Study And Development On Vehicle Controller Unit For Low Speed Pure Electric Vehicle

At present, the development of the pure electric vehicle is faster and faster because of its advantages of low-noise, non-pollution, energy conservation and environmental protection. And low speed pure electric vehicle will occupy the important position in the field of pure electric vehicles because of their properties for low technical cost, strong practicality, non-pollution and low energy comsumption, etc. As the core control component of a pure electric vehicle, the vehicle controller unit plays an important role on the vehicle’s rideability and security. So it is significant to develop a vehicle controller unit of low speed pure electric vehicle.In this paper, supported by the Key Project of Hunan Provincial Science & Technology Department [2013GK2005, 2012GK4009], the research situation and prospect of pure electric vehicle controller unit at home and abroad are deeply analyzed. And the vehicle controller of a remoulded low speed pure electric car is designed and developed by means of simulation and experiment. The main research work and innovative points are as follows:(1) The power system structure of a remoulded low speed pure electric car based on Chery QQ3 traditional gas car was analyzed. And the vehicle control system structure and the CAN communication network topology based on the remoulded pure electric car were designed. At the same time, the general design method of vehicle controller’s hardware and software were proposed.(2) The pure electric vehicle control strategy was designed, including the drive control strategy and fault handling strategy. The economic mode, general mode and power mode drive control strategy were made based on motor torque MAP, and a smart mode based on fuzzy recognition of the driver’s intention was designed. After simulation in Matlab/Simulink, the results showed that each mode control strategy has the capability to control vehicle travel according to its target, especially the smart mode control strategy can recognize the driver’s different intention intelligently according to the accelerator pedal openning and accelerator pedal openning rate, and it can also concurrently achieving the economy, power performance and controllability.(3) The functions of the low speed vehicle controller unit was defined and divided, and Freescale 16-bit single chip microcomputer MC9S12XEP100 was selected as the main control chip. According to the requirement of controller and the modularization design concept, the controller hardware circult was designed, and the printed circult board was designed and made according to hardware anti-jamming.(4) The vehicle controller software was divided into two parts, the application layer and the driver layer, which were designed according to the modularization design concept. Then, the Lab VIEW PC software was designed which can be debugged with vehicle controller unit through USBCAN module. Finally, the four mode drive control program were tested, and the running results which were same with the simulation results verified the availability of controller hardware and software.