Multistage force amplification of piezoelectric stacks

• US 9,048,759 B2
• Filed: 11/10/2011
• Issued: 06/02/2015
• Est. Priority Date: 11/17/2010
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Xu, Tian-Bing, Siochi, Emilie J., Zuo, Lei, Jiang, Xiaoning, Kang, Jin Ho
• Primary Examiner(s): Rosenau, Derek
• Assistant Examiner(s): GORDON, BRYAN P
• Application Number:
  US13/293,846
• Publication Number:
  US 20120119620A1
• Time in Patent Office: 1,300 Days
• Field of Search: 310/328, 310/339
• US Class Current: 1/1
• CPC Class Codes: H02N 2/043 Mechanical transmission means, e.g. for stroke amplification
• CPC Class Codes: H02N 2/186 Vibration harvesters

Abstract

Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

Claims

1. An apparatus for harvesting mechanical vibration/motion energy from a piezoelectric device, the apparatus comprising:

an outer flextensional casing;

a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing, each cell having a flextensional cell structure and wherein each cell receives an input force from the outer flextensional casing and provides an output force that is amplified based on the input force; and

a piezoelectric stack coupled to each flextensional cell structure of each cell wherein the piezoelectric stack is comprised of multiple piezoelectric layers each connected serially to an electrode and wherein the piezoelectric stack of each flextensional cell structure provides the energy as electrical charges to the electrodes based on the output force received from each cell,

wherein the last cell receives an input force that is the output force from the first cell and the last cell provides a first output apparatus force that is the product of the input apparatus force, the output force of the first cell, and the output force of the last cell,

wherein the flextensional casing is arranged orthogonally with respect to the first cell and the last cell.

2. The apparatus of claim 1, wherein the energy harvested is based on the first output apparatus force.

3. The apparatus of claim 1, wherein the apparatus provides deformation based on the first output apparatus force.

4. The apparatus of claim 1, wherein each flextensional cell structure receives the input force along a first axis and provides the output force along a second axis that is amplified compared to the first input force.

5. The apparatus of claim 1, wherein the multiple piezoelectric layers of each piezoelectric stack are connected in parallel.

6. The apparatus of claim 1, wherein a voltage is applied to each piezoelectric stack.

7. The apparatus of claim 1, wherein an overall stiffness of the apparatus is reduced to increase amplification of each input force for each cell.

8. The apparatus of claim 1, the apparatus further comprising:

one or more intermediate cells serially coupled to each other, each intermediate cell having a flextensional cell structure and each intermediate cell receives an input force and provides an output force that is amplified based on the input force wherein the one or more intermediate cells integrated into the apparatus such that the one or more intermediate cells are serially coupled between the first cell and the last cell,

wherein the output force of the first cell is the input force of a first intermediate cell and the output force of a last intermediate cell is the input force of the last cell, and

wherein a second output apparatus force that is the product of the input force, of the first cell, the output force of the first cell, the output force of each intermediate cell, and the output force of the last cell.

9. The apparatus of claim 8, wherein the piezoelectric energy harvested in each piezoelectric stack is based on the second output apparatus force, a stiffness of that piezoelectric stack, a mechanical to electrical energy conversion efficiency of that piezoelectric stack, a frequency of the input force, and an interaction time.

10. The apparatus of claim 8, wherein the apparatus provides displacement based on the second output apparatus force and a stiffness of that piezoelectric stacks.

11. The apparatus of claim 1, wherein the piezoelectric are relaxor piezoelectric single crystal multilayer stacks.

12. A method for harvesting mechanical vibration/motion from a piezoelectric device, the method comprising:

providing an outer flextensional casing and a first cell and a last cell of a transducer coupled to the outer flextensional casing, each cell having a flextensional cell structure that includes a piezoelectric stack coupled to each flextensional cell structure of each cell, wherein the piezoelectric stack comprises multiple piezoelectric layers each connected to an electrode and the flextensional casing is arranged orthogonally with respect to the first cell and the last cell;

receiving an input force from the outer flextensional casing at the first cell;

amplifying the input force at the first cell to provide an output force for the first cell;

receiving the output force of the first cell as the input force of the last cell;

amplifying the input force at the last cell to provide an output force for the last cell; and

harvesting the energy as electrical charges at the electrodes,

wherein a first transducer output force is product of the input force of the first cell, the output force of the first cell, and the output force of the last cell and the energy is harvested based on the first transducer output force.

