Broadband Energy Harvesting Research Articles

Multiple broadband magnetoelectric response in thickness-controlled Ni/[011] Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 single crystal/Ni laminates

We report the realization of a multiple, broadband, magnetoelectric (ME) response using Ni/[011]-Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) single crystal/Ni laminates that take advantage of the multiple mechanical resonances inherent to laminates with anisotropic piezoelectric properties. The ME voltage coefficient of the laminates showed three distinct resonance frequencies and large in-plane anisotropy in its sign and magnitude owing to the anisotropic planar piezoelectric coefficient of [011]-oriented PMN-PZT single crystals. Upon serially connecting three such laminates with different thickness ratios between the Ni and PMN-PZT layers, we observed two distinct frequency windows with bandwidths of ∼60 kHz showing flat, giant ME responses of over 16 V/cm Oe, which suggests that these ME laminates are good candidates for application in broadband field sensors or energy harvesters.

Energy Harvesting Dynamic Vibration Absorbers

Energy harvesting is a promise to harvest unwanted vibrations from a host structure. Similarly, a dynamic vibration absorber is proved to be a very simple and effective vibration suppression device, with many practical implementations in civil and mechanical engineering. This paper analyzes the prospect of using a vibration absorber for possible energy harvesting. To achieve this goal, a vibration absorber is supplemented with a piezoelectric stack for both vibration confinement and energy harvesting. It is assumed that the original structure is sensitive to vibrations and that the absorber is the element where the vibration energy is confined, which in turn is harvested by means of a piezoelectric stack. The primary goal is to control the vibration of the host structure and the secondary goal is to harvest energy out of the dynamic vibration absorber at the same time. Approximate fixed-point theory is used to find a closed form expression for optimal frequency ratio of the vibration absorber. The changes in the optimal parameters of the vibration absorber due to the addition of the energy harvesting electrical circuit are derived. It is shown that with a proper choice of harvester parameters a broadband energy harvesting can be obtained combined with vibration reduction in the primary structure.

Broadband vibration energy harvesting based on cantilevered piezoelectric bi-stable composites

Bi-stable composites are considered for vibration based energy harvesting, thanks to the broadband nature of their dynamic response. In this letter, a cantilevered piezoelectric bi-stable composite concept is introduced for broadband energy harvesting. The proposed configuration allows for exploiting the large strains developed close to the clamped root, significantly enhancing the harvesting effectiveness in comparison to previous settings. A simple model is used for designing the dynamic response aiming to maximise broadband oscillations. Experimental results reveal wide bands of high power conversion. Additionally, a shunting circuit suitable for broadband conversion is employed, further increasing the effectiveness of the proposed concept.

Metamaterial-inspired structures and concepts for elastoacoustic wave energy harvesting

Enhancement of structure-borne wave energy harvesting is investigated by exploiting metamaterial-based and metamaterial-inspired electroelastic systems. The concepts of wave focusing, localization, and funneling are leveraged to establish novel metamaterial energy harvester (MEH) configurations. The MEH systems transform the incoming structure-borne wave energy into electrical energy by coupling the metamaterial and electroelastic domains. The energy harvesting component of the work employs piezoelectric transduction due to the high power density and ease of application offered by piezoelectric materials. Therefore, in all MEH configurations studied in this work, the metamaterial system is combined with piezoelectric energy harvesting for enhanced electricity generation from waves propagating in elastic structures. Experiments are conducted to validate the dramatic performance enhancement in MEH systems as compared to using the same volume of piezoelectric patch in the absence of the metamaterial component. It is shown that MEH systems can be used for both broadband and tuned wave energy harvesting. The MEH concepts covered in this paper are (1) wave focusing using a metamaterial-inspired parabolic acoustic mirror (for broadband energy harvesting), (2) energy localization using an imperfection in a 2D lattice structure (for tuned energy harvesting), and (3) wave guiding using an acoustic funnel (for narrow-to-broadband energy harvesting). It is shown that MEH systems can boost the harvested power by more than an order of magnitude.

