# US 2018/0026482 A1 · Power transmission system, foreign object detection device, and coil device

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- Number: US 2018/0026482 A1
- Document ID: US20180026482A1
- Status: Published application
- Kind: A1
- Application number: 15/543,055
- Filed: 2016-01-14
- Published: 2018-01-25
- Earliest claimed: 2015-01-19
- Assignees: IHI Corporation
- Applicants: Ihi Corporation
- Inventors: Atsushi ASANO; Kentarou FURIYA; Jun ARAKI; Masahiko GOTO
- Web page: https://patentgrep.com/patent/US20180026482A1

## CPC

- B60L 53/124: Detection or removal of foreign bodies
- B60L 53/12: Inductive energy transfer
- B60L 53/30: Constructional details of charging stations
- H01F 38/14: Inductive couplings
- H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J 50/12: of the resonant type
- H02J 50/60: responsive to the presence of foreign objects, e.g. detection of living beings
- B60L 2270/147: electro magnetic [EMI]
- H02J 50/005: {Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices}
- 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
- 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
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A foreign object detection device for a coil device including a second coil to transmit power to a first coil wirelessly or receive power from the first coil wirelessly including: a foreign object detection coil configured to be located between the first coil and the second coil; and a cover configured to cover an upper portion of the foreign object detection coil, wherein a top surface of the cover includes at least one inclined surface inclined relative to a coil plane of the second coil, and the inclined surface is inclined downward from a low sensitivity region where detection sensitivity of the foreign object detection coil is relatively lower to a high sensitivity region where the detection sensitivity of the foreign object detection coil is relatively higher.

## Claims

### Claim 1

A foreign object detection device for a coil device including a second coil to transmit power to a first coil wirelessly or receive power from the first coil wirelessly, the foreign object detection device comprising:
a foreign object detection coil configured to be located between the first coil and the second coil; and
a cover configured to cover an upper portion of the foreign object detection coil,
wherein a top surface of the cover includes at least one inclined surface inclined relative to a coil plane of the second coil, and
the inclined surface is inclined downward from a low sensitivity region where detection sensitivity of the foreign object detection coil is relatively lower to a high sensitivity region where the detection sensitivity of the foreign object detection coil is relatively higher.

### Claim 2 (depends on 1)

The foreign object detection device according to claim 1, wherein
the top surface of the cover includes an end inclined surface inclined downward and extending to an end of the top surface.

### Claim 3 (depends on 1)

The foreign object detection device according to claim 1, wherein
the at least one inclined surface includes a plurality of inclined surfaces of directions different from each other.

### Claim 4 (depends on 1)

The foreign object detection device according to claim 1, wherein
the foreign object detection coil is disposed in parallel to the inclined surface.

### Claim 5 (depends on 1)

The foreign object detection device according to claim 1, further comprising:
a vibration device configured to vibrate the cover.

### Claim 6 (depends on 1)

The foreign object detection device according to claim 1, wherein
the foreign object detection coil includes a detection loop that is a conductive wire of a loop shape, and
the low sensitivity region overlaps the conductive wire when viewed from a direction of a center axis of the detection loop and the high sensitivity region overlaps an inner portion surrounded by the detection loop when viewed from the direction of the center axis of the detection loop.

### Claim 7 (depends on 1)

A coil device including the foreign object detection device according to claim 1 and the second coil,
wherein the cover further covers the second coil.

### Claim 8

A power transmission system including a power transmitter including a coil device used for wireless power transfer and a foreign object detection device for the coil device, the power transmission system comprising:
first and second detection coils configured to be disposed on a casing of the coil device, each of the first and second detection coils including two terminals;
a selector configured to select one of one terminal of the first detection coil and one terminal of the second detection coil as a first terminal and select one of the other terminal of the first detection coil and the other terminal of the second detection coil as a second terminal; and
a controller configured to perform a first foreign object determination process that causes the selector to select the one terminal of the first detection coil as the first terminal and the other terminal of the second detection coil as the second terminal to determine whether there is an electrically conductive foreign object depending on whether connection between the first terminal and the second terminal is in a short circuit state or an open state, and to perform a second foreign object determination process that causes the selector to select the two terminals of the same detection coil from either the first detection coil and the second detection coil as the first terminal and the second terminal to determine whether there is the foreign object depending on a change in an amount of magnetic flux interlinking with the same detection coil.

### Claim 9 (depends on 8)

The power transmission system according to claim 8, wherein
the controller causes the selector to select the two terminals of the same detection coil as the first terminal and the second terminal and determines whether there is a failure according to whether the connection between the first terminal and the second terminal is in the short circuit state or the open state.

### Claim 10 (depends on 9)

The power transmission system according to claim 9, wherein
the casing includes a cover and a base defining an accommodation space to accommodate the coil device,
the selector includes a plurality of input terminals and each of the plurality of input terminals corresponds to one of the terminals of the first detection coil and the second detection coil,
the first detection coil and the second detection coil are provided in the cover, and
each terminal of the first detection coil and the second detection coil is electrically connected to the input terminal corresponding to each terminal by the cover being attached to the base.

### Claim 11 (depends on 9)

The power transmission system according to claim 9, wherein
the controller controls the power transmitter such that power feeding for wireless power transfer is prohibited, when it is determined that there is the failure.

### Claim 12 (depends on 8)

The power transmission system according to claim 8, wherein
the controller controls the power transmitter such that power feeding for wireless power transfer is prohibited or lower power than at the time of the wireless power transfer is fed, when it is determined that there is the electrically conductive foreign object.

### Claim 13 (depends on 8)

The power transmission system according to claim 8, wherein
the foreign object detection device includes the first detection coil, the second detection coil, and the selector, and
the power transmitter includes the controller.

### Claim 14 (depends on 8)

The power transmission system according to claim 8, wherein
the foreign object detection device includes the first detection coil, the second detection coil, the selector, and the controller.

### Claim 15

A foreign object detection device for a coil device used for wireless power transfer from a power transmitter, the foreign object detection device comprising:
first and second detection coils configured to be disposed on a casing of the coil device, each of the first and second detection coils including two terminals;
a selector configured to select one of one terminal of the first detection coil and one terminal of the second detection coil as a first terminal and select one of the other terminal of the first detection coil and the other terminal of the second detection coil as a second terminal; and
a controller configured to perform a first foreign object determination process that causes the selector to select the one terminal of the first detection coil as the first terminal and the other terminal of the second detection coil as the second terminal to determine whether there is an electrically conductive foreign object depending on whether connection between the first terminal and the second terminal is in a short circuit state or an open state, and to perform a second foreign object determination process that causes the selector to select the two terminals of the same detection coil from either the first detection coil and the second detection coil as the first terminal and the second terminal to determine whether there is the foreign object depending on a change in an amount of magnetic flux interlinking with the same detection coil.