Electric vehicle wireless charging coil alignment

Issue: Two automotive trends for passenger vehicles include vehicle electrification and autonomy. For electric vehicles, battery capacity and driving range is a major concern. A common solution seen today is the use of charging stations in parking lots at workplaces, shopping centers, and similar so that vehicles can charge more hours in a day. Current systems are plug-in wired systems, and the auto industry is standardizing and developing wireless charging technology. A key motivation, besides convenience, is vehicle autonomy on the horizon where the vehicle may drop the driver off at their destination, and the vehicle autonomously drives to a parking spot waiting to be hailed to return. In this scenario, there would be no operator to plug in the vehicle to charge, and a wireless charging approach is necessary.

A major problem in wireless charging is alignment between the two coils on the vehicle and ground pad sides. Misalignment and large separation distance can cause weakened coupling between the coils which results in a loss in power transfer and reduced efficiency. Also, with weak coupling electromagnetic noise generated is more substantial, which can cause interference with other electronics, especially at high power levels used in such charging systems.

Objective: The goal of this project is to characterize problems associated with the various types of misalignment, and develop a system that will mechanically align the ground pad module to the vehicle parked above it for optimal performance.

Student Involvement: Sample problems that students will address are to: (i) carry out background research on what challenges can be expected due to misalignment between wireless charging coils, (ii) Using an available charging system, experimentally measure power transfer efficiency and emitted electromagnetic noise using a spectrum analyzer as a function of controlled misalignment variables, and (iii) research and develop a sensing approach to estimate the misalignment and a mechanism to for alignment.