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Low external field inductor

Imported: 24 Feb '17 | Published: 24 Aug '04

James Edward Layton

USPTO - Utility Patents

Abstract

An inductor is wound axially around a cylindrical center structure, such as a core or form, so that each turn includes portions extending axially along a circumferential outer surface of the center structure and portions extending across the end surfaces of the center structure. Adjacent axial portions, which are preferably but not necessarily consecutive turns, carry current in the same direction to the extent possible. External magnetic fields therefore fall off rapidly and at least partially offset so that the inductor can handle high currents such as those relating to filtered electric power transmitted into a borehole for powering artificial lift equipment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, and in which:

FIG. 1 depicts a borehole production system employing a low external field inductor for filtering a drive transmitting power into the borehole according to one embodiment of the present invention;

FIGS. 2A through 2C are circuit diagrams for suitable filter configurations including low external field inductors for use in the electric power structure of a borehole production system according to various embodiments of the present invention;

FIGS. 3A through 3C are various views of the windings of a low external field inductor according to one embodiment of the present invention;

FIGS. 4 through 6 are various plots of the magnetic field produced by a low external field inductor according to one embodiment of the present invention; and

FIGS. 7 and 8 are end views of alternative winding configurations for a low external field inductor according to one embodiment of the present invention.

Claims

1. An inductor, comprising:

2. An inductor comprising:

3. An inductor according to claim 2, wherein the portions of each turn extending across ends of the center structure cross over portions of previous turns extending across ends of the center structure.

4. An inductor according to claim 2, wherein the first and second set of adjacent axial portions are both formed by consecutive turns.

5. An inductor comprising:

6. An inductor according to claim 5, wherein the first and second adjacent axial portions are formed by uniformly spaced consecutive turns progressing around the outer surface of the center structure.

7. A power system for borehole production, comprising:

8. A The power system according to claim 7, wherein consecutive turns of the windings include the at least two adjacent axial portions.

9. The power system according to claim 7, wherein the portions of each turn extending across ends of the center structure cross over portions of previous turns extending across ends of the center structure.

10. The power system according to claim 7, wherein the windings include a first set of adjacent axial portions on a first portion of the outer surface of the center structure which are all wound to carry current in a first axial direction and a second set of axial portions on a second portion of the outer surface of the center structure which are all wound to carry current in a second axial direction opposite the first axial direction.

11. The power system according to claim 10, wherein the first and second set of adjacent axial portions are both formed by consecutive turns.

12. The power system according to claim 7, wherein the turns include first adjacent axial portions on a first half of the outer surface of the center structure all wound to conduct current in a first axial direction within the first adjacent axial portions and second adjacent axial portions on a second half of the outer surface of the center structure all wound to conduct current in a second axial direction within the second adjacent axial portions.

13. The power system according to claim 12, wherein the first and second adjacent axial portions are formed by uniformly spaced consecutive turns progressing around the outer surface of the center structure.

14. A method of forming an inductor, comprising:

15. A method of forming an inductor, comprising:

16. A method of forming an inductor, comprising:

17. The method according to claim 16, wherein the step of winding turns axially around the center structure further comprises:

18. The method according to claim 16, further comprising: