DETECTION DEVICE, ENERGY RECEIVER, ENERGY TRANSMITTER, POWER TRANSMISSION SYSTEM, AND DETECTION METHOD

• US 20140159503A1
• Filed: 07/17/2012
• Published: 06/12/2014
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Murakami, Tomomichi, Nakano, Hiroaki, Hashiguchi, Takaaki, Yoshino, Yoshitaka, Komiyama, Shinji, Kozakai, Osamu, Fukuda, Shinichi, Murayama, Yuji, Bunsen, Keigo
• Granted Patent: US 9,612,353 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: G01V 3/06 using ac
• CPC Class Codes: G01V 3/08 operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices with electromagnetic waves G01V3/12
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

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.

Claims

1. An energy receiver comprising:

a power reception coil configured to receive power from a power transmission coil using a first alternating-current signal having a first frequency; and

a Q-value measurement circuit configured to detect 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.

2. The energy receiver of claim 1, wherein the detection section is configured to measure a Q value of the 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 measuring the Q value and as a feeding coil in a contactless power feed, and

a capacitance of a capacitor in a circuit used in the power feed is different from a capacitance of a capacitor in a 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 including the power reception coil during power feed.

6. The energy receiver of claim 1, wherein the Q-value measurement circuit 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 using a first alternating-current signal having a first frequency; and

a Q-value measurement circuit configured to detect a foreign object between the power transmitter and the power receiver using a second alternating-current signal having 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 using a first alternating-current signal having a first frequency; and

a detection section configured to detect a foreign object within a range of the power transmission coil using a second alternating-current signal having a second frequency that is different than the first frequency.

10. A detection device comprising:

a detection section connected to a circuit including a coil, the detection section configured to detect a state of electromagnetic coupling to the coil.

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

12. The detection device of claim 11, further comprising:

a power transmission coil configured for use in a contactless power feed.

13. The detection device of claim 10, wherein the detection section is configured to detect whether a conductor or a circuit including 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 configured to calculate the Q value using 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 when the conductor or the arbitrary coil is not in the proximity to the coil to permit the 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 using a half-bandwidth method of obtaining a Q value using 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 including 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 when the conductor or the arbitrary coil is not in the proximity to the coil to permit the 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 using a half-bandwidth method of obtaining a Q value using 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 including 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 when the conductor or the arbitrary coil is not the proximity to the coil to permit the 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 including the coil using a self-balancing bridge circuit and a vector ratio detector, the processing section configured to calculate the Q value using 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 when the conductor or the arbitrary coil is not in the proximity to the coil to permit the state of the electromagnetic coupling to be determined.

18. The detection device of claim 10, further comprising:

a tap connected to the coil and configured for use in a contactless power feed.

19. The detection device of claim 11, wherein,

the coil is configured for measuring the Q value and as a feeding coil in a contactless power feed, and

a capacitance of a capacitor in a circuit used in a contactless power feed is different from a capacitance of a capacitor in a circuit used in the measurement of the Q value.

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