Bistable Energy Harvester Research Articles

An ultralow-frequency high-efficiency rotational energy harvester with bistability principle and magnetic plucking mechanism

In this paper, we propose an energy harvester that overcomes the bottleneck problem under ultralow-frequency rotational motion. The harvester consists of bistable dual piezoelectric energy harvesters (BD-PEH) with the magnetic plucking mechanism. The driving magnet is introduced to provide the magnetic plucking to BD-PEH. Therefore, the BD-PEH can operate at high-frequency vibrations across the potential well under ultralow-frequency rotation, which enhances energy harvesting efficiency. A numerical model of the harvester is developed, and the model results are in agreement with the experimental results. The effect of the depth of the potential well on the performance of the harvester is analyzed. The deeper the potential well, the higher the energy output, but it will reduce the bandwidth of the harvester. The experimental results show that the highest average power output is 0.81 mW at 1.2 Hz. In conclusion, the energy harvester proposed in this paper can generate enough energy to drive low-power electronic devices under ultralow-frequency rotational motion.

Chaotic responses across the potential barrier of bistable vortex-induced vibration energy harvesters

Large-amplitude interwell limit cycle oscillations (LCOs) are regarded as an ideal high-output state of multistable vibration energy harvesters. However, chaotic responses, which result in lower output voltages than interwell LCOs, can be observed in bistable vortex-induced vibration energy harvesters (VIVEHs). In this paper, the chaos in bistable VIVEHs is investigated through numerical simulation, theoretical analyses, and experimental validation. The distribution of the periodic solutions obtained by the incremental harmonic balance (IHB) method and chaos judgment using Lyapunov exponents are elucidated. It is found that the bistable VIVEH shows intrawell periodic solutions at high reduced wind speeds (RWSs) and period-doubling bifurcation appears with the periodic solutions turning into chaos with decreasing RWS. Analyses of the influence of nonlinear parameters on the chaotic responses identify the nonlinear stiffness as the dominant factor contributing to the chaos. Meanwhile, the chaotic responses and interwell LCOs would exist at the same RWS with different initial states. Finally, wind tunnel experiments confirm the occurrence of homologous chaotic responses of the bistable VIVEH which feature aperiodic jumping back and forth motion between two potential wells, in agreement with numerical simulations. Overall, this paper provides a framework for analyzing the chaotic responses of bistable VIVEHs, offering valuable insights for complex response mechanism understanding.

Equivalent damping coefficient of a bistable piezoelectric cantilever beam energy harvester via experimental-analytical balanced energy method

This study shed light on the simultaneous effects of bistability and electrical resistor on the equivalent damping of a piezoelectric cantilever beam energy harvester. Damping coefficient has a direct effect on the frequency bandwidth of an oscillating system. This paper, extends the experimental-analytical balanced energy (BE) method to obtain the damping change due to bistability of a piezoelectric energy harvester. By using extended Hamilton principle and Euler-Lagrange formulation with nonlinear magnetic field relations, the governing equations of the system are derived. Then the equivalent BE viscous damping model was adopted and the equivalent damping term is achieved. In BE method, the test signals are registered into the proposed BE algorithm, then the equivalent viscous damping coefficient of the system will be obtained. In the end, the effects of bistability and electrical resistor of the power circuit of piezoelectric patch is discussed. According to the results, by increasing the bistability of the system, the equivalent damping of the system will also increase. Besides by escalation the value of electrical load in piezoelectric power circuit, the value of the equivalent damping coefficient reaches a maximum value. This behavior is originated from the extracted power of the system.

