DETECTION APPARATUS, ELECTRIC POWER RECEIVING APPARATUS, ELECTRIC POWER TRANSMISSION APPARATUS, WIRELESS ELECTRIC POWER TRANSMISSION SYSTEM, AND DETECTION METHOD

• US 20130027078A1
• Filed: 07/18/2012
• Published: 01/31/2013
• Est. Priority Date: 07/25/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nakano, Hiroaki, Hashiguchi, Takaaki, Fukuda, Shinichi, Fujimaki, Kenichi
• Granted Patent: US 9,467,205 B2
• Time in Patent Office: Days
• US Class Current: 324/764.01
• 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 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A method for wireless power transmission includes obtaining, via a Q-value circuit, first and second voltages at respective first and second nodes of a resonance circuit. The first and second voltages are effective to determine if foreign matter is present in a space affecting wireless power transmission. The method includes controlling a switching section between the Q-value circuit and the resonance circuit such that at least a part of the electric power transmission process occurs at a different time than when the first and second voltages are obtained.

Claims

1. An energy receiver to receive energy in a wireless manner from an energy transmitter, said energy receiver comprising:

a resonance circuit including at least an inductor, a first capacitor, and a second capacitor; and

a Q-value circuit connected to the resonance circuit, the Q-value circuit being configured to obtain a first voltage taken at a first node of the resonance circuit and a second voltage taken at a second node of the resonance circuit,

wherein,

the first and second capacitors are connected in series between the first and second nodes.

2. The energy receiver of claim 1, wherein the Q-value circuit includes:

a computing section to compute a Q-value based on the first and second voltages, the Q-value being a ratio of the first voltage relative to the second voltage; and

a control section to compare the Q-value with a threshold value to determine if foreign matter is in a space affecting the wireless reception of energy.

3. The energy receiver of claim 1, further comprising:

a switching section having a plurality switches to selectively connect the resonance circuit to the Q-value circuit,

wherein,

the Q-value circuit includes a control section that is configured to control the switching section such that electric power is received by the energy receiver at a different time than when the first and second voltages are obtained, and

the Q-value circuit is configured to detect an electromagnetically coupled state of at least the inductor.

4. The energy receiver of claim 3, wherein:

the switching section is operable to switch to a state in which an electrostatic capacitance value of the resonance circuit is decreased.

5. The energy receiver of claim 3, wherein:

the energy receiver is configured to switch from a first resonance frequency to a second resonance frequency, and increase impedance of the resonance circuit.

6. The energy receiver of claim 3, wherein:

the inductor is a tapped coil, and

the switching section is configured to select a tap of the tapped coil.

7. The energy receiver of claim 3, further comprising:

third and fourth capacitors,

wherein,

the third capacitor is coupled to the inductor,

the fourth capacitor is coupled between first ends of each of the inductor and the third capacitor and a ground potential.

8. A method to detect foreign matter in a space affecting wireless transmission of electric power from a transmitter to a receiver, said method comprising:

receiving electric energy from a resonance circuit that includes at least an inductor, a first capacitor, and a second capacitor; and

obtaining a first voltage taken at a first node of the resonance circuit and a second voltage taken at a second node of the resonance circuit,

wherein,

the first and second capacitors are connected in series between the first and second nodes.

9. An energy transmitter to transmit energy in a wireless manner to an energy receiver, said energy transmitter comprising:

a resonance circuit including at least an inductor, a first capacitor, and a second capacitor; and

a Q-value circuit connected to the resonance circuit, the Q-value circuit being configured to determine a relationship of a first voltage taken at a first node relative to a second voltage taken at a second node,

wherein,

the first and second capacitors are connected in series between the first and second nodes.

10. A detection apparatus comprising:

a resonance circuit including at least a coil and a capacitor;

a detection unit configured to measure a Q value of the resonance circuit;

a circuit switching unit configured to switch a circuit configuration of the resonance circuit between electric power supply time and Q value measurement time; and

a control unit configured to control switching by the circuit switching unit.

11. The detection apparatus according to claim 10, wherein the detection unit measures the Q value of the resonance circuit and detects an electromagnetically coupled state of the coil and the outside.

12. The detection apparatus according to claim 11, wherein the circuit switching unit switches the circuit configuration of the resonance circuit between electric power supply time and Q value measurement time, and changes a resonance frequency of the resonance circuit.

13. The detection apparatus according to claim 11, wherein the circuit switching unit switches the circuit configuration of the resonance circuit between electric power supply time and Q value measurement time, changes the resonance frequency of the resonance circuit, and increases impedance at the resonance frequency of the resonance circuit.

14. The detection apparatus according to claim 11, wherein the circuit switching unit switches the circuit configuration of the resonance circuit between electric power supply time and Q value measurement time, and increases impedance at the resonance frequency of the resonance circuit.

15. The detection apparatus according to claim 12, wherein the circuit switching unit changes an electrostatic capacitance value of electrostatic capacitance components of the resonance circuit at the time of Q value measurement.

16. The detection apparatus according to claim 15, wherein the circuit switching unit changes the electrostatic capacitance value of the electrostatic capacitance components in parallel with the coil of the resonance circuit at the time of Q value measurement.

17. The detection apparatus according to claim 15, wherein the circuit switching unit changes the electrostatic capacitance value of the electrostatic capacitance components in series with the coil of the resonance circuit at the time of Q value measurement.

18. The detection apparatus according to claim 15, wherein the resonance circuit is configured in such a manner that the capacitor is connected in series with the coil.

19. The detection apparatus according to claim 15, wherein the resonance circuit is configured in such a manner that the capacitor is connected in parallel with the coil.