Design And Implementation Of Vehicle Wireless Charging Communication Protocol And Control System

As energy crisis and environmental pollution exacerbates,governments and automotive industry have realized the importance of energy saving and carbon emission reduction,which is the direction of future automotive technology.New energy vehicle uses electric energy as power,which is clean and renewable,to reserve energy and reduce emission.Wired charging is the traditional technique of vehicle charging,but is complicated in practical operation and has safety risks.With the development of wireless charging technology,it becomes a feasible and more suitable way of vehicle charging.In wireless charging,there is no electrical connection between vehicle and charging facility,which saves the work of manual connecting,making charging process more convenient and safer.As is known,the charging process is controlled by a monitoring system,however,the traditional vehicle charging control system is only designed for wired charging,and is not suitable for wireless charging to exploit its advantages.In this thesis,we summarize the demands of wireless charging control system and implements one with functions listed as below:In the respect of system design,this thesis summarizs new demands of the control system with the adoption of wireless charging,and designs a hybrid system architecture,which combines C/S structure with B/S structure.The control system consists of three kinds of devices:Local Server(LS)as server,Power Control Unit(PCU)and Vehicle Control Unit(VCU)as client.LS controls the Charging facility via PCU,and battery in vehicle via VCU.According to the system demands,all devices of this system are developed using OK335xD development board,which has high performance and plenty of interfaces,as the hardware platform,and Linux,which is stable and mature,as software platform.In the respect of communication protocol design,the message format of the control system is designed based on TLV format,which uses TLV format in data fields to ensure the efficiency of transmission.In order to ensure data security,all message will be encrypted using SSL/TLS protocol.Based on RSA algorithm and Non-Symmetic Encryption Technology,this thesis proposes a mutual authentication protocol for server and client in the control system.A RSA key pair will be used in this protocol,whose private key will be saved in server,and public key will be saved in client.To confirm the legality of the peer side,server and client checks whether the key of the peer side is paired with its own key.Moreover,this thesis proposes an automatch protocol.According to this protocol,VCU sets up communication connection with paired PCU.In the respect of programming and implementation,this thesis designs the functions of server and client in the control system using modularization idea.To save thread resources,epoll I/O multiplexing is used in server's program.State machine is used in client's program to simplify the logic.This thesis implements some tools and frameworks,including module tool,connection pool,message parsing framework,and used them in the main functions of server and client in the control system,finally implemented the connection establishment process and mutual authentication process between server and client,and automatch process between VCU and PCU,laying foundations for the following communications.