Electric vehicle automatic stop using wireless power transfer antennas

The challenge of battery's inefficiency, large and wasting space in Electric Vehicles (EVs) can be overcome by the Wireless Power Transfer technology (WPT), a technology that can electrically conduct energy from source to the electric device without interconnecting medium. Thinking one step further, the antennas that will be used in such WPT system could also be used for positioning in one-dimension as an additional benefit. This paper proposes a scheme of the positioning system using WPT antennas by considering the power gradient that the vehicle observes via the receiving antenna. PI controller is used with driving time limit to ensure safety. As an inspection for the controller's stability, simulation results are shown. Then the proposed method is implemented in the actual experimental system. The results show that, with the proposed method, the vehicle can be stopped at the position with maximum received power. The system can also be applied to parking areas with limited space or difficulty in positional awareness such as in tight space or slope surface, drive-through paying booth, e.g., toll ways, where the drivers are assisted to stop the car appropriately.