# US 10,122,192 B2 · Sense coil geometries with improved sensitivity for metallic object detection in a predetermined space

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- Number: US 10,122,192 B2
- Document ID: US10122192B2
- Status: Granted
- Kind: B2
- Application number: 14/818,051
- Filed: 2015-08-04
- Published: 2016-08-18
- Granted: 2018-11-06
- Earliest claimed: 2015-02-17
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Swagat Chopra; Leandro Alberto Percebon; Michael Werner
- Web page: https://patentgrep.com/patent/US10122192B2

## CPC

- H02J 7/70: characterised by the mechanical construction
- B60L 53/122: Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
- B60L 53/124: Detection or removal of foreign bodies
- B60L 53/126: Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
- B60L 53/36: by positioning the vehicle
- B60L 53/38: specially adapted for charging by inductive energy transfer
- G01V 3/10: using induction coils
- G01V 3/101: {by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil (measuring impedance or characteristics derived therefrom G01R27/00, e.g. quality factor G01R27/26)}
- H02J 50/10: using inductive coupling
- H02J 50/12: of the resonant type
- H02J 50/60: responsive to the presence of foreign objects, e.g. detection of living beings
- H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
- H02J 50/90: involving detection or optimisation of position, e.g. alignment
- H02J 2105/37: exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV]
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
- Y02T 90/12: Electric charging stations
- Y02T 90/14: Plug-in electric vehicles
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

This disclosure provides systems, methods and apparatus for detecting a presence of an object. In one aspect an apparatus for detecting a presence of an object is provided. The apparatus includes a sense coil formed from a conductor having a predetermined shape configured to attenuate currents induced in the conductor by an external time-varying magnetic field. The sense coil has an electrical characteristic that varies as a function of the presence of the object. The apparatus comprises a detection circuit coupled to the sense coil and configured to detect the presence of the object in response to detecting a difference between a measured value of the electrical characteristic and a reference value for the electrical characteristic. The reference value for the electrical characteristic is substantially the same as the measured value of the electrical characteristic in the absence of the object over at least a portion of the sense coil.

## Claims

### Claim 1

An apparatus for detecting a presence of an object, the apparatus comprising:
a sense coil having a plurality of sides defined by a conductor, wherein for each of the plurality of sides of the sense coil, the conductor bows toward a center of the sense coil as the conductor extends from an outer portion of the respective side of the sense coil toward a middle portion of the respective side of the sense coil, and wherein the sense coil has an electrical characteristic that varies as a function of the presence of the object; and
a detection circuit coupled to the sense coil and configured to detect the presence of the object in response to detecting a difference between a measured value of the electrical characteristic and a reference value for the electrical characteristic.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the reference value for the electrical characteristic is substantially the same as the measured value of the electrical characteristic in the absence of the object over at least a portion of the sense coil.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein a shape of the sense coil decreases a difference between a maximum measurable value of the electrical characteristic when the object is located over at least a portion of the sense coil and the measured value of the electrical characteristic when the object is located substantially over a center of the sense coil as compared to a substantially rectangular sense coil.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein at each corner of corresponding sides of the coil, the conductor is bent at an acute angle with respect to a direction of extension of each of the corresponding sides to form substantially rounded corners.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the acute angle is substantially 45°.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein at each corner of corresponding sides of the coil, the conductor is bent at a substantially 90 degree angle with respect to a direction of extension of each of the corresponding sides.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the conductor of the coil forms a plurality of windings and for at least one winding on one side of the plurality of sides of the coil, the conductor extends in a substantially straight line along the entire side.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the conductor of the coil forms a plurality of windings and wherein successive windings of the plurality of windings bow toward a center of the coil to an increasing extent from an outermost winding to an innermost winding.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the conductor of the coil forms a plurality of windings and wherein the conductor extends in a substantially straight line along an entirety of each of the plurality of sides for at least one of the plurality of windings.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein the middle portion of opposite sides of the coil are closer to one another than the outer portion of the opposite sides of the coil are to one another.

### Claim 11 (depends on 1)

The method of claim 1, wherein the reference value for the electrical characteristic is substantially the same as the measured value of the electrical characteristic in the absence of the object over at least a portion of the sense coil.

### Claim 12

A method for detecting a presence of an object, the method comprising:
determining a measured value of an electrical characteristic of a sense coil that varies as a function of the presence of the object, the sense coil having a plurality of sides defined by a conductor, wherein for each of the plurality of sides of the sense coil, the conductor bows toward a center of the sense coil as the conductor extends from an outer portion of the respective side of the sense coil toward a middle portion of the respective side of the sense coil, and
detecting the presence of the object in response to detecting a difference between the measured value of the electrical characteristic and a reference value for the electrical characteristic.

### Claim 13 (depends on 12)

The method of claim 12, wherein a shape of the sense coil decreases a difference between a maximum measurable value of the electrical characteristic when the object is located over at least a portion of the sense coil and the measured value of the electrical characteristic when the object is located substantially over a center of the sense coil as compared to a substantially rectangular sense coil.

### Claim 14 (depends on 12)

The method of claim 12, wherein at each corner of corresponding sides of the coil, the conductor is bent at an acute angle with respect to a direction of extension of each of the corresponding sides to form substantially rounded corners.

### Claim 15 (depends on 14)

The method of claim 14, wherein the acute angel is substantially 45°.

### Claim 16 (depends on 12)

The method of claim 12, wherein at each corner of corresponding sides of the coil, the conductor is bent at a substantially 90 degree angle with respect to a direction of extension of each of the corresponding sides.

### Claim 17 (depends on 12)

The method of claim 12, wherein the conductor of the coil forms a plurality of windings and for at least one winding on one side of the plurality of sides of the coil, the conductor extends in a substantially straight line along the entire side.

### Claim 18 (depends on 12)

The method of claim 12, wherein the conductor of the coil forms a plurality of windings and wherein successive windings of the plurality of windings bow toward a center of the coil to an increasing extent from an outermost winding to an innermost winding.

### Claim 19 (depends on 12)

The method of claim 12, wherein the conductor of the coil forms a plurality of windings and wherein the conductor extends in a substantially straight line along an entirety of each of the plurality of sides for at least one of the plurality of windings.

### Claim 20 (depends on 12)

The method of claim 12, wherein the middle portion of opposite sides of the coil are closer to one another than the outer portion of the opposite sides of the coil are to one another.