Modelling and Simulation of centralized electric vehicle ... - Core

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Procedia Engineering 31 (2012) 746 – 750

International Conference on Advances in Computational Modeling and Simulation

Modelling and Simulation of centralized electric vehicle charging station wireless communication networks Chao Liu, Qiuzhan Zhou*, Jikang Hu, Hailong Xu, Hebin Zhang College of Communication Engineering JiLin University, Renmin street 5988,Jilin.Changchun.130022,China

Abstract The electric vehicles (EV) charging in the electric vehicles charging station (EVCS) needs to keep continuous communication with the charging station. As a low cost and low data rate wireless network technology, the ZigBee is suitable for setting up wireless networks in the EVCS. By researching the operation characteristics of the EVCS, we proposed a routing protocol for the EVCS wireless networks based on the AODV routing protocol. Using the network simulation software NS-2 simulates the EVCS wireless networks environment. The simulation is based on different load parameters of wireless networks performance, demonstrated the feasibility of the Zigbee networks to the wireless network of the EVCS networks.

© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Kunming University of Science and Technology Open access under CC BY-NC-ND license. Keywords: EVCS; Zigbee; NS-2; routing protocol; wireless communication networks

1. Introduction With limited petroleum resources on earth are depleted gradually, the energy problems become increasingly serious. Protecting the environment; reducing fossil energy consumption and a greenhouse gas emission have become a worldwide consensus [1]. In the consumption of petroleum resources, the traditional vehicles fuel consumption occupies a large proportion. At the same time, a large number of vehicles exhaust emissions on the environment lead to a great deal of pollution [2]. The EV has great * Corresponding author. Tel.: +86-13504465154; fax: +86-0431-85095243. E-mail address: [email protected].

1877-7058 © 2011 Published by Elsevier Ltd. Open access under CC BY-NC-ND license. doi:10.1016/j.proeng.2012.01.1096

Chao Liu et al. / Procedia Engineering 31 (2012) 746 – 750

advantages in environmental protection and energy-saving aspects, so many automobile manufacturers and governments are vigorously promoting the development of the EV [3]. Different from the traditional gas stations, the EV needs to stay a long time in the EVCS, so it is necessary for vehicles and charging stations to keep communication for a better information exchange on the vehicles charging management. As a promising wireless networks technology, the ZigBee has the characteristics of low cost, low complexity, low power consuming; self-organization, reliability, and ease of use features, etc. It is suitable for setting up the EVCS wireless communication networks [4]. 2. Routing protocol in the EVCS wireless network Routing protocol plays a very important role in the wireless mobile Ad Hoc Networks. The commonly used self organized network routing protocol can be divided into two categories, one is the active routing protocol (also called routing table protocol), and the other is a passive routing protocol (also a source of origin of the on-demand routing protocol.) In the active routing protocols, each node in the network sends the path information periodically, and then according to the received path information send by other nodes updating their routing table. Different from the active routing protocols, the reactive routing protocol is established only when the source node need in the active routing protocol. When a node needs to send the information to another node, it will start the route lookup in the whole networks to find a route to reach the destination node. The route lookup process is ended while the new route is found, or the arrangements of all possible routes have been tried [5]. (9¶s operation statuses in EVCS wireless networks environment can be divided into two states, (1) the EV is approaching or leaving the EVCS, (2) the EV states in the EVCS. According to the two different states, we can adept different routing strategies to optimize the data transmission and enhance networks performance objectives. Using the AODV routing algorithm, before the data transmission, the ZigBee wireless networks first starts the route lookup routine, only after the establishment of such routes for data transfer [6, 7]. The EV and the EVCS exchange information between are limited. If we add the information that needed to transmit to the route lookup information at the time of route lookup, it can effectively reduce the number of the messages and conserves the networks resources effectively. Therefore, we designed a new routing protocol for the EVCS wireless networks called AODVcsr(AODV for Charging Station Routing) routing protocol based on the AODV routing protocol. The AODVcsr resolve the following two main questions: (1) Transmits date information: When the routing lookup starts, some important information about charging station will be transmitted at the same time. This information, including the current grid load, realtime electricity pricing, unoccupied charging piles, waiting time, will be sent with the routing lookup. (2)Routing protocol switch: The EV will not move while it is charging. Meanwhile, this EV becomes a fixed node in the EVCS wireless networks. The static routing protocol can be used instead of resourceintensive dynamic routing protocols to exchange the information in the networks nodes until the EV is fully charged. Then the EV becomes a mobile node again. It transmits the information with the EVCS networks using the dynamic routing protocol. 3. Simulation The throughput of networks, node to node delay and the packet loss rate are the major consideration to evaluate the wireless networks [7]. This paper uses the network simulation software Ns-2 to simulate the EVCS wireless networks environment. We used the AODVcsr and the AODV routing protocol in the EVCS

