NON-LINEAR PIEZOELECTRIC MECHANICAL-TO-ELECTRICAL GENERATOR SYSTEM AND METHOD

• US 20080315722A1
• Filed: 09/03/2008
• Published: 12/25/2008
• Est. Priority Date: 10/20/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Clingman, Dan J., Arbogast, Darin J.
• Granted Patent: US 7,732,994 B2
• Time in Patent Office: Days
• US Class Current: 310/328
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H10N 30/304 Beam type

Abstract

A non-linear power generator system that may include a flexible beam for receiving a mechanical input, the flexible beam being supported in a bowed configuration; an electrically responsive member supported adjacent one end of the flexible beam so as to be under a compressive force exerted by the flexible beam; and the flexible beam being adapted to move towards a flattened shape from the bowed shape in response to the mechanical input, to transmit the mechanical input to the electrically responsive member, to cause a compression of the electrically responsive member that results in an electrical output signal being generated by the electrically responsive member.

Claims

1. A non-linear power generator system comprising:

a flexible beam for receiving a mechanical input, the flexible beam being supported in a bowed shape;

an electrically responsive member supported adjacent one end of the flexible beam so as to be under a compressive force exerted by said flexible beam; and

said flexible beam being adapted to move towards a flattened shape from said bowed shape in response to said mechanical input, to transmit said mechanical input to said electrically responsive member, to cause a compression of said electrically responsive member that results in an electrical output signal being generated by said electrically responsive member.

2. The system of claim 1, wherein said mechanical input comprises an oscillating mechanical input signal.

3. The system of claim 2, wherein said mechanical input is provided by a piston of a Stirling engine.

4. The system of claim 1, further comprising a coupling assembly including a plurality of wheels for interfacing an end of said flexible beam to an end of said electrically responsive member.

5. The system of claim 1, wherein a change in length of said electrically responsive member is approximated by the formula:

Δ

length of electrically responsive member

$\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{length}<br><br><br><br>\mathrm{of}<br><br><br><br>\mathrm{electrically}<br><br><br><br>\mathrm{responsive}<br><br><br><br>\mathrm{member}=\frac{{\mathrm{\pi <br><br>}}^2<br><br>D^2}{4<br><br>L}$

where “

D”

represents the distance separating a line bisecting the free ends of the flexible beam, and a line tangent to the midpoint of the beam; and

where “

L”

represents the length of the unbowed flexible beam.

6. The system of claim 1, wherein said flexible beam provides a varying force amplification factor approximated by the following equation:

$\mathrm{Fm}=\frac{{\mathrm{\pi <br><br>}}^2<br><br>D}{2<br><br>L}$

where Fm is the force magnification factor of said mechanical input signal.

7. The system of claim 1, wherein said electrically responsive member comprises a piezoceramic stack.

8. The system of claim 1, wherein said electrically responsive member comprises a magnetostrictive material.

9. A non-linear, mechanical-to-electrical power generator, comprising:

a flexible beam secured at a first end to a first structure, and at a second end to a coupling assembly, and being held between said non-moveable structure and said coupling assembly in a compressed, non-linear orientation;

an electrically responsive member supported adjacent said flexible beam and to a second structure; and

said flexible beam adapted to receive a mechanical input force at a point along its length that flexes said flexible beam, and concurrently causes said electrically responsive member to be compressed and to generate an electrical output signal.

10. The generator of claim 9, wherein said flexing of said flexible beam comprises moving said flexible beam from a bowed shape to a flattened shape.

11. The generator of claim 10, wherein movement of said flexible beam causes said flexible beam to move from a bowed configuration to a flattened configuration, and wherein said movement into said flattened configuration provides an amplification factor of at least about four over a force associated with said mechanical input force.

12. The generator of claim 9, wherein said mechanical input force is directed along a path generally normal to said flexible beam.

13. The generator of claim 9, further comprising a plurality of wheels for supporting the coupling assembly to enable linear rolling movement of the coupling assembly.

14. The generator of claim 9, wherein a change in length of said electrically responsive member is approximated in relation to said flexible beam by a formula comprising:

Δ

length of electrically responsive member

$\mathrm{\Delta <br><br>}<br><br><br><br>\mathrm{length}<br><br><br><br>\mathrm{of}<br><br><br><br>\mathrm{electrically}<br><br><br><br>\mathrm{responsive}<br><br><br><br>\mathrm{member}=\frac{{\mathrm{\pi <br><br>}}^2<br><br>D^2}{4<br><br>L}$

where “

D”

represents the distance separating a line bisecting the free ends of the flexible beam, and a line tangent to a midpoint of the beam; and

where “

L”

represents the length of flexible beam in an unbowed condition.

15. The generator of claim 9, wherein movement of said flexible beam from said bowed shape to said flattened shape, and then to another bowed shape causes said electrically responsive member to generate two distinct electrical signals.

16. The generator of claim 9, wherein said electrically responsive member comprises a piezoceramic stack.

17. The generator of claim 9, wherein said electrically responsive member is comprised of a magnetostrictive material.

18. A method for generating electrical power from a mechanical input signal, comprising:

using a flexible beam secured under compression to assume a bowed orientation, to receive said mechanical input signal;

using said flexible beam to transmit said mechanical input signal to an electrically responsive member;

supporting said electrically responsive member such that said member experiences a compressive stress from said flexible beam when said flexible beam moves from said bowed orientation to a flattened orientation; and

using said flexible beam to alternatively compress and decompress said electrically responsponsive member, in response to said mechanical signal, to generate electrical output signals from said electrically responsive member.

19. The method of claim 18, wherein using said flexible beam to transmit said mechanical signal comprises using said flexible beam to also amplify said mechanical signal as said mechanical signal is applied by said flexible beam to said electrically responsive member.

20. The method of claim 18, further comprising using a Stirling engine to generate said mechanical signal.