The Research Of Electric Drive System Of Electric Vehicle Fault Monitor System

In recent years,with the worsening environmental pollution and decreasing oil fuel,electric vehicle(EV)has become a popular transportation tool.Although it brings convenience to people's life and alleviates the pressure on environment,it is still in its infancy and there is a lot of technical problems that need to be resolved.As an important part of EV,electric drive system is also more likely to malfunction.Therefore,it is very meaningful for carrying out fault diagnosis monitoring on the electric drive system.In this paper,the author reviewed domestic and foreign literature which were related to the fault diagnosis and monitoring of electric drive system,and also did the corresponding technology survey.The working environment of the electric drive system is very complicated and the probability of malfunction is very high.This paper investigated the fault diagnosis monitoring on the over-temperature of motor controller,overpressure,overcurrent and over-temperature of electric motor,motor shorted and IGBT fault.According to the working characteristics and requirements of the electric drive system,the communication protocol of CAN network was studied,and the system of hardware circuit and software realization were established,and the developed monitoring system was tested.In the aspect of communication protocol,this study combined CAN communication protocol with SAE J1939 protocol,and designed an appropriate communication protocol for EV which consisted of physical layer,data link layer and application layer.It can realize the function of message formulation,message analysis and packaging,and fault code design.For hardware design of the system,this paper used STM32f10 ZE as main control chip to realize the real-time processing of data.The power conversion module consists of four identical and independent modules,each of which selects MP2359 and AMS1117-3.3 chip to transfer 12 V DC into 5V and 3.3V DC voltage,then the main control chip and every module can apply them.CAN communication module takes TJA1050 as CAN transceiver and builds up CAN communication interface circuit;the fault display module uses ILI19341 to display the fault information of system;storage module chooses the SD card with 8G to preserve the fault code,the fault occurrence time and GBK font;fault warning module selects the driving source buzzer of S8050 audion to realize failure warning.In the aspect of software design,this paper wrote corresponding programming to each module on the MDK5 platform.Among them,the CAN communication module sets up CAN message structure,reads CAN message,also makes analysis and diagnosis on message based on the rules of CAN communication protocol.So it can realize the operationof message storage,read and elimination in the fault storage module.The fault display module can real-time display fault information and happening time,so the fault alarm module can send out alerting signal when the fault is diagnosed at the level of 1 or 2.When testing the system,this paper simulated various kinds fault in electric drive system,used CANTest simulating network node of electric drive system,sends message periodically through USBCAN card.The USBCAN card also receive fault-tolerant message that is sent out by fault diagnosis system.The monitoring system will diagnose received message,display fault message on the LCD screen and then raise an alarm.