported by a navigation system that will inform the user about the location of the charging lane, the price of charging and the availability of the charging lane to serve the EV. The navigation system will calculate the most efficient energy and create a charging plan for the EV trip. Lane control access will be regulated by adequate systems that notify nearby EV about the lane location and status. Identification of the EV approaching the lane and the EV
978-1-4673-8035-5/15 $31.00 © 2015 IEEE DOI 10.1109/DSD.2015.111
User accounts management, booking and billing: The EV driver needs a user account to book the charging infrastructure and receive the bill of the consumed electric energy.
• Human Machine Interface (HMI): design of the proper HMI to enable interaction with the ICT solutions without disturbing the driving process. II. EV IDENTIFICATION The charging infrastructure needs to recognize pre-booked or other authorized vehicles in order to activate the charging process. We can distinguish two identification levels. In the first level, the charging infrastructure needs to recognize the EV approaching the charging lane. In the second level each charging pad needs to identify the approaching EV. In the following sections we will describe solutions for each identification levels.
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A. Identification of an EV approaching the charging lane For this identification level, two techniques can be used: the Automatic License Plate Recognition (ALPR) and Dedicated Short-Range Communications (DSRC).
development should be done to shield Portunes against cyberattacks.
The ALPR is the extraction of vehicle’s license plate information from an image or a sequence of images. The extracted information can be utilized with or without a database in many applications, such as an electronic payment system (toll payment and parking fee payment), freeway and arterial monitoring systems for traffic surveillance. A camera is used by an ALPR to capture image of the license plate. The quality of the acquired images is a great factor in the achievement of the ALPR. Under different environmental conditions, such as day and night, ALPR has to rapidly and successfully treat license plates. License plates from different nations should be supported by ALPR. Different colors, languages and fonts can be found in license plates; a single color background or background images can exist in license plates. Dirt, lighting, and towing accessories on the car can obstruct the license plates. [2] The ALPR system is quite mature to support the need of on- road charging EV
Charging infrastructure will need a system to recognize users, allowing them to book charging infrastructure and be billed. The driver may use different charging lanes during his trip. A system is needed to enable the creation of a user account that is interoperable between different energy retailers. Each week or month, the system should deliver a bill detailing the different charging operator that delivered energy to the EV and the price of the consumed energy. The system should enable the linking of the EV user to a credit or debit card to automate the payment of the delivered energy. Enabling the booking of the charging infrastructure will ensure that the charging lane is compatible with the EV charging system and contains enough energy to charge the EVs; it is interesting to use a booking system that will handle reservation from the users of EV.
III. USER ACCOUNTS, BOOKINGS AND BILING
The EV user should have a Human Machine Interface (HMI) in his EV that enables the transmission of reservations with minimum interaction in order to avoid disturbing the driving process. The system should enable the EV user to cancel the booking in case the user realizes that he has enough energy to travel to his destination, a major delay in travelling and when the lane is out of service. For billing reasons the system should interface with a clearing house that compensates the different energy operators.
Dedicated Short-Range Communications (DSRC) is a set of radio channels that are designed to Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) wireless communications [3]. V2V and V2I communications have many aims; they intend to enhance the awareness of drivers about the surrounding environment (presence and position of other vehicles, pedestrians, obstacles and other objects). They aim to rapidly disseminate emergency-related messages (e.g., accident ahead), in order to promptly trigger appropriate countermeasures (e.g., emergency braking); they communicate to drivers information about nearby road works, speed limits and traffic conditions. They permit road operators to get information about the moving vehicles on road (such as their identity, position and route). DSRC is used for Electronic Toll Collection in many countries.
The eco-FEV backend [3] system responds to many requirements of the dynamic wireless charging. Further testing will lead to improvement of the system. IV. GUIDANCE TO CHARGING LANE The EV driver needs to be guided to the charging lane, before he reaches the charging lane, he should be notified by specific messages and signs. Variable message signs (VMS) and Lane Control Signals can be used for this goal.
DSRC can be considered as a ready to support the requirement identifications of on-road dynamic charging of EV. Further experimentation will reveal necessary adaptation over state of the art.
A. Variable Message Sign Variable message signs (VMSs) can transmit traffic and roadway information to motorists, VMS is considered as an element of the Intelligent Transport System. VMS can be utilized to supply a variety of traffic information, e.g., traffic conditions, accident warnings, special event announcements, road construction notices, speed limits, alternative routes, etc. One of the essential applications of VMS is the supply of authentic message content and winning over the motorists to comply the displayed guidelines. This application is of the concern to traffic operators when route deviation is wanted under both recurring and non-recurring congestion. A wellplanned VMS system can assist to relieve traffic problems, hence cutting down the travel time and meeting motorist’s demand. [7]
B. Identification of EV approaching the charging pad Depending on the length of the charging pad (usually less than one meter) the contact between the charging pad and the EV may not exceed 10 ms when the EV is travelling at the speed of 100 km/h. For this reason, we need an authentication protocol for charging pads to authenticate an EV’s identity in much less than 10 ms so as to allow enough time for the actual energy transfer process. The PORTUNES [1] can be an interesting protocol as it uses pseudonyms to supply location privacy, permits EVs to roam between different charging sections and to obtain a single bill. It reaches fast authentication by relying on symmetric keys and on the spatiotemporal location of the EV. Portunes permits the EV to render authentication information within 0.3 ms, and permits charging pads to check the information within 0.5 ms. Portunes is more efficient than ECDSA [2] which needs 25 ms for signature and requires over 40 ms for verification. Further
VMS can meet the on road-charging needs and a standardization effort by traffic authorities is needed to specify symbols for dynamic charging infrastructure.
