Energy receiver, detection method, power transmission system, detection device, and energy transmitter

Patent metadata

Field	Value
Publication number	US-9530558-B2
Application number	US-201214126969-A
Country	US
Kind code	B2
Filing date	Jul 2, 2012
Priority date	Jul 5, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

An energy receiver includes: a power receiver coil configured to wirelessly receive power transmitted from a power transmitter; a detection section configured to detect a foreign object; and a power storage section configured to supply power to the detection section during detection of the foreign object.

First claim

What is claimed:

1. An energy receiver comprising:
power receiving circuitry including a receiver coil configured to wirelessly receive power transmitted from a power transmitter;
detection circuitry directly connected to the power receiving circuitry, the detection circuitry comprising a Q factor detection circuit; and
test signal generation circuitry directly connected to the power receiving circuitry;
wherein,
the detection circuitry is configured to determine a plurality of quality factor values for the power receiving circuit using the Q factor detection circuit and the test signal generation circuitry and then compare the determined plurality of quality factor values with a threshold quality factor value to detect presence of a foreign object, wherein when the foreign object is detected power receiving circuitry is configured to stop receiving power transmitted;
a power storage section configured to supply power to the Q factor detection circuit during detection of the foreign object; and

a communications unit in communication with the detection circuitry.

2. The energy receiver of claim 1 , further comprising: a power regulator connected between the power storage section and the detection circuitry.

3. The energy receiver of claim 1 , further comprising a control section that activates the detection section during suspension of wireless power transmission to the power receiver coil using power stored in the power storage section.

4. The energy receiver of claim 3 , wherein the control section includes an arithmetic processing section and a determination section, the arithmetic processing section configured to (i) calculate the determined quality factor values related to the power receiver circuit, and (ii) output the determined quality factor values to the determination section, the determination section configured to compare the determined quality factor values with the threshold quality factor value and determine whether the foreign object is within a range of the power receiver coil.

5. The energy receiver of claim 4 , further comprising:
a memory configured to store the threshold quality factor value,
wherein,
the memory is non-volatile memory in communication with the control section, and
the threshold quality factor value is obtained when the power receiver coil is substantially isolated from the foreign object.

6. The energy receiver of claim 1 , further comprising a switch in communication with the power storage device, the switch positioned to (i) connect the power storage device and the power regulator to provide power for detection of the foreign object during suspension of wireless power transmission, and (ii) disconnect the power storage section and the detection section when the foreign object is not being detected.

7. A detection method comprising:
charging a power storage device using power wirelessly received by a power receiver circuit including a power receiver coil;
communicating with a wireless power transmitter to cause power transmitter to not transmit power, and then provide power stored by the power storage device to a detection circuit directly connected the power receiver; and
detecting whether a foreign object is within a range of the power receiver coil by
generating by a test signal generation circuit directly connected to the power receiver one or more test signals having different frequencies and
determining various quality factor values for the power receiver circuit using Q factor detection circuitry within the detection circuit and the one or more test signals having different frequencies, and then comparing the determined quality factor values to a threshold quality factor value; and
stopping power reception of the power receiver when the foreign object is detected.

8. The detection method of claim 7 , further comprising: activating detection circuitry during suspension of wireless power transmission to the power receiver coil using power stored in the power storage section.

9. The detection method of claim 7 , wherein:
each test signal has a unique frequency; and
Q factor detection of whether the foreign object is within the range of the power receiver coil Q factor depends on which, if any, of the determined quality factor values exceeds the threshold quality factor value.

10. The detection method of claim 9 , wherein the charging of the power section includes receiving power from the power receiver circuit based on power consumed during the determination of the determined quality factor values.

11. The detection method of claim 8 , further comprising:
obtaining the threshold quality factor value when the power receiver coil is isolated from the foreign object;
storing the threshold quality factor value in a non-volatile memory in communication with a control section;
calculating each determined quality factor value using an arithmetic processing section of the control section; and
comparing the determined quality factor values with the threshold quality factor value using a determination section of the control section.

12. The detection method of claim 7 , wherein the powering of the detection section includes (i) connecting the detection section to the power storage section using a switch so that power is provided to the power storage section during suspension of wireless power transmission for detection of the foreign object, and (ii) disconnecting the power storage section and the detection section when not detecting for the foreign object.

13. A power transmission system comprising a power transmitter configured to wirelessly transmit power to a power receiver, wherein:
the power transmitter includes
(i) a power transmission coil to wirelessly transmit power to the power receiver,
(ii) an AC signal power supply connected to the power transmission coil,
(iii) a power transmitter communications section, and
(iv) a power transmitter control section to control the supply of the AC signal to the power transmission coil in response to a signal transmitted from the power receiver and received via the power transmitter communications section, and

the power receiver includes
(i) power receiving circuitry including a receiver coil configured to wirelessly receive power transmitted from a power transmitter,
(ii) detection circuitry comprising Q factor detection circuitry directly connected to the power receiving circuitry,
(iii) test signal generation circuitry directly connected to power receiving circuitry,
(iv) detection circuitry configured to determine a plurality of quality factor values for the power receiving circuitry using the Q factor detection circuitry and the test signal generation circuitry and then compare the determined plurality of quality factor values with a threshold quality factor value to detect presence of a foreign object, wherein when the foreign object is detected the power receiving circuitry is configured to stop receiving power transmitted,
(v) a power storage section configured to supply power to the detection circuitry during detection of the foreign object, and
(vi) a power receiver communications unit in communication with the detection circuitry.

14. The power transmission system of claim 13 , wherein the detection circuitry, the test signal generation circuitry and the power storage section include switches controlled by control circuitry in the detection circuitry.

15. The power transmission system of claim 13 , wherein the power receiver control section is configured to cause the power receiver communications controller to communicate a signal to the power transmitter and to activate the detect

Assignees

• Nakano Hiroaki
• Fukuda Shinichi
• Murayama Yuji
• Fujimaki Kenichi
• MURAKAMI Tomomichi
• Sony Corp

Inventors

• Nakano Hiroaki
• Fukuda Shinichi
• Murayama Yuji
• Fujimaki Kenichi
• MURAKAMI Tomomichi

Classifications

• G01V3/101 Primary

  by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil (measuring impedance or characteristics derived therefrom G01R27/00, e.g. quality factor G01R27/26) · CPC title

• H02J50/12

  of the resonant type · CPC title

• H02J50/60 Primary

  responsive to the presence of foreign objects, e.g. detection of living beings · CPC title

• H01F38/14 Primary

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title