Design of MEMS-based cantilever-type piezoelectric energy harvester for low frequency vibrations

Abstract

Piezoelectric energy harvesters find applicability in remote area of application because of simple design and operation. Piezoelectric layer length and thickness are the key parameters for controlling the resonance frequency and optimal output. In this paper the effect of position of piezoelectric layer has been investigated. Finite element method (FEM) results have been obtained for varying the position of the piezoelectric layer from 50 to 200 µm for thicknesses of 5 µm. It has been observed the variation of the position of the piezoelectric layer has an effect on the displacement, von-Mises stress of the cantilever which affects the net potential generated. The base of the cantilever is Silicon; lead zirconate titanate (PZT) piezoelectric material has been selected for the analysis. The length of the silicon cantilever has been fixed to 200 µm. The parameters for simulation are set as: Variation of position of piezoelectric layer lpiezo as; 50, 100, 150, and 200 µm. Thickness of beam Tcanti = 10 µm. Length of beam Lcanti = 200 µm. Displacement, von-Mises stress and electric potential has been obtained from FEM results for the piezoelectric layer position variation from 50 to 200 µm. The displacement of the cantilever changes from 84.03 to 41.25 µm, von-Mises stress of the cantilever increases from 2.96 × 106 to 6.45 × 106 N/m2 and the electric potential increases from 0.3224 to 0.5446 V when the position is varied from 50 to 200 µm. The results depicts that there is an effect of variation of position of piezoelectric layer on the total displacement, net stress and electric potential generated by the cantilever.