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wireless networks in the constructed environment, performance parameters of wireless network simulation. The paper compares the difference of the network throughput, end to end delay, and the packet loss rate in these two cases. According to the EVCS practical work environment, this paper uses the simulation software Ns-2 to create a 50 × 50 m2 EVCS. The nodes were randomized into 25, 50, 75, applied two different routing protocols, respectively, to transmit Poisson data group, by the simulation based on different networks load performance of wireless networks. To achieve the purpose, we wrote a Bash script to automate the entire simulation process, and process simulation data, mapping the network performance data charts. The terminal nodes randomly selected direction of movement, the speed is 0.1~8.3m/s of uniform motion, average speed is 0.41m/s, the analog EV was. Bash script automate all the simulation work, the establishment of experimental simulation of the required 45 different scenarios, using Ns-2 simulation. According to Trace files generated, the networks performance parameters obtained data and graphics networks performance parameters. Bash script automatically changes the network parameters, resulting in different networks scenarios. Table 1 shows the scenarios related to simulation parameters of the EVCS wireless networks simulation. Table 1. The scenarios related to simulation parameters of the charging station wireless networks simulation Data stream format

Poisson

Total number of nodes Number of Routing node Network load

25

50

75

5

10

15

From 20% to 100% of the points five increments

Routing protocol

AODV, AODVcsr Coordinator node

Node 0

Radio wave propagation

Dual-path reflection model

Figure 1 shows the simulation in the wireless networks with 75 nodes transmuting Poisson data packet, under the working condition of the maximum network load.

Fig. 1. The charging station wireless network simulation environment


In the Figure 2, the throughput of networks is larger by using the AODVcsr routing protocol than by using the AODV routing protocol to transmit Poisson data packet in the EVCS wireless networks.

Fig.2. The throughput of networks in the different routing protocol

Fig.3. The network delay time in the different routing protocol

In the Figure 3, the networks delay time while transmitting the Poisson data packet by using the AODV routing protocol although there are some fluctuations, but the vast majority of cases, network delay time less than 0.05 seconds, and the data transfer process is relatively stable. Then, by using the AODVcsr routing protocol the network delay time is larger, sometimes even more than 0.05 seconds. Overall, the networks delay time is larger by using the AODVcsr routing protocol than by using the AODV routing protocol to transmit Poisson data packet in the charging station wireless networks. But overall is still less than 0.1 seconds, in most cases less than 0.05 seconds. In figure 4, it can be seen that using the AODVcsr routing protocol to transmit the Poisson data packet, the packet loss rate was significantly less than using the AODV routing protocol, and packet loss rate in most cases values were Less than 20% by the different working scenarios of packet loss rate. At the same time we can discover that the changes in networks load impact of its loss rate is not very clear, as the networks packet loss rate increases the load value does not correspond to the trend.

Fig.4. The packet loss rate in different routing protocol

The simulation results, we can find the proposed routing protocol AODVcsr for EVCS wireless networks. We can get higher throughput, lower packet loss rate, also the end to end delay times compared

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to using the AODV Routing protocol should be larger, but also within the acceptable range. At the same, with appropriate routing protocol ZigBee wireless networks to meet the common case of EVCS wireless communications requirements. 4. Conclusion When AODVcsr routing protocol is used in the EVCS ZigBee wireless networks, the EVCS wireless networks can get higher data throughput, lower packet loss rate, and the end to end delay is within the acceptable range. It can meet the real-time communication challenges that the EVCS wireless networks communication needs in the near future EVCS applications. Acknowledgements The authors gratefully acknowledge the support from the National Natural Science Foundations of China (No.60906034, No.61101155) and NSF of Jilin province project(No.201115029). References [1] LI Ming, etc. Research of EV Charge-Station Monitor System [J], Control & Automation, 2010.. [2] YAN Hui, etc. Development of Supervisory Control System for Electric Vehicles Charging Station [J], Power System Technology, 2009, 1 [3] Wang Yunyan,etc. Management Information System of Electric Vehicles Charge ± Station [J], Microcomputer Development, 2005, 11 [4] Kulshrestha, P.; Swaminathan, K.; Mo-Yuen Chow1; Lukic, S.. Evaluation of ZigBee communication platform for controlling the charging of PHEVs at a municipal parking deck [C]. 2009 IEEE Vehicles Power and Propulsion Conference (VPPC) 7-10 Sept. 2009. pp. 1211-1214. [2] Strunk Jr W, White EB. The elements of style. 3rd ed. New York: Macmillan; 1979. [5] Gowrishankar.S, SubirKumarSarkar, T.G.Basavaraju. Performance Analysis of AODV, AODVUU, AOMDV and RAODV over IEEE 802.15.4 in Wireless Sensor Networks [C]. 2nd IEEE International Conference on Computer Science and Information Technology, 2009. ICCSIT 2009. pp. 59-63. 2009. [6] Ashutosh Bhatia, Praveen Kaushik. A Cluster Based Minimum Battery Cost AODV Routing Using Multipath Route for ZigBee [C]. 16th IEEE International Conference on Networks, 2008. pp. 1-7. 02 February 2009. [7] Marina Petrova, Janne Riihijärvi, Petri Mähönen and Saverio Labella. Performance Study of IEEE 802.15.4 Using Measurements and Simulations [C]. Wireless Communications and Networking Conference, 2006. WCNC 2006. IEEE. pp. 487-492. 18 September 2006.