Wireless power transmission

• US 9,729,973 B2
• Filed: 02/20/2013
• Issued: 08/08/2017
• Est. Priority Date: 02/20/2012
• Status: Active Grant

• Current Assignee: Airbus Operations Limited (Airbus SE)
• Original Assignee: Airbus Operations Limited (Airbus SE)
• Inventors: Sainthuile, Thomas, Paget, Christophe, Delebarre, Christophe, Grondel, Sbastien
• Primary Examiner(s): Tran, Thienvu
• Assistant Examiner(s): Sun, Pinping
• Application Number:
  US13/771,684
• Publication Number:
  US 20130236038A1
• Time in Patent Office: 1,630 Days
• Field of Search: 367155
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00

Abstract

A method, apparatus and software are disclosed for wireless power transmission in which the power transmission frequency is optimised.

Claims

1. A method for wireless power transmission between a plurality of piezoelectric power harvesting devices attached to a structure and a wireless transmission device comprising a piezoelectric generator attached to said structure, said piezoelectric generator being arranged to generate vibrations in said structure, said method comprising the steps of:

controlling the piezoelectric generator to generate vibrations in said structure at a first test generation frequency to power the plurality of piezoelectric harvesting devices;

receiving, at the wireless power transmission device, a first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the first plurality of response messages being indicative of a harvested voltage generated by a respective piezoelectric harvesting device in the plurality of piezoelectric power harvesting devices in response to the vibrations in said structure at the first test generation frequency generated by said piezoelectric generator;

controlling the piezoelectric generator to generate vibrations in said structure at a second test generation frequency to power the plurality of piezoelectric harvesting devices, the second test generation frequency being different to the first test generation frequency;

receiving, at the wireless power transmission device, a second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the second plurality of response messages being indicative of a harvested voltage generated by a respective piezoelectric harvesting device in the plurality of piezoelectric power harvesting devices in response to the vibrations in said structure at the second test generation frequency generated by said piezoelectric generator;

selecting a generation frequency from one of said first test generation frequency and said second test generation frequency based on said first plurality of response messages and said second plurality of response messages, and in accordance with a predetermined formula applied to the first plurality of response messages and the second plurality of response messages; and

controlling said piezoelectric generator to generate vibrations in said structure at said generation frequency.

2. The method according to claim 1 in which said vibrations are Lamb waves.

3. The method according to claim 1 in which said vibrations comprise one or more non-dispersive Lamb wave modes.

4. The method according to claim 1 in which said predetermined formula comprises selecting said generation frequency as the first test generation frequency or the second test generation frequency corresponding to a highest harvested voltage produced by any one of said piezoelectric power harvesting devices.

5. The method according to claim 1 in which said predetermined formula comprises selecting said generation frequency as the first test generation frequency or the second test generation frequency depending on whether the first plurality of response messages or the second plurality of response messages indicate a greater proportion of harvested voltages which exceed a predetermined threshold from all of said plurality of piezoelectric power harvesting devices.

6. The method according to claim 1 performed in response to a predetermined set of changes of state associated with said structure.

7. The method according to claim 6 in which said structure is an aircraft and said set of changes of state comprises one or more operational states of said aircraft.

8. The method of claim 7 wherein the one or more operational states of said aircraft include one or more of:

start-up of aircraft systems, landing of the aircraft, refueling of the aircraft, standing by the aircraft for at least a predetermined period and the aircraft reach a cruising altitude.

9. The method of claim 8 wherein the steps of receiving first and second response messages and selection of the generation frequency are performed in response to two or more of the landing, the refueling, the standing and the reaching of the cruising altitude.

10. The method according to claim 1 in which said piezoelectric power harvesting devices are arranged to harvest power from the generation frequency applied to the structure and from ambient vibration in said structure.

11. The method according to claim 1 in which said piezoelectric power harvesting devices each comprise a wireless communications device configured to communicate the response messages.

12. The method according to claim 1 in which the first plurality of response messages and the second plurality of response messages are transmitted in response to a request to each of said power harvesting device from said wireless power transmission device.

13. The method according to claim 1 in which said piezoelectric power harvesting devices each are arranged to power a respective sensor.

14. The method according to claim 13 in which each of said piezoelectric power harvesting devices and the respective sensors use the same piezoelectric element for sensing and power harvesting respectively.

15. The method according to claim 1 in which the in which the first test generation frequency and the second test generation frequency are selected from a range of test frequencies from 1 kHz to 2 MHz.

