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 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.

A method of fabricating an inductor device includes preparing a conductive coil, connecting two terminals to one of two ends of the conductive coil, molding a pillar from a plurality of first composite material powders by a pressing process where each first composite material powder is composed of a first magnetic material powder coated with a first thermosetting resin, placing the pillar in a surrounding space formed by the conductive coil, molding a cladding body from a plurality of second composite powders where the second composite material powders is composed of a second magnetic material powder coated with a second thermosetting resin, heating the cladding body, the conductive coil and the pillar cladded by the cladding body such that the plurality of first magnetic material powders are bonded by the cured first thermosetting resin and the plurality of second magnetic material powders are bonded by the cured second thermosetting resin.

A method of fabricating an inductor device includes preparing a conductive coil, connecting two terminals to one of two ends of the conductive coil, molding a pillar from a plurality of first composite material powders by a pressing process where each first composite material powder is composed of a first magnetic material powder coated with a first thermosetting resin, placing the pillar in a surrounding space formed by the conductive coil, molding a cladding body from a plurality of second composite powders where the second composite material powders is composed of a second magnetic material powder coated with a second thermosetting resin, heating the cladding body, the conductive coil and the pillar cladded by the cladding body such that the plurality of first magnetic material powders are bonded by the cured first thermosetting resin and the plurality of second magnetic material powders are bonded by the cured second thermosetting resin.

A dry-type transformer, comprises a magnetic core, at least one high voltage (HV) winding, and at least one low voltage (LV) winding inductively coupled to the magnetic core. The transformer is made by determining a shape of an electric field that is generated, 3D printing a dielectric structure shaped to conform to the determined shape of the electric field, and mounting the dielectric structure between the HV and LV windings. A dielectric barrier arrangement for electrically isolating a coil of a transformer assembly from a further coil of the transformer assembly or from a core of the transformer assembly comprises a first dielectric structure having a first cylindrical dielectric structure extending along a longitudinal axis (L).

A power electronic converter includes a plurality of converter cells, each comprising an inductive power transfer stage having a coupled inductor coupling first and second sides of the converter cell, wherein the inductor comprises a first winding around a first magnetic core and a second winding around a second magnetic core; wherein the first winding and the first magnetic core are separated from the second winding and the second magnetic core by a flat electric insulation layer that provides electric insulation between the first and second sides of the converter cell; wherein at least two of the coupled inductors are arranged so that their insulation layers form a single contiguous insulation layer.

A power electronic converter includes a plurality of converter cells, each comprising an inductive power transfer stage having a coupled inductor coupling first and second sides of the converter cell, wherein the inductor comprises a first winding around a first magnetic core and a second winding around a second magnetic core; wherein the first winding and the first magnetic core are separated from the second winding and the second magnetic core by a flat electric insulation layer that provides electric insulation between the first and second sides of the converter cell; wherein at least two of the coupled inductors are arranged so that their insulation layers form a single contiguous insulation layer.

There is provided an insulated electric wire formed by covering a rectangular conductor wire having a rectangular cross-sectional shape with an insulating film. The insulating film is formed of an inner layer covering a surface of the rectangular conductor wire, and an outer layer covering a surface of the inner layer. A thickness (t.sub.1) of a section of the inner layer, which covers one short side of two facing short sides of the same length of a rectangular cross section of the rectangular conductor wire, is greater than a thickness (t.sub.2) (including that t.sub.2=0) of a section of the inner layer which covers the other short side. An elastic modulus and/or a yield stress of the inner layer are less than an elastic modulus and/or a yield stress of the outer layer.

There is provided an insulated electric wire formed by covering a rectangular conductor wire having a rectangular cross-sectional shape with an insulating film. The insulating film is formed of an inner layer covering a surface of the rectangular conductor wire, and an outer layer covering a surface of the inner layer. A thickness (t.sub.1) of a section of the inner layer, which covers one short side of two facing short sides of the same length of a rectangular cross section of the rectangular conductor wire, is greater than a thickness (t.sub.2) (including that t.sub.2=0) of a section of the inner layer which covers the other short side. An elastic modulus and/or a yield stress of the inner layer are less than an elastic modulus and/or a yield stress of the outer layer.

An inductor unit includes a conductive structure, a first magnetic element and an insulating layer. The conductive structure has a bottom conductive layer, a top conductive layer, and a first side conductive layer extending from the bottom conductive layer to the top conductive layer. The first magnetic element is disposed on the bottom conductive layer of the conductive structure. The insulating layer is disposed on the bottom conductive layer of the conductive structure, wherein the insulating layer covers and surrounds the first magnetic element. The circuit structure including the inductor unit and the methods for manufacturing the same are also provided.