A magnetic plucking frequency up-conversion piezoelectric energy harvester with nonlinear energy sink structure

In low and wide frequency vibration environments, the efficiency of vibration energy harvesters is relatively low. This paper presents a magnetic plucking frequency-up-conversion bistable Piezoelectric Energy Harvester (PEH) that features a Nonlinear Energy Sink (NES) structure for low and wide frequency vibration absorption. Based on the Euler-Bernoulli stepped beam theory, a theoretical model was derived from the Lagrange equation. The system's bandwidth and power generation capability were analyzed through frequency sweeping. This study thoroughly investigated the up-conversion working mechanism of the NES magnetically plucked PEH super-harmonic vibration. The results reveal that the system encompasses two power generation frequency bands: interwell periodic vibration and chaotic vibration. Under an excitation acceleration of 0.25 g, the interwell periodic vibration range during forward frequency sweep is from 3.30 to 4.31 Hz with an average power of 4.71 mW, and during reverse sweep, it is from 2.02 to 4.05 Hz with 2.43 mW. The coordination between NES and PEH is one of the crucial factors affecting power generation. Frequency mismatch can lead to asymmetrical displacement and alternating strong-weak voltage outputs.

A broadband bistable energy harvester with self-decreasing potential barrier effect: Design, modeling and experiments

The conventional bistable energy harvester (CBEH) is difficult to break through the potential barrier for large-amplitude inter-well motion under weak excitation environments, which results in a narrow effective bandwidth. This paper proposes a bistable energy harvester with self-decreasing potential barrier effect (BEH-DPBE) for harvesting low-frequency vibrational energy. A spring is introduced to transform the fixed end of the S-type power generating beam into a movable end, while its oscillator has a dual function of dynamically reducing the potential barrier in the return trip and enhancing the potential energy in the outward trip. The characteristics of the proposed energy harvester are evaluated and analyzed by combining finite element simulations, numerical studies, and experiments. Finally, the effects of key parameters, such as the spring pre-compression, proof mass, and load resistance, are studied. In low-frequency conditions, the effective bandwidth and peak-to-peak voltage of BEH-DPBE are 6.35 Hz (5.98–12.33 Hz) and 10.1 V, respectively. The proposed BEH-DPBE can effectively capture energy in low-frequency ambient vibrations.

Wave-inspired piezoelectric bistable energy harvester considering stress distribution: Design, simulation and experimental investigation

The rapid development of IoT technology has spurred the need for self-driven and low-power sensors. Numerous research studies focused on exploring the efficiency of energy harvesting as a means of powering miniaturized sensors, but the issue of the fatigue life of these energy harvesters has been largely overlooked. Inspired by wave motion, this study proposes a novel bistable piezoelectric energy harvester. The host structure of the harvester is made of a 301 stainless steel sheet preformed to a W-shaped beam, with PVDF piezoelectric films on its upper and lower surfaces. The results show that the proposed wave-inspired beam can significantly improve stress distribution, and the peak stress is 27.5 % lower than that of the arch beam. Experimental results show that the peak open-circuit output voltage can reach 11.8 V, when the pre-deformation height of the wave-inspired beam is 5 mm, the mass of the proof mass is 20 g and the frequency range is 13.6 Hz-18.9 Hz. When the excitation frequency is 13 Hz, the maximum root-mean-square voltage of the PVDF piezoelectric film and output power can reach 4.64 V and 16.25μW (single piece), respectively.

Approximate moment dynamic of stochastic resonance facilitating bistable energy harvesting systems

Approximate moment dynamic of stochastic resonance facilitating bistable energy harvesting systems

Piezoelectric energy harvester for wind turbine blades based on bistable response of a composite beam in post-buckling

A bistable piezoelectric energy harvester (PEH) is presented for harvesting power from vibrations occurring at low frequencies, as is the case of wind turbine blades. The axial compressive prestress of a piezoelectric composite beam at post-buckling serves as the bistability source, leading to high mechanical to electric power conversion. An in-house harvesting circuit connected to the piezoelectric terminals is used for demonstration of its harvesting power capabilities. A finite element (FE) model is used to analyze and optimize the coupled nonlinear electromechanical response of the PEH, including structure and circuit. A physical prototype has been manufactured and tested for validation of the electromechanical design and the FE modeling approach. Predictions and measurements indicate an increase of harvested power with applied prestress up to a transition point, where a sudden drop in power occurs. Good comparison between numerical and experimental results verified the modeling approach, whereas deviations related to physical boundary conditions at large compressive forces affected the prediction of the transition point in harvested power. The harvester produced 1.32 mW of electrical power under tonal base excitation of 1 g at 8 Hz. Hence, the nonlinear PEH has demonstrated its capability to harvest energy at frequencies much lower than its first linear modal frequency and could thus serve as a promising solution for powering IoT devices and sensors in large vibrating structures.

