Resonant energy MEMS array and system including dynamically modifiable power processor

• US 6,954,025 B2
• Filed: 05/13/2003
• Issued: 10/11/2005
• Est. Priority Date: 05/13/2002
• Status: Expired due to Fees

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Ngo, Khai D. T., Nishida, Toshikazu, Sheplak, Mark, Cattafesta, Louis N. III
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): Aguirrechea, J.
• Application Number:
  US10/436,534
• Publication Number:
  US 20040007942A1
• Time in Patent Office: 882 Days
• Field of Search: 310/319, 310329-330, 310/339
• US Class Current: 310/339
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H02N 2/188 adapted for resonant operation
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00

Abstract

An integrated MEMS resonant generator system includes a substrate, a plurality of piezoelectric micro generators disposed on the substrate, the micro generators each generating a voltage output in response to vibrational energy received, and at least one power processor disposed on the substrate. The power processor electrically coupled to outputs of the plurality of micro generators. When the input conditions change, the power processor can dynamically adjust its switching functions to optimize the power delivered to a load or energy storage reservoir.

Claims

1. An integrated MEMS resonant generator-based system, comprising:

a substrate;

a plurality of piezoelectric micro generators disposed on said substrate, said micro generators comprising at least one suspended structure including a piezoelectric layer, said suspended structure attached to an inertial mass, each of said plurality of micro generators generating a voltage output across said piezeolectric layer through deflection of said suspended structure in response to vibrational energy received, and

at least one power processor disposed on said substrate, said power processor electrically coupled to outputs of said plurality of micro generators.

2. The system of claim 1, wherein said plurality of micro generators collectively provide more than one resonant frequency.

3. The system of claim 1, wherein said said power processor has an imput and an output, said imput of said power processor electrically coupled to outputs of said plurality of micro generators, said power processor comprising:

a sensor for measuring at least one electrical parameter provided at said outputs of said plurality of micro generators;

at least one switch electrically connected to outputs of said plurality of micro generators, and

a controller for controlling dynamic switching of said switch based on said electrical parameter, said switching increasing power provided at said output of said power processor.

5. The system of claim 3, wherein said controller dynamically adjusts an input impedance of said power processor, said input impedance dynamically matching output impedances of said plurality of micro generators.

6. The system of claim 5, wherein said system provides a power conversion efficiency of at least 75%.

7. The system of claim 3, wherein said controller dynamically maximizes charge transferred into a load or an energy reservoir.

8. The system of claim 1, wherein said substrate comprises single crystal silicon, said inertial mass utilizing an entire thickness of said substrate.

9. The system of claim 1, wherein said plurality of micro generators are interconnected to form a plurality of sub-arrays comprising groups from said plurality of micro generators.

11. The system of claim 1, wherein a switching frequency of said power processor is from 100 Hz to 1 kHz.

12. The system of claim 1, wherein said power processor provides an inductor, wherein an inductance of said inductor is less than 100 nH.

4. The system of clain 3, wherein said power processor further comprises a rectifier coupled to said outputs of said plurality of micro generators for generating a rectified voltage wherein said sensor comprises a peak detector, said dynamic switching of said power processor being based on said peak detector determining instants when said rectified voltage is at a peak value.

10. The system of clain 9, wherein said power processor includes a plurality of reconfigurable switches, said plurality of reconfigurable switches dynamically alterable groupings of said plurality of micro generators to form reconfigurable ones of said sub-arrays.

13. A method of generating electrical energy from vibrational energy, comprising the steps of:

providing an integrated MEMS resonant generator system comprising a substrate, a plurality of piezoelectric micro generators disposed on said substrate, said micro generators comprising at least one suspended structure including a piezoelectric layer, said suspended structure attached to an inertial mass each of said plurality of micro generators generating a voltage output across said piezeolectric layer through deflection of said suspended structure in response to vibrational energy received, and at least one power processor disposed on said substrate, said power processor electrically coupled to outputs of said plurality of micro generators;

subjecting said system to external vibrational energy, and

providing electrical energy from summing said plurality of voltage outputs.

14. The method of claim 13, wherein said plurality of micro generators collectively provide more than one resonant frequency.

15. The method of claim 13, further comprising the steps of sensing a change in said vibrational energy and dynamically adjusting a switching function of said power processor to maximize power delivered to a load or an energy storage device.

16. The method of claim 13, wherein said substrate is single crystal silicon die.

17. The method of claim 13, further comprising the step of dynamically reconfiguring at least one connection between said plurality of micro generators.

18. The method claim 13, wherein said system includes a power processor, and at least one switch electrically connected to outputs of said plurality of micro generators, further comprising the steps of rectifying said electrical energy summed from said plurality of voltage outputs to generate a rectified voltage, peak detecting said rectified voltage, and dynamically switching said power processor being based on instants when said rectified voltage is at a peak value.

19. The method claim 13, wherein said system includes a power processor and at least one switch electrically connected to outputs of said plurality of micro generators, further comprising the step of dynamically adjusting an input impedance of said power processor, said input impedance dynamically matching output impedances of said plurality of micro generators.