08-02-2010, 10:25 AM
Nonlinear Piezolectric Generators
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presenterd by:
Francesco Cottone
Outline
Introduction: mobile powering issues
Present Vibration Piezoelectric Power Generators
Non-linear piezo-osclillator models
numerical result (Matlab)
finite elements modelling of linear and non-linear oscillators (Comsol)
Conclusions and forthcoming work
Applications examples of WSN
Environmental Monitoring
Habitat Monitoring
Integrated Biology
Structural Monitoring
Interactive and Control
RFID
Medical biosensors
Emergency medial response
Pursuer-Evader
Intrusion Detection
Automation
Interactive museum exhibits
Military applications
Conclusions
Piezoelectric converters appear to be the most attractive for meso-scale devices with a maximum demonstrated power density of approximately 200 mW/cm^3 vs. 100 mW/cm3 for capacitive MEMS devices.
If external excitation is harmonic and itâ„¢s tuned to resonance frequency of the device we can obtain high mechanical energy transfer but it is possible to reach it even with a bi-stability dynamics
For an external excitation with noise or out of resonance, FEA shows that a non-linear bistable beahviour amplify up to a factor 30 or more the vibrational energy extraction
Most of vibrational energy sources live al relative low frequency (for example near hundred Hz) so itâ„¢s hard to tune the resonance mode of the device to external frequencies
