Demonstration of piezoelectric cantilever arrays for broadband vibration harvesting

Piezoelectric cantilever as a resonant structure can be used both as sensor as well as energy harvester and hence can be integrated as a self-powered system. When excited at a frequency near to its resonant, maximum electrical power is generated, therefore it functions as a micro-power generator. When excited to a frequency which is far from the range of the resonant, the voltage signal generated is comparatively linear at the non-resonant region and proportional to the acceleration level, therefore in this region of frequency it functions as a sensor. This paper demonstrates the application of an array of piezoelectric cantilevers to harvest energy from a broadband vibration source and powering up a op-amp to amplify the signal obtained from a similar but shorter piezoelectric cantilever. The frequency response of the piezoelectric cantilever is characterized by applying different proof masses and altering the cantilever length with the intention to alter the resonant and non-resonant frequency region of the piezoelectric cantilevers into same operating frequency range of 200 Hz to 300 Hz. It is noticed that the self-powered accelerometer works well at an acceleration level above 0.8-g.