Design And Implementation Of Advanced CAN-based In-vehicle-network In Electric Vehicle

As rapid and continuous increase of domestic car ownership, some bad influences have been taken to human lives, such as traffic jams in big cities, and air pollution due to automobile exhaust. In addition, there has been an enormous increase in the global demand for energy in recent years as a result of automobile industry development and automobile consumption growth. Automobile manufacturers all over the world have been looking for new energy drivetrains which make no air pollution to environments and are easy to find the source. Electric vehicle(EV) came up as a new trend. It is cleaner comparing to traditional vehicle and it’s easy to refuel as well. However, extra electric and electronic components are needed in electric vehicle for complicated signal exchange and interaction control, such as electrical sensors, electronic control modules and actuators, etc. Meanwhile, electric vehicle can’t drive in case of shortage of power supply which requires efficient energy management mechanism. Thus there is significant value to study in-vehicle-network(IVN) performance of EV.This thesis proposes a CAN-based distributed IVN which based on the research regarding the disadvantage of traditional signal exchange mode and energy management mechanism. The CAN-based IVN is a good usage that based on CAN bus of high bit rate and high real-time capability. It is physically interconnected via twisted pairs,which avoids from using numerous dedicated cable harnesses to connect electric and electrical systems all over a vehicle. Not only had this physical connection implemented high efficiency communication, but also helped to lose weight which is an extra bonus of extended range. Furthermore, high fault tolerance is supported, i.e. one node with a minor error would not disturb rest of the network; one node with major error would disconnect from rest of the network to avoid from disturbing other nodes. According to the aim of advanced CAN-based in-vehicle-network, a CAN-based distributed system is proposed. And this thesis emphatically analyzes the detailed requirements network management on various power modes and application layer of communication. All of these lead to detailed design in the next step.As soon as detailed requirements are specified, brief described the corresponding hardware circuit design which includes MCU peripheral interface circuit,communication control transceiver model selection. After hardware design has beendone, the design and implementation of system software are introduced in detail. In accordance with the principles of software hierarchical design, emphatically introduces the detailed implementation of network management layer and application layer of communication. Mechanisms of wakeup and sleep for the network are given in network management design. Communicate initialization, transmission and reception of data frames are given in application design.The system has gone through test and verification. The test results show that the proposed advanced CAN-based in-vehicle-network system has achieved the functional targets of high real-time capability, high energy efficiency management and strong robustness. It has improved communication performance and energy management performance comparing to those of previously traditional vehicle. Eventually it has improved comfort and economy.