Research On Vehicle Control Unit Hardware Of New-energy Battery Electric Vehicle

The development of new-energy electric vehicles is important to remit the shortage of oil and protect the human living environment.Compared with other new-energy electric vehicles,the new-energy battery electric vehicles have the advantages of high energy efficiency,simple structure,light weight and low noise.Developing the new-energy battery electric vehicles is the tendency of automobile industry in the future.The vehicle control system plays a decisive role in driving performance of the new-energy battery electric vehicles.And the vehicle control unit plays a significant role in the operation of motor,charging-discharging of battery,monitoring of driving cycle.First,this paper introduces the background of the research on new-energy electric vehicles and the over-all structure of different new-energy electric vehicles.Then the development status on vehicle control unit of the new-energy battery electric vehicles is described.And the over-all design solution of vehicle control unit is formulated.The design of hardware circuit is based on Freescale's 16-bits MCU chip ‘MC9S12XEP100MEG 144-LQFP'.The MCU chip minimum system includes power circuit,clock circuit,reset circuit and BDM circuit.At the same time,external circuits are designed,such as analog signal circuit,digital signal circuit,CAN communication circuit and 485 communication circuit.The software Multisim is used to fulfill circuit simulation of power circuit,analog signal circuit and digital signal circuit.After taking into account the electromagnetic compatibility and anti-jamming performance,PCB board is designed.This paper shows the study on control strategy of software system.And the partial program codes are given here.At last,the vehicle control unit hardware is connected to the computer.The upper-computer software based on LabVIEW is used to fulfill signal waveform test,such as gear,acceleration and brake signal.The result shows that signal waveform is continuous and without jitter.The vehicle control unit meets the demand of signal collection and achieves the expected goal.