Nonlinear dynamics of an asymmetric bistable energy harvester with an adjustable unilateral stopper

Nonlinear dynamics of an asymmetric bistable energy harvester with an adjustable unilateral stopper

Enhanced energy harvesting from random excitations: A dynamic amplifier-augmented hybrid bistable piezoelectric energy harvester

In the energy harvesting field, it is critical to efficiently convert ambient vibrations into usable electrical energy, especially under conditions characterized by low amplitude and random excitations. This study introduces a novel hybrid bistable piezoelectric energy harvester (HBPEH) designed to optimize energy conversion in challenging environmental conditions. The HBPEH features a unique piezoelectric cantilever beam integrated with a dynamic amplifier at the fixed end, significantly enhancing both rotational and lateral displacements of the beam. This innovation lowers the threshold for snap-through events, crucial for maximizing energy transfer in bistable systems, and enables superior energy harvesting capabilities. Furthermore, the HBPEH demonstrates significantly higher power outputs when subjected to excitation intensities beyond critical levels, outperforming conventional energy harvesters. Extensive numerical and theoretical analyses confirm that the HBPEH offers a promising solution for applications hindered by suboptimal energy conversion rates. Its ability to operate effectively under diverse and unpredictable excitation conditions underscores the HBPEH's robustness and superiority in advanced energy harvesting scenarios. The design improvements introduced in this study highlight the potential of the HBPEH to transform energy harvesting approaches. By addressing the limitations of traditional harvesters, the HBPEH provides enhanced efficiency and reliability, making it suitable for a broader range of practical applications in variable environmental conditions.

Design, modeling and experiments of bistable piezoelectric energy harvester with self-decreasing potential energy barrier effect

It is difficult for conventional bistable energy harvesters to undergo interwell motion in weak excitation environment. In this study, a bistable energy harvester with self-decreasing potential energy barrier effect is proposed, which innovatively turns a fixed end of S-shaped generator beam into the movable end with a spring oscillator, which effectively decreases the potential energy barrier and makes the harvester susceptible to interwell motion. Furthermore, a theoretical analysis of the nonlinear driving magnetic force and the system governing equations is carried out, then a numerical simulation of potential energy surface of harvester is performed to demonstrate the effect of the self-decreasing potential energy barrier in detail. The effect of spring pre-compression and stiffness of the moveable end on the system potential energy is analyzed by numerical simulation. Finally, the key parameters affecting the output performance, such as spring pre-compression, magnets distance, and external load resistance, are analyzed. The harvester has a maximum effective bandwidth of 6.62Hz (4.61–11.23Hz), a maximum peak-to-peak voltage of 10.2V, an RMS voltage of 1.3V, and a maximum output power of 2.91 μW. The proposed harvester achieves efficient broadband energy harvesting in low frequency environments.

A novel T-shaped beam bistable piezoelectric energy harvester with a moving magnet

Vibration energy harvesting holds the promise of providing autonomous power for low-power electronic devices. To improve the issue of the limited bandwidth of the piezoelectric energy harvester, this work proposes a novel T-shaped beam bistable piezoelectric energy harvester with a moving magnet. The moving magnet can not only provide nonlinear force to adjust bandwidth, but also increase the number of system resonance peaks, which improves the utilization of the magnet, enhancing the adaptability of the vibration energy harvesting device to the environment. Established a mathematical model and validated it through experiments. Some parameters, such as external resistance, magnet spacing, and spring stiffness, are analyzed by theoretical analysis. The results indicate that, at an acceleration amplitude of 0.3 g and a frequency of 15.7 Hz, the peak output power of the main support beam is 2.36 mW. Similarly, at an acceleration amplitude of 0.3 g and a frequency of 15.6 Hz, the peak output power of the parasitic cantilever beam is 0.56 mW, demonstrating its potential to power low-power electronic components. The moving magnet provides an additional resonance peak for the harvester, offering a new method for the design of broadband magnetic nonlinear piezoelectric energy harvesters in the near future.

