Wideband Vibration Energy Harvesting Research Articles

Wideband vibration isolation and energy harvesting based on a coupled piezoelectric-electromagnetic structure

This paper proposes a dual-purpose coupled piezoelectric-electromagnetic structure (DCPES) for wideband vibration isolation and energy harvesting. It includes two piezoelectric elements and one electromagnetic element, which are used to harvest energy from low-level and low-frequency vibrations and isolate some undesired vibrations. These two combinations result in low resonant frequencies and available nonlinearity. The electromagnetic element mutually complements with piezoelectric elements, and has positive stiffness and hard nonlinearity to damp vibrations with an isolated mass platform. The corresponding dynamic model of the DCPES is established, and the response displacement and output voltage are predicted numerically. In addition, the effects of excitation amplitude, the magnetic constant of the magnet, geometric parameters of the piezoelectric beam, and equivalent mass of the mass platform on displacement transmissibility and output response are explored. More importantly, experimental tests are performed to verify the design and numerical analysis. It is found that the DCPES can efficiently convert vibration energy into electrical energy in a wide frequency range of 5–13 Hz, and successfully dampens oscillations in the frequency range above 13 Hz (the displacement transmissibility is less than 1). The peak output power of the electromagnetic element is up to 15.2 mW, and the total peak output power of two piezoelectric elements reaches 4.6 mW under the excitation amplitude of 0.8 g (g = 9.8 m/s2). Case studies of parameters show that simultaneous wider bandwidth, higher output response, and vibration isolation can be achieved by changing the parameters of the DCPES.

Frequency band broadening and charge density enhancement of a vibrational triboelectric nanogenerator with two stoppers

Vibrational triboelectric nanogenerators (V-TENG) can be used to harvest broadband vibration energy due to the nonlinear impact force induced by a stopper. However, V-TENGs with a single stopper have limited bandwidth and surface charge density, which has limited their application in wideband vibration energy harvesting. Herein, a V-TENG with two stoppers and a charge pumping effect is proposed for frequency band broadening and charge density enhancement. The theoretical analysis and experimental validation have indicated the V-TENG with two stoppers could improve the bandwidth by 75% compared with one stopper at a gap distance of 0.5 mm. Moreover, a charge pump can be constructed with two output channels, which has improved surface charge density by about 14 times. With the frequency varying from 18 to 38 Hz, the V-TENG can continually power 400 LEDs and charge a commercial capacitor quickly. This work has shown an encouraging method for enhancing the performance of V-TENGs, which also has great prospects in harvesting wideband vibration energy from machines, cars, ships, and human motions for self-powered electronics.

Graded multifunctional piezoelectric metastructures for wideband vibration attenuation and energy harvesting

Unlike well-studied locally resonant (LR) metamaterials with a periodic array of identical resonators, ‘graded’ LR metamaterials consist of an array of resonators with a spatially varying parameter, yielding wideband wave attenuation and mode trapping/localization, among other features. In this work, we explore a graded LR piezoelectric metamaterial-based structure (i.e. metastructure) in which the grading parameter, namely the inductive shunt resonant frequency of the unit cells, follows a predefined variation pattern in space (e.g. first-order, quadratic, or fractional). We investigate the effect of such patterns on (i) the vibration attenuation bandwidth, (ii) the localization of vibration modes, and (iii) the harvested power. To this end, we consider a piezoelectric bimorph cantilever hosting an array of piezoelectric unit cells with spatially varying inductive shunts. Fully coupled electromechanical equations describing the metastructure’s linear transverse displacement and unit cell voltages are given with a modal analysis framework and solved using the matrix inversion method. The results show that (i) the first-order grading pattern yields the widest bandgap with 65% increase in the bandwidth compared to the standard uniform LR pattern, (ii) the localization of vibration modes follows in shape the corresponding frequency grading pattern, and (iii) the largest power is harvested for the fractional grading pattern. Furthermore, all of the graded resonator configurations result in wider bandwidth in energy harvesting as compared to the uniform resonators case. Overall, the results unveil the fundamental characteristics of this class of graded piezoelectric metastructures and support the design of such multifunctional piezoelectric metastructures for concurrent vibration attenuation and energy harvesting.

