Varun Ramakrishnan Bharadwaj presents his master’s thesis

Student: Varun Ramakrishnan Bharadwaj
Main Supervisor: Fredrik Bruzelius
Examiner: Fredrik Bruzelius
Opponent: Srinidhi Sollapura Vasanna

Abstract of thesis

In today’s world, electrical vehicles are growing in demand for obvious reasons. To support this growth, countries around the world are trying different strategies to develop the right infrastructure for electrification. One such system is electric roads where the battery electric vehicles are energized when in motion through the transport infrastructure.

Pickups are a mechanical extension to the chassis of a vehicle that is used to "pick up" electrical current. This pickup uses a spring system to extend on to the rail below and draw traction current. Since this pickup is placed between the chassis and the road, and also experiences forces from both ends i.e., due to the surface irregularities in road and due to suspension dynamics of the vehicle, it is important to model the pickup to determine the contact force existing between the two conductive surfaces.

A relationship established between the contact force and contact resistance was extended to the vehicle-pickup setup modelled in this project. For higher contact forces, it was seen that the contact resistance reduces drastically (at any given traction current). Lower contact resistance is good and is needed to get a better quality of electrical connection (i.e., continuous energy flow). This can be achieved by having less deflections on the pickup which depends on a number of parameters, including the construction of the pickup itself and then the external conditions i.e., type of roads on which the vehicle is in motion.

As expected, the integrated model of the vehicle and the pickup performs better on expressways than regional roads due to the difference in amplitudes on both the roads. Further, a relationship on the contact force and resistance helped in securing the parameters that have an impact on the quality of the electrical connection which is primarily the pickup itself (material, construction setup, stiffness).
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