Transformer designs for very high isolation with high coupling

Patent metadata

Field	Value
Publication number	US-12087489-B2
Application number	US-202016923893-A
Country	US
Kind code	B2
Filing date	Jul 8, 2020
Priority date	Jul 8, 2019
Publication date	Sep 10, 2024
Grant date	Sep 10, 2024

Abstract

Various examples are provided related to transformer designs that offer very high isolation while maintaining high coupling between the windings. In one example, an isolation transformer includes a first excitation coil wound around a first core and a second excitation coil wound about a second core. The second core is electrically separated from the first core by a high resistivity magnetic material or a non-conductive material. The first and second cores can include corresponding core segments arranged in a trident geometry or a quindent geometry. The core segments can align when the first excitation coil is inserted into a void of the second excitation coil. The isolation transformer designs are mechanically separable which can result in safe, energized, plug operations.

First claim

Therefore, at least the following is claimed:

1. An isolation transformer, comprising:
a first excitation coil and a second excitation coil, the first excitation coil wound around a first core comprising at least one core element, each of the at least one core element of the first core including:
a first section extending axially through the first excitation coil from a first end to a second end, and
a second section extending from the first end of the first section, the second section substantially perpendicular to the first section, the first excitation coil and the first section of each of the at least one core element of the first core encased in a housing configured for removable insertion into a central void of the second excitation coil, the first excitation coil and the first section of each of the at least one core element of the first core encased in the housing axially insertable and removable from the central void of the second excitation coil while energized; and

a second core of the second excitation coil, the second core comprising at least one corresponding core element, each of the at least one corresponding core element of the second core including a first section and a second section extending from a first end of the first section of that corresponding core element, the second section of each of the at least one corresponding core element substantially perpendicular to the first section of that corresponding core element, the second excitation coil wound around the central void and adjacent to the second core, where a side surface at a distal end of the second section of each of the at least one corresponding core element of the second core aligns with an end surface at a second end of the first section of a corresponding one of the at least one core element of the first core, and an end surface at a second end of the first section of each of the at least one corresponding core element of the second core aligns with a side surface at a distal end of the second section of the corresponding one of the at least one core element of the first core when the first excitation coil and the first section of each of the at least one core element of the first core encased in the housing are inserted into the central void of the second excitation coil, the second core electrically separated from the first core by a high resistivity magnetic material or a non-conductive material.

2. The isolation transformer of claim 1 , wherein the high resistivity magnetic material comprises ferrite.

3. The isolation transformer of claim 1 , wherein the non-conductive material comprises an insulator.

4. The isolation transformer of claim 1 , wherein the first and second excitation coils are referenced to different electrical potentials.

5. The isolation transformer of claim 1 , wherein the at least one core element of the first core comprises a plurality of core elements, each of the plurality of core elements comprising:
the first section extending through the first excitation coil from the first end, the first section substantially parallel to the first section of the other core elements of the first core, and
the second section extending from the first end of the first section, the second section substantially perpendicular to the first section.

6. The isolation transformer of claim 5 , wherein the at least one corresponding core element of the second core comprises a plurality of corresponding core elements, each of the plurality of corresponding core elements comprising:
the first section substantially parallel to the first section of the other corresponding core elements of the second core, and
the second section extending from the first end of the first section, the second section substantially perpendicular to the first section, where the side surface at the distal end of the second section of each corresponding core element of the plurality of corresponding core elements aligns with the end surface at the second end of the first section of the corresponding one of the plurality of core elements of the first core, and the end surface at the second end of the first section of each corresponding core element of the plurality of corresponding core elements aligns with the side surface at the distal end of the second section of the corresponding one of the plurality of core elements of the first core when the first excitation coil and the first sections of the plurality of core elements of the first core encased in the housing are inserted into the central void of the second excitation coil.

7. The isolation transformer of claim 1 , wherein the second excitation coil is between the first excitation coil and the first section of each of the at least one corresponding core element of the second core.

8. The isolation transformer of claim 1 , wherein the first core comprises a plurality of core elements distributed about a longitudinal axis of the first excitation coil, where each of the plurality of core elements comprises:
the first section extending through the first excitation coil from the first end, the first section substantially parallel to the first section of the other core elements of the first core, and
the second section extending from the first end of the first section, where the second section of each of the plurality of core elements extends radially outward from and substantially perpendicular to the first section.

9. The isolation transformer of claim 8 , wherein the plurality of core elements comprises a pair of core elements, the second section of each of the pair of core elements extending opposite each other.

10. The isolation transformer of claim 9 , wherein each of the pair of core elements have a rectangular cross-section comprising a length and a width shorter than the length.

11. The isolation transformer of claim 10 , wherein a side of the first section of one core element of the pair of core elements is aligned with a side of the first section of the other core element of the pair of core elements.

12. The isolation transformer of claim 9 , wherein the plurality of core elements comprises a second pair of core elements, the second section of each of the second pair of core elements extending opposite each other and substantially perpendicular to the second sections of the other pair of core elements.

13. The isolation transformer of claim 8 , wherein the second core comprises a plurality of corresponding core elements distributed about the first excitation coil, where each of the plurality of corresponding core elements comprises:
the first section substantially parallel to the first section of the other core elements of the second core, and
the second section extending from the first end of the first section and substantially perpendicular to the first section, where the distal end of the second section of each of the plurality of corresponding core elements aligns with the second end of the first section of the corresponding one of the plurality of core elements of the first core, and the second end of the first section of each of the plurality of corresponding core elements aligns with the distal end of the second section of the corresponding one of the plurality of core elements of the first core when the first excitation coil and the first sections of the first core elements are inserted into the central void of the second excitation coil.

14. The isolation transformer of claim 1 , wherein the first excitation coil and the first core are encased in the housing.

15. The isolation transformer of claim 14 , wherein the central void of the second excitation coil is configured to receive the housi

Assignees

• Univ North Carolina State
• Us Dept Energy

Inventors

• Beddingfield Richard Byron
• Bhattacharya Subhashish
• Wong Tsz Sing
• Ohodnicki Paul

Classifications

• H01F27/24 Primary

  Magnetic cores · CPC title

• H01F27/02

  Casings · CPC title

• H01F27/263

  Fastening parts of the core together · CPC title

• H01F3/14

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

• H01F27/2823

  Wires (H01F27/2866 takes precedence) · CPC title