High-density single-turn inductor

Patent metadata

Field	Value
Publication number	US-2021343467-A1
Application number	US-202016865730-A
Country	US
Kind code	A1
Filing date	May 4, 2020
Priority date	May 4, 2020
Publication date	Nov 4, 2021
Grant date	—

Abstract

An inductor having a coaxial structure is described. In one example, the structure of the single-turn inductor can include a conductor, an insulation layer, a shielding layer, and a magnetic core. An air duct can be located between the shielding layer and the magnetic core. The shielding layer and the magnetic core can both be connected to a ground. In one example, the single-turn inductor can include a single-layer termination structure formed on terminations of the shielding layer. In another example, the single-turn inductor can include a double-layer termination structure formed on terminations of the shielding layer. Displacement current in the single-turn inductor can be reduced using, for example, lumped equivalent circuit models, a semi-conductive shielding layer model, or a resistive layer and conductive shielding layer model.

First claim

1 . A single-turn inductor, comprising:
a conductor; a solid insulator enclosing at least a portion of the conductor; a shielding layer enclosing at least a portion of the solid insulator, the shielding layer comprising at least one termination; and a magnetic core enclosing at least a portion of the shielding layer.

2 . The single-turn inductor of claim 1 , wherein the conductor comprises a copper bar, Litz wire, or a copper braid.

3 . The single-turn inductor of claim 1 , wherein the solid insulator comprises a resin-rich mica tape.

4 . The single-turn inductor of claim 1 , wherein a thickness of the solid insulator is based at least in part on an electric field distribution in the solid insulator.

5 . The single-turn inductor of claim 1 , further comprising a stress control layer formed on the at least one termination.

6 . The single-turn inductor of claim 5 , further comprising an additional insulation layer formed on the stress control layer.

7 . The single-turn inductor of claim 1 , further comprising an air duct between the shielding layer and the magnetic core.

8 . The single-turn inductor of claim 1 , wherein the shielding layer and the magnetic core have a same ground potential.

9 . The single-turn inductor of claim 1 , further comprising an external grounding resistor connected to one side of the single-turn inductor for damping a displacement current caused by a parasitic capacitance between the conductor and the shielding layer.

10 . The single-turn inductor of claim 1 , further comprising an external grounding resistor connected to an opposite side of the single-turn inductor as a source of a displacement current caused by a parasitic capacitance between the conductor and the shielding layer.

11 . The single-turn inductor of claim 1 , wherein the shielding layer is a semi-conductive shielding layer.

12 . The single-turn inductor of claim 1 , further comprising a resistive layer between the conductor and the solid insulator, wherein the shielding layer is a conductive shielding layer.

13 . A method, comprising:
providing a conductor; wrapping a solid insulator around the conductor, the solid insulator comprising resin-rich mica tape; curing the solid insulator; forming a shielding layer on an outer surface of solid insulator, the shielding layer comprising a silver-coated copper conductive coating; and curing the shielding layer.

14 . The method of claim 13 , wherein the conductor comprises a copper bar, Litz wire, or a copper braid.

15 . The method of claim 13 , further comprising forming a stress control layer on at least one termination of the shielding layer.

16 . The method of claim 15 , wherein the stress control layer comprises an electrical stress control tape.

17 . The method of claim 15 , further comprising forming an additional insulation layer on an outer surface of the stress control layer.

18 . The method of claim 17 , wherein the additional insulation layer comprises a rubber mastic tape

19 . The method of claim 13 , further comprising connecting a grounding resistor to the shielding layer.

20 . The method of claim 13 , wherein curing the solid insulator comprises:
hot-pressing the solid insulator; and oven-curing the solid insulator.

Assignees

• Virginia Tech Intellectual Properties Inc

Inventors

• Song He
• Wang Jun
• Xu Yue
• Burgos Rolando
• Boroyevich Dushan

Classifications

• H01F27/36

  Electric or magnetic shields or screens (movable for varying inductance H01F21/10) · CPC title

• H01F27/2885

  with shields or electrodes (shields or electrodes for pancake coils H01F27/2871; construction of electric or magnetic shields or screens H01F27/36) · CPC title

• H01F3/14

  Constrictions; Gaps, e.g. air-gaps (in magnetic shunt paths H01F3/12) · CPC title

• H01F27/085

  Cooling by ambient air · CPC title

• H01F27/324

  Insulation between coil and core, between different winding sections, around the coil; Other insulation structures · CPC title