Fault detection in the DC bus of a vehicle

Abstract

In this thesis, the topic of fault detection in the DC and communication buses of a vehicle was addressed. Typical fault detection methods were examined and the most appropriate one for the automotive DC bus was further investigated. More techniques commonly used in aviation are investigated and compared. A Matlab Simulink simulation model for reflectometry techniques (Time Domain, Sequence Time Domain, Spread Spectrum-Time Domain and a new Spread Spectrum Frequency Shift Time Domain Technique) was developed and verified experimentally for Time Domain Reflectometry in coaxial cables and CAN twisted pair wires. Since in a fault condition an impedance variation occurs which causes diferent reflections of the voltage wave, it is possible to determine the fault condition and its spatial location in a cable. Different cross-correlation and wavelet analysis digital signal processing techniques were tried out