A hula-hooping-like nonlinear buckled elastic string electromagnetic energy harvester for omnidirectional broadband excitations

This paper reports a hula-hooping-like nonlinear buckled elastic string electromagnetic energy harvester for wideband vibration energy harvesting. The harvester is comprised of a magnetic rotor attached at the middle of a clamped-clamped buckled elastic string and a stator with an embedding coil array. Attributed to the geometric nonlinear characteristic of the elastic string, the harvester can convert the reciprocate vibration in arbitrary in-plane direction to a hula-hooping-like curvilinear translation plane motion. A hardening nonlinear wideband voltage response was demonstrated by sweep excitation from 5\\,∼\\,23 Hz. The output peak power for a single coil can reach 1.12 mW at a 5 ms−2 excitation. To overcome the phase delay effects between the voltages of three spatially distributed coils, they were rectified separately and connected serially or parallelly to provide the final output. An open circuit peak voltage of 0.53 V was obtained from the serial connection at a 4 ms−2 up-sweep excitation, under which a 100μF capacitor was successfully charged to 0.35 V within 120 s. The omnidirectional energy scavenging performance of the harvester was further validated experimentally, suggesting its great promise for practical vibration energy harvesting.

Ultra-wideband piezoelectric energy harvester based on Stockbridge damper and its application in smart grid

Transmission lines are often located in the field, and the long-term effective power supply for the online monitoring devices is an urgent problem for smart grid. To overcome this challenge, we propose a wide-band piezoelectric vibration energy harvester inspired by the Stockbridge damper in transmission lines system. The energy harvester has two subsystems, both of which are designed based on the 1:2 internal resonance principle. Thus, the harvester can exhibit up to four resonant frequencies. The geometric nonlinearity is introduced into the governing equations, and the coupled electrical circuit equation of this system is derived from the Gauss law. Theoretical simulations and experimental measurements show that the internal resonance can achieve a wider operating bandwidth. Based on the actual transmission line type and the measured wind speed data, the performance of energy harvester is analyzed. It demonstrates that the harvester can suppress the vortex-induced vibration of the transmission line within the wind velocity range of 1–4 m/s. The bandwidth of the internal resonance region can be up to 12.05 Hz. At the mean time, the harvest power for online monitoring devices could reach to 12.89 mW. The external noise is simulated by Gaussian white noise. The signal-to-noise ratio is introduced to consider the effect of the noise on the performance of the energy harvester. The results turn out that the harvester exhibits good robustness when the ratio is above 3 dB.

Energy and Phase Space Analysis of Response Stabilization Control for Nonlinear Wideband Vibration Energy Harvesting

Energy and Phase Space Analysis of Response Stabilization Control for Nonlinear Wideband Vibration Energy Harvesting

Toward self-powered nonlinear wideband vibration energy harvesting with high-energy response stabilization

This paper describes an effort to develop a nonlinear wideband vibration energy harvester with self-powered stabilization control of its high-energy response. In a Duffing-type nonlinear wideband energy harvester, a well-recognized difficulty of coexisting attractors arises so that the emergence of the response in the high-energy branch is not guaranteed because it depends on the initial conditions to which steady-state solutions the state is attracted. The response stabilization control technique introduces a negative resistance which returns the harvested power to the nonlinear resonator to destabilize the undesirable low-energy solution and make the high-energy solution globally stable. In this paper, the power balance of the response stabilization control under intermittent disturbances is first experimentally studied, and a charging circuit to self-power the negative impedance converter (NIC) in the control circuit is then developed. It is concluded that the energy consumed by the NIC can be retrieved by the energy harvesting in 100 seconds even in the worst case.

A magnetically-sprung nonlinear resonator for wideband vibration energy harvesting consisting of magnetic composite and ring magnets

This paper presents a novel design of a magnetically-sprung mechanical resonator for wideband vibration energy harvesting. In this design, a magnet composite consisting of two cylindrical magnets composed in a repelling arrangement is used as a moving mass, which is magnetically suspended between two ring magnets. This configuration yields more significant variation of stiffness in a shorter stroke compared with the previous design, resulting in wider operation band even under small excitation.

Investigation on the design and application of 3-dimensional wide-band piezoelectric energy harvester for low amplitude vibration sources

