Research On Storage Battery Monitor System On Electric Vehicle Based On CAN Bus

From environment protection and energy source, electric vehicle need have a great development. Modern EV was centralized outcome in the newest production of auto, power drag, power control, chemistry, new energy sources, new material and computer. Development item of EV was composed of lots of subsystems. Each subsystem had own the strategy of management and controlment. The interception of network, bus, storage battery manage system and interface display system were carried through experiment and research.CAN bus was considered the best communication configuration of EV and became the first select network of interior vehicle. This paper collected lots of information about domestic and international using CAN bus, which were especially used in vehicle. CAN bus was multiple masters equity system, sustained competition. It was application and development of computer network technique in modernization control technique domain. CAN bus was giving us a wide new arena and developed our skill to full.Storage battery was the heart of EV. Because of the dispersed quality of storage battery, storage battery in series easily appeared imbalance problem, or when one cell was broken but it was not detected, resulting in a chain reaction of a group of batteries broken. So we need monitor cell. This equipment of stock power was good and bad which was most important for equipment's reliable run. This paper took lead acid battery for a example, constructed storage battery monitor system of basing on CAN bus, entered practice phase of CAN bus.89C51 of MCS-51 series was the kernel of this system which was composed of data collecting module, CAN bus intelligent node, interface card and PC. Data collecting module collected correlation parameter of twelve cells, collecting signal included cell voltage, discharge current and accumulative value of quantity of discharge and temperature. Temperature included the temperature of leading battery and environment temperature of a group of battery. Using resistance dispartment voltage measured every cell voltage; Using Hall current sensor transformed current to voltage, then again transforming current value; Using programmable single bus numeric sensor DS18B20 achieved collecting temperature signal; Using software program measured accumulative quantity of discharge; A/D used MAX 1270 chip of serial interface.This system used assemble language and included main program of PC, software design of CAN bus intelligent node included initialization of CAN node and messages transfer,subprogram of A/D conversion, Subprogram of the quantity of charge operation and subprogram of temperature conversion. Data receiving process program and display interface of PC used DelphiT.O to program, whose langue base was Pascal and called the fourth program langue. Based on window and object oriented programming way, close combinedWindows system, at the same time shouldered powerful function of Visual C++ and flexible characteristic of Visual Basic. It has powerful function, simple using and rapid rate of code performing.By design of circuit theory diagram, software and hardware debugging and actual measuring, this system has successfully run.