Detection apparatus, power supply system, and method of controlling detection apparatus

Patent metadata

Field	Value
Publication number	US-9892848-B2
Application number	US-201414259358-A
Country	US
Kind code	B2
Filing date	Apr 23, 2014
Priority date	May 16, 2013
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A detection apparatus includes: a measurement coil disposed in a vicinity of a power reception coil configured to receive power supplied through a magnetic field; a measurement section configured to measure a voltage of the measurement coil as a measurement coil voltage; and a foreign object detection section configured to obtain an electrical characteristic value of at least one of the power reception coil and the measurement coil on the basis of the measurement coil voltage, and to detect a foreign object in the magnetic field if the electrical characteristic value is lower than a predetermined lower limit threshold value.

First claim

What is claimed is:

1. A detection apparatus comprising:
a measurement coil disposed in a vicinity of a power reception coil configured to receive power supplied through a magnetic field;
a measurement section configured to measure a measurement coil voltage of the measurement coil; and
a foreign object detection section configured to
obtain an electrical characteristic value of at least one of the power reception coil and the measurement coil on a basis of the measurement coil voltage,
determine whether the electrical characteristic value is lower than a predetermined lower limit threshold value, and
responsive to determining that the electrical characteristic value is lower than the predetermined lower limit threshold value, output a signal that is indicative of a detection of a foreign object to a power reception control circuit of a power reception apparatus,
wherein the power reception control circuit is configured to control a load connection circuit to disconnect a battery based on the signal that is indicative of the detection of the foreign object.

2. The detection apparatus according to claim 1 ,
wherein the foreign object detection section is further configured to
determine whether the electrical characteristic value is higher than an upper limit threshold value greater than the predetermined lower limit threshold value, and
responsive to determining that the electrical characteristic value is higher than the upper limit threshold value, output the signal that is indicative of the detection of the foreign object to the power reception control circuit.

3. The detection apparatus according to claim 2 ,
wherein the upper limit threshold value is higher than a reference value being the electrical characteristic value when there is a lack of the foreign object, and the predetermined lower limit threshold value is a lower value than the reference value.

4. The detection apparatus according to claim 1 ,
wherein the measurement section is configured to further measure a voltage and a current of the power reception coil, and
the foreign object detection section is configured to obtain impedance of the power reception coil from the measurement coil voltage, and the voltage and the current of the power reception coil as the electrical characteristic value.

5. The detection apparatus according to claim 1 ,
wherein the measurement section is configured to further measure a voltage of the power reception coil as a power reception coil voltage, and
the foreign object detection section is configured to obtain a voltage ratio of the measurement coil voltage and the power reception coil voltage as the electrical characteristic value.

6. The detection apparatus according to claim 5 ,
the power reception coil is configured to receive a first power and a second power having a different amount of power with each other in sequence, and
the foreign object detection section is configured to obtain, as the electrical characteristic value, a difference between the voltage ratio obtained when the first power is received, and the voltage ratio obtained when the second power is received.

7. The detection apparatus according to claim 1 ,
wherein the measurement coil is configured to have a smaller coil surface area than that of the power reception coil.

8. The detection apparatus according to claim 7 ,
wherein the measurement coil is disposed inside the power reception coil.

9. The detection apparatus according to claim 1 ,
wherein the measurement coil is disposed on a substantially same plane as that of the power reception coil.

10. The detection apparatus according to claim 1 ,
wherein the measurement coil is disposed at a position where a coil surface of the measurement coil and that of the power reception coil have a substantially same center position.

11. The detection apparatus according to claim 1 ,
wherein the power is power supplied from a power supply apparatus, and
the detection apparatus further comprising a transmission section configured to transmit a control signal requesting a decrease in an amount of the power if the foreign object is detected.

12. A detection apparatus comprising:
a measurement coil disposed in a vicinity of a power supply coil of a power supply apparatus and disposed external to a power reception apparatus including a power reception coil, the power supply coil configured to supply power through a magnetic field to the power reception coil;
a measurement section configured to measure a measurement coil voltage of the measurement coil; and
a foreign object detection section configured to
obtain an electrical characteristic value of at least one of the power supply coil and the measurement coil on a basis of the measurement coil voltage,
determine whether the electrical characteristic value is lower than a predetermined lower limit threshold value, and
responsive to determining that the electrical characteristic value is lower than the predetermined lower limit threshold value, output a signal that is indicative of a detection of a foreign object to a power supply control section of the power supply apparatus.

13. A power supply system comprising:
a power reception apparatus including a power reception coil configured to receive power through a magnetic field; and
a power supply apparatus including
a power supply coil configured to supply the power through the magnetic field,
a power supply control circuit configured to control the power supply coil,
a measurement coil disposed in a vicinity of the power supply coil,
a measurement section configured to measure a measurement coil voltage of the measurement coil, and
a foreign object detection section configured to
obtain an electrical characteristic value of at least one of the power supply coil and the measurement coil on a basis of the measurement coil voltage,
determine whether the electrical characteristic value is lower than a predetermined lower limit threshold value, and
responsive to determining that the electrical characteristic value is lower than the predetermined lower limit threshold value, output a signal that is indicative of a detection of a foreign object to the power supply control circuit.

14. A method of controlling a detection apparatus, the method comprising:
measuring, by a measurement section of a power supply apparatus, a measurement coil voltage of a measurement coil disposed in a vicinity of a power supply coil configured to supply power supplied through a magnetic field;
obtaining, by a foreign object detection section of the power supply apparatus, an electrical characteristic value of at least one of the power supply coil and the measurement coil on a basis of the measurement coil voltage;
determining, by the foreign object detection section, whether the electrical characteristic value is lower than a predetermined lower limit threshold value; and
outputting, by the foreign object detection section, a signal that is indicative of a detection of a foreign object to a power supply control circuit of the power supply apparatus in response to determining that the electrical characteristic value is lower than the predetermined lower limit threshold value.

15. The detection apparatus according to claim 1 ,
wherein the measurement coil and the power reception coil are used in combination with each other.

16. The detection apparatus according to claim 1 ,
wherein the measurement coil comprises a first one or more coils, and wherein the power reception coil comprises a second one or more coils.

17. The detection appar

Assignees

• Sony Corp

Inventors

• Omae Uichiro
• Kiyakawauchi Tamotsu

Classifications

• H02J7/933

  the cycle being controlled or terminated in response to electric parameters · CPC title

• H01F38/14 Primary

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H02J50/12

  of the resonant type · CPC title

• H02J50/60

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

• G01V3/101

  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) · CPC title