In order to realize 3-dimensional, wide-band vibration energy harvesting in low-frequency and low-amplitude environments, a multi-layer Z-type beam piezoelectric harvester structure is proposed. Nonlinear mass and instabilities of horizontal and longitudinal are introduced by the multi-layer Z-type beam structure. Simulation and experiment results show that when the number of beam layer is 7 and excitation intensity is 0.8 g, there are more than 4 voltage peaks within 5–40 Hz, the maximum voltage is above 16 V, the maximum output power can reach 180 μW, which greatly widens harvesting frequency band. When exciting in horizontal and vertical directions, the maximum voltages peaks are all above 10 V, the number of voltage peaks are all above 5, maximum output powers can reach 108 μW and 53 μW respectively, by which 3-dimensional energy harvesting is verified. Next, the performances of arrays are studied. When the arrays number is 12, excitation intensity reduces to 0.2 g, nearly 90% of the voltage response amplitudes for parallel arrays within 15–40 Hz are above 4 V, almost all the voltage response amplitudes for series arrays are above 5 V within 17–40 Hz, even response amplitudes are all above 10 V within 23–33 Hz. The maximum output power generated by parallel arrays is up to 864.5 μW. So, wide-band 3-dimensional vibration energy harvesting for low amplitude environment is realized by multi-layer Z-type vibration energy harvester. Finally, the feasibility that wireless switch could be powered by the multi-layer Z-type vibration energy harvester parallel arrays from low-frequency and low-amplitude environment is verified.

Application of Wideband Vibration Energy Harvesting to Actual Facility Environment

Application of Wideband Vibration Energy Harvesting to Actual Facility Environment

Stiffness control of a nonlinear mechanical folded beam for wideband vibration energy harvesters

Abstract This paper presents a novel approach to design and optimize geometric nonlinear springs for wideband vibration energy harvesting. To this end, we designed a spring with several folds to increase its geometric nonlinearities. A numerical analysis is performed using the Finite Element Method to estimate its quadratic and cubic spring stiffness. A nonlinear effective spring constant is then calculated for different values of the main folding angle. We demonstrate that this angle can increase nonlinearities within the structure resulting in higher bandwidths, and that it is possible to control the behavior of the system to have softening-type or hardening-type response depending on the choice of the folding angle. Based on the Lindstedt-Poincaré perturbation technique, a first order approximation is determined to predict the frequency-response of the system. In order to validate the perturbation analysis, numerical solutions based on long-time integration method and mixed VHDL-AMS/Spice simulations are presented. Finally, this method is applied to a previously published device and shows a good agreement with experiments.

Wideband Vibration Energy Harvesting by a Magnetically-Sprung Oscillator Using Ring Magnets

Wideband Vibration Energy Harvesting by a Magnetically-Sprung Oscillator Using Ring Magnets

Development of Interposer with Bi-stable Mechanism for Wide-band Vibration Energy Harvesting

Development of Interposer with Bi-stable Mechanism for Wide-band Vibration Energy Harvesting

Magnetically coupled flextensional transducer for wideband vibration energy harvesting: Design, modeling and experiments

The combination of nonlinear bistable and flextensional mechanisms has the advantages of wide operating frequency and high equivalent piezoelectric constant. In this paper, three magnetically coupled flextensional vibration energy harvesters (MF-VEHs) are designed from three magnetically coupled vibration systems which utilize a magnetic repulsion, two symmetrical magnetic attractions and multi-magnetic repulsions, respectively. The coupled dynamic models are developed to describe the electromechanical transitions. Simulations under harmonic excitation and random excitation are carried out to investigate the performance of the MF-VEHs with different parameters. Experimental validations of the MF-VEHs are performed under different excitation levels. The experimental results verify that the developed mathematical models can be used to accurately characterize the MF-VEHs for various magnetic coupling modes. A comparison of three MF-VEHs is provided and the results illustrate that a reasonable arrangement of multiple magnets can reduce the threshold excitation intensity and increase the harvested energy.

Independent nonlinearity tuning of planar spring via geometrical design for wideband vibration energy harvesting

This paper reports a novel nonlinearity tuning method through sophisticated geometrical design for wideband energy harvesting application. By carefully controlling the thickness to length ratio of the planar spring beams, the nonlinear stiffness coefficient can be intentionally and precisely adjusted, while the linear stiffness coefficient can be kept unchanged. Thanks to the different effects on the linear and nonlinear parts, both the resonant frequency of the linear part and the bandwidth range of nonlinear vibration can be designed separately. As a proof of concept, MEMS-based electromagnetic vibrational energy harvesters employing the independent nonlinearity tuning method have been designed and fabricated. Both simulation and experiment were conducted to validate our method. At the acceleration of 0.5g, the micro-fabricated device is able to tune the operating bandwidth of the output voltage from 37Hz to as wide as 75Hz. This design can easily tune the length and thickness of the spring beams without changing the volume of the whole energy harvester device, which is compatible with MEMS batch fabrication process.

