Traditional Piezoelectric Energy Harvester Research Articles

A piezoelectric and electromagnetic hybrid energy harvester based on two-stage magnetic coupling

Traditional piezoelectric energy harvesters cannot adapt to environmental energy with low frequency, wideband, and randomness because of the narrow working bandwidth. The introduction of magnetic coupling can improve the narrow-band characteristics of piezoelectric energy harvesting structures. To explore more efficient broadband methods, this paper designs a piezoelectric and electromagnetic hybrid energy harvester (PEEH) based on two-stage magnetic coupling to realize the expansion of piezoelectric energy harvesting bandwidth. In this paper, the magnetic pole alternating frequency is changed and the output of the structure is tested, and the operating frequency bands under different alternating frequencies are compared according to the test results. It can be seen from the experimental results that the output performance of the structure is obviously improved by increasing the AC frequency of the magnetic pole while reducing the optimal frequency point of the structure. When the number of magnets in the rotor magnet array is 6, increasing the pole alternating frequency can effectively improve the output performance of the electromagnetic unit when the rotor speed is low, and can also increase the maximum output voltage and energy harvest bandwidth of the piezoelectric unit by 189% and 150%, respectively. Therefore, by increasing the alternating frequency of magnetic poles, the output voltage of the structure can be improved, and the bandwidth of the structure can be broadened.

Double-speed piezoelectric–electromagnetic hybrid energy harvester driven by cross-moving magnets

Energy harvesters have gained popularity as green energy devices that transform mechanical energy from the environment into electricity. However, traditional piezoelectric energy harvesters are limited by narrowband response, and the output capability of electromagnetic energy harvesters is dependent on the rate of magnetic field changes on the coil, which is constrained by the device’s structure. To address these issues, this paper presents a hybrid energy harvester (HEH) that combines coils and arc magnets, forming an electromagnetic component (EMEH). Additionally, it incorporates a piezoelectric cantilever beam (PECB) as a piezoelectric component (PEH). Unlike traditional electromagnetic energy harvesters, this design utilizes two arc magnets to drive the rotating brackets, thereby achieving the opposite movement of the coil and magnet. This increases the relative velocity and consequently enhances the rate of magnetic field change on the coil. Simultaneously, it achieves frequency up-conversion by inducing vibration in the PECB through magnetic force. Under an external excitation of 5.5 Hz, the PEH achieves a maximum power of 0.362 mW at a load resistance of 330 kΩ, while the EMEH with 1200 turns of coil attains a maximum power of 8.74 mW at a load resistance of 110 Ω. The power density of the PEH reaches 94.96 μW cm−3. These results highlight the significant potential of the proposed energy harvester for powering low-power devices.

An innovative piezoelectric energy harvester inspired by a line tooth: design, dynamic model and broadband harvesting conditions

Piezoelectric energy harvesting is commonly considered to be a promising field of development for microelectronic devices due to its potential to address a variety of key supply problems. However, due to their geometric designs, traditional piezoelectric energy harvesters (PEHs) tend to only be able to cultivate energy from vibrations flowing in one direction. The results of PEHs only capable of harvesting mono-directional vibrations are that they suffer from narrow resonance frequency bands and low energy conversion efficiency. To overcome these difficulties, this paper proposes a PEH inspired by a line tooth (PEH-ILT) with the ability to collect three-dimensional stochastic vibrations. To do so, the PEH-ILT possesses a nonlinear geometric shape which can, in theory, be designed arbitrarily. An example PEH-ILT is illustrated in this paper as well corresponding nonlinear piezoelectric constitutive equations. The cylindrical spiral curve is inspired by the line tooth design and is intended to replicate a nonlinear electro-mechanical model and its electrical output. Furthermore, the PEH-ILT is evaluated in this study by interacting with the four basic vibrations such devices are expected to encounter. In addition, the broadband piezoelectric energy harvesting conditions of the PEH-ILT are parsed and determined through the Melnikov theory, providing a theoretical explanation to the broadband conditions of the harvester. And this study can lay the theoretical basis for practical applications.

