Intelligent Power Management of Electric Vehicle with Li-Ion Battery Sheng Chen 1,a, Chih-Chen Chen 2,b

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1 Applied Mechanics and Materials Vols (2013) pp Online available since 2013/Feb/13 at (2013) Trans Tech Publications, Switzerland doi: / Intelligent Power Management of Electric Vehicle with Li-Ion Battery Sheng Chen 1,a, Chih-Chen Chen 2,b 1 Department of Electrical Engineering Hwa-Hsia Institute of Technology, New Taipei City, Taiwan 2 Department of Management Information Systems Hwa-Hsia Institute of Technology, New Taipei City, Taiwan a senchen@cc.hwh.edu.tw, b wei@cc.hwh.edu.tw Keywords: lithium batteries, inverter, power management Abstract. The paper aims the power management of Li-ion battery on the electric vehicle to record motor-using behaviors for each electric vehicle in a cloud server. After retrieving information from each electric vehicle, developed algorithm will be able to conclude a proper charging scheme for each electric car according to their using history. Therefore, optimizing rapid charging scheme become possible, and the cloud information can also assist power grid to manage power flow under crucial circumstances. To do integrated management of batteries, the design starts from setting up LiFePO 4 batteries charging/discharging characteristic curve under different load. Considering the mobility of battery information access, the work proposes a cloud server work as database and computing center. The more information collected by the cloud, the more precise of the battery-using model is. The database collects data including battery SOC, battery voltage, discharging current, temperature etc. The battery life simulation also works in the cloud by the information about SOC, open-circuit voltage, discharging current and temperature. According to cloud data analysis, charging current 5C/10C/20C under rapid charging grid s load monitoring is possible; the process of environmental development and hardware planning can train students to use hardware, firmware and software design platform for the skills development for future employment. Introduction In Taiwan, there are hundreds of millions of oil-fueled vehicles and motorcycles, has caused a lot of environmental pollution and oil consumption, electric vehicles are expected to occupy a signicant portion of the automotive market share in the near future, the use of Li-ion(LiFePO 4 ) battery as a vehicle motor power to replace the fuel, is the best choice of today's environmental issues; An electric vehicle has only an electric drive-train powered by Li-ion battery; in the past, motor vehicles is the inverter-driven with lead-acid batteries, in order to slim and light in weight, most of the current cell has replaced by Li-ion battery with its weight reduction, energy saving effect and high energy density; The cost and performance of the electric vehicle is primarily determined by the type of battery and its management system ; but when nearly one million electric vehicles on electric system, the load flow of charging current and large information of the battery will impacts the power and control system; this paper proposed the implementation of intelligent cloud of electric vehicle battery management system and the proposed innovative ways to provide for the revitalization of the domestic industry opportunities as the Fig.1 shown. The main parts of the propose architecture, which is scalable to accommodate more number of battery cells to manage. The mass connection of electric vehicles to the existing network can cause very harmful effects on it. Power loss or damage to equipment could be dangerous common situations in the network,due to the overload introduced with these recharging processes. In addition, to avoid damaging conventional consumers of electrical energy, it is also vital the electric vehicle interaction with the network [1]. Moreover, in the moments, when an extra power capacity is needed, this power would be taken from their distributed storage elements, which are none other than the batteries of electric vehicles; these new elements will have a successful integration into the power system, the system gradually become more intelligent and robust, where information and control systems are predominant with a view to obtaining a proper operation of electrical system and the design electrical and control of a network architecture. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, (ID: , Hwa-Hsia Institute of Technology, New Taipei City, Taiwan-20/10/14,14:30:39)

