Foreign object detector, foreign object detection system, use of a foreign object detector, and method of detecting a foreign object

Patent metadata

Field	Value
Publication number	US-11101704-B2
Application number	US-201716614758-A
Country	US
Kind code	B2
Filing date	May 23, 2017
Priority date	May 23, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A foreign object detector, a foreign object detection system and a method for operating the foreign object detector are disclosed. In an embodiment, a foreign object detector includes a conducting wire with a first section and a second section, a first node, a second node and an intermediate node, wherein the first section electrically connects the first node to the intermediate node and has a plurality of three or more vertical segments, and wherein the second section electrically connects the intermediate node to the second node and has a plurality of three or more horizontal segments.

First claim

The invention claimed is:

1. A foreign object detector comprising:
a conducting wire with a first section and a second section, a first node, a second node and an intermediate node,
wherein the first section electrically connects the first node to the intermediate node and has a plurality of three or more vertical segments, and
wherein the second section electrically connects the intermediate node to the second node and has a plurality of three or more horizontal segments;
a driver circuit,
wherein the conducting wire establishes an impedance element, and
wherein the driver circuit is configured to excite the impedance element with a resonance; and
an evaluation circuit configured to detect a change of a parameter of the conducting wire selected from an impedance of the conducting wire, an amplitude of a signal of the conducting wire or a resonance frequency of a signal of the conducting wire, the evaluation circuit further configured to detect foreign metallic or dielectric matter in the vicinity of the conducting wire based on the detected change of the parameter;
wherein the vertical segments of the first section and the horizontal segments of the second section are arranged in respective first and second meander patterns, the second meander pattern overlaid over the first meander pattern to establish mesh elements at intersection points of the vertical and horizontal elements.

2. The foreign object detector of claim 1 , wherein a number of the vertical segments of the first section and a number of the horizontal segments of the second section are odd numbers.

3. The foreign object detector of claim 1 , wherein a number of the vertical segments of the first section and a number of the horizontal segments of the second section are even numbers.

4. The foreign object detector of claim 1 , further comprises turning segments between the vertical segments and between the horizontal segments, wherein the turning segments have a shape of an arc of a circle, and wherein a winding number of a turning segment is 0.5.

5. The foreign object detector of claim 1 , wherein the first section and the second section establish at intersection points rhomboid mesh elements.

6. The foreign object detector of claim 1 , wherein the conducting wire establishes a mesh that has a shape of a rectangle.

7. The foreign object detector of claim 1 , further comprising one or more additional conducting wires each of the additional wires establishing a mesh.

8. The foreign object detector of claim 1 , wherein the evaluation circuit is configured to distinguish between metallic and dielectric matter in a vicinity of the conducting wire.

9. The foreign object detector of claim 1 , wherein the conducting wire establishes a mesh that has a shape of a rectangle, a section of a lateral surface of a cylinder, or a section of a lateral surface of a cone, and wherein the foreign object detector further comprises one or more additional conducting wires each of the additional wires establishing a mesh.

10. The foreign object detector of claim 1 , further comprises turning segments between the vertical segments and between the horizontal segments, wherein the turning segments a shape of two 90° turns, and wherein a winding number of a turning segment is 0.5.

11. The foreign object detector of claim 1 , further comprises turning segments between the vertical segments and between the horizontal segments, wherein the turning segments have a shape of four 45° turns, and wherein a winding number of a turning segment is 0.5.

12. The foreign object detector of claim 1 , wherein the conducting wire establishes a mesh that has a shape of a section of a lateral surface of a cylinder.

13. The foreign object detector of claim 1 , wherein the conducting wire establishes a mesh that has a shape of a section of a lateral surface of a cone.

14. A detection system comprising:
the foreign object detector according to claim 1 .

15. A method for using the foreign object detector according to claim 1 , the method comprising:
detecting, by the foreign object detector, foreign metallic or dielectric matter in a vicinity of a wireless power transmission (WPT) system.

16. A method for using the foreign object detector according to claim 1 , the method comprising:
operating the foreign object detector before and/or during operation of a wireless power transmission (WPT) system.

17. A method for detecting a foreign metallic object by the foreign object detector of claim 1 , the method comprising:
exciting the conducting wire of the foreign object detector with an AC signal;
monitoring the parameter being the impedance of the conducting wire, an amplitude of the AC signal or a resonance frequency of the AC signal; and
detecting a change of the monitored parameter.

18. The method of claim 17 , wherein an inductive behavior of the conductive wire indicates a presence of the foreign metallic object.

19. A method for detecting a foreign dielectric object by the foreign object detector of claim 1 , the method comprising:
exciting the conducting wire of the foreign object detector with an AC signal;
monitoring the parameter being the impedance of the conducting wire, an amplitude of the AC signal or a resonance frequency of the AC signal; and
detecting a change of the monitored parameter.

20. The method of claim 19 , wherein a capacitive behavior of the conducting wire indicates a presence of the foreign dielectric object.

Assignees

• Tdk Electronics Ag

Inventors

• Fechting Pierre
• Tejeda Abiezer

Classifications

• G01V3/104 Primary

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

• H02J50/60 Primary

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

• G01V3/102

  by measuring amplitude · CPC title

• H02J50/12

  of the resonant type · CPC title