Wireless power transfer apparatus and method thereof

• US 8,299,652 B2
• Filed: 04/06/2010
• Issued: 10/30/2012
• Est. Priority Date: 08/20/2008
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Sample, Alanson P., Smith, Joshua R.
• Primary Examiner(s): Barnie, Rexford
• Assistant Examiner(s): Fauth, Justen
• Application Number:
  US12/754,954
• Publication Number:
  US 20100187913A1
• Time in Patent Office: 938 Days
• Field of Search: None
• US Class Current: 307/104
• 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:

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;

measuring a signal at each transmission frequency at an antenna of the transmitter;

determining whether one or more receiving devices are coupled to the transmitter based on the measured signal including if a number of local minima of the measured signal versus frequency is greater than or equal to 2; 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.

2. The method according to 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.

3. The method according to claim 1, wherein said determining whether the one or more receiving devices are coupled to the transmitter further includes if a minimum of the measured signal versus frequency is below a threshold value.

4. The method according to claim 1, wherein the second power level is higher than the first power level.

5. An apparatus comprising:

a transmitter, including an antenna, wherein the transmitter is configured to transmit power at a multiplicity of frequencies between a first transmission frequency and a second transmission frequency at a first power level; and

a controller configured to measure a signal at each transmission frequency at an antenna of the transmitter and determine whether one or more receiving devices are coupled to the transmitter based on the measured signal by determining if a number of local minima of the measured signal versus frequency is greater than or equal to 2, wherein

the transmitter is further configured to transmit power 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.

6. The apparatus according to claim 5, 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.

7. The apparatus according to claim 5, wherein, to determine whether the one or more receiving devices are 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.

8. The apparatus according to claim 5, wherein the second power level is higher than the first power level.

9. A method comprising:

transmitting 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 from an antenna of a transmitter, wherein the power signal at the second power level is incremented in transmission frequency from a first value to a second value;

measuring a time signal indicative of a transmitter-to-receiver coupling criteria at each frequency point;

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

determining whether the second component meets the transmitter-to-receiver coupling criteria; and

transmitting, from the antenna of the transmitter to a receiver, at the first power level and at one or more frequencies between the first frequency and the second frequency if the receiver is determined to be coupled based on the transmitter-to-receiver coupling criteria.

10. The method according to claim 9, wherein the measured time signal is measured at the antenna of the transmitter or at an antenna of the receiver.

11. The method according to claim 9, wherein the measured time signal indicative of the transmitter-to-receiver coupling criteria 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.

12. The method according to claim 9, wherein the transmitter-to-receiver coupling criteria measured at the transmitter is a minimum value of the ratio of the reflected voltage wave amplitude to the forward voltage wave amplitude, or a minimum value of the ratio of the reflected power to the forward power, or a minimum value of the reflected voltage wave amplitude, or a minimum value of the reflected voltage wave amplitude.

13. The method according to claim 9, wherein the transmitter-to-receiver coupling criteria is measured at the receiver and is a maximum value of received power, or a maximum value of received voltage.

14. A method comprising:

transmitting 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 from an antenna of a transmitter, wherein the power signal at the second power level is incremented in transmission frequency from a first value to a second value;

measuring a time signal indicative of a transmitter-to-receiver coupling criteria at each frequency point;

separating the measured time signal into a first component and a second component including using a demodulation circuit where the measured time signal is separately multiplied by an amplitude-scaled version of the power signal at the first power level at the first frequency and the power signal at the second power level at the second frequency and each resulting signal is subsequently low-pass filtered to result in the first component and the second component;

determining whether the second component meets the transmitter-to-receiver coupling criteria; and

transmitting, from the antenna of the transmitter to a receiver, at the first power level and at one or more frequencies between the first frequency and the second frequency if the receiver is determined to be coupled based on the transmitter-to-receiver coupling criteria.

15. The method according to claim 14, wherein the measured time signal indicative of the transmitter-to-receiver coupling criteria 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.

16. The method according to claim 14, wherein the transmitter-to-receiver coupling criteria measured at the transmitter is a minimum value of the ratio of the reflected voltage wave amplitude to the forward voltage wave amplitude, or a minimum value of the ratio of the reflected power to the forward power, or a minimum value of the reflected voltage wave amplitude, or a minimum value of the reflected voltage wave amplitude.

17. The method according to claim 14, wherein the transmitter-to-receiver coupling criteria is measured at the receiver and is a maximum value of received power, or a maximum value of received voltage.

18. An apparatus comprising:

a transmitter, including an antenna, 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, wherein the power signal at the second power level is incremented in transmission frequency from a first value to a second value; and

a controller configured to measure a time signal indicative of a transmitter-to-receiver coupling criteria at the antenna of the transmitter at each frequency point, separate the measured time signal into a first component and a second component by performing a frequency transform of the measured time signal and isolating a component of the measured time signal corresponding to a frequency band around the second frequency, and determine whether the second component meets the transmitter-to-receiver coupling criteria, wherein

the transmitter is further configured to transmit, from the antenna of the transmitter, at the first power level and at one or more frequencies between the first frequency and the second frequency if the transmitter-to-receiver coupling criteria is met.

19. The apparatus according to claim 18, wherein the transmitter-to-receiver coupling criteria is measured at the receiver and is a maximum value of received power, or a maximum value of received voltage.

20. The apparatus according to claim 18, wherein the measured time signal indicative of the transmitter-to-receiver coupling criteria 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.

21. An apparatus comprising:

a transmitter, including an antenna, 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, wherein the power signal at the second power level is incremented in transmission frequency from a first value to a second value; and

a controller configured to;

measure a time signal indicative of a transmitter-to-receiver coupling criteria at the antenna of the transmitter at each frequency point,

separate the measured time signal into a first component and a second component by using a demodulation circuit where the measured time signal is separately multiplied by an amplitude-scaled version of the power signal at the first power level at the first frequency and the power signal at the second power level at the second frequency and each resulting signal is subsequently low-pass filtered to result in the first component and the second component, and

determine whether the second component meets the transmitter-to-receiver coupling criteria,

wherein the transmitter is further configured to transmit, from the antenna of the transmitter, at the first power level and at one or more frequencies between the first frequency and the second frequency if the transmitter-to-receiver coupling criteria is met.

22. The apparatus according to claim 21, wherein the measured time signal indicative of the transmitter-to-receiver coupling criteria 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.