Low-frequency wideband vibration energy harvesting by using frequency up-conversion and quin-stable nonlinearity

This work presents models and experiments of an impact-driven and frequency up-converted wideband piezoelectric-based vibration energy harvester with a quintuple-well potential induced by the combination effect of magnetic nonlinearity and mechanical piecewise-linearity. Analysis shows that the interwell motions during coupled vibration period enable to increase electrical power output in comparison to conventional frequency up-conversion technology. Besides, the quintuple-well potential with shallower potential wells could extend the harvester's operating bandwidth to lower frequencies. Experiments demonstrate our proposed approach can dramatically boost the measured power of the energy harvester as much as 35 times while its lower cut-off frequency is two times lower than that of a conventional counterpart. These results reveal our proposed approach shows promise for powering portable wireless smart devices from low-intensity, low-frequency vibration sources.

Wideband, low-frequency springless vibration energy harvesters: part I

We present a novel architecture for wideband and low-frequency vibration energy harvesting (VEH). Springless vibration energy harvesters (SVEH) employ impact oscillators as energy harvesting elements. A seismic mass moves along a linear guide limited by stoppers at both ends of the track. An electromagnetic transducer converts the kinetic energy captured by the mass into electrical energy. Experiments using prototypes of the horizontal SVEH demonstrated low frequency harvesting (<20 Hz), wideband harvesting (up to 6.0 Hz), and an optimal rectified output power of P = 12 mW for a base acceleration amplitude of 0.5 g. A model of the electromagnetic SVEH was developed and validated experimentally. A figure of merit was defined to quantify realizable output power in linear and nonlinear VEHs. Comparison using this figure of merit shows that electromagnetic SVEHs outperform their linear counterparts by 92%–232% for acceleration amplitudes in the range of 0.4–0.6 g.

A batch-fabricated electret-biased wideband MEMS vibration energy harvester with frequency-up conversion behavior powering a UHF wireless sensor node

This paper reports a batch-fabricated, low-frequency and wideband MEMS electrostatic vibration energy harvester (e-VEH), which implements corona-charged vertical electrets and nonlinear elastic stoppers. A numeric model is used to perform parametric study, where we observe a wideband bi-modality resulting from nonlinearity. The nonlinear stoppers improve the bandwidth and induce a frequency-up feature at low frequencies. When the e-VEH works with a bias of 45 V, the power reaches a maximum value of 6.6 μW at 428 Hz and 2.0 grms, and is above 1 μW at 50 Hz. When the frequency drops below 60 Hz, a ‘frequency-up’ conversion behavior is observed with peaks of power at 34 Hz and 52 Hz. The −3 dB bandwidth is more than 60% of its central frequency, both including and excluding the hysteresis introduced by the nonlinear stoppers. We also perform experiments with wideband Gaussian noise. The device is eventually tested with an RF data transmission setup, where a communication node with an internal temperature sensor is powered. Every 2 min, a data transmission at 868 MHz is performed by the sensor node supplied by the e-VEH, and received at a distance of up to 15 m.

A Compressive-Mode Wideband Vibration Energy Harvester Using a Combination of Bistable and Flextensional Mechanisms

In this paper, a compressive-mode wideband vibration energy harvester using a combination of bistable and flextensional mechanisms is proposed. The structure consists of a cantilever with a magnet fixed at its free end, and a flextensional actuator with a magnet fixed at its free end. A theoretical model is developed to characterize the compressive-mode wideband vibration energy harvester. Both simulations and experiments are carried out to validate the design and analysis of the compressive-mode wideband vibration energy harvester. The results show that the device can work in broadband, and the piezoelectric constant d31 can be enlarged 134 times. The experimental results also indicate that the harvester can generate the power about 31 μW with the resistive load 390 kΩ, while the magnetic pressure is 2.9 N. A developed design including two flextensional actuators symmetrically arranged is also presented. The experimental results show that the two flextensional actuators in the developed design can harvest more energy than one flextensional actuator in the primal design.

Enhanced Broadband Vibration Energy Harvesting Using a Multimodal Nonlinear Magnetoelectric Converter

In this work, we present a multimodal wideband vibration energy harvester designed to scavenge energy from ambient vibrations over a wide frequency range. The harvester consists of a folded cantilever, three magnetoelectric (ME) transducers, and two magnetic circuits. The folded cantilever enables multi-resonant response formed by bending of each stage, and the nonlinear magnetic forces acting on the folded cantilever beam allow further broadening of the frequency response. We also investigate the effects of the position of the ME transducer on the electrical output in order to achieve optimal performance. The experimental results show that the vibration energy harvester exhibited three resonance peaks in a range of 5 Hz to 30 Hz, a wider working bandwidth of 10.1 Hz, and a maximum average power value of 31.58 μW at an acceleration of 0.6 g (with g = 9.8 m/s2).