16. A method for wireless power transmission between a plurality of piezoelectric power harvesting devices attached to a structure and a wireless transmission device comprising a piezoelectric generator attached to said structure, said piezoelectric generator being arranged to generate vibrations in said structure, said method comprising:

receiving, at the wireless power transmission device, a first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the first plurality of response messages being indicative of a harvested voltage generated by a respective piezoelectric harvesting device in the plurality of piezoelectric power harvesting devices in response to a first test generation frequency generated by said piezoelectric generator;

receiving, at the wireless power transmission device, a second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the second plurality of response messages being indicative of a harvested voltage generated by a piezoelectric power harvesting device in the plurality of piezoelectric power harvesting devices in response to a second test generation frequency, different from the first test generation frequency, generated by said piezoelectric generator;

selecting a generation frequency from one of said first test generation frequency and said second test generation frequency based on said first plurality of response messages and said second plurality of response messages, and in accordance with predetermined formula applied to the first plurality of response messages and the second plurality of response messages, wherein said predetermined formula comprises selecting said generation frequency as the first test generation frequency or the second test generation frequency corresponding to a higher cumulative voltage from all of said plurality of piezoelectric power harvesting devices, and

driving said piezoelectric generator to generate vibrations in said structure at said generation frequency.

17. A method for wireless power transmission between a plurality of piezoelectric power harvesting devices attached to a structure and a wireless transmission device comprising a piezoelectric generator attached to said structure, said piezoelectric generator being arranged to generate vibrations in said structure, said method comprising:

receiving, at the wireless power transmission device, first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the first plurality response messages indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices in response to a first test generation frequency generated by said piezoelectric generator;

receiving, at the wireless power transmission device, second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the second plurality of response messages being indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices in response to a second test generation frequency, different from the first test generation frequency, generated by said piezoelectric generator;

selecting a generation frequency from one of said first test generation frequency and said second test generation frequency by applying a predetermined formula to the first plurality of response messages and the second plurality of response messages; and

driving said piezoelectric generator to generate vibrations in said structure at said generation frequency,

wherein said determining of the harvested voltages and said selecting of said generation frequency is repeated at a higher test frequency resolution for a predetermined frequency band comprising said selected generation frequency.

18. An apparatus for wireless power transmission to a plurality of piezoelectric power harvesting devices attached to a structure, the apparatus comprising a piezoelectric generator attachable to said structure, said generator being arranged to generate vibrations in said structure, said apparatus being operable to:

control the piezoelectric generator to generate vibrations in said structure at a first test generation frequency to power the plurality of piezoelectric harvesting devices;

receive a first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the first plurality of response messages being indicative of a harvested voltage transmitted a respective one the plurality of piezoelectric power harvesting devices, in response to the vibrations in said structure at the first test generation frequency applied by said generator to the structure;

control the piezoelectric generator to generate vibrations in said structure at a second test generation frequency to power the plurality of piezoelectric harvesting devices, the second test generation frequency being different to the first test generation frequency;

receive a second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response messages in the second plurality of response message being indicative of a harvested voltage transmitted by a respective one of the plurality of piezoelectric power harvesting devices, in response to the vibrations in said structure at the second test generation frequency generated by said piezoelectric generator;

select a generation frequency from one of said first test generation frequency and said second test generation frequency based on said first plurality of response messages and the second plurality of response messages in accordance with a predetermined formula; and

control said generator to generate vibrations in said structure at said generation frequency.

19. The apparatus according to claim 18 in which said vibrations are Lamb waves.

20. The apparatus according to claim 18 in which said vibrations comprise one or more non-dispersive Lamb wave modes.

21. The apparatus according to claim 18 in which said predetermined formula comprises selecting said generation frequency as whichever of the first test generation frequency and said second test generation frequency produces the highest voltage from any one of said piezoelectric power harvesting devices.

22. The apparatus according to claim 18 in which said predetermined formula comprises selecting said generation frequency as whichever of the test generation frequency and the second test generation frequency produces the greatest proportion of voltages from all of said piezoelectric power harvesting devices which exceeds a predetermined threshold.

23. The apparatus according to claim 18 performed in response to a predetermined set of changes of state associated with said structure.

24. The apparatus according to claim 23 in which said structure is an aircraft and said set of changes of state comprises one or more operational states of said aircraft.

25. The apparatus according to claim 18 in which said power harvesting devices are arranged to harvest power from the selected generation frequency and from ambient vibration in said structure.

26. The apparatus according to claim 18 in which said piezoelectric power harvesting devices each comprise a wireless communications device.

27. The apparatus according to claim 18 in which first plurality of response messages and second plurality of response messages are sent in response to a request to each of said power harvesting devices from said apparatus.

28. The apparatus according to claim 18 in which said plurality of respective piezoelectric power harvesting devices are each arranged to power a respective sensor.

29. The apparatus according to claim 28 in which each of said plurality of piezoelectric power harvesting devices comprises a piezoelectric element, wherein said plurality of respective sensors and said plurality of piezoelectric power harvesting devices use the same respective piezoelectric element for sensing and power harvesting respectively.

30. The apparatus according to claim 18 in which the first test generation frequency and the second test generation frequency are selected from a range of test frequencies from 1 kHz to 2 MHz.

