Detection apparatus, power receiving apparatus, non-contact power transmission system and detection method

• US 10,352,970 B2
• Filed: 06/29/2018
• Issued: 07/16/2019
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Komiyama, Shinji
• Primary Examiner(s): Patel, Dharti H
• Application Number:
  US16/023,315
• Publication Number:
  US 20180321280A1
• Time in Patent Office: 382 Days
• Field of Search: 307104, 324127
• CPC Class Codes: G01R 15/18 using inductive devices, e.g. transformers
• CPC Class Codes: G01R 21/006 Measuring power factor
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00
• CPC Class Codes: H02J 4/00 Circuit arrangements for mains or distribution networks not specified as ac or dc
• 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
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

Disclosed herein is a detection apparatus including: a resonant circuit provided with a Q-factor measurement coil and one or more capacitors to serve as a circuit for receiving pulses; a response-waveform detecting section configured to detect the waveform of a response output by the resonant circuit in response to the pulses; and a Q-factor measuring section configured to measure a Q factor of the resonant circuit from the response waveform detected by the response-waveform detecting section. It is possible to increase the precision of detection of a metallic foreign substance existing between a power transmitting side and a power receiving side.

Claims

1. An apparatus comprising:

a resonant circuit including a coil and one or more capacitors;

a signal source configured to generate a signal that is input into the resonant circuit;

a Q-factor measuring section configured to (a) measure a first voltage at a first terminal of the coil when the signal-source signal is input into the resonant circuit, and (b) obtain a Q-factor of the coil using the measurement of the first voltage; and

a determination section configured to determine whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value.

2. The apparatus of claim 1, wherein the signal-source comprises:

a pulse generator with circuitry to generate signal pulses; and

a resistor to generate the signal based on the signal pulses.

3. The apparatus of claim 1, further comprising a control section operative to stop transmission of electric power by a power transmitter to a power receiver in response to detection of a foreign object in the close vicinity of the coil.

4. The apparatus of claim 1, wherein the frequency of the signal is equal to a resonance frequency of the resonant circuit.

5. The power transmitting apparatus of claim 4, wherein the frequency of the signal is equal to a resonance frequency of the resonant circuit.

6. The power transmitting apparatus of claim 4 configured to obtain the Q-factor of the coil before power transmission occurs.

7. The power transmitting apparatus of claim 4, configured to determine the existence of a foreign object in the close vicinity of the coil when the Q-factor obtained by the Q-factor measuring section is lower than the predetermined reference value.

8. The apparatus of claim 1, wherein the Q-factor measuring section is configured to measure the first voltage twice, and obtain the Q-factor using the two measurements of the first voltage.

9. The apparatus of claim 8, wherein the Q-factor measuring section is configured to measure the first voltage at a first time and at a second time lagging behind the first time by a predetermined time period.

10. The apparatus of claim 8, wherein the Q-factor measuring section is configured to obtain the Q-factor using Equation 3:

11. The apparatus of claim 8, wherein the Q-factor measuring section is configured to measure the first voltage at a second time when the first voltage is in a predetermined range including the first voltage at a first time.

12. The apparatus of claim 11, wherein the predetermined range set for the first voltage at the second time is a range of 40% to 25% of the first voltage at the first time.

13. The apparatus of claim 8, wherein, the Q-factor measuring section is configured to measure the first voltage again at a second point of time after the lapse of a determined time period as when the first voltage has not entered a predetermined range not including the first voltage at a first point in time within the predetermined time period.

14. The apparatus of claim 13, wherein the predetermined range set for the first voltage at the second point in time is only in a range of 40% to 25% of the first voltage at the first point in time.

15. The apparatus of claim 8, wherein the Q-factor measuring section is configured to obtain the Q-factor using Equation 15:

16. The apparatus of claim 1, wherein the Q-factor measuring section is configured to measure a second voltage at a second terminal of the coil when the signal-source signal is input into the resonant circuit, and obtain the Q-factor using the measurements of the measurements of the first voltage and the second voltage.

17. A power transmitting apparatus comprising:

a resonant circuit including a coil and one or more capacitors;

a signal-source configured to input a signal to the resonant circuit;

a Q-factor measuring section configured to measure a first voltage at a first terminal of the coil and a second voltage at a second terminal of the coil when the signal-source signal is input into the resonant circuit, and to obtain a Q-factor of the coil using the first voltage and the second voltage;

a determination section configured to determine whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value; and

a power transmitting section configured to transmit electric power wirelessly to a power receiving apparatus.

18. The power transmitting apparatus of claim 17, wherein the signal-source comprises:

a pulse generator with circuitry to generate signal pulses; and

a resistor to generate the signal based on the signal pulses.

19. The power transmitting apparatus of claim 17, further comprising a control section operative to stop transmission of electric power by the power transmitter to the power receiver in response to detection of a foreign object in the close vicinity of the coil.

20. A method comprising:

providing a resonant circuit including (a) a coil and one or more capacitors, (b) a signal-source configured to generate a signal that is input into the resonant circuit, (c) a Q-factor measuring section configured to (1) measure a first voltage at a first terminal of the coil when the signal-source signal is input into the resonant circuit, and (2) obtain a Q-factor of the coil using the measurement of the first voltage, and (c) a determination section configured to determine whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value;

inputting the signal-source signal into the resonant circuit;

measuring the first voltage at the first terminal;

obtaining a Q-factor of the coil using the measurement of the first voltage; and

determining whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value.

21. A power transmitting apparatus comprising:

providing a resonant circuit including (a) a coil and one or more capacitors, (b) a signal-source configured to input a signal to the resonant circuit, (c) a Q-factor measuring section configured to measure a first voltage at a first terminal of the coil and measure a second voltage at a second terminal of the coil when the signal-source signal is input into the resonant circuit, and to obtain a Q-factor of the coil using the first voltage and the second voltage, (d) a determination section configured to determine whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value, and (e) a power transmitting section configured to transmit electric power wirelessly to a power receiving apparatus;

inputting the signal-source signal into the resonant circuit;

measuring the first voltage at the first terminal;

measuring the second voltage at the second terminal;

obtaining a Q-factor of the coil using the measurement of the first voltage and the measurement of the second voltage; and

determining whether or not a foreign object exists in close vicinity of the coil by comparing the Q-factor obtained by the Q-factor measuring section with a predetermined reference value.