| With the increasing in car ownership,energy and environmental problems are increasingly serious.The low pollution,zero emissions electric vehicles attracted the attention of countries around the world,and theirs research and development become hot spots.Governments have enacted policies and regulations to promote the development of electric vehicles,with a view to occupy the leading position in science and technology in the future of the automotive industry.Four independent in-wheel drive motor electric vehicles,as the ultimate driving form of the future cars,has an unparalleled advantage,but also there are some technical difficulties,which are battery,motor,and electric control three key technologies.In this paper,taking a in-wheel electric vehicle as the research object,designed a power control system CAN network for it.The network consists of vehicle controller,four motor controllers,battery management systems,digital instrumentation and vehicle charging eight nods.In this paper,first,the communication of the nodes is analyzed according to the requirements of the vehicle function.Then the CAN network application layer is developed with reference to the SAE J1939 protocol,also based on the traditional CAN communication,the TTCAN transmission protocol is adopted,and designed a TTCAN protocol message matrix to meet the wheel motor electric vehicle power system high real-time and reliability requirements.And then the CANoe network simulation software is used to simulate the designed network.Finally,built a physical experimental platform according to the existing conditions,including the hardware and software design of the remaining seven nodes except the vehicle charger and tested the CAN network experimentally.The experimental results show that the success rate of TTCAN network communication based on time trigger is 100%,which can better meet the real-time requirement of the system.Because the TTCAN protocol requires strict time synchronization of each node,and this network uses the ordinary CAN controller,the hardware itself does not have the time synchronization management function.Therefore,in this paper,each node uses a separate timer resource to manage the local time.The main controller node as a global time management,each basic cycle will send a reference frame to adjust the time drift of each node.In this way,achieved a good timer synchronization management,which laid the ground work for the further application of TTCAN network. |