Harnessing energy from hand-shaking vibration for electronics through a magnetic rolling pendulum bistable energy harvester

Converting the kinetic energy of human movement into electricity provides a solution for the power supply of portable electronics for communication, medical treatment, positioning, search-and-rescue, etc. Due to the characteristics of high sensitivity and snap-through, a magnetic rolling pendulum bistable energy harvester (MRP-BEH) based on magnetic-spring mechanism is proposed for scavenging energy from handshaking vibration. The harvester possessing the advantage of small damping exploits the rolling oscillation of a suspended magnet. By establishing the electromechanical model, numerical outcomes of the MRP-BEHs with different potential well depths are investigated through the response under constant and sweep frequency excitations. Particularly, the complex dynamic behaviors are characterized by basins of attraction and bifurcation diagrams. A prototype is fabricated, and experiments are undertaken under harmonic and handshaking excitations. Experimental results are consistent with numerical simulations, and excitation of 0.5 g witnesses a broadband frequency range from 5.18 Hz to 10.02 Hz for the harvester with proper system parameters. Regarding the excitation of handshaking, an instantaneous maximum power of 21.9 mW and an average power of 4.21 mW is achieved with matched load resistance. By boosting the output voltage with a transformer, the charging and discharging experiments of capacitors for powering various electronics demonstrate the broad application prospects of the harvester. This research, in a nutshell, broadens the methodology for achieving bistable oscillation and introduces a fresh perspective for designing high-efficiency energy harvesters attuned to human motion.

Nonlinear dynamics and performance evaluation of an asymmetric bistable energy harvester with unilateral piecewise nonlinearity

Nonlinear dynamics and performance evaluation of an asymmetric bistable energy harvester with unilateral piecewise nonlinearity

Predictive lumped model for a tunable bistable piezoelectric energy harvester architecture

In this article, we propose the modelling of a tunable bistable piezoelectric energy harvester (or BPEH) architecture. The latter is a type of ambient energy converter that continues to gain attention due to their wideband frequency response. As the non-linear dynamics of BPEHs imply significant modeling complexity, dynamic lumped models are necessary to predict BPEHs’ dynamic response and should fit the type of architecture studied. The BPEH architecture of interest uses post-buckled beams to create bistability and an amplified piezoelectric actuator (or APA) to convert the ambient vibrations. To date, no dynamic lumped models have been found in existing literature that account for both the electromechanical conversion and the dynamic behavior of buckled beams, with a specific focus on their axial and bending stiffness, for this BPEH architecture. Additionally, the proposed BPEH architecture offers buckling level tunability, which is achieved using an additional APA. Hence, the aim of this paper is to propose a new lumped model for a BPEH architecture that considers the effect of the post-buckled beams’ stiffness and of the additional APA through an elasticity factor κ― . This lumped model is established using Euler Lagrange equations and is experimentally validated on a tunable BPEH prototype. This validation shows an average relative error below 6% between the model predictions and experimental dynamic response of the prototype to an ascending frequency sweep, compared to an average relative error that is around 14% for the model proposed in literature. Moreover, numerical simulations using the proposed model lead to the conclusion that there is an optimal elasticity factor κ― that ensures the maximum power output while maintaining the frequency bandwidth.

Magnetic coupling and amplitude truncation based bistable energy harvester

We present a two-degree-of-freedom bistable piezoelectric energy harvester (PEH) combining both magnetic coupling and amplitude truncation mechanisms to improve the electrical response when installed within compact spaces. The PEH processes a time-varying potential well and each beam has two electrical responses due to the interaction between two magnets. The collision-induced amplitude truncation behavior leads to high-frequency vibration responses, which reduces the matching impedance of the PEH. The Hamilton's principle and the Galerkin method was applied to establish the distributed parameter model for the system. By numerical calculations, the influence of the magnet distance and beam stiffness ratio on the static potential well, as well as the influence of excitation acceleration and stop gap on the voltage and power response were explored. A series of experiments were conducted to validate the voltage and power responses under sweep and fixed frequency excitations. The experimental and simulation results agree with each other. Due to the effect of magnetic coupling, the response frequency bandwidth of the cantilever beam widens by more than 7 Hz. The frequency-up effect generated by collision increases the response power of the system with the maximum of 307.8 mW at 103.6 Ω in experiments, and the combination of the two widens the impedance matching range of the system. This broadband structure with a wide impedance matching range and limited motion is more suitable for practical applications.

