Research on On-line Monitoring Methods of High Voltage Parameter in Electric Vehicles

Safety control and protection strategy of high-voltage system of electric vehicles include analysis of circuit condition before connection to high voltage terminal, transient current prevention for capacitive load, real-time monitoring and analysis of high-voltage system during operation, disconnecting strategy of high voltage terminals, vehicle dynamic safety and cooperative management of electrical systems, etc. Monitoring and analysis of some critical parameters of high voltage system such as insulation, electrical harness and connector condition are the basis and difficulties in high-voltage safety and protection. This paper presents several mathematical models of monitoring critical parameters, and experiments were also done to evaluate the model. Disadvantages of the commonly used calculation method are discussed. Single point insulation defect model is introduced and diagnosis method of multiple points defect is also discussed. To satisfy high voltage safety management system based on micro-controller, online diagnosis method of related parameters is studied. Hardware-in-loop (HIL) and complete vehicle experiment were conducted to prove the validity, response and reliability of the proposed method.