Wireless power transmission

Patent metadata

Field	Value
Publication number	US-9729973-B2
Application number	US-201313771684-A
Country	US
Kind code	B2
Filing date	Feb 20, 2013
Priority date	Feb 20, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

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

First claim

The invention claimed is:

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 co

Assignees

• Airbus Operations Ltd

Inventors

• Paget Christophe
• Sainthuile Thomas
• Delebarre Christophe
• Grondel Sébastien

Classifications

• H04R17/00 Primary

  Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) · CPC title

• H02N2/181 Primary

  Circuits; Control arrangements or methods · CPC title

• G01M5/0066

  by exciting or detecting vibration or acceleration (vibration testing of structures G01M7/00) · CPC title