Design, Analysis and Experimental Investigation of Micro Piezoelectric Vibrational Energy Harvester with Enhanced Power Extraction at Low Frequency

Wireless sensor nodes (WSNs) and embedded microsystems (EMS) have become a center of focus for researchers from all over the world due to their enormous sensing and monitoring applications in multiple areas including biotechnology, agriculture, healthcare, and consumer electronics. To ensure proper functioning of these systems, continuous power supply is required. The research paper presents a piezoelectric vibrational energy harvester that is designed with enhanced power extraction capability at low frequency. A compliant trapezoidal beam with optimized proof mass placement at one end, to enhance piezoelectric output, is designed, fabricated, and experimentally tested. The parametric design of the energy harvester consists of a piezoelectric ceramic crystal barium titanate (BaTiO3) bonded to an optimized micro-folded trapezoidal beam. The designed energy harvester has been analytically modeled using Euler beam theory and simulated using MATLAB. The static, dynamic and piezoelectric energy conversion response of the energy harvester is verified through finite element method (FEM) based Multiphysics simulations. The fabrication of the energy harvester design has been carried out using low-cost wire cutting process. The experimental characterization of the proposed energy harvester shows that 32.36 V voltage and 2.216 mW power can be extracted at the operational frequency of 15 Hz with a factor of safety of 1.30. The experimental characterization results showed a good agreement with the FEM simulations with an error < 7%. The proposed energy harvester can be used to power WSNs, EMS, micro control units and microdevices using low frequency vibrations.