An electric transformer comprising a coil made of at least one winding, the winding being made of a wire comprising a first section, a second section and a middle section between the first and the second sections, the first section forming a first spiral around an axis (Z) and the second section forming a second spiral around the axis, the first and second spirals being located in two separate planes perpendicular to the axis, an inner end of the first spiral, respectively the second spiral, located near the axis being near the middle section of the winding and an outer end of the first spiral, respectively the second spiral, located away from the axis being near a free end of the winding, the first spiral and the second spiral turning around the axis in opposite directions.

An electric transformer comprising a primary coil, a secondary coil and a first magnetic circuit, the first magnetic circuit comprising at least a first limb and a second limb, the primary coil being wound around the first limb of the first magnetic circuit and the secondary coil being wound around the first limb or the second limb of the first magnetic circuit, wherein the electric transformer further comprises a second magnetic circuit acting as a component for setting a total impedance of the electric transformer at a predetermined value, the second magnetic circuit comprising at least a third limb, only one coil among the primary coil and the secondary coil being wound around the third limb of the second magnetic circuit, the second magnetic circuit being independent of the first magnetic circuit.

An electric transformer comprising a primary coil, a secondary coil and a first magnetic circuit, the first magnetic circuit comprising at least a first limb and a second limb, the primary coil being wound around the first limb of the first magnetic circuit and the secondary coil being wound around the first limb or the second limb of the first magnetic circuit, wherein the electric transformer further comprises a second magnetic circuit acting as a component for setting a total impedance of the electric transformer at a predetermined value, the second magnetic circuit comprising at least a third limb, only one coil among the primary coil and the secondary coil being wound around the third limb of the second magnetic circuit, the second magnetic circuit being independent of the first magnetic circuit.

A reactor includes a plurality of windings, a coupling core, and an inductor core. A coupling core configured to form a coupling closed magnetic circuit that magnetically couples the plurality of windings, the plurality of windings being wound around the coupling core; and. An inductor core, which includes a main part, a first projection part projecting from one end of the main part, and a second projection part projecting from another end of the main part, and each of the first projection part and the second projection part is magnetically connected to the coupling core. The inductor core forms an inductor closed magnetic circuit together with a part of the coupling core around which one winding of the plurality of windings is wound.

A reactor includes a plurality of windings, a coupling core, and an inductor core. A coupling core configured to form a coupling closed magnetic circuit that magnetically couples the plurality of windings, the plurality of windings being wound around the coupling core; and. An inductor core, which includes a main part, a first projection part projecting from one end of the main part, and a second projection part projecting from another end of the main part, and each of the first projection part and the second projection part is magnetically connected to the coupling core. The inductor core forms an inductor closed magnetic circuit together with a part of the coupling core around which one winding of the plurality of windings is wound.

A magnet coil for magnetic Czochralski single crystal growth includes: a first coil, a second coil, and an auxiliary coil arranged between the first coil and the second coil. A distance between the first coil and a first edge of the auxiliary coil close to the first coil is equal to a distance between the second coil and a second edge of the auxiliary coil close to the second coil. The auxiliary coil, the first coil and the second coil have a common central axis. When being energized, a direction of a current in the first coil is opposite to a direction of a current in the second coil, and a magnetic field generated by a current in the auxiliary coil is used for enhancing a cusp magnetic field between the first coil and the second coil.

A magnet coil for magnetic Czochralski single crystal growth includes: a first coil, a second coil, and an auxiliary coil arranged between the first coil and the second coil. A distance between the first coil and a first edge of the auxiliary coil close to the first coil is equal to a distance between the second coil and a second edge of the auxiliary coil close to the second coil. The auxiliary coil, the first coil and the second coil have a common central axis. When being energized, a direction of a current in the first coil is opposite to a direction of a current in the second coil, and a magnetic field generated by a current in the auxiliary coil is used for enhancing a cusp magnetic field between the first coil and the second coil.

A shunt reactor includes a primary winding and a steel core is. The steel core includes a bottom yoke, a top yoke, a first core limb, a second core limb, and a main limb. The first core limb, the second core limb and the main limb are arranged in parallel and in between the top yoke and the bottom yoke to form a support for a magnetic flux through the steel core. The primary winding is wound around the main limb. The shunt reactor further includes an auxiliary winding wound around the bottom yoke, top yoke, first core limb, or second core limb, and is configured to generate auxiliary power. The primary and the auxiliary windings are electrically insulated from the steel core and from each other. A cooling fan is configured to be driven by the auxiliary power generated by the auxiliary winding.

An electromagnetic device for converting energy comprises: a ferromagnetic core of essentially planar shape and delimited by a peripheral contour; a primary winding and a secondary winding formed by primary turns and secondary turns, respectively. The device includes, arranged against the peripheral contour, a first block and a second block and a ferromagnetic material, and has a magnetic permeability lower than that of the ferromagnetic core. At least one primary turn and/or at least one secondary turn is formed around or passing through the first block and/or the second block to form, respectively, a first leakage inductance and/or a second leakage inductance.

A wireless power system for an implantable device is described. The system includes multiple inductive charging coils to increase an effective area for receiving an electromagnetic charging field from a wireless charging device. The multiple inductive charging coils produce different alternating current signals in response to receiving the electromagnetic charging field. The system includes a rectifying circuit for rectifying the alternating current signals into direct current signals. The system also includes a current combination circuit for combining the multiple direct current signals into a single direct current for powering an operation of the implantable device. Methods and devices for implementing the power system in an implantable device are also described.