Design and simulation of piezoelectric micro power harvester for capturing acoustic vibrations

Piezoelectric Micro-Power Harvester (PMPH), harvests mechanical vibration sources available in the environment and converts it to usable electric power via piezoelectric effects. The low power requirements and small device dimensions enable PMPH to supply enough power necessary to a variety of applications such as wireless sensor nodes, wrist watches and cell phone signals, thus proving to be an excellent alternative source for traditional lithium iodide battery especially in body sensor nodes. In this paper we design PMPH that is able to harvest environmental vibration sounds and convert it to usable electrical power for artificial cochlea. Spring mass damper system with single degree of freedom is used to model PMPH. COMSOL Multiphysics 4.2 is used to simulate PMPH. a linear relationship between voltage and external load for piezoelectric materials during Static analysis is observed, Eigenfrequency is used to find the resonance frequencies for six modes of operation and its deflection shape, PMPH harvest the maximum acoustic vibration at first mode of operation at 589 Hz. Simulation results using Transient analysis show that PMPH total displacement about 6 μm and output voltage at center of piezoelectric material about 4*10^-15V_p-p at steady state and can harvest acoustic vibration at 598Hz and convert it to electric power about 23nW, which is sufficient for cochlear implant application.