Broadband energy harvesting through a piezoelectric beam subjected to dynamic compressive loading

This paper investigates the design and analysis of a broadband piezoelectric energy harvester that uses a simply supported piezoelectric beam compressed by dynamic loading. The beam is restrained at one end and carries a moving mass at the other end where a magnetic force is applied axially. Taking advantage of the flexibility of the slender beam and the nonlinearity of the magnetic force, the design aims to enhance the harvester’s functionality with a broad frequency bandwidth. Both theoretical and experimental investigations are performed in this study over a range of excitation frequencies. Specifically, the electromechanical model of the harvester is analytically developed by means of the energy-based method and the extended Hamilton’s principle. Using the derived model, a parametric study is carried out to obtain the harvester’s voltage response under parametric excitations. Furthermore, the effects of various parameters on the harvester’s voltage response are examined. A prototype harvester is fabricated and experimentally tested. The theoretical model is validated against experimental data to confirm the harvester’s nonlinear response behaviors and enhanced capabilities. Both simulation and experiment illustrate that the harvester exhibits a softening nonlinearity and hence a broad frequency bandwidth with large-amplitude voltage response. It is also shown from numerical simulations that the harvester’s performance can be further improved by properly selecting the end mass and reducing the mechanical damping. The present findings demonstrate that dynamic compressive loadings can be successfully utilized to increase the harvester’s voltage output and frequency bandwidth.

Survey on broadband techniques for vibration energy harvesting

Various energy harvesting systems have been proposed in the last years. The use of ambient energy, such as vibration energy, has evoked great interests. Most vibration-based converters generate the maximum power only when the generator is excited at its resonance frequency. To overcome this limitation, researchers focus on strategies for increasing the working bandwidth of an energy harvester. Due to the amount of different approaches for broadband energy harvesting, we suggest a categorization. This review presents a classification of the current techniques. Every technique has its own benefits and drawbacks and is suitable for different applications. This review presents the categorization and describes each conversion technique. Typical research approaches are shown to get a better understanding of the energy harvesting techniques. The advantages and drawbacks are presented, and the suitability is shown for each category.

Optimal configurations of bistable piezo-composites for energy harvesting

This paper presents an arrangement of bistable composites combined with piezoelectrics for broadband energy harvesting of ambient vibrations. These non-linear devices have improved power generation over conventional resonant systems and can be designed to occupy smaller volumes than magnetic cantilever systems. This paper presents results based on optimization of bistable composites that enables improved electrical power generation by discovering the optimal configurations for harvesting based on the statics of the device. The optimal device aspect ratio, thickness, stacking sequence, and piezoelectric area are considered. Increased electrical output is found for geometries and piezoelectric configurations, which have not been considered previously.

Broadband energy-harvesting using a two degree-of-freedom vibrating body

In this letter, we introduce the concept and describe the realization of a two degree-of-freedom piezoelectric energy-harvesting device. The proposed system consists of a proof mass (i.e., a rigid body) and two cantilever beams; it can utilize both translational and rotational degrees of freedom. Therefore, it exhibits double power peaks and an increased frequency bandwidth, and it can generate power more efficiently than conventional vibration-based single degree-of-freedom devices.

A low profile vibro-impacting energy harvester with symmetrical stops

This paper reports on an investigation into the use of a vibro-impact approach to construct a relatively broadband kinetic energy harvester. Potentially, the vibro-impacting process may be exploited as an autotuning mechanism for energy harvesting in an environment where the source vibration spectrum varies in time, such as an aircraft in flight. The energy harvester examined in this paper is based on a vibro-impacting oscillator with double-sided, symmetrical, piezoelectric bimorph-stops. The energy harvester operates in the frequency range of 100–113 Hz and has a (non-optimized) maximum energy of 5.3 mW from an rms host vibration of 450 mG.

Design and experiment of multiple piezoelectric bimorphs for scavenging vibration energy

This paper presents a mathematical model for designing broadband piezoelectric energy harvesters by integrating multiple piezoelectric bimorphs (MPBs) with different resonant frequencies into a system. The finite element method (F EM) was used to predict the resonant frequencies of the MPBs. To verify the theoretical analysis, the resonant frequencies o f the MPBs were measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental results. The performance of MPBs is studied in energy harvesting. The results show that the MPBs can effectively increase the output power and enable broadband energy harvesters.

Broadband vibration-based energy harvesting improvement through frequencyup-conversion by magnetic excitation

Traditional vibration-based energy harvesters are designed for a specific base excitationfrequency by matching its fundamental natural frequency. This work presentsthe modeling and analysis of a nonlinear, magnetically excited energy harvesterthat exhibits efficient broadband, frequency-independent performance utilizing apassive auxiliary structure that remains stationary relative to the base motion.This system is especially effective in the regime of driving frequencies well belowits fundamental frequency, thus enabling a more compact design solution overtraditional topologies. A model based on Euler–Bernoulli beam theory is coupled to alinear circuit and a model of the nonlinear, magnetic interaction to produce adistributed parameter magneto-electromechanical system. This model is used in bothharmonic and stochastic base excitation case studies. The results of these simulationsdemonstrate multiple-order-of-magnitude power harvesting performance improvementat low driving frequencies and an insensitivity to time-varying base excitation.Furthermore, the proposed system is shown to outperform an optimally designed,standard energy harvester in the presence of broadband, random base excitation.