Detection coil, detection apparatus, and detection system

Patent metadata

Field	Value
Publication number	US-11796709-B2
Application number	US-202017096054-A
Country	US
Kind code	B2
Filing date	Nov 12, 2020
Priority date	Jun 19, 2018
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

A detection coil includes a first group of coils, a second group of coils, and a third group of coils that are continuously wound and coaxial, and the second group of coils is located between the first group of coils and the third group of coils. A coil that generates the first magnetic field is coaxial with the first group of coils, the second group of coils, and the third group of coils. A sum of the induced electromotive forces of the first group of coils, the second group of coils, and the third group of coils is zero. When a metal foreign matter exists, a sum of the induced electromotive forces of the first group of coils, the second group of coils, and the third group of coils is not zero.

First claim

What is claimed is:

1. A detection apparatus, comprising:
a first voltage divider resistor comprising:
a first end; and
a second end;

a second voltage divider resistor comprising:
a third end coupled to the second end; and
a fourth end; and

a detection coil, wherein the detection coil is a planar coil comprising:
a first group of coils coupled to the first end;
a second group of coils; and
a third group of coils coupled to the fourth end and the second group of coils such that the second group of coils is located between the first group of coils and the third group of coils,
wherein the first group of coils, the second group of coils, and the third group of coils are coaxial and each comprise a turn of continuously-wound coil,

wherein a voltage at the first end of the first voltage divider resistor and the second end of the first voltage divider resistor is equal to a first value of an induced electromotive force from the second group of coils in a first magnetic field when the detection apparatus is disposed in the first magnetic field, and wherein a first direction of the voltage is opposite to a second direction of the induced electromotive force.

2. The detection apparatus of claim 1 , wherein the first group of coils, the second group of coils, and the third group of coils are coaxial with a coil that generates the first magnetic field.

3. The detection apparatus of claim 1 , wherein the first group of coils, the second group of coils, or the third group of coils comprises a continuously wound multi-turn coaxial coil.

4. The detection apparatus of claim 1 , wherein the first group of coils, the second group of coils, and the third group of coils meet a first formula when the first group of coils, the second group of coils, and the third group of coils have a same quantity of coil turns, wherein the first formula is as follows:

(

Δφ
1

+

Δφ
3

)

×

R
⁢
1

R
⁢
1

+

R
⁢
2

+
R

=

Δφ
2

,

wherein R1 is a resistance value of the first voltage divider resistor, R2 is a resistance value of the second voltage divider resistor, and R is a sum of resistance values of the first group of coils and the third group of coils, wherein Δφ 1 is a variation of a magnetic flux of a first turn of a first coil in the first group of coils in the first magnetic field in a time period Δt and is based on a magnetic induction intensity of the first magnetic field and a first coil area of the first turn of the first coil, wherein Δφ 2 is a variation of a magnetic flux of a second turn of a second coil in the second group of coils in the first magnetic field in the time period Δt and is based on the magnetic induction intensity of the first magnetic field and a second coil area of the second turn of the second coil, and wherein Δφ 3 is a variation of a magnetic flux of a third turn of a third coil in the third group of coils in the first magnetic field in the time period Δt and related to the magnetic induction intensity of the first magnetic field and a third coil area of the third turn of the third coil.

5. The detection apparatus of claim 4 , wherein the first group of coils, the second group of coils, and the third group of coils meet a second formula as follows:

(

Δ
⁢

∫

S
⁢
1

B
⁢
d
⁢
s

+

Δ
⁢

∫

S
⁢
3

Bds

)

×

R
⁢
1

R
⁢
1

+

R
⁢
2

+
R

=

Δ
⁢

∫

S
⁢
2

B
⁢
d
⁢
s

,

wherein S1 is the first coil area, wherein S2 is the second coil area, wherein S3 is the third coil area, wherein

Δ
⁢

∫

S
⁢
1

B
⁢
d
⁢
s

is the variation of the magnetic flux of the first turn of the first coil, wherein

Δ
⁢

∫

S
⁢
2

B
⁢

Assignees

• Huawei Tech Co Ltd

Inventors

• He mou
• Chen Wei
• Zhu Yongfa

Classifications

• G01V3/104 Primary

  using several coupled or uncoupled coils (G01V3/101 takes precedence) · CPC title

• G01V3/081

  the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00) · CPC title

• G01V3/38

  Processing data, e.g. for analysis, for interpretation, for correction · CPC title

• H02J50/10

  using inductive coupling · CPC title

• H02J50/60

  responsive to the presence of foreign objects, e.g. detection of living beings · CPC title