Multi-frequency piezoelectric energy harvester

• US 20040075363A1
• Filed: 10/21/2002
• Published: 04/22/2004
• Est. Priority Date: 10/21/2002
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Malkin, Matthew C., Davis, Christopher L.
• Granted Patent: US 6,858,970 B2
• Time in Patent Office: Days
• US Class Current: 310/321
• CPC Class Codes: H10N 30/306 Cantilevers

Abstract

An energy harvesting device is provided. The energy harvesting device includes structural members covered with piezoelectric material resonating at different primary frequencies. As the structure to which the energy harvesting device is secured vibrates over a range of frequencies, more than one member resonates or is close to resonance. As such, multiple members work simultaneously to create electrical energy.

Claims

1. An energy harvesting device comprising:

a structure having a plurality of discrete resonant frequencies; and

a piezoelectric member disposed in vibration receiving relation to said structure.

2. The device of claim 1 further comprising:

a circuit electrically communicating with said piezoelectric member.

3. The device of claim 1 wherein said structure further comprises a plurality of elongated members, said elongated members varying in resonant frequencies.

4. The device of claim 3 wherein each of said elongated members has a different resonant frequency.

5. The device of claim 3 wherein said elongated members vary in at least one of length, mass, and mass distribution.

6. The device of claim 3 wherein said elongated members further comprise aluminum.

7. The device of claim 6 wherein said aluminum elongated members are coated with a non-conductive material.

8. The device of claim 1 wherein said device is substantially planar.

9. The device of claim 1 wherein said structure further comprises:

an essentially annular housing; and

a plurality of inwardly projecting beams.

10. The device of claim 1 wherein said structure further comprises:

a central hub; and

a plurality of radially projecting beams.

11. An energy harvesting device comprising:

a base;

a plurality of cantilevered beams extending from said base, said plurality of beams varying in resonant frequencies; and

a piezoelectric member coupled to said plurality of beams in a vibration receiving relationship.

12. The device of claim 11 wherein said plurality of beams vary in at least one of length, mass, and mass distribution.

13. The device of claim 11 further comprising:

a circuit electrically coupled to said piezoelectric member.

14. The device of claim 11 wherein said piezoelectric member further comprises a plurality of piezoelectric members separately coupled to said plurality of beams.

15. The device of claim 14 wherein a pair of said plurality of piezoelectric members are coupled to each beam.

16. A device comprising:

a base;

a plurality of cantilevered beams extending from said base, said plurality of beams having different lengths yielding different resonant frequencies;

a piezoelectric member coupled to each beam; and

a circuit electrically connected to each piezoelectric member.

17. The device of claim 16 wherein said device is substantially planar.

18. The device of claim 16 wherein said base further comprises a substantially annular member.

19. The device of claim 16 further comprising electrodes coupled to each piezoelectric member and said circuit.

20. The device of claim 16 further comprising a second piezoelectric member coupled to each beam.