Optimisation of a Membrane Based Piezoelectric Vibrational Energy Harvester for High Output Power and Low-Frequency Operations

Abstract

Low power electronic devices and sensors as part of wireless sensor networks demand an independent self-powered source of energy typically through reliable energy scavenging methods. Micro electro-mechanical system (MEMS)-based Vibrational Energy Harvesting (VEH) with the cantilever-based design is proved to be a potential source. Apart from cantilevers, other MEMS structures like membranes can act as a wideband vibrational energy harvester because it provides a broader resonant peak as compared to cantilever beams. This paper presents a MEMS piezoelectric vibration energy harvester (PVEH) with circular membrane architecture. The effects of membrane diameter and the proof mass diameter on the resonant frequency are analysed. Optimisation of the diameters of the outer membrane and proof mass are carried out. For the first time, the optimum ratio of membrane diameter to proof mass diameter for designing the energy harvester with the least resonant frequency is reported here. Here Aluminum Nitride (AlN) is used as the piezoelectric material.