Abstract: A secondary coil structure for an electric vehicle charging system is characterized by a flexible sheet of synthetic plastic material which acts as a substrate for a coil connected with the top surface of the sheet. The coil has an axis generally normal to the sheet. A second sheet of material is connected with the first sheet with the coil arranged between the sheets. The secondary coil may be configured to match the configuration of a component of the vehicle with which the secondary coil is connected. When electric current is introduces into the coil, the coil generates an elongated magnetic field with a lower maximum value in the vicinity of the vehicle components than that created by a conventionally wound coil, thereby minimizing heat generated in steel components of the vehicle body.

Abstract: A method and apparatus for aligning a vehicle with an inductive charging system is characterized by the addition of alignment coils to a secondary coil on the vehicle. For efficient inductive charging, it is necessary that the vehicle mounted secondary coil be aligned with a stationary primary coil of a transformer of the inductive charging system. When the primary coil is energized, it produces a magnetic field which induces a voltage in the alignment coils as a function of the proximity of the alignment coils to the central axis of the primary coil. The voltage differential between opposed pairs of alignment coils is determined by a comparator which then generates a directional signal which can be used by the operator of the vehicle to position the vehicle for closer alignment of the vehicle secondary coil with the primary coil and more efficient charging.

Abstract: An inductive charging system for vehicle battery chargers includes a transformer having a stationary primary coil and a secondary coil mounted on the vehicle. The primary coil is mounted in a charging station and has a power source connected therewith. When the vehicle is parked adjacent to the charging station, the secondary coil on the vehicle is proximate to the primary coil in the station. The power source is activated to deliver current to the primary coil which generates a magnetic field to induce a voltage in the secondary coil. A controller is connected with the power source to adjust the voltage delivered to the primary coil. A feedback loop between the secondary coil and the controller delivers a secondary voltage signal to the controller which continuously adjusts the power source in order to maintain the secondary output voltage at a predetermined value.

Abstract: A method and apparatus for hands free inductive charging of batteries for an electric vehicle is characterized by the use of a transformer having a primary coil connected with a charging station and a secondary coil connected with a vehicle. More particularly, the when the vehicle is parked adjacent to the charging station, the primary coil is displaced via a self alignment mechanism to position the primary coil adjacent to the secondary coil to maximize the inductive transfer of charging current to the secondary coil. The self alignment mechanism preferably utilizes feedback signals from the secondary coil to automatically displace the primary coil in three directions to position the primary coil for maximum efficiency of the transformer.