Study and Implementation of an Insulation Monitor Device for Automotive Applications

Electric Vehicles (EV's) are the dominant mobility solution in respond to the current advances in global environmental needs. Ensuring safety conditions for the EV to operate are one of the main and more relevant concerns of the development of new and enhanced Battery Management Systems (BMS).Therefore, dealing with safety is a critical task and involves the monitoring of different parameters such as the resistance paths, also called Isolation Resistance, from the high voltage terminals of the battery pack to the chassis of the vehicle. Monitoring the Isolation Resistance is a task managed by a dedicated subsystem of the BMS called Isolation Monitoring Device (IMD) and the current market trend involves the use of a simple and complex task to improve the monitoring and estimation of the Isolation Resistance. The aim of this thesis is to study and implement an automotive IMD that constantly monitors the isolation resistance by developing an evaluation board based on a design reference improved with the use of enhanced digital and analogical electronics, capable of estimate with low uncertainty the Isolation Resistance of the system and to warn in the eventuality of isolation resistance fault. Further analysis of the results obtained on a preliminary validation of the system will be used to propose hardware and firmware enhancements in order to reduce the uncertainty of Isolation Resistance estimation and obtain a 100% automotive device.