Prediction and Analysis of Parasitic
Components in Conductor Layouts
Sabine Alexandersson
Doctoral Dissertation in Industrial Electrical Engineering
Department of Industrial Electrical Engineering and Automation
2008-LUND UNIVERSITYAbstractThe electronics in the automotive industry is facing a new era where safety
critical functions are electrified, as for example drive-by-wire technology. At
the same time as the number of electrical loads in the vehicles is increasing,
the time to market is decreasing. Full scale prototypes of a vehicle are often
only available at a late stage in the development process where changes are
rather costly. This implies that prediction and simulation of a system are of
importance and are useful already at an early stage of the development
process. There are economic benefits that can be gained by prediction and
simulation of the system such as: reduction of time to market, virtual tests,
virtual prototypes and optimization of electronic circuits with respect to
safety margins of filters.
The high number of electrical loads in the vehicle leads to different cable
harnesses routed along the body and chassis of the vehicle. These cable
harnesses will contain both power conductors and communication
conductors, routed close together. When conductors are routed close to each
other, a signal on one conductor can interfere with the signal on another
conductor. This phenomenon is called crosstalk.
Crosstalk can increase the noise levels, create unplanned spikes or destroy
data on nearby conductors. Hence it should always be a prime suspect in an
electromagnetic interference investigation or a candidate for prediction.
Crosstalk between two conductors is coupled by the mutual inductance and
capacitance. When these parameters are known, the crosstalk can be
estimated by using a circuit simulation.
The mutual inductance and capacitance between the conductors as well as the
self inductance and capacitance of each conductor depend on the
surrounding environment. This implies that the conductor layout is an
important factor when it comes to designing a system that is robust against
crosstalk.
Chapter 2
Automotive electromagnetic compatibility
