Piezoelectric energy harvester for rolling bearings with capability of self-powered condition monitoring

A low-frequency rotational electromagnetic energy harvester using a magnetic plucking mechanism

/pdf/multistable-vibration-energy-harvesters-principle-progress-1x8i0ilt.pdf

Multistable vibration energy harvesters: Principle, progress, and perspectives

Piezoelectric stacks demonstrate excellent properties for energy harvesting owing to the high energy conversion efficiency and long lifetime. However, force amplification frames are commonly required to amplify the load applied to piezoelectric stacks. This paper proposes an energy harvester based on piezoelectric stacks without force amplification frames. The piezoelectric stacks are composed of annular piezoelectric sheets separated into several conductive sectors on the surface and mounted on a beam through a threaded sleeve and a nut. Experiments and simulations are carried out to evaluate the output performance of the energy harvester when the beam vibrates in transverse direction. The effects of excitation frequency, sector number, preload level, mounting position and piezoelectric sheet number on the output voltage are evaluated. Results from experiments and simulations show that the energy harvester gets the highest output gain as the excitation frequency reaches the resonant frequency of beam. When the piezoelectric sheets are divided into two insulated semi-circular regions, the best output performance can be obtained under the same loading conditions. Increasing the preload level is also beneficial for achieving high output voltage. However, this effect gets insignificant when the preload reaches to a certain value. The output gain of the energy harvester increases with the number of piezoelectric sheets. The output voltage is higher when the energy harvester is mounted at the beam center than that mounted at the beam ends.

https://iopscience.iop.org/article/10.1088/1361-665X/ab4e09/pdf

Energy harvesting of beam vibration based on piezoelectric stacks

Modeling approach for flexible shaft-disk-drum rotor systems with elastic connections and supports

In this Letter, we propose an enhanced vibro-impact energy harvester using acoustic black holes (ABHs) for scavenging low-frequency vibration energy. The energy harvester involves two beams: a relatively rigid piezoelectric generating beam with ABH profile and a flexible driving beam with a tip mass mounted at the end. The tip mass and the generating beam collide repeatedly under low-frequency excitations. Experimental studies are conducted to investigate the output performance of the energy harvester by comparing the output power and voltage of generating beams with different tailored ends. Finite element analysis is also carried out to evaluate the influence of electrode number of the piezoelectric sheet attached to the ABH beam on the output performance of the energy harvester. It is shown that the impacts between the tip mass and generating beam are capable of transferring vibration energy from the low-frequency band to high-frequency band, where ABH gets a desirable energy focalization effect to improve the output performance of the energy harvester. The energy harvester achieves the best output performance when its electrode is divided into two parts with the excellent power of 0.7 mW at the low frequency range from 5 to 13 Hz.

Vibro-impact energy harvester for low frequency vibration enhanced by acoustic black hole

Energy harvesting from rotating machines for self-powered sensor networks has attracted increasing attentions in the last decade. In this work, an energy harvester employing piezoelectric stacks for rotating machinery is proposed, which cannot only harvest kinetic energy from bending deformation of rotating shaft but also has the capability of rotor fault detection. The structure and working concept of the energy harvester are initially presented. Afterward, a theoretical model for the energy harvester is established to clarify its output characteristics. Then, vibration tests under different rotating speeds are carried out with a prototype mounted on a rotor test rig. The effects of electrical connections of piezoelectric stacks, rotor geometry, energy harvester location, and fastener preload on the output performance of energy harvester are evaluated. Finally, the applications of powering a scientific calculator and detecting typical faults of rotor systems including rotor crack and rub impact faults are demonstrated. Apart from fault detection capability, the proposed energy harvester has the advantages of long lifespan and causing little interference with the rotational motion, which overcomes the inherent deficiencies of commonly studied beam-type energy harvesters and manifest the potential of proposed energy harvester for the long-term condition monitoring of rotating machines.

Liufeng Zhang

Papers

Piezoelectric energy harvester for rolling bearings with capability of self-powered condition monitoring

Energy harvesting of beam vibration based on piezoelectric stacks

Modeling approach for flexible shaft-disk-drum rotor systems with elastic connections and supports

Vibro-impact energy harvester for low frequency vibration enhanced by acoustic black hole

Energy harvesting from gravity-induced deformation of rotating shaft for long-term monitoring of rotating machinery