Dynamical analysis of a network of bistable energy harvesters with higher-order interactions

Dynamical analysis of a network of bistable energy harvesters with higher-order interactions

Harnessing multi-stable piezoelectric systems for enhanced wind energy harvesting

With the ongoing evolution of microelectronic devices toward lower power consumption, the utilization of piezoelectric materials for energy harvesting from wind-induced vibrations has garnered considerable attention. This study employs a combined approach involving finite element analysis and experiments to investigate the energy harvesting efficiency of the multi-stable piezoelectric wind energy harvester (MPWEH) and compares its performance with two alternative systems. The MPWEH demonstrates higher strains in both the x and y directions during reciprocating cross-well vibrations, establishing its superior energy harvesting efficiency compared to the alternative systems. Notably, at a wind speed of 8 m s−1, the MPWEH generates an output power nearly six times higher than local bistable piezoelectric energy harvester (LBPEH). The MPWEH achieves the maximum power density of 9.8125 mW cm−3, whereas the LBPEH registers the power density of 1.625 mW cm−3. The experimental results indicate that, under the optimal load resistance of 40 kΩ and a wind speed of 14 m s−1, the MPWEH achieves a peak output power of 2.76 mW, with a power density of 17.25 mW cm−3. The versatile applicability of the MPWEH extends across various low-power consumption microelectronic devices, positioning it as a valuable candidate for empowering continuous monitoring sensors in diverse domains.

Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

In the practical environment, it is very common for the simultaneous occurrence of base excitation and crosswind. Scavenging the combined energy of vibration and wind with a single energy harvesting structure is fascinating. For this purpose, the effects of the wind speed and random excitation level are investigated with the stochastic averaging method (SAM) based on the energy envelope. The results of the analytical prediction are verified with the Monte-Carlo method (MCM). The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester (BEH) realize the performance enhancement for a weak base excitation. However, as the strength of the wind increases to a particular level, the influence of the random base excitation on the dynamic responses is weakened, and the system exhibits a periodic galloping response. A comparison between a BEH and a linear energy harvester (LEH) indicates that the BEH demonstrates inferior performance for high-speed wind. Relevant experiments are conducted to investigate the validity of the theoretical prediction and numerical simulation. The experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind speeds. However, as the speed of the incoming wind is up to a particular level, the disadvantage of the BEH becomes clear and evident.

Segmented layered bistable piezoelectric laminates for enhanced energy harvesting from wind‐induced vibration

AbstractIn this study, a segmented layered bistable piezoelectric energy harvester (SBPEH) has been developed and thoroughly investigated for its wind energy harvesting capabilities. The SBPEH's performance was comprehensively evaluated through the creation of a detailed 3D finite element model using Abaqus and XFlow software, and further validated via rigorous wind tunnel experiments. The results of this research demonstrate the SBPEH's remarkable potential for wind energy harvesting. With a wide operational wind speed range, it achieved a maximum measured power output of 5.476 mW, coupled with an outstanding power density of 68.45 mW/cm3, both of which were realized at a wind speed of 13 m/s. It is worth noting that as the wind speed surpasses a specific threshold, the energy harvesting efficiency of the SBPEH experiences a decline, emphasizing the importance of identifying the optimal operational wind speed range for maximizing energy output. These findings offer valuable insights for the enhancement and application of SBPEHs, contributing to the advancement of renewable energy technologies and providing an eco‐friendly solution for power generation.Highlights The study introduces a new segmented layered bistable piezoelectric energy harvester (SBPEH) design for wind energy harvesting, addressing the limitations of traditional harvesters. Performance is evaluated through 3D finite element modeling, ABAQUS, Xflow simulations, and wind tunnel experiments. The SBPEH operates efficiently across a broad wind speed range (6–14 m/s), showcasing optimal output power of 5.476 mW at 13 m/s.