EP-4736199-A1 - MAGNETICALLY PERMEABLE CORE AND TRANSFORMER INCLUDING THE SAME

Abstract

A magnetically permeable core includes an integral multilayer film continuously extending along a length between opposing first and second longitudinal ends of the multilayer film and wound to form a plurality of substantially concentric coil loops. The plurality of substantially concentric coil loops has an average height H1 in a height direction of the core and a largest lateral dimension D1 in an in-plane direction of the core, wherein D1/H1 ≥ 2. The multilayer film includes a plurality of substantially co-extensive layers including at least one magnetically permeable layer and at least one adhesive layer bonding the concentric coil loops to each other. For at least one pair of inner and outer coils in the plurality of substantially concentric coil loops, the inner and outer coils have relative magnetic permeabilities different by at least 10% at a same frequency in a range from about 10 kilohertz to about 10 megahertz.

Inventors

• KIM, JINWOOK
• WOO, Seong-Woo
• KONG, JIWOONG
• Stricker, Andrea
• MO, Sang-Jun

Assignees

• 3M Innovative Properties Company

Dates

Publication Date

20260506

Application Date

20240620

Claims (15)

1. 1. A magnetically permeable core for use in a transformer and comprising an integral multilayer film continuously extending along a length of the multilayer film between opposing first and second longitudinal ends of the multilayer film and wound to form a plurality of substantially concentric coil loops numbering at least 50 in total and, in combination, having an average height Hl in a height direction of the core, and a largest lateral dimension DI in an in-plane direction of the core, Dl/Hl > 2, the coil loops comprising an innermost coil loop comprising the first longitudinal end of the multilayer film and an outermost coil loop comprising the second longitudinal end of the multilayer film, the multilayer film comprising a plurality of substantially co-extensive layers comprising at least one magnetically permeable layer and at least one adhesive layer bonding the concentric coil loops to each other, wherein for at least one pair of inner and outer coils in the plurality of substantially concentric coil loops, the inner and outer coils have relative magnetic permeabilities different by at least 10% at a same frequency in a range from about 10 kHz to about 10 MHz.
2. 2. The magnetically permeable core of claim 1, wherein at least one same magnetically permeable layer in the at least one magnetically permeable layer in each of the inner and outer coils in the at least one pair of inner and outer coils is intentionally cracked across substantially an entirety of the corresponding coil to form a plurality of interconnected cracks defining a plurality of magnetically permeable islands, wherein the islands in the inner and outer coils have respective average largest lateral dimensions SI and S2, SI < S2.
3. 3. The magnetically permeable core of claim 2, wherein the cracks in the interconnected cracks extend across an entire thickness of the at least one same magnetically permeable layer isolating the islands from each other.
4. 4. The magnetically permeable core of claim 1 , wherein for each pair of inner and outer coils in the plurality of substantially concentric coil loops, the inner and outer coils have respective relative magnetic permeabilities pl and p2, wherein l < p2.
5. 5. The magnetically permeable core of claim 1, wherein a relative magnetic permeability of the multilayer film varies by at least 10% between the opposing first and second longitudinal ends of the multilayer film.
6. 6. The magnetically permeable core of claim 1, wherein between the opposing first and second longitudinal ends of the multilayer film, a maximum relative magnetic permeability of the multilayer film is greater than about 500 and a minimum relative magnetic permeability of the multilayer film is less than about 400.
7. 7. The magnetically permeable core of claim 1, wherein each of the inner and outer coils in the at least one pair of inner and outer coils comprises ion implants affecting a relative magnetic permeability of the coil, wherein average ion densities of the ion implants in the inner and outer coils are different by at least 10%.
8. 8. The magnetically permeable core of claim 1, wherein at least one same magnetically permeable layer in the at least one magnetically permeable layer in each of the inner and outer coils in the at least one pair of inner and outer coils is intentionally cracked across substantially an entirety of the corresponding coil to form a plurality of interconnected cracks defining a plurality of magnetically permeable islands, wherein the cracks in the inner and outer coils have respective average crack densities Cl and C2 per square millimeter, Cl > C2.
9. 9. The magnetically permeable core of claim 1, wherein at least one of opposing top and bottom major surfaces of the core comprises a regular pattern comprising a plurality of substantially parallel features across the corresponding major surface.
10. 10. A magnetically permeable core comprising at least one magnetically permeable layer wound to form a plurality of substantially concentric magnetically permeable loops numbering at least 50 in total, a relative magnetic permeability of the at least one magnetically permeable layer modulated along a length thereof so that average relative magnetic permeabilities of at least one pair of inner and outer loops in the plurality of magnetically permeable loops are different by at least 10%.
11. 11. The magnetically permeable core of claim 10, wherein the relative magnetic permeability of the at least one magnetically permeable layer is modulated along the length thereof by intentionally cracking the at least one magnetically permeable layer.
12. 12. A transformer comprising a substantially planar magnetically permeable core, and first and second wire windings wound around the magnetically permeable core to form respective primary and secondary windings of the transformer, the substantially planar magnetically permeable core having an average height Hl and a largest lateral dimension DI, Dl/Hl > 5, such that when energized, the primary winding generates a magnetic flux within the substantially planar magnetically permeable core that varies by less than about 50% along a radial direction of the core.
13. 13. The transformer of claim 12, wherein the substantially planar magnetically permeable core comprising an elongated multilayer film wound to form a plurality of substantially concentric coil loops numbering at least 50 in total, the multilayer film comprising a plurality of substantially co-extensive layers comprising at least one magnetically permeable layer and at least one adhesive layer bonding the concentric coil loops to each other.
14. 14. The transformer of claim 13, wherein at least one same magnetically permeable layer in the at least one magnetically permeable layer is intentionally cracked in each of at least one pair of inner and outer coil loops in the plurality of substantially concentric coil loops to form a plurality of interconnected cracks defining a plurality of magnetically permeable islands, wherein the islands in the inner and outer coil loops have respective average largest lateral dimensions SI and S2, SI < S2.
15. 15. The transformer of claim 12, wherein the substantially planar magnetically permeable core is at least partially embedded in an electrically insulative and magnetically non-permeable substrate.

