Wireless Sensor Net Based Study On Comprehensive Energy Monitoring Technology Of Electric Vehicle

As one of the three most significant portions of Electric Vehicles (EV), Electric vehicle-used energy system has been considered to be the bottleneck that restrains the development of EV. Its performance affects the whole capability of the EV. Therefore management for energy system is quite necessary. The task of energy management system is monitoring and controlling batteries effectively to increase their service efficiency and service life. Moreover, the management system could pre-estimate succeeding running capability of EV according to battery status. In conclusion, studies on energy management system are of great significance.This thesis raised a research scheme on WSN (Wireless Sensor Network) which is applied to energy management system of EV. It is to explore and take research on the possibility of and technical approach to combine the advantage of WSN and electrical propulsion control technology of EV. According to the system demand and battery packs assignment, this thesis designed the general monitoring system of battery packs within EV based on WSN technology. This system could take measurements on multi-battery packs to gain real-time data of within monomer while the EV is running, charging or even in the static state, afterwards process and transmit them based on ZigBee technology to the user interface, then handle and calculate received data, furthermore the result could be displayed, saved and reused. Throughout the monitoring system, a subsystem set to collect data from single battery pack is configured in order to test the battery cell. By adding ZigBee wireless communication modules to those subsystems a WSN formed. The data collected in the network is transmitted wirelessly to the user interface on PC which is connected with the ZigBee coordinator, and then the data is calculated, processed, eventually comes the state of the charge (SOC) of the battery in various conditions to provide correct guidance for the EV, including its succeeding running miles and climbing ability.With demand analysis, this paper designed the software and hardware system of the WSN which was used to test the energy storage battery packs of the EV. The hardware system consists of the data acquisition unit, A/D conversion unit, serial interface, power and simulation interface, radio frequency module. The software system was also described in detail combining with protocol of the ZigBee technology, including the corresponding control of hardware modules described above. Also the paper did research on the process of buildup of the wireless communication network and the process of data transmitting and receiving, did profound analysis and comparison between many SOC forecast methods on the actual energy storage system, then selected the rational SOC forecast method of super-capacitor. At last, an interactive user interface procedure was designed for comprehensive testing system of the battery packs based on LabVIEW to process, display, save and reuse the data.