DETECTING DEVICE, POWER RECEIVING DEVICE, CONTACTLESS POWER TRANSMISSION SYSTEM, AND DETECTING METHOD

• US 20160141920A1
• Filed: 01/20/2016
• Published: 05/19/2016
• Est. Priority Date: 11/30/2011
• Status: Active Grant

• Current Assignee: C/O SONY CORPORATION
• Original Assignee: C/O SONY CORPORATION
• Inventors: Bunsen, Keigo, Nakano, Hiroaki, Murakami, Tomomichi, Fukuda, Shinichi
• Granted Patent: US 10,819,161 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 27/04 in circuits having distributed constants , e.g. having very long conductors or involving high frequencies
• CPC Class Codes: G01V 3/02 operating with propagation of electric current
• 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 50/10 using inductive coupling
• 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 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices

Abstract

Disclosed herein is a detecting device including a coil electromagnetically coupled to the external, a resonant circuit that includes at least the coil, and a detecting section that superimposes a measurement signal for measuring the Q-factor of the resonant circuit on a power transmission signal transmitted to the coil in a contactless manner and removes the power transmission signal from an alternating-current signal obtained by superimposing the measurement signal on the power transmission signal. The detecting section measures the Q-factor by using the alternating-current signal from which the power transmission signal is removed.

Claims

1. A device comprising:

a detection section comprising a circuitry, wherein the circuitry is configured to;

superimpose a measurement signal for measuring a Q-factor of a resonant circuit, that includes at least a coil coupled to an external device, on a power transmission signal transmitted to the coil in a contactless manner; and

remove the power transmission signal from an alternating-current signal, obtained by superimposing the measurement signal on the power transmission signal,

wherein the detection section is configured to measure the Q-factor by using the alternating-current signal from which the power transmission signal is removed.

2. The device according to claim 1, wherein the power transmission signal is an alternating-current signal with a first frequency and the measurement signal is an alternating current signal with a second frequency different from the first frequency.

3. The device according to claim 2, wherein the detection section includes:

a resonant frequency adjuster that is connected to the resonant circuit and is configured to change resonant frequency of the resonant circuit from the first frequency to the second frequency;

a first frequency remover configured not to not allow passage of the alternating-current signal with the first frequency and configured to allow passage of at least the alternating-current signal with the second frequency; and

a Q-factor measuring section configured to calculate the Q-factor by using the alternating-current signal that has passed through the first frequency remover and includes the measurement signal.

4. The device according to claim 3, wherein the Q-factor measuring section is configured to:

acquire a first voltage applied between both ends of the coil configuring the resonant circuit and the resonant frequency adjuster;

acquire a second voltage applied between both ends of the coil from the alternating-current signal that has passed through the first frequency remover; and

calculates the Q-factor from a ratio between the first voltage and the second voltage.

5. The device according to claim 3, wherein the Q-factor measuring section is configured to calculate the Q-factor by using a half width method in which the Q-factor is obtained from a band corresponding to √

2 times an absolute value of impedance of a series resonant circuit including at least the coil at resonant frequency.

6. The device according to claim 3, wherein the Q-factor measuring section is configured to calculate the Q-factor by using a half width method in which the Q-factor is obtained from a band corresponding to 1/√

2 times an absolute value of impedance of a parallel resonant circuit including at least the coil at resonant frequency.

7. The device according to claim 3, further comprising a communication section is configured to transmit the Q-factor measured by the detection section to a power transmission side of the power transmission signal.

8. The device according to claim 3, further comprising

a second frequency remover connected to a side to which a load on an opposite side to at least the coil across the resonant circuit is connected,

wherein the second frequency remover is configured to allow passage of the alternating current signal with the first frequency, and

wherein the second frequency remover is configured not to allow passage of at least the alternating-current signal with the second frequency.

9. The device according to claim 3, wherein the resonant frequency adjuster includes at least one of a capacitor or a coil, and wherein the resonant frequency adjuster is connected between the resonant circuit and the first frequency remover.

10. The device according to claim 3, further comprising a separator configured to be connected to a side to which a load on an opposite side to at least the coil across the resonant circuit is connected, wherein the separator is configured to electrically separate the load from the resonant circuit when the detection section measures the Q-factor.

11. The device according to claim 10, further comprising:

a power storage device configured to be charged with at least power consumed in measurement of the Q-factor in the detection section by using the power transmission signal received by the coil from the external device,

wherein the detection section is configured to measure the Q-factor by using the power stored in the power storage in a period when connection between the resonant circuit and the load is set off.

12. The device according to claim 3, further comprising:

a memory section configured to store a reference value, wherein the reference value is a Q-factor which is determined when no conductor near the coil or a circuit including any coil exists.

13. The device according to claim 12, further comprising:

a determining section configured to compare the Q-factor obtained by the Q-factor measuring section with the stored reference value to determine a state of electromagnetic coupling between the coil and the external device.

14. The device according to claim 13, wherein the state of electromagnetic coupling between the coil and the external device is whether or not a conductor near the coil or the circuit including any coil exists.

15. A detection method comprising:

superimposing a measurement signal for measuring a Q-factor of a resonant circuit, that includes at least a coil coupled to an external device, on a power transmission signal transmitted to the coil in a contactless manner by a detection section included in a detection device;

removing the power transmission signal from an alternating-current signal obtained by superimposing the measurement signal on the power transmission signal; and

measuring the Q-factor by using the alternating-current signal from which the power transmission signal is removed.

16. The detection method according to claim 15, wherein

the power transmission signal is an alternating-current signal with a first frequency and the measurement signal is an alternating-current signal with a second frequency different from the first frequency.

17. The detection method according to claim 15, wherein the Q-factor is measured by using a half width method in which the Q-factor is obtained from a band corresponding to √

2 times an absolute value of impedance of a series resonant circuit including at least the coil at resonant frequency.

18. The detection method according to claim 15, wherein the Q-factor is measured by using a half width method in which the Q-factor is obtained from a band corresponding to 1/√

2 times an absolute value of impedance of a parallel resonant circuit including at least the coil at resonant frequency.

19. The detection method according to claim 15, further comprising comparing the calculated Q-factor with a reference value to determine a state of electromagnetic coupling between the coil and the external device, and wherein the reference value is a Q-factor which is determined when no conductor near the coil or a circuit including any coil exists.