Advances on nonlinear MEMS harvesters

Transcription

1 Summer School: Energy Harvesting at micro and nanoscale July 6, 01 Erice (TP), Sicily, Italy Advances on nonlinear MEMS harvesters Salvatore Baglio Dipartimento di Ingegneria Elettrica, Elettronica e Informatica nanotechlab Università degli Studi di Catania salvatore.baglio@dieei.unict.it

2 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

3 Introduction and motivations Several situations can be considered where one would need a source of electrical energy while in the middle of nowhere you may want to make a phone call and your mobile phone battery is dead! milocca.wordpress.com

4 Introduction and motivations Several situations can be considered where one would need a source of electrical energy Out of other many different possibilities often vibrations are present and can represent a powerful source of energy that can be therefore exploited for several uses milocca.wordpress.com

5 Introduction and motivations Several situations can be considered where one would need a source of electrical energy Out of other many different possibilities often vibrations are present and can represent a powerful source of energy that can be therefore exploited for several uses This applies also to modern systems!

6 Introduction and motivations Vibrational source Coupling mechanical structure Mechanical-toelectrical conversion Output energy Accelerations: Magnitude Power Spectrum Linear Nonlinear Piezoelectric Electrostatic Electromagnetic direct use of power store power

7 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

8 Linear versus Bistable approach Linear resonant cantilever Bistable cantilever

9 Linear versus Bistable approach Bistable cantilever mx + dx + Ψ = f t Ψ U x x U x = kx + ax + b 3 + c x = U Ψ = U x = x kx + ax + b 3 + c = 3ax ax + b 5 + kx

10 Linear versus Bistable approach Bistable cantilever BE-SOI technology SOI wafer: 15 μm c-si layer, 450 μm carrier substrate, μm buried oxide; Front and back side DRIE etching technique. Fabrication: Centre Nationale Microeletronica (CNM), Barcelona, Spain

11 Linear versus Bistable approach Bistable cantilever BE-SOI technology

12 @ σ= 50 mn Linear versus Bistable approach Bistable cantilever BE-SOI technology

13 Linear versus Bistable approach Bistable cantilever BE-SOI technology Permanent magnet deposited: - Nd Fe B material - Cylindrical shape - Radius and height of 500µm

14 Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup MEMS device Wheatstone bridge microtranslator shaker

15 Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup Conditioning circuit MEMS device Output strain gauge Permanent magnets stack

16 @ 0.88 g σ=0 μn Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup

17 @ 0.88 g σ=0 μn Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup

18 @ 0.88 g σ=0 μn Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup =1.5 mm =1.6 mm =1.7 mm =1.8 mm =.4 mm =4.5 mm

19 @ 0.88 g σ=0 μn Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup

20 @ 0.88 g σ=0 μn Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup

21 Linear versus Bistable approach Bistable cantilever BE-SOI technology: experimental setup

22 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

23 Magnetic versus Nonmagnetic The basic device structure

24 Magnetic versus Nonmagnetic The basic device structure Unstable equilibrium position nd Stable equilibrium position

25 Magnetic versus Nonmagnetic Analytical modeling m x dx ( x) f t ( x) du ( x) dx Pseudo-Rigid-Body Model U( x) K 1 1 K x K pl 1 arcsin 0 r pl cos arcsin r cos r pl r EI x EI pl 1 K1 K pl 19 3 r rpl 1 0

26 Magnetic versus Nonmagnetic Analytical modeling m x dx ( x) Potential energy function vs Mass displacement f t ( x) du ( x) dx Pseudo-Rigid-Body Model U( x) K 1 1 K x K pl 1 arcsin 0 r pl cos arcsin r cos r pl r EI x EI pl 1 K1 K pl 19 3 r rpl 1 0

27 Magnetic versus Nonmagnetic FEM (Ansys) modeling Force vs Displacement Potential energy vs Displacement Unstable equilibrium position nd Stable equilibrium position

28 Magnetic versus Nonmagnetic FEM (Ansys) modeling The collection of electrical energy will take place in the areas where the largest deformations occour

29 Magnetic versus Nonmagnetic Parameter sensitivity analysis

30 Magnetic versus Nonmagnetic Parameter sensitivity analysis Parameter: Rigid link lenght

31 Magnetic versus Nonmagnetic Parameter sensitivity analysis Parameter: Lateral bridge lenght

32 Magnetic versus Nonmagnetic Parameter sensitivity analysis Parameter: Flexible link lenght

33 Magnetic versus Nonmagnetic Parameter sensitivity analysis Parameter: Base angle 0

34 Magnetic versus Nonmagnetic Dynamic simulations SDE, Itō form. Input: Wiener process(dw t ). State variables: position (x 1 ), velocity (x ). dx dx 1 xdt 1 cx m x 1 dt dw t m 1N s

35 Magnetic versus Nonmagnetic Dynamic simulations SDE, Itō form. Input: Wiener process(dw t ). State variables: position (x 1 ), velocity (x ). dx dx 1 xdt 1 cx m x 1 dt dw t m 8N s

36 Magnetic versus Nonmagnetic Dynamic simulations

37 Magnetic versus Nonmagnetic Device design Metal MUMPS

38 Magnetic versus Nonmagnetic

39 Magnetic versus Nonmagnetic Device design: multiple rigid links

40 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

41 Two working magnets The magnetic bistable cantilever uses TWO magnets One of these DOESN T contribute to the energy harvesting process It is possible to improve the efficiency by making BOTH the magnets contributing to the energy harvesting process Fabrication process will also be facilitated by the adoption of two magnets having the same orientations in magnetization

42 Two working magnets Modeling knl k y x x1 mx 1 dx 1 kx 1 k nl1 x 1 k nl_ acc ( x x 1 ) knl_acc mx dx kx k nl x k nl_ acc ( x x 1 ) x = 0 knl_acc k nl1 x x k nl x k knl k nl_ acc ( x x 1 )

43 Two working magnets Dispacement [m] Simulations

44 Two working magnets Displacement [mm] Displacement [mm] Experimental results 5 a = 5.86 g x Time [s] 4 x Time [s]

45 Two working magnets Amplitude [db] Amplitude [db] Experimental results PSD Frequency [Hz] Frequency [Hz]

46 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

47 Two Dimensional vibrations harvester The idea: from 1-D to -D

48 Two Dimensional vibrations harvester Experimental validation: 45 acceleration

49 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

50 TriStable vibrations harvester Experimental prototype Middle state (C3) Up state (C3) Down state (C3)

51 Outline Introduction and motivations Sources available for Energy harvesting wind, sun, vibrations, Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

52 Magnetically coupled array Four cantilevers with magnetic coupling and different resonant frequency C 1 C C 3 C 4 m 1 m m 3 m 4 m 1 = 0.8 g - f 1 = 3Hz m = 1.6 g - f = 0Hz m 3 =.5 g - f 3 = 17Hz m 4 = 0.88 g - f 4 = 4Hz f 1 f f 3 f 4 m i = m magnet + m additional_load

53 wrapping up Linear versus bistable approach Bistable: Magnetic versus Nonmagnetic approach MEMS technologies: mechanically bistable Magnetic: One working magnet versus two working magnets Magnetic: 1-D versus -D Magnetic: Bi-stable versus Tri-stable Magnetic: magnetically coupled cantilever array versus single bistable

54 Thanks for your attention