Wireless power transfer apparatus and method thereof

• US 9,461,478 B2
• Filed: 10/10/2012
• Issued: 10/04/2016
• Est. Priority Date: 08/20/2008
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Smith, Joshua R., Sample, Alanson P.
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): WILLOUGHBY, TERRENCE RONIQUE
• Application Number:
  US13/648,736
• Publication Number:
  US 20130057080A1
• Time in Patent Office: 1,455 Days
• Field of Search: None
• US Class Current: 1/1
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

In accordance with various aspects of the disclosure, a method and apparatus is disclosed that includes features of transmitting power from a transmitter of a wireless power system at a multiplicity of frequencies between a first transmission frequency and a second transmission frequency at a first power level and transmitting power from the transmitter at a second power level and at one or more frequencies between the first transmission frequency and the second transmission frequency if the one or more receiving devices are determined to be coupled to the transmitter.

Claims

1. A method comprising:

measuring a signal associated with a transmitter of a wireless power system at a plurality of transmission frequencies; and

determining whether a receiving device is coupled to the transmitter based on the measured signal, said determining comprising determining if a number of local minima of the measured signal versus frequency is greater than or equal to 2.

2. The method of claim 1, further comprising:

based on a determination that the receiving device is coupled to the transmitter, configuring the transmitter to transmit power at a first power level greater than a second power level and at a frequency within the plurality of transmission frequencies.

3. The method of claim 1, wherein the measured signal is selected from the group consisting of:

a reflected voltage wave amplitude, a ratio of the reflected voltage wave amplitude to a forward voltage wave amplitude, a reflected power, and a ratio of the reflected power to a forward power.

4. The method of claim 1, said determining whether a receiving device is coupled to the transmitter further comprising determining if a minimum of the measured signal versus frequency is below a threshold value.

5. The method of claim 1, said measuring comprising measuring the signal at an antenna of the transmitter.

6. An apparatus comprising:

a controller configured to measure a signal associated with a transmitter of a wireless power system at a plurality of transmission frequencies, and determine if a number of local minima of the measured signal versus frequency is greater than or equal to 2 to determine whether a receiving device is coupled to the transmitter.

7. The apparatus of claim 6, wherein, based on a determination by the controller that the receiving device is coupled to the transmitter, the controller is further configured to actuate the transmitter to transmit power at a first power level greater than a second power level and at a frequency within the plurality of transmission frequencies.

8. The apparatus of claim 6, wherein the measured signal is selected from the group consisting of:

a reflected voltage wave amplitude, a ratio of a reflected voltage wave amplitude to a forward voltage wave amplitude, a reflected power, and a ratio of a reflected power to a forward power.

9. The apparatus of claim 6, wherein, to determine whether the receiving device is coupled to the transmitter, the controller is further configured to determine if a minimum value of the measured signal versus frequency is below a threshold value.

10. The apparatus of claim 6, wherein the controller is further configured to measure the signal at an antenna of the transmitter.

11. A method comprising:

measuring a time signal associated with a transmitter of a wireless power system at a plurality of transmission frequencies, the time signal indicative of a transmitter-to-receiver coupling criterion, wherein the transmitter is configured to transmit a superposition of a power signal at a first power level at a first frequency with a power signal at a second power level at a second frequency;

separating the measured time signal into a first component and a second component, said separating comprising performing a frequency transform of the measured time signal, and isolating the second component of the measured time signal corresponding to a frequency band around the second frequency; and

determining whether the second component meets the transmitter-to-receiver coupling criterion.

12. The method of claim 11, wherein a determination that the second component meets the transmitter-to-receiver coupling criterion indicates that a receiver is coupled to the transmitter, the method further comprising:

based on an indication that that the receiver is coupled to the transmitter, configuring the transmitter to transmit power at the first power level and at a frequency between the first frequency and the second frequency.

13. The method of claim 11, wherein the measured time signal is measured at an antenna of the transmitter or at an antenna of a receiver.

14. The method of claim 13, wherein, if the measured time signal is measured at the antenna of the transmitter, the transmitter-to-receiver coupling criterion is a minimum value of a ratio of a reflected voltage wave amplitude to a forward voltage wave amplitude, or a minimum value of a ratio of a reflected power to a forward power, or a minimum value of a reflected voltage wave amplitude, or a minimum value of a reflected voltage wave amplitude.

15. The method of claim 13, wherein, if the measured time signal is measured at the antenna of the receiver, and the transmitter-to-receiver coupling criterion is a maximum value of received power, or a maximum value of received voltage.

16. The method of claim 11, wherein the measured time signal is selected from the group consisting of:

a reflected voltage wave amplitude, a ratio of a reflected voltage wave amplitude to a forward voltage wave amplitude, a reflected power, and a ratio of a reflected power to a forward power.

17. A method comprising:

measuring a time signal associated with a transmitter of a wireless power system at a plurality of transmission frequencies, the time signal indicative of a transmitter-to-receiver coupling criterion, wherein the transmitter is configured to transmit a superposition of a power signal at a first power level at a first frequency with a power signal at a second power level at a second frequency;

separating the measured time signal into a first component and a second component, said separating comprising;

multiplying, at using a demodulation circuit, the measured time signal with an amplitude-scaled version of the power signal at the first power level at the first frequency to generate a first multiplied signal;

multiplying, at using the demodulation circuit, the measured time signal with and the power signal at the second power level at the second frequency to generate a second multiplied signal; and

performing, a low-pass filter, filtering of the first multiplied signal and the second multiplied signal to generate the first component and the second component; and

determining whether the second component meets the transmitter-to-receiver coupling criterion.

18. The method of claim 17, wherein the measured time signal is selected from the group consisting of:

a reflected voltage wave amplitude, a ratio of a reflected voltage wave amplitude to a forward voltage wave amplitude, a reflected power, and a ratio of a reflected power to a forward power.