关键词: 纯电动汽车；高压上电；整车控制器；电机控制器；故障分析

Abstract: According to the current development trend of pure electric vehicles and the increasing number of pure electric vehicle failures, it aims to strengthen the mastery of the structure and principle of pure electric vehicles by ordinary maintenance personnel. First of all, the article analyzes the control relationship between the high-voltage system of pure electric vehicles, and analyzes the control logic of the high-voltage power-on process of Geely Emgrand EV450 model in detail. According to the mastered logic of high-voltage power-up control, it is mainly divided into five categories: high-voltage interlock disconnection failure, high-voltage contactor adhesion failure, vehicle controller failure, battery management system failure, and motor controller failure. Finally,according to the actual case of Geely Emgrand EV450, it analyzes the possible causes of the failure of the high-voltage system to power. The analysis process is mainly through the owner's description of the fault phenomenon, the recovery of fault phenomenon and the fault code displayed by the fault diagnosis instrument for diagnostic trouble code (DTC) analysis. It is confirmed that it is a vehicle control unit (VCU) power supply failure or VCU's own fault, and then the VCU power line is tested. After testing and analysis, it is confirmed that the cause of the high-voltage failure is +B power supply fuse damage. Therefore, when troubleshooting and analyzing, you not only have a good understanding of high and low voltage electronic control, but also master the control logic between vehicle control unit, battery management system, motor control unit and other systems.In case of failure, you can comprehensively judge the fault range according to the fault phenomenon and fault code.

Key words: Pure electric vehicle; High voltage power-on; Vehicle controller; Motor controller; Fault analysis