Detection device, energy receiver, energy transmitter, power transmission system, and detection method

Patent metadata

Field	Value
Publication number	US-9612353-B2
Application number	US-201214233043-A
Country	US
Kind code	B2
Filing date	Jul 17, 2012
Priority date	Jul 21, 2011
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A detection device includes a coil configured to be electromagnetically coupled with an outside, and a detection section connected to a circuit including the coil. The detection section is configured to measure a Q value of the circuit using an alternating-current signal at a frequency different from a frequency of an alternating-current signal of contactless power feed.

First claim

What is claimed is:

1. An energy receiver, comprising:
a power reception coil configured to receive power from a power transmission coil by use of a first alternating-current signal which has a first frequency; and
a detection section configured to detect a foreign object within a range of the power reception coil by use of a second alternating-current signal which has a second frequency that is different than the first frequency.

2. The energy receiver of claim 1 , wherein the detection section is configured to measure a Q value of a first circuit and detect a state of electromagnetic coupling to the power reception coil.

3. The energy receiver of claim 2 , wherein,
the power transmission coil is configured for use in a contactless power feed, and
the power transmission coil is different than the power reception coil.

4. The energy receiver of claim 2 , wherein,
the power reception coil is configured for measurement of the Q value and configured as a feeding coil in a contactless power feed, and
a capacitance of a capacitor in a second circuit used in the power feed is different from a capacitance of a capacitor in the first circuit used in the measurement of the Q value.

5. The energy receiver of claim 1 , wherein the detection section is configured to measure a Q value of a circuit which includes the power reception coil during power feed.

6. The energy receiver of claim 1 , wherein the detection section includes a capacitor connected to a Q-value measurement coil to form a resonant circuit, a capacitance value of the capacitor and an inductance value of the Q-value measurement coil being adjustable to a desired resonance.

7. A detection method, comprising:
transmitting power from a power transmission coil to a power reception coil using a first alternating-current signal having a first frequency; and
detecting a foreign object within a range of the power reception coil using a second alternating-current signal having a second frequency that is different than the first frequency.

8. A power transmission system, comprising:
a power transmitter configured to wirelessly couple with a power receiver and transmit power to the power receiver by use of a first alternating-current signal which has a first frequency; and
a Q-value measurement circuit configured to detect a foreign object between the power transmitter and the power receiver by use of a second alternating-current signal which has a second frequency that is different than the first frequency.

9. An energy transmitter, comprising:
a power transmission coil configured to wirelessly transmit power to a power receiver by use of a first alternating-current signal which has a first frequency; and
a detection section configured to detect a foreign object within a range of the power transmission coil by use of a second alternating-current signal which has having a second frequency that is different than the first frequency.

10. A detection device, comprising:
a detection section connected to a first circuit which includes a coil, the detection section configured to detect a foreign object within a range of the coil by use of a first alternating-current signal at a first frequency which is different from a second frequency of a second alternating-current signal of a contactless power feed; and
a tap connected to the coil and configured for use in the contactless power feed.

11. The detection device of claim 10 , wherein the detection section is configured to measure a Q value of the first circuit.

12. The detection device of claim 11 , further comprising:
a power transmission coil configured for use in the contactless power feed.

13. The detection device of claim 10 , wherein the detection section is configured to detect whether a conductor or a circuit which includes an arbitrary coil is within a proximity to the coil.

14. The detection device of claim 11 , wherein the detection section includes (i) a processing section configured to obtain a first voltage applied between the coil and a capacitor in a resonant circuit and a second voltage applied at both ends of the coil, the processing section is configured to calculate the Q value by use of a ratio between the first voltage and the second voltage, and (ii) a determination section configured to compare the Q value calculated by the processing section with a threshold value set based on a Q value measured based on a determination that a conductor or an arbitrary coil is not in the proximity to the coil to permit a state of the electromagnetic coupling to be determined.

15. The detection device of claim 11 , further comprising:
a processing section configured to calculate the Q value by a half-bandwidth process which obtains a Q value by a band in which an impedance is √2 times of an absolute value of an impedance at a resonant frequency of a series resonant circuit which includes the coil and a capacitor; and
a determination section configured to compare the Q value calculated by the processing section with a threshold value set based on a Q value measured based on a determination that a conductor or an arbitrary coil is not in the proximity to the coil to permit a state of the electromagnetic coupling to be determined.

16. The detection device of claim 11 , further comprising:
a processing section configured to calculate the Q value by a half-bandwidth process which obtains a Q value by a band in which an impedance is 1/√2 times of an absolute value of an impedance at a resonant frequency of a parallel resonant circuit which includes the coil and a capacitor; and
a determination section configured to compare the Q value calculated by the processing section with a threshold value set based on a Q value measured based on a determination that a conductor or an arbitrary coil is not in the proximity to the coil to permit a state of the electromagnetic coupling to be determined.

17. The detection device of claim 11 , further comprising:
a processing section configured to obtain a real part and an imaginary part of an impedance of a resonant circuit which includes the coil by use of a self-balancing bridge circuit and a vector ratio detector, the processing section is configured to calculate the Q value by use of a ratio therebetween; and
a determination section configured to compare the Q value calculated by the processing section with a threshold value set based on a Q value measured in advance based on a determination that a conductor or an arbitrary coil is not in the proximity to the coil to permit a state of the electromagnetic coupling to be determined.

18. The detection device of claim 11 , wherein,
the coil is configured for measurement of the Q value and configured as a feeding coil in the contactless power feed, and
a capacitance of a capacitor in a second circuit used in the contactless power feed is different from a capacitance of a capacitor in the first circuit used in the measurement of the Q value.

19. The detection device of claim 10 , wherein the detection section is configured to measure a Q value of a circuit which includes the power reception coil during a power feed.

Assignees

• MURAKAMI Tomomichi
• Nakano Hiroaki
• Hashiguchi Takaaki
• Yoshino Yoshitaka
• Komiyama Shinji
• Kozakai Osamu
• Fukuda Shinichi
• Murayama Yuji
• BUNSEN Keigo
• Sony Corp

Inventors

• MURAKAMI Tomomichi
• Nakano Hiroaki
• Hashiguchi Takaaki
• Yoshino Yoshitaka
• Komiyama Shinji
• Kozakai Osamu
• Fukuda Shinichi
• Murayama Yuji
• BUNSEN Keigo

Classifications

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• G01V3/06 Primary

  using AC · CPC title

• H01F38/14

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

• H02J50/60

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

• G01V3/08

  operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) · CPC title