Design and Experimental Investigation of a Rotational Piezoelectric Energy Harvester with an Offset Distance from the Rotation Center.

Jun Chen,Sheng Wang,Xiangfu Liu,Mingjie Guan,Hengyang Wang

doi:10.3390/mi13030388

Abstract

Rotational energy harvesting technology has attracted more and more attention recently. This paper presents a piezoelectric rotational energy harvester that can be mounted with an offset distance from the rotation center. The piezoelectric energy harvester is designed to be dynamically excited by the force due to gravity, which causes the piezoelectric cantilever beams in the harvester to vibrate periodically as the harvester rotates. A novel design of the harvester structure with a hollow mass is proposed and analyzed in this paper. Experiments were performed to investigate the design and analysis. A power output of 106~2308 μW can be achieved at the rotating frequencies of 0.79~14 Hz with a piezoelectric cantilever beam in the prototyped energy harvester. Results showed that the prototyped harvester can be mounted on a rotating wheel hub and output sufficient power in a wide frequency range for wireless monitoring sensors.

Highlights

Technologies of kinetic energy harvesting have achieved rapid progress in recent decades due to their ability to harvest ambient kinetic energy to generate electricity.Among the kinetic motion, rotational motion has been widely used for various applications, including engines [1], turbines [2–5], rotating shafts [6], human motions [7–10] and vehicle wheels [11–13]
This paper is aimed at introducing an innovative design of rotational piezoelectric energy harvester that can be mounted at a distance offset from the rotational center without using the magnetic device
Similar to our previous design [25], a cantilever beam structure is used to increase the strain delivered to a piezoelectric element on the surface of the cantilever, and a metal beam is used as the substrate beam to achieve a high robustness

Summary

Introduction

Technologies of kinetic energy harvesting have achieved rapid progress in recent decades due to their ability to harvest ambient kinetic energy to generate electricity. Due to the centrifugal force in rotational environments, many vibration-based energy harvesting methods are not applicable. Research on rotational piezoelectric energy harvesting mainly includes methods based on mechanical plucking, magnetic excitation, and gravity. Hsieh et al [23] investigated various cantilever configurations for rotational piezoelectric energy harvester They found that centrifugal force plays an important role for passive self-tuning of resonance. This paper is aimed at introducing an innovative design of rotational piezoelectric energy harvester that can be mounted at a distance offset from the rotational center without using the magnetic device. It can generate a high output voltage and high output power in a wide rotation frequency range.

System Design and Theoretical Analysis

Experimental Validations

Conclusions and Discussion