Modeling and Finite Element Analysis of a micro energy harvester

Remote energy efficiency for wireless micro sensor devices in multimedia, signal processing and communication technologies is of paramount interest not only for ensuring continuous network operation despite primary battery limitations, but also for reducing carbon footprint in communication systems. Increasing demands of energy supply for micro devices, in particular, with the advance of complex multimedia tasks, and shorter communication distances as in sensors or machine-to-machine communications, energy cost of signal processing becomes comparable to transmit energy. Battery limitations can be partly alleviated by energy harvesting technology that can collect various forms of energy such as solar, wind, kinetic from ambient environment and convert into electrical energy. In this work, device modeling and Finite Element Analysis (FEA) of a Micro-Electro-Mechanical Systems (MEMS) Energy Harvester (EH) is presented. The MEMS-EH converts ambient fluid-flow into electrical energy by piezoelectric means. A layered flexible cantilever that vibrates due to the fluid-flow Kármán Vortex Street generated in the wake of a D-shaped bluff-body is modeled in COMSOL Multiphysics. Different application modes were carried out to investigate various response of the MEMS-EH and feasibility of the design. Simulation of the MEMS-EH in Laminar fluid Flow Regime showed von Mises effective stress 10.97 GPa and the maximum displacement of the cantilever tip 60 μm. The MEMS-EH has no rotating part and without any tip mass. Design guideline of the MEMS-EH model is presented in detail followed by simulation results. From the analysis, the prospects of this fluid-flow driven MEMS-EH device to function as an efficient kinetic energy conversion into electricity for micro sensor is reported.