DETECTOR, POWER TRANSMITTER, POWER RECEIVER, POWER FEED SYSTEM, AND DETECTION METHOD

• US 20140001881A1
• Filed: 03/08/2012
• Published: 01/02/2014
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Murakami, Tomomichi, Yoshino, Yoshitaka
• Granted Patent: US 10,003,221 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: G01R 27/2611 Measuring inductance
• CPC Class Codes: G01V 3/10 using induction coils
• 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 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

There are provided a detector and the like that are capable of conveniently detecting conductor or a circuit including a coil. The detector includes a detecting section that determines a Q value or a degree of variation thereof in a circuit including a coil capable of electromagnetic coupling with an external object and that performs detection concerning a state of the electromagnetic coupling with the external object based on a determined result.

Claims

1. A detector comprising

a detecting section determining a Q value or a degree of variation of the Q value in a circuit including a coil capable of electromagnetic coupling with an external object and performing detection concerning a state of the electromagnetic coupling with the external object based on a determined result.

2. The detector according to claim 1, wherein the detecting section detects whether a conductor or another circuit including another coil is present in the vicinity of the coil as the state of the electromagnetic coupling with the external object.

3. The detector according to claim 2, wherein when the presence of the conductor or the another circuit in the vicinity of the coil is detected, the detecting section further detects whether the detected object is one of the conductor and the another circuit.

4. The detector according to claim 3, wherein the detecting section detects whether the detected object is one of the conductor or the another circuit based on a result of determining whether communication with the external object via the coil is possible.

5. The detector according to claim 4, wherein the detecting section decides that the detected object is the another circuit when it is determined that the communication with the external object is possible, and decides that the detected object is the conductor when it is determined that the communication with the external object is not possible.

6. The detector according to claim 4, further comprising a communication control section controlling the communication with the external object, wherein

when the presence of the conductor or the another circuit in the vicinity of the coil is detected, the detecting section instructs the communication control section to output a transmission signal to the detected object and determines whether the communication with the external object is possible depending on the presence or absence of a response to the transmission signal.

7. The detector according to claim 6, wherein the detecting section determines that the communication with the external object is possible when there is a response to the transmission signal, and determines that the communication with the external object is not possible when there is no response to the transmission signal.

8. The detector according to claim 1, wherein the detecting section includes:

an arithmetic processing section calculating the Q value or a degree of variation of the Q value; and

a determination section determining a state of the electromagnetic coupling with the external object by comparing the Q value or a degree of variation of the Q value that is calculated by the arithmetic processing section with a predetermined threshold.

9. The detector according to claim 8, wherein the circuit is a resonant circuit including the coil and a capacitor, and

the arithmetic processing section calculates the Q value in the resonant circuit from a ratio of a first voltage that is a voltage between the coil and the capacitor in the resonant circuit to a second voltage that is a voltage across the coil in the resonant circuit.

10. The detector according to claim 8, wherein the circuit is a resonant circuit including the coil and a capacitor, and

the arithmetic processing section calculates the Q value in the resonant circuit by using a half-value width method in the resonant circuit.

11. The detector according to claim 10, wherein the resonant circuit is a series resonant circuit, and

the arithmetic processing section calculates the Q value in the series resonant circuit using the half-value width method based on a resonant frequency in the series resonant circuit and a bandwidth frequency at which impedance of √

2 times as much as an absolute value for impedance at the resonant frequency is achieved.

12. The detector according to claim 10, wherein the resonant circuit is a parallel resonant circuit, and

the arithmetic processing section calculates the Q value in the parallel resonant circuit using the half-value width method based on a resonant frequency in the parallel resonant circuit and a bandwidth frequency at which impedance of (1/√

2) times as much as an absolute value for impedance at the resonant frequency is achieved.

13. The detector according to claim 8, wherein the circuit is a resonant circuit including the coil and a capacitor, and

the arithmetic processing section determines a real part component and an imaginary part component of impedance in the resonant circuit using an automatic balanced bridge circuit and a vector ratio detector, and calculates the Q value in the resonant circuit from a ratio of the real part component to the imaginary part component.

14. The detector according to claim 8, wherein the threshold corresponds to a Q value in the circuit under a condition that the conductor and the another circuit are not present in the vicinity of the coil.

15. The detector according to claim 1, wherein the detecting section performs detection concerning a state of the electromagnetic coupling with the external object by the combined use of the Q value in the circuit and one of an L value in the circuit and a value of a coupling factor k in the event of the electromagnetic coupling.

16. A power transmitter, comprising:

a power transmitting coil capable of electromagnetic coupling with an external object;

a power transmitting section performing power transmission using the power transmitting coil; and

a detecting section determining a Q value or a degree of variation of the Q value in a circuit including the power transmitting coil and performing detection concerning a state of the electromagnetic coupling with the external object based on a determined result.

17. A power receiver, comprising:

a power receiving coil capable of electromagnetic coupling with an external object;

a power receiving section performing power reception using the power receiving coil; and

a detecting section determining a Q value or a degree of variation of the Q value in a circuit including the power receiving coil and performing detection concerning a state of the electromagnetic coupling with the external object based on a determined result.

18. A power feed system, comprising:

one or a plurality of power receivers; and

one or a plurality of power transmitters performing power transmission utilizing the electromagnetic coupling for the power receivers, wherein

the power transmitter has a power transmitting coil capable of electromagnetic coupling with an external object, and a power transmitting section performing power transmission using the power transmitting coil,

the power receiver has a power receiving coil capable of electromagnetic coupling with an external object, and a power receiving section performing power reception using the power receiving coil, and

a detecting section determining a Q value or a degree of variation of the Q value in a circuit including one of the power transmitting coil and the power receiving coil and performing detection concerning a state of the electromagnetic coupling with the external object based on a determined result is provided one or both of the power transmitter and the power receiver.

19. The power feed system according to claim 18, wherein the detecting section is provided in the power receiver.

20. A detection method, comprising:

a first step of determining a Q value or a degree of variation of the Q value in a circuit including a coil capable of electromagnetic coupling with an external object; and

a second step of performing detection concerning a state of the electromagnetic coupling with the external object based on a result determined in the first step.