Design And Research Of Mobile Charging Management System For Electric Vehicle

As the number of electric vehicles continues to grow,it is increasingly difficult for traditional fixed recharging piles to meet the daily charging needs of electric vehicles.The mobile charging device replaces the traditional fixed charging pile with its convenient and fast charging feature to solve the difficult problem of electric car charging.In this paper,a mobile charging management system for electric vehicles is designed with embedded technology,which combines charging management with charging service functions.Its purpose is to facilitate the management and maintenance of the management staff at the same time to the electric vehicle charging users to bring a good sense of experience.Based on the detection function of the lithium battery SOC in the mobile charging management system,this paper firstly studies the estimation algorithm of the lithium battery SOC.A phased estimation algorithm is proposed for the lithium battery SOC,which is suitable for mobile charging device.By constructing a second-order equivalent circuit model based on the original modified Thevenin model,the parameter identification of the lithium battery was made by the least squares method,and the error of SOC threshold was corrected.The parameters of temperature,battery life SOH and voltage are optimized at two different stages of charge and discharge,and the estimation precision is improved.In this case,the new algorithm is verified by HPPC experiment,and its estimation error is less than 2% in the discharge phase of lithium battery and 3% in the charging phase.Secondly,according to the reservation navigation function of mobile charging management system,the optimal path planning algorithm of emergency rescue charging is studied.Combining with the urban road information network model,an abstract "{ node collection } + { arc section collection } + { road right collection } + { traffic flow collection } + { road class collection }" is proposed.The road model is represented by a directional empowerment diagram.An optimization study of the original Dijkstra algorithm was carried out on the basis of the pavement model,according to the idea of A* algorithm,based on the priority factor of the target location,the efficient curve segment is calculated directly by using the double dot method.Steering's delay correction factor was introduced to correct the time calculation error caused by steering at the node junction.On the basis of optimization algorithm,an optimal path navigation scheme for mobile charging emergency rescue is designed.Finally,based on the embedded development platform of OK6818,the function design of mobile charging management system is completed and the debugging platform is set up.On the hardware,the design of the hardware interface circuit of the electrical energy metering function module,transaction settlement function module,appointment navigation function module,and the hardware circuit design of the lithium battery SOC detection module respectively.On the software,by analyzing the communication protocol between the electric meter and the IC card module and the embedded control module,the corresponding communication program is written in the Android Studio software.Furthermore,the algorithm of online estimation algorithm of the lithium battery SOC and the optimal path planning algorithm for emergency rescue charging are prepared.Finally,set up the debugging platform to perform functional debugging and overall debugging of the mobile charging management system.After debugging,the function modules can meet the design requirements,and the whole mobile charging device can operate safely and smoothly.