Laetitia Pradere

Detection of Electric Contact Resistance Variations in Automotive Connectors

Car manufacturers have to size electric and electronic systems to avoid the risk of short circuits while, at the same time, ensuring a viable economic balance. In other words, the copper mass must be sufficient for safety reasons but not excessive for cost reasons. It is, thus, necessary to monitor the critical points of the electric architecture in order to make an appropriate decision to maintain a high level of safety. However, due to physical and economic constraints, direct temperature measurement of these critical points is seldom possible. Moreover, temperature monitoring at these points would not allow one to determine whether the rise in temperature was related to degradation of the contact or whether it was due to the generation of thermal power by another component. The objective of this paper is, thus, to propose a new method to monitor critical points of the electric architecture that does not require direct measurements. In order to achieve this objective, an electrothermal model of the architecture was developed, and a diagnosis method was used. The method was applied to detect abnormal variations in the contact resistance inside a connector, which is a critical point commonly encountered in the electrothermal chain of automotive vehicles. The efficiency of the algorithm was evaluated on a dedicated test bench. The proposed approach is able to detect a deviation of about 10% in the contact resistance, thus validating the proposed methodology.

Finite length wire electro-thermal modeling for automotive applications using H 2 -norm based approximation of a fractional model

In automotive application field, reducing electric conductors dimensions is significant to decrease the embedded mass and the manufacturing costs. It is thus essential to develop tools to optimize the wire diameter according to thermal constraints and protection algorithms to maintain a high level of safety. In order to develop such tools and algorithms, accurate electro-thermal models of electric wires are required. However, thermal equation solutions lead to implicit fractional transfer functions involving an exponential that cannot be embedded in a car calculator. This paper thus proposes an integer order approximation methodology based on a spatial discretization for this class of fractional transfer functions. Moreover, the H2-norm is used to minimize approximation error. Accuracy of the proposed approach is confirmed with measured data on a 1.5 mm2 wire implemented in a dedicated test bench.

Integrated plasmonic nanoantenna for out-of-plane beam steering

We numerically study the giant coupling between a Si3N4 waveguide and a silver nanoparticle chain at visible wavelengths and the resulting integrated nanoantenna showing tunable out-of-plane beaming in both angle and intensity.