31. An apparatus for wireless power transmission to a plurality of piezoelectric power harvesting devices attached to a structure, the apparatus comprising a piezoelectric generator attachable to said structure, said generator being arranged to generate vibrations in said structure, said apparatus being operable to:

receive a first plurality of response messages each indicative of a harvested voltage generated by a respective one of piezoelectric power harvesting devices, in response to a first test generation frequency applied by said generator to the structure;

receive a second plurality of response messages each indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices, in response to a second test generation frequency, different from the first test generation frequency, apply by the generator to the structure;

select a generation frequency from one of said first test generation frequency and said second test generation frequency based on said first plurality of response messages and said second plurality of response messages in accordance with a predetermined formula, wherein said predetermined formula comprises selecting said generation frequency as whichever of the first test generation frequency and said second test generation frequency produces the highest cumulative voltage from all of said piezoelectric power harvesting devices, and

drive said generator to generate vibrations in said structure at said generation frequency.

32. An apparatus for wireless power transmission to a plurality of piezoelectric power harvesting devices attached to a structure, the apparatus comprising a piezoelectric generator attachable to said structure, said generator being arranged to generate vibrations in said structure, said apparatus being operable to:

receive a first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the first plurality of response messages being indicative of a harvested voltage transmitted by a respective one of the plurality of piezoelectric power harvesting devices, in response to a first test generation frequency applied by said generator to the structure;

receive a second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the second plurality of response messages being indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices, in response to a second test generation frequency, different from the first test generation frequency, apply by the generator to the structure;

select a generation frequency from one of said first test generation frequency and said second test generation frequency based on said first plurality of response messages and said second plurality of response messages, in accordance with a predetermined formula; and

drive said generator to generate vibrations in said structure at said generation frequency,

wherein said determining of the harvested voltage and said selecting said generation frequency is repeated at a higher test frequency resolution for a predetermined frequency band comprising said selected generation frequency.

33. A computer program stored on a non-transitory computer readable medium and loadable into the internal memory of a computer, comprising software code portions arranged, when said program is executed by a computer, cause the computer to perform a method of wireless power transmission comprising:

controlling a piezoelectric generator to generate vibrations in a structure at a first test generation frequency to power a plurality of piezoelectric harvesting devices attached to said structure;

receiving, at the wireless power transmission device, a first plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the first plurality of response messages being indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices in response to the vibrations in said structure at the first test generation vibration frequency applied by the piezoelectric generator to the structure;

controlling the piezoelectric generator to generate vibrations in said structure at a second test generation frequency to power the plurality of piezoelectric harvesting devices, the second test generation frequency being different to the first test generation frequency;

receiving, at the wireless power transmission device, a second plurality of response messages from the plurality of piezoelectric power harvesting devices, each response message in the second plurality of response messages being indicative of a harvested voltage generated by a respective one of the plurality of piezoelectric power harvesting devices in response to the vibrations in said structure at the second test generation frequency applied by the piezoelectric generator to the structure;

selecting a generation frequency from one of the first test generation frequency and the second test generation frequency based on a predetermined formula applied to the first plurality of response messages and the second plurality of response messages; and

subsequent to the selection of the generation frequency, controlling the piezoelectric generator to generate vibrations in said structure in said structure at said generation frequency.

34. A method for wireless power transmission between piezoelectric power harvesting devices attached to a structure and a wireless transmission device comprising a piezoelectric generator attached to said structure, the method comprising:

controlling the piezoelectric generator to generate vibrations in the structure at a first test generation frequency to power the piezoelectric harvesting devices;

receiving, at the wireless power transmission device, a first set of response messages from the piezoelectric power harvesting devices, wherein each of the response messages in the first set is indicative of a harvested voltage generated by a respective one the piezoelectric power harvesting devices in response to the vibrations in the structure at the first test generation frequency generated by the piezoelectric generator;

controlling the piezoelectric generator to generate vibrations in the structure at a second test generation frequency to power the piezoelectric harvesting devices, the second test generation frequency being different to the first test generation frequency;

receiving, at the wireless power transmission device, a second set of response messages from the piezoelectric harvesting devices, wherein each of the response messages in the second set is indicative of a harvested voltage generated by a respective one the piezoelectric power harvesting devices in response to the vibrations in the structure at the second test generation frequency generated by the piezoelectric generator;

selecting a generation frequency from one of the first test generation frequency and the second test generation frequency based on the first and second sets of response messages; and

after the selection, controlling the piezoelectric generator to generate vibrations in the structure at the generation frequency to power the piezoelectric power harvesting devices.

35. The method of claim 34 wherein the pluralities of the harvested voltages on which the selection is based are aggregates of each of the pluralities of the harvested voltages.

36. The method of claim 34 wherein the pluralities of the harvested voltages on which the selection is based are sums of each of the pluralities of the harvested voltages.