Description

MAGNETICALLY PERMEABLE CORE AND TRANSFORMER INCLUDING THE SAME Technical Field The present disclosure relates to a magnetically permeable core for use in a transformer and a transformer including the magnetically permeable core. Background A transformer includes a magnetic core and conductor wires wound around the magnetic core. When a current flows in the conductor wires, a magnetic flux is generated and is confined in the magnetic core. However, the magnetic flux may have a different distribution within the magnetic core. Due to this phenomenon, there may be a non-uniform distribution of the magnetic flux. The non-uniform distribution of the magnetic flux may cause localized magnetic saturation at a localized area. Furthermore, the non-uniform distribution of the magnetic flux may create excessive heat in the localized area. Summary In a first aspect, the present disclosure provides a magnetically permeable core for use in a transformer. The magnetically permeable core includes an integral multilayer film continuously extending along a length of the multilayer film between opposing first and second longitudinal ends of the multilayer film. The multilayer film is wound to form a plurality of substantially concentric coil loops. The plurality of substantially concentric coil loops numbers at least 50 in total and, in combination, has an average height Hl in a height direction of the core and a largest lateral dimension DI in an in-plane direction of the core, wherein Dl/Hl > 2. The coil loops include an innermost coil loop including the first longitudinal end of the multilayer film and an outermost coil loop including the second longitudinal end of the multilayer film. The multilayer film includes a plurality of substantially co-extensive layers including at least one magnetically permeable layer and at least one adhesive layer bonding the concentric coil loops to each other. For at least one pair of inner and outer coils in the plurality of substantially concentric coil loops, the inner and outer coils have relative magnetic permeabilities different by at least 10% at a same frequency in a range from about 10 kilohertz (kHz) to about 10 megahertz (MHz). In a second aspect, the present disclosure provides a transformer including the magnetically permeable core of the first aspect. The transformer further includes first and second wire windings wound around the magnetically permeable core to form respective primary and secondary windings of the transformer. In a third aspect, the present disclosure provides a magnetically permeable core including at least one magnetically permeable layer wound to form a plurality of substantially concentric magnetically permeable loops numbering at least 50 in total. A relative magnetic permeability of the at least one magnetically permeable layer is modulated along a length thereof so that average relative magnetic permeabilities of at least one pair of inner and outer loops in the plurality of magnetically permeable loops are different by at least 10%. In a fourth aspect, the present disclosure provides a transformer including a substantially planar magnetically permeable core, and first and second wire windings wound around the magnetically permeable core to form respective primary and secondary windings of the transformer. The substantially planar magnetically permeable core has an average height Hl and a largest lateral dimension DI, wherein DI /Hl > 5, such that when energized, the primary winding generates a magnetic flux within the substantially planar magnetically permeable core that varies by less than about 50% along a radial direction of the core. Brief Description of Drawings Exemplary embodiments disclosed herein are more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labelled with the same number. FIG. 1A is a schematic top perspective view of a transformer, according to an embodiment of the present disclosure. FIG. IB is a schematic side view of the transformer of FIG. 1A, according to an embodiment of the present disclosure. FIG. 2A is a photograph illustrating a plan top view of a magnetically permeable core of the transformer, according to an embodiment of the present disclosure; FIG. 2B is a schematic side view of the magnetically permeable core of FIG. 2A, according to an embodiment of the present disclosure; FIG. 3A is a schematic perspective view of a multilayer film of the magnetically permeable core of FIG. 2 A, according to an embodiment of the present disclosure; FIG. 3B is a schematic plan top view of the multilayer film of FIG. 3 A, according to an embodiment of the present disclosure; FIG. 3C is a schematic cross