High output power density and strong vibration durability in a modified barbell-shaped energy harvester based on multilayer Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals

Traditional piezoelectric energy harvesters are made of piezoelectric ceramics with a cantilever structure, which show a low output energy density. Thus, they are difficult to meet the requirements for self-powered electronics. Herein, we report a modified barbell-shaped piezoelectric energy harvester (BSPEH) based on two d33-mode cuboid Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 multilayer single crystal stacks (ten wafers with a thickness of 0.5 mm and d33 ∼ 1300 pC/N). Due to the electrically parallel and series connections of multilayer piezoelectric elements and the high figure-of-merit d33 × g33 of the single crystal, the maximum power density of BSPEH could reach 39.7 mW cm−3 (under an acceleration of 5 g), which is much higher than that of traditional cantilever piezoelectric energy harvesters (CPEHs), ∼0.1 mW cm−3. A maximum output voltage of 50.4 Vp–p was obtained when two crystal stacks are connected in series, and a maximum output current of 880 µA can be obtained when two crystal stacks are connected in parallel. Furthermore, the energy harvesting properties of BSPEH stay almost the same after 106 vibration cycles, while the properties of CPEH decrease 20% after 105 vibration cycles. This work indicates that BSPEH has a great potential in the application of wireless sensor networks for realizing the self-power of the equipment.

Research and Application of Vibration Energy Harvester Using Macro-Fiber Composite

The traditional piezoelectric energy harvester has been used to power to the low-power wireless sensor network node. But its ceramic layer is fragile under the condition of large amplitude, high intensity and long time excitation. In order to solve this problem, the piezoelectric fiber composite MFC acts as a piezoelectric energy harvester. It is more flexible and has a longer service life. The relationship between the output power, energy conversion efficiency of MFC and the load is studied in this paper. The vibration power generation model of the cantilever beam MFC energy absorbing device is established, and the weak energy generated by the MFC energy harvester is collected by the energy collection management chip LTC3588-1. Powering circuit to low-power wireless sensor network node is designed. The experimental results show that there is a certain error between the theoretical and experimental values of the model, but it can reflect the relationship between MFC output power, energy conversion efficiency and load. The cantilever beam MFC energy absorbing device can meet the low power wireless sensing. The power supply of the network node is required.

Material influence in newly proposed ferroelectric energy harvesters

Recently, a novel method for mechanical energy harvesting has been proposed, which is based on stress-induced polarization switching in ferroelectric materials. Compared with the traditional piezoelectric energy harvesters, a huge improvement in the output energy has already been theoretically demonstrated. In this article, the influence of different materials on the energy-harvesting performance associated with this new strategy is further studied. The state-of-the-art phase-field model is adopted to investigate the nonlinear hysteretic energy-harvesting process in two nanoscale ferroelectric energy harvesters, which are respectively based on two typical ferroelectric materials—single-crystal BaTiO3 and PbTiO3. In both cases, the effects of the bias voltage and bias resistance are carefully investigated and the optimum values are obtained. Later, the energy-harvesting process and energy flow details in both harvesters working at the optimum conditions are presented and carefully compared in the context of real applications. Furthermore, the energy-harvesting performance of a BaTiO3-based nanoscale piezoelectric energy harvester with equivalent material size is additionally simulated with the finite element method and compared with the corresponding results of the ferroelectric energy harvesters, where obvious advantages associated with the new strategy are demonstrated.

Experimental study on a wide-band piezoelectric energy harvester with rotating beams vibrating in perpendicular directions

ABSTRACTWe present here a new design for a wide-band piezoelectric energy harvester. Our system consists of two mutually perpendicular cantilever beams with attached PZT (lead zirconate titanate) patches. Traditional piezoelectric energy harvesters can only generate a single resonance peak and therefore they are limited by a narrow band and low power output. In this paper, by using two piezoelectric cantilever beams aligned in a mutually perpendicular direction, two resonance peaks are observed. Additionally, by adjusting the rotation angle of these beams, the operational frequency bandwidth has been enlarged by 70%–100%. Therefore, our new piezoelectric energy harvester has the potential to harvest energy in a wider frequency range for practical applications with variable frequency sources.

Design and development of a broadband magnet-induced dual-cantilever piezoelectric energy harvester

In this article, a broadband magnet-induced dual-cantilever piezoelectric energy harvester is designed and developed. The dual-cantilever structure consists of an outer and an inner beams with magnets attached to the tips. The magnets generate nonlinear repulsive force between the two beams and make the structure bistable. In the theoretical model, each beam is considered as a single-degree-of-freedom system with magnetic force applied at the free end. From the simulation results, chaotic motion is observed in a wide frequency range. A prototype of the harvester is built and verified with the simulation results. The simulation and experimental results show good agreement with respect to the power bandwidth and amplitude. The distance between magnets is adjusted to observe its effect on the power response of the harvester. The inner and outer beams are simulated and tested independently first to observe the performance of each beam. Finally, an interface circuit is designed to combine all piezoelectric plates to acquire the overall performance. By comparing with the traditional piezoelectric energy harvester, the new design is shown to provide a significant improvement in bandwidth.