Power from motion - alternative energyfor microelectronicsPit PillatschResearch PostgraduateImperial College LondonSupervi...
ContentsIntroductionPiezoelectric Impulse Excited GeneratorExperimental Set-UpResultsComparisonsKey advantages            ...
Energy Harvesting        Solar: very high achievable power outputs (1500 μW/cm2), however        only outdoors        Ther...
Inertial Devices                   4
Rotational Devices                     Operation under any orientation,                     independent of gravity        ...
Piezoelectric Impulse Excited Generator                             Plucking of a piezoelectric beam                      ...
Experimental Setup                     7
Comparisons                        Seiko Kinetic watch: (-) many moving parts,                        (-) prone to wear, (...
Comparisons                            Pozzi 2011: piezoelectric, (+) large bandwidth,                            (-) only...
Key Advantages  Taking the best from all the other devices and getting rid of limitationsNo mechanical impact/contact on p...
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Energy Harvester Oct 12

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Energy Harvester Oct 12

  1. 1. Power from motion - alternative energyfor microelectronicsPit PillatschResearch PostgraduateImperial College LondonSupervisors: Prof. E.M. Yeatman, Prof. A.S. Holmes 1
  2. 2. ContentsIntroductionPiezoelectric Impulse Excited GeneratorExperimental Set-UpResultsComparisonsKey advantages 2
  3. 3. Energy Harvesting Solar: very high achievable power outputs (1500 μW/cm2), however only outdoors Thermal: limited by the Carnot efficiency, which is dependent on the temperature difference, commercially available for industrial applications Radio Frequency: in use for wireless power transfer with a dedicated source, tissue attenuation can be high Inertial Energy: available as vibrations, fluid flows, etc., highly dependent on external excitation, commercially available for industrial applicationsWith an increased number of wearable and implantable body sensors, power supply needs to be addressed 3
  4. 4. Inertial Devices 4
  5. 5. Rotational Devices Operation under any orientation, independent of gravity Rotational and linear external acceleration due to eccentric mass No inherent displacement limit for the proof mass travel, i.e. continuous rotation Power limit in a purely rotational case: 5
  6. 6. Piezoelectric Impulse Excited Generator Plucking of a piezoelectric beam Beam vibration at natural frequency enhances electro-mechanical coupling over large frequency range No gears necessary No mechanical contact due to magnetic coupling, good for long lifetime Small number of parts, reduced cost Convenient for miniaturization Suitable for wearable and implantable applications 6
  7. 7. Experimental Setup 7
  8. 8. Comparisons Seiko Kinetic watch: (-) many moving parts, (-) prone to wear, (-) electromagnetic means lower voltagesMitcheson 2004: electrostatic, (-) voltages are very high , (-) operation only at resonance frequency and in one linear direction Pillatsch 2011: piezoelectric, (+) large frequency range but only one linear direction, (-) gravity can cause difficulties depending on orientation 8
  9. 9. Comparisons Pozzi 2011: piezoelectric, (+) large bandwidth, (-) only one rotational direction, (-) needs two attachment points, (-) direct impact on piezo when plucking can damage the brittle material Gu 2011: (-) only one linear direction, (-) direct impact on piezo can damage the brittle material Galchev 2010: (-) only one linear direction 9
  10. 10. Key Advantages Taking the best from all the other devices and getting rid of limitationsNo mechanical impact/contact on piezo when pluckingPiezo allows very useful voltagesLarge frequency rangeOnly one moving partOnly one attachment pointOperation under linear and rotational motionIndependent of orientation and gravityCurrent status:Maximal power output of 2.6 μW at 1.45 VrmsBest effectiveness of conversion currently around 5.8%Future work on optimal parameters for magnetic beam plucking 10

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