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routing application for the dynamic charging of EV. In fact Web mapping has many advantages over traditional mapping forms. It has a low price since web server, hardware and tools for producing web maps are relatively inexpensive or free. Products can be distributed and reproduced either at no cost or at very limited expenses. The web maps also enable greater collaboration between users. Web Maps implementation can provide real time information about charging lane availability, charging pricing, expected time to reach destination and traffic conditions[8][9].
B. Lane Control Signal Lane Control Signals (LCS) are particular overhead signals that allow or prohibit the use of specific lanes of a street or highway or that show the impending forbiddance of their use. Lane control signals are differentiated by positioning of special signal faces over a certain lane of the roadway and by their distinctive shapes and symbols. Lane Control Signals are most commonly employed for reversible-lane control, but are also employed in irreversible freeway lane applications. [4]. LCS is a good candidate to meet the on-road charging needs and some work related to standardization may be required by traffic authorities to design specific signals for dynamic on-road charging EV lanes.
Modeling the problem of routing for a dynamic charging electric vehicle is a challenging task because, it is not clear of which cost will be assigned to the roads with charging lane. The cost assigned to a road will not only depend on the presence of a charging lane but also on the choice of the driver to charge during travel. Routing algorithms for dynamic onroad charging EV needs to be investigated, so that the calculated route takes into consideration about the driver destination, time of arrival and financial budget for recharging actions. Deciding when to consider a charging lane as available requires an extensive research. For instance, a charging lane may notify the driver that it is unavailable if the number of booking requests is high based on traffic prediction.
V. DRIVING ASSISTANCE WHILE CHARGING The EV needs to align its receiving coil with the road transmitting coil in order to increase energy efficiency transfer and a lane keeping system (LKS) [5] can be used to achieve this goal. A LKS usually relies on a camera placed behind the wind shield mirror to detect the road lanes. The LKS can even correct automatically the vehicle path; LKS uses a vehicle path prediction system to warn the driver before he actually leaves the lane. In order to automatically correct the vehicle trajectory, the position between the vehicle and the charging pad can be measured using certain techniques[6]. The lane sensing can rely on the infrared sensor or camera; however a limitation of the camera system is that it is not accurate enough in bad weather conditions. The infra-red sensor is cheaper than the camera and is not affected by poor visibility, but it cannot predict lane departure. A magnetic field sensor [7] can be used to detect the presence of the charging coil on the road and experimentation is needed to evaluate the LKS capability to rely on this type of sensors .In case a lane departure is detected, a lane departure warning can be issued by audible or visual warning or haptic feedback.
VII. HUMAN MACHINE INTERFACE Last but not least, the specific characteristics of the electric vehicles capable of dynamic on-road charging raise the need to develop a dedicated human machine interface (HMI). As a general requirement, the HMI should deliver the information in real-time and according to the driver’s workload unobtrusively, so the driver can concentrate on the road[10]. Nomadic devices like smartphones should be properly integrated with the rest of car systems[11] and the development of the HMI should be user-centric. HMI for advanced driver-assistance systems can take profit of the research development concerning 3D sound, so the driver can be warned early and prevent collision with other vehicles[12]. Extending the driving range relies on HMI that stimulates the driver to use the regenerative braking and drive to the nearest charging lane when needed[13]. In the same context, the driver will be supplied with a HMI for charging authorization, charging monitoring and charging interruption in case of poor energy transfer. In addition the driver should be able to book a charging lane with minimum interaction with the vehicle HMI.
LKS can respond to the needs of on-road dynamic EV charging. VI. DYNAMIC ROUTING Dynamic routing will give guidance to EV driver to reach the destination and plan charging actions. The routing system should enable the user to choose an itinerary and specify which charging lanes to use. While the user is driving, the routing system should spot the charging lane and inform the driver about their positions. The routing system will inform the user also about availability of the charging lane so that, the driver can charge the EV when he reaches the charging lane.
The electric engine of the EV makes less sound than the engine of a conventional car which relaxes the driver more while driving. On the other hand, the driver cannot rely too much on his audibility for the information about the status of the engine and the battery, so we need to develop an HMI to inform the driver when the powertrain is ready to work[13].
The web mapping solutions such as Google Maps, MapQuest and OpenStreetMap can be used to develop a
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Fig 1 Different steps to charge an EV using a charging lane [6]
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VIII. CONCLUSION On-road dynamic charging for EVs is a promising technology that is expected to encourage the public to embrace the electromobility. In this paper, we identified hot topics related to the ICT necessary for the implementation of this technology and proposed a critical analysis of possible solutions. We reviewed the different ICT solutions that can be used to fulfill dynamic EV charging. The analyzed ICT solutions respond to need of the EVs drivers in terms of routing, booking, billing, EV identification, guidance to charging lane and assistance while charging. “Fig. 1” summarizes the different steps to charge an EV using a charging lane. Fig. 1 describes the ICT solutions that are used to achieve the charging action. ACKNOWLEDGMENT This work was also supported by the European Commission under FABRIC, a collaborative project part of the FP7 for research, technological development and demonstration (Grant Agreement NO 605405). The authors would like to thank all partners within FABRIC for their cooperation and valuable contribution. REFERENCES [1]
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