A resonant induction wireless power transfer coil assembly designed for low loss includes a wireless power transfer coil, a non-saturated backing core layer adjacent the wireless power transfer coil, an eddy current shield, a gap layer between the backing core layer and the eddy current shield, and an enclosure that encloses the wireless power transfer coil, backing core layer, gap layer and eddy current shield. The gap layer has a thickness in a thickness range for a given thickness of the backing core layer where eddy current loss in the eddy current shield is substantially flat over the thickness range. A thickness of the backing core layer and a thickness of the gap layer are selected where a total power loss comprising power loss in the backing core layer plus eddy current loss over the gap layer is substantially minimized.

A one-piece permanent magnet is provided for use in an electric machine. The permanent magnet comprises a groove having a depth d which is equal to the thickness of the permanent magnet. The groove has a meandering or helical course with a subsection having the form of the letter S or the letter Z.

A transformer is provided, which includes a tank having an enclosed volume with an insulating material, the tank including at least one channel extending through the tank, wherein the interior of the at least one channel is separated from the enclosed volume of the tank by a channel wall. A transformer core is provided outside of the enclosed volume, including at least one core leg extending through the tank via the at least one channel. At least one coil is located inside the enclosed volume, the coil being wound about the at least one channel, the tank has an inner wall or outer wall including a weakly-conductive layer, which includes fibers embedded in an impregnating material.

A planar inductor may include a first coil and a second coil. The first coil may include a first trace that forms a first set of turns. The second coil may include a second trace that forms a second set of turns. A distance between the turns of the first set of turns may be equal to a distance between the turns of the second set of turns. A width of the first trace may be equal to a width of the second trace. The first coil and the second coil may be physically positioned or sized according to a/b in which a represents the width of the first trace and b represents the distance between the turns of the first set of turns.

Systems and methods for improving winding losses in transformers are disclosed. In one aspect, a transformer includes a first magnetic core having an interior portion and an exterior portion, a second magnetic core in contact with the interior and exterior portions, a plurality of primary and secondary windings formed around the interior portion, where the interior portion is formed from one of a first magnetic material and a second magnetic material, and the exterior portion is formed from one of the first magnetic material and the second magnetic material, where the first magnetic material has different properties than the second magnetic material. In another aspect, the first magnetic core includes a third portion that extends across and is in contact with the interior portion and the exterior portion, where the third portion is formed from one of the first magnetic material and the second magnetic material.

A combined metal powder magnetic core and an inductance device formed by same. The combined metal powder magnetic core comprises upper and lower magnet yokes and core columns arranged therebetween; wherein the upper and lower magnet yokes are respectively C-shaped, two ends of the upper and lower magnet yokes are respectively butted with the two core columns to form a magnetic loop, an air gap is arranged at the butted position between the upper and lower magnet yokes, and the interval of the central areas of the air gap is smaller than that of the marginal areas thereof.

A magnet comprising a center disc having a center disposed as a center of the magnet, a face of the center disc is substantially perpendicular to a central axis of the magnet. The magnet further comprises a first plurality of outer discs disposed around the center disc in a bundled rod construction, a face of each of the first plurality of outer discs substantially perpendicular to the central axis of the magnet, wherein the center disc and each disc of the first plurality of outer discs is electrically insulated from every other disc.

An electrically conductive material configured having at least one opening of various unlimited geometries extending through its thickness is provided. The opening is designed to modify eddy currents that form within the surface of the material from interaction with magnetic fields that allow for wireless energy transfer therethrough. The opening may be configured as a cut-out, a slit or combination thereof that extends through the thickness of the electrically conductive material. The electrically conductive material is configured with the cut-out and/or slit pattern positioned adjacent to an antenna configured to receive or transmit electrical energy wirelessly through near-field magnetic coupling (NEMC). A magnetic field shielding material, such as a ferrite, may also be positioned adjacent to the antenna. Such magnetic shielding materials may be used to strategically block eddy currents from electrical components and circuitry located within a device.