The research project AuLa is a cooperation between the University Fachhochschule Aachen, the machine building company 3Win GmbH and the AixControl GmbH. The project aim is the development of an automated charging system for electric vehicles. A thin box with the charging electronics will be placed on the surface. The electric car will be parked over the box and an inductive charging plug will automatically find its corresponding socket in the car with the help of an axis motion control system. The charging process will start automatically and after finishing, the plug is moved back into the box. Users of electric cars don't have to handle the dirty charging cable and plug manually. They just have to park their car over the station and do not have to take care about charging their car, it will be done automatically.

To maximize the transferable power, a medium-frequency (about 100kHz) design for the inductive plug and socket combination was chosen. In a first approach the inductive charging plug was assumed to be hexagonal consisting of three low cost ETD cores. For a good utilization of the core, a copper foil coil was selected.
The outline was a compromise of transferable power and space restrictions by different electric cars. An experimental setup and special FEM simulations showed that this configuration is not reasonable. Therefore, the geometry of the plug was reworked. Under usage of special ferrites an axially symmetric plug is the most promising candidate. This plug is part of current examinations.

Our cooperation partners Fachhochschule Aachen GmbH and 3Win GmbH develop and manufacture the box and the robotics for charging system. The sliding system has to compensate inaccuracies of the car's position after parking. Additionally, it facilitates the plug to drive upwards to the socket into the car.
The encapsulating box has to face many challenges. It has to be waterproof and stiff enough so that it can be overrun by cars. Additionally it has a maximum hight limited by the underfloor clearance by cars. Furthermore, it must offer sufficient protection against tripping and a smooth-running flap mechanism to cover the inductive plug.