13. The method of claim 12, wherein the multiple piezoelectric layers of each piezoelectric stack are connected in parallel.

14. The method of claim 12, further comprising providing deformation based on the first output transducer force and an overall stiffness of the piezoelectric device.

15. The method of claim 12, the method further comprising:

receiving the input force along a first axis at each flextensional cell structure; and

providing the output force along a second axis that is amplified compared to the first input force.

16. The method of claim 15, wherein the multiple piezoelectric layers are layers of PMN-PT or PZN-PT single crystal materials.

17. The method of claim 12, the method further comprising reducing the stiffness of the transducer thereby increasing the amplification of the each input force for each cell.

18. The method of claim 12, the method further comprising applying a voltage to each piezoelectric stack.

19. The method of claim 12, the method further comprising:

providing one or more intermediate cells serially coupled to each other, each intermediate cell having a flextensional cell structure and each intermediate cell receives an input force and provides an output force that is amplified based on the input force wherein the one or more intermediate cells are integrated into the transducer such that the one or more intermediate cells are serially coupled between the first cell and the last cell; and

providing the output force of the first cell as the input force of a first intermediate cell, providing the output force of a last intermediate cell as the input force of the last cell and providing a second output transducer force that is the product of the input force, of the first cell, the output force of the first cell, the output force of each intermediate cell, and the output force of the last cell.

20. The method of claim 19, the method further comprising harvesting the piezoelectric energy based on the second output transducer force, a stiffness of each piezoelectric stack, a mechanical to electrical energy conversion efficiency of each piezoelectric stack, a frequency of the input force, and an interaction time.

21. The method of claim 19, the method further comprising providing deformation based on the second output transducer force and a stiffness of that piezoelectric stacks.

22. The method of claim 12, wherein the piezoelectric stack is a relaxor piezoelectric single crystal multilayer stack.

23. The method of claim 12, wherein the method is conducted at or near cryogenic temperature conditions.

24. An apparatus for harvesting mechanical vibration/motion energy through a piezoelectric device, the apparatus comprising:

an outer flextensional casing;

a first cell and a last cell serially coupled to each other and the outer flextensional casing, each cell having a flextensional cell structure and wherein each cell receives an input force from the outer flextensional casing and provides an output force that is amplified based on the input force; and

a relaxor piezoelectric single crystal-based multilayer stack (piezoelectric stack) coupled to each flextensional cell structure of each cell wherein the piezoelectric stack is comprised of multiple piezoelectric layers each connected to an electrode and wherein the piezoelectric stack of each flextensional cell structure provides the piezoelectric energy as electrical charges to the electrodes based on the output force received from each cell,

wherein the last cell receives an input force that is the output force from the first cell and the last cell provides a first output apparatus force that is the product of the input apparatus force, the output force of the first cell, and the output force of the last cell,

wherein the piezoelectric energy harvested is based on the first output apparatus force, and

wherein the flextensional casing is arranged orthogonally with respect to the first cell and the last cell.

25. The apparatus of claim 24, wherein each flextensional cell structure receives the input force along a first axis and provides the output force along a second axis that is amplified compared to the first input force.

26. The apparatus of claim 25, wherein the multiple piezoelectric layers of each piezoelectric stack are connected in parallel.

27. The apparatus of claim 24, the apparatus further comprising:

one or more intermediate cells serially coupled to each other, each intermediate cell having a flextensional cell structure and each intermediate cell receives an input force and provides an output force that is amplified based on the input force wherein the one or more intermediate cells integrated into the apparatus such that the one or more intermediate cells are serially coupled between the first cells and the last cells,

wherein the output force of the first cell is the input force of a first intermediate cell and the output force of a last intermediate cell is the input force of the last cell, and

wherein a second output apparatus force that is the product of the input force, of the first cell, the output force of the first cell, the output force of each intermediate cell, and the output force of the last cell and the piezoelectric energy harvested is based on the second output apparatus force, a stiffness of that piezoelectric stack, a mechanical to electrical energy conversion efficiency of that piezoelectric stack, a frequency of the input force, and an interaction time.