Short-circuit current detection in electric vehicles

Abstract: In recent years the vehicle industries have been making much efforts to reduce the environmentalimpact by switching from the traditional combustion engine to electrification with battery driven electricvehicles. Producing electric trucks requires more batteries and operates at a higher voltage and currentthan commercial electric cars. Therefore, detection and protection from short-circuits are crucial issuesin the development of these vehicles to ensure safety. This master thesis project aims to investigatedifferent methods for current measurement, which are commercially available and used in the batteryjunction box in an electric vehicle for current monitoring and detection of overcurrent and short-circuits. A practical experimental validation is then performed to test the desaturation detection method as ashort-circuit detection method with a solid state breaker. The experimental results showed that theshort-circuit could be detected within just 7µs and the total time for the solid state breaker to detectand cut the circuit could be done within around 15µs. The discussion around the current measurementmethod came to the conclusion that the Hall sensor or the flux gate current transducer could be apossible replacement of the shunt that is currently being used in order to reduce losses as the systemoperates at higher current levels. Comparison of this method with different existing current measurement sensors is suggested to do inthe future work.