Energy - Bayern Innovativ

Micro Energy Harvesting Power Supply for Distributed and Embedded Systems

Philipp Bingger and Peter Woias Albert-Ludwig-University of Freiburg Department of Microsystems Engineering (IMTEK) Laboratory for Design of Microsystems Freiburg, Germany

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 1

Wire or battery … or what ?

rope

distributed and „embedded“ sensor systems in greenhouses © Crossbow

sensor

tire pressure sensors

medical implants © Vitatron

battery service person (vertigo-proof) Sensors in redwood trees © University of California Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 2

Micro Energy Harvesting: The Vision wireless data link

Energy-Autonomous Embedded Systems „always on“ no battery recharging or exchange no power cords

sensor input

easy to install … … at numerous application sites wireless microcontroller energy and transmitter

microsensor

system management energy management

heat, light movement, other bugs,…

energy conversion generator

materials and energy storage

energy storage

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 3

Micro energy harvesting – IMTEK‘s PhD program Fact sheet

Research topics

financed by DFG and industry 3 associated members 22+1 PhD scholarhips

energy transduction mechanisms materials for energy harvesting energy storage and management system considerations

start: October 2006 run-time: 4.5 years (1st phase) Associated Members

Members

Sponsors

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 4

Piezoelectric bending generators: Principle

q = d 31 ⋅ σ piezo,11

dq d (d 31 ⋅ σ 11 ) I = = dt dt

Design challenges homogeneous mechanical stress ¨ higher output power tunable resonance frequency

¨ broader application range, more power

smart system integration

¨ cheaper, easier fabrication

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 5

Optimized vibrational piezo generator (2007)

E. Just et al., Proc. GMM-Workshop “Energieautarke Mikrosysteme”, 2006 F. Goldschmidtböing, P. Woias, Journ. Micromech. Microeng. 18, 2008, 104013 spectral output power (no seismic mass)

influence of a seismic mass

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 6

Frequency-tunable piezo generator (2008)

Principle

force

Actuation force in the „arms“ will stiffen the resonating beam and thus change its resonance frequency ¨ high tuning range (22%) ¨ loss of Q factor with increasing force C. Eichhorn et al., Proc. PowerMEMS 2008, Sendai, Japan, 309-312. Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 7

Fabrication: Piezo-Polymer-Composites (2003) feed

vent molding form

electrical contact

piezo disk

piezoceramic disk with metal electrodes

molding form mounting block

liquid thermosetting polymer

20 mm

polymer layer seismic mass vibration

Advantages structure definition and piezo integration in one single step

piezo disk

cured polymer

low-cost perspective via inject molding extremely high design flexibility actuators and generators in one single technology Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 8

Impact-type piezo generator (2005)

M. Wischke et al., Proc. Transducers 2007, Lyon, France, 875-878.

6 mWp @ 36N pulse (100 ms)

Advantages stress-homogenized hinge design for a maximal output power high output power high output voltage stacked devices for power multiplication

Philipp Bingger, Peter Woias, Effiziente Elekronik, 1.12.2009

Sheet 9

Electromagnetic generators: Principle and examples

rotor generator

U = −N⋅

dΦ dt

P = 800 µW multi-resonant generator Univ. Hongkong, 2002 electromechanic quartz clockwork

battery

Properties AC currents from motion or induced AC fields bad to fair voltage range (mV…V) moderate source impedance (