Abstract: A resonator circuit for a contactless energy transmission system for charging electric vehicles and a contactless energy transmission system for charging electric vehicles are described. The resonator circuit may include first and second terminals, multiple windings, and first and second switching elements. The windings may be divided into first and second groups. A connection node may be arranged between the first and second groups of windings and connected via the first switching element to the first terminal, and the connection node is connected via the first group of windings to the second terminal. The second switching element may be arranged between the second group of windings and the first terminal. The first connection node may be formed in a star-shaped manner between the first group of windings, the second group of windings, and the first switching element.

Abstract: An inductive device comprises a plate-shaped ferrite core and a hybrid double-D solenoid coil which is arranged over the plate-shaped ferrite core and has a plurality of turns. The plurality of turns is grouped into at least two groups, each having at least two immediately consecutive turns which in a group have monotonically increasing or decreasing turn diameters, wherein the last turn of a group has a turn diameter that is larger than that of the first turn of the following group if the turn diameter of the turn immediately preceding the last turn within the group is smaller than the turn diameter of the last turn, or has a turn diameter that is smaller than that of the first turn of the following group if the turn diameter of the turn immediately preceding the last turn is larger than the turn diameter of the last turn.

Abstract: An inductive device comprises a plate-shaped ferrite core and a hybrid double-D solenoid coil which is arranged over the plate-shaped ferrite core and has a plurality of turns. The plurality of turns is grouped into at least two groups, each having at least two immediately consecutive turns which in a group have monotonically increasing or decreasing turn diameters, wherein the last turn of a group has a turn diameter that is larger than that of the first turn of the following group if the turn diameter of the turn immediately preceding the last turn within the group is smaller than the turn diameter of the last turn, or has a turn diameter that is smaller than that of the first turn of the following group if the turn diameter of the turn immediately preceding the last turn is larger than the turn diameter of the last turn.