2 Applied Mechanics and Materials Vols The aim in Fig.1 demonstrates the important need for an active control that achieves the correct integration of both distributed generation and distributed storage via the electric vehicle in the current electrical system. The micro-grid of Intelligent cloud of electric vehicle battery management system for recharging electric vehicles is a center with a vehicle-to-grid (V2G) system; which is able to evacuate energy into the electrical system when the system is appealed. Fig.1 Intelligent cloud of electric vehicle battery management system Basic Structures of Electric Vehicle The basic units of the cloud power management in this system is the individual structures of electric vehicle (EV), and the deep inside for EV as the Fig. 2 shown is important; there are include three parts of this system, which are mechanical unit, main controller unit, and energy unit ;the over voltage and under voltage are detected for diagnostics, measures temperature and pack voltage, pack current and pack temperature are for monitor; It also provides methods for precise battery series cell balancing [3]. Mechanical Unit Main Controller Unit Wheel 1 Wheel 4 Transmission Wheel 2 Wheel 3 BLDC Motor IGBT/MOS Inverter PSOC Main Controller Slow-up/down Emergency Stop Power Management Unit LiFePO4 Battery Bank Super Capacitor Bank Auxiliary Power Source Energy Unit Balancing Monitoring Protecting Controller DC/DC Converter Steering Unit Steering Charging System Fig. 2 Basic Structures of Electric Vehicle

3 1560 Mechatronics and Applied Mechanics II Electric Vehicle Power Driver The brushless DC motor is applied for electric vehicle as the Fig.3 shown, S I1 ~S I6 are the inverter gate signal to drive motor for variable speed running, and to control forward/reverse direction by the embedded PSOC programming with different frequency and sequence, depending on the desired mode of running; The Sa, Sb switch signal determine the operation mode of the battery power charger,the time sequence of gate are shown in Fig.4,which can be divided into three modes: boost driving mode, direct driving mode and charging mode [2]. C S I1 S I3 S I5 V R L S I4 S I6 S I2 V S V T S I1 S I2 S I3 S I4 S I5 S I6 Gate Controller Fig.3 The power and inverter of brushless DC motor applied for electric vehicle Boost Drive S I1 S I2 S I3 S I4 S I5 S I6 Inverter Speed Control T 1 T 2 T 3 T 4 T 5 T 6 T 1 T 2 T 3 T 4 Direct Drive T 1 T 2 T 3 T 4 Charging Mode T 1 T 2 T 3 T 4 Forward Operation Reverse Fig.4 The time table of vehicle motor speed/direction and power mode control

4 Applied Mechanics and Materials Vols Series Li-ion batteries active balancing with super capacitor Fig.5 is the switching super capacitor balancing methods on EV power system, which is active balancing the charge of cells in a series connection cells strings. It is low losses, simple, and compact in size, which is easy from photo type implement to practical application. Fig.5 The switching super capacitor balancing methods on EV power system Conclusion Intelligent Power Management of Electric Vehicle undergo significant transformation to achieve environmental and energy sustainability. The brushless DC motor is applied for electric vehicle with power mode adopted flexible speed for steering; the switching super capacitor balancing methods on EV power system is low losses, simple, and compact in size, which is easy from photo type implement to practical application. The batteries energy of electric vehicles from their distributed storage elements will supply the additional power capacity to the electric grid when the grid is needed. The EV with Li-ion batteries increasing will enhance microgrids capability to further facilitate renewable energy sources and the power management of Li-ion battery on the electric vehicle to record motor-using behaviors for each electric vehicle in a cloud server improve efficiency by V2G services. According to the cloud data, charging current under rapid charging grid s load monitoring is possible [4]; the process of environmental development and hardware planning can train students to use hardware, firmware and software design platform for the skills development for future employment. References [1] Che Changjin and Qu Yongyin, Research on Drive Technology and Control Strategy of Electric Vehicle Based on SVPWM-DTC, International Conference on Mechatronic Science, Electric Engineering and Computer, pp , Aug [2] Liangrong Wang, Jianing Liang, Guoqing Xu, Kun Xu, Zhibin Song, A Novel Battery Charger for Plug-in Hybrid Electric Vehicles, Proceeding of the IEEE International Conference on Information and Automation Shenyang, China, pp ,June [3] S. Chen, C. K. Wang, and H.P. Huang, Intelligent Cell-balance Algorithm with Pseudo-series Connected Battery on the Security Robot, The 6th Taiwan Power Electronics Conference &Exhibition(TPECE 2007), Sep. 7th, [4] B. Roberts and C. Sandberg, The role of energy storage in development of smart grids, Proceedings of the IEEE, vol. 99, no. 6, pp , 2011.

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