PiezoMEMS Nonlinear Low Acceleration Energy Harvester with an Embedded Permanent Magnet.

Nathan Jackson

doi:10.3390/mi11050500

Abstract

Increasing the power density and bandwidth are two major challenges associated with microelectromechanical systems (MEMS)-based vibration energy harvesting devices. Devices implementing magnetic forces have been used to create nonlinear vibration structures and have demonstrated limited success at widening the bandwidth. However, monolithic integration of a magnetic proof mass and optimizing the magnet configuration have been challenging tasks to date. This paper investigates three different magnetic configurations and their effects on bandwidth and power generation using attractive and repulsive magnetic forces. A piezoMEMS device was developed to harvest vibration energy, while monolithically integrating a thick embedded permanent magnet (NdFeB) film. The results demonstrated that repulsive forces increased the bandwidth for in-plane and out-of-plane magnetic configurations from <1 to >7 Hz bandwidths. In addition, by using attractive forces between the magnets, the power density increased while decreasing the bandwidth. Combining these forces into a single device resulted in increased power and increased bandwidth. The devices created in this paper focused on low acceleration values (<0.1 g) and low-frequency applications.

Highlights

Vibration-based energy harvesting systems have been extensively investigated over the past decade as a method to create self-sustaining systems [1]
microelectromechanical systems (MEMS) devices often have high Q-factors, which helps in increasing power, but at the cost of narrowing the bandwidth
This paper investigates the power and bandwidth effects of varying magnetic nonlinear energy harvesters with varying magnetic configurations

Summary

Introduction

Vibration-based energy harvesting systems have been extensively investigated over the past decade as a method to create self-sustaining systems [1]. Vibration energy harvesters convert mechanical energy to electrical energy through electrostatic, electromagnetic, triboelectric, or piezoelectric channels. MEMS-based vibrational energy harvesting devices have two major limitations that have limited their success, namely their (i) low power density and (ii) narrow bandwidth. Typical linear MEMS energy harvesters have narrow bandwidths of 1–2 Hz and operate at low resonant frequency (

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Conclusion