System and method of magnetic shielding for sensors

Patent metadata

Field	Value
Publication number	US-9429488-B2
Application number	US-201414249991-A
Country	US
Kind code	B2
Filing date	Apr 10, 2014
Priority date	Apr 10, 2014
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

A system includes a magnetostrictive sensor. The magnetostrictive sensor includes a driving coil configured to receive a first driving current and to emit a first magnetic flux portion through a target and a second magnetic flux portion. The magnetostrictive sensor also includes a first sensing coil configured to receive the first magnetic flux portion and to transmit a signal based at least in part on the received first magnetic flux portion. The received first magnetic flux portion is based at least in part on a force on the target. The magnetostrictive sensor further includes a magnetic shield disposed between the driving coil and the first sensing coil. The magnetic shield is configured to reduce the second magnetic flux portion received by the first sensing coil.

First claim

The invention claimed is:

1. A system comprising:
a magnetostrictive sensor comprising:
a driving coil configured to receive a first driving current and to emit a first magnetic flux portion through a target and a second magnetic flux portion;
a first sensing coil configured to receive the first magnetic flux portion and to transmit a signal based at least in part on the received first magnetic flux portion, wherein the received first magnetic flux portion is based at least in part on a force on the target; and
a magnetic shield disposed between the driving coil and the first sensing coil, wherein the magnetic shield is configured to reduce the second magnetic flux portion received by the first sensing coil, and the magnetic shield comprises a flexible circuit disposed about the driving coil.

2. The system of claim 1 , comprising:
a driving pole, wherein the driving coil is disposed about the driving pole; and
a first sensing pole, wherein the first sensing coil is disposed about the first sensing pole.

3. The system of claim 2 , wherein the magnetic shield is disposed about the driving pole.

4. The system of claim 2 , comprising a second sensing pole and a second sensing coil disposed about the second sensing pole, wherein the driving pole is disposed between the first sensing pole and the second sensing pole.

5. The system of claim 1 , wherein the magnetic shield comprises an inner magnetic shield disposed about the driving coil and an outer magnetic shield disposed about the driving coil and the first sensing coil.

6. The system of claim 1 , wherein the flexible circuit comprises a compensation coil configured to receive a second driving current and to emit a third magnetic flux portion with a magnitude substantially equal to the second magnetic flux portion and with a direction substantially opposite to the second magnetic flux portion.

7. The system of claim 6 , comprising a controller configured to control the second driving current.

8. A system comprising:
a magnetostrictive sensor comprising:
a driving coil configured to receive a first driving current and to emit a first magnetic flux portion through a target and a second magnetic flux portion;
a first sensing coil configured to receive the first magnetic flux portion and to transmit a signal to a controller based at least in part on the received first magnetic flux portion; and
a magnetic shield comprising a flexible circuit, wherein the magnetic shield is disposed between the driving coil and the first sensing coil and the magnetic shield is configured to reduce the second magnetic flux portion received by the first sensing coil; and

the controller configured to determine a force applied to the target based at least in part on the signal.

9. The system of claim 8 , comprising:
a driving pole, wherein the driving coil is disposed about the driving pole; and
a first sensing pole, wherein the first sensing coil is disposed about the first sensing pole.

10. The system of claim 9 , wherein the magnetic shield is disposed about the driving pole.

11. The system of claim 8 , wherein the magnetic shield comprises an inner magnetic shield disposed about the driving coil and an outer magnetic shield disposed about the driving coil and the first sensing coil, wherein the outer magnetic shield is configured to reduce external electromagnetic interference received by the driving coil and the first sensing coil.

12. The system of claim 8 , wherein the flexible circuit comprises a compensation coil and the controller is configured to control a second driving current through the compensation coil to emit a third magnetic flux portion with a direction substantially opposite to the second magnetic flux portion.

13. The system of claim 12 , wherein the controller is configured to control the second driving current based at least in part on a spacing between the driving coil and the sensing coil, or a distance between the magnetostrictive sensor and the target, or any combination thereof.

14. The system of claim 8 , wherein the controller is configured to determine the force applied to the target of a turbine engine, a compressor, a pump, a generator, or a combustion engine, or any combination thereof.

15. A method comprising:
supplying a first current to a driving coil of a magnetostrictive sensor;
emitting a first magnetic flux portion from the driving coil through a target;
emitting a second magnetic flux portion from the driving coil;
sensing the first magnetic flux portion with a sensing coil of the magnetostrictive sensor; and
reducing the second magnetic flux portion received by the sensing coil based at least in part on a magnetic shield of the magnetostrictive sensor disposed between the driving coil and the sensing coil, wherein the magnetic shield comprises a flexible circuit.

16. The method of claim 15 , comprising reducing noise received by the sensing coil based at least in part on a housing, wherein the housing comprises a first layer configured to magnetic shield the sensing coil from high frequency noise and a second layer configured to magnetic shield the sensing coil from low frequency noise.

17. The method of claim 15 , comprising:
generating a signal based at least in part on the first magnetic flux portion sensed with the sensing coil; and
determining a force on the target based at least in part on the signal.

18. The method of claim 15 , comprising:
supplying a second current to a compensation coil of the magnetic shield; and
emitting a third magnetic flux portion from the compensation coil in a direction substantially opposite to the second magnetic flux portion.

19. The method of claim 18 , comprising controlling the second current to the compensation coil based at least in part on a spacing between the driving coil and the sensing coil, or a distance between the magnetostrictive sensor and the target, or any combination thereof.

Assignees

• Gen Electric

Inventors

• Lu Dan Tho
• Sipila Pekka Tapani
• Hatch Charles Terrance
• Campbell Lam Arthur
• Garcia Clemente Miguel

Classifications

• G01L1/125 Primary

  by using magnetostrictive means (magnetostrictive sensors H10N35/101) · CPC title

• G01L3/102

  involving magnetostrictive means (magnetostrictive sensors H10N35/101) · CPC title

• G01L9/16

  by making use of variations in the magnetic properties of material resulting from the application of stress · CPC title