Vibration Energy Harvesting Device Research Articles

A miniaturized electromagnetic energy harvester with volt-level output based on stacked flexible coils

The bottleneck of the miniaturized electromagnetic vibration energy harvester (EVEH) device is the limited output voltage and power. Commonly reported mV-level AC output of the EVEHs cannot be rectified and used. In this work, we report a cost-effective EVEH device based on batch-fabricated flexible springs and coils. At an acceleration of ±1 g peak-to-peak amplitude (±9.8 m s−2), a maximum output peak-to-peak voltage of 1.57 V and an output power of 91.8 μW are measured, at a frequency of 66 Hz. The output voltage of the EVEH is successfully rectified, amplified (passively) and used to charge a supercapacitor.

A new electromagnetic vibrational energy harvesting device for swaying cables

An original vibrational energy harvesting device with regard to the vibrational performance of far-end cables was designed under the condition that no power can be supplied to the far end of freight cableways in transmission and distribution projects. The device was designed to have a Y-shaped radial gear-rack structure. The random vibrations of the cable are converted into three one-way rotary motions of a Y-shaped device terminal using a Y-shaped rack unit and one-way gear-rack units. The device then harvests the electric energy through a super-capacitor and supplies power to equipment in areas out of the reach of the power supply along the cableway. An analysis and dynamic simulation of the Y-shaped rack unit and one-way gear-rack units demonstrate that the Y-shaped layout of the device adapts well to the random vibration of the cable. The device was proven to have successfully harvested the vibrational energy of the cable in several directions on its radial plane, showing good prospects in supplying power to far-end wireless surveillance equipment for freight cableways in remote mountainous areas.

Voltage enhancing using multi-magnetic arrangement for low frequency vibrational energy harvesting

Power extraction from ambient vibrations is currently needed or the technology, and the amount of energy in ambient vibration is low and is sufficient to operate small devices. In the present article a methodology is proposed to extract the maximum amount of power from these sources. This paper includes the method to increase the output voltage in a vibration energy harvesting device. The vibration amplitude depends on stiffness, mass damping, vibrating source amplitude and frequency. Various methods are developed to increase the voltage output from these devices. An induced voltage can be further increased by changing the initial relative position between the magnet and coil. Magnetic flux density is found to be maximum in the vicinity of the coil. When the top magnet side matches with the coil centre, then the induced voltage is found to be maximum as compared to other relative positions between the coil and magnet. The multi-magnet arrangement has been used to enhance the total output of the device by keeping appropriate relative position of magnet with respect to the coil. A theoretical and experiment investigation is conducted on these methods, and a theoretical simulation is carried out using a FEA tool, and the experimental results closely match with the theoretical results. Four magnet coils have been considered in this study which gives the maximum output of 1.937 V, 1.426 V, 2.01 V and 2.27 V at 14 Hz frequency. With the help of a multi-magnet arrangement, maximum 7.64 V and 11.44 mW is reached. It observed that the multi-magnet arrangement is the best and gives the maximum voltage output as compared to other methods.

무전원 배관 감육 검사 시스템용 압전 진동 에너지 수확의 실험적 검증

Aimed at a self-powered real-time pipe-wall-thinning monitoring system, a piezoelectric vibration energy harvesting device is installed on a pipe in a pipeline system with internal fluid flow and its plausibility as a power source of a sensor node is checked experimentally. To this end, a bimorph cantilevered plate with two piezoelectric single crystal layers is designed to a measured excitation frequency of 154 Hz, the average output power of which is measured to be around 30 μW/(m/sSUP2/SUP)SUP2/SUP in the laboratory test using a electrodynamic shaker. To clamp the designed bimorph cantilevered plate on a vibrating curved surface of a pipe with little effects on its modal properties, a band-type mounting scheme is proposed in this work. It is experimentally shown that piezoelectric vibration energy harvesting can be an alternative to battery-powered solutions, though the reliability issue still remains.

Issues in vibration energy harvesting

In this study, fundamental issues related to bandwidth and nonlinear resonance in vibrational energy harvesting devices are investigated. The results show that using bandwidth as a criterion to measure device performance can be misleading. For a linear device, an enlarged bandwidth is achieved at the cost of sacrificing device performance near resonance, and thus widening the bandwidth may offer benefits only when the natural frequency of the linear device cannot match the dominant excitation frequency. For a nonlinear device, since the principle of superposition does not apply, the ‘‘broadband” performance improvements achieved for single-frequency excitations may not be achievable for multi-frequency excitations. It is also shown that a large-amplitude response based on the traditional ‘‘nonlinear resonance” does not always result in the optimal performance for a nonlinear device because of the negative work done by the excitation, which indicates energy is returned back to the excitation. Such undesired negative work is eliminated at global resonance, a generalized resonant condition for both linear and nonlinear systems. While the linear resonance is a special case of global resonance for a single-frequency excitation, the maximum potential of nonlinear energy harvesting can be reached for multi-frequency excitations by using global resonance to simultaneously harvest energy distributed over multiple frequencies.

Design and application of FeCo-related composites as novel sensors and vibration-energy harvesting devices

Design and application of FeCo-related composites as novel sensors and vibration-energy harvesting devices

Modeling and Experiment of Electromagnetic Energy Harvester System by Using Dual Moving Mechanical Systems at Low Frequency Range.

This paper presented a concept of single degree of freedom (SDOF) electromagnetic vibration energy harvester device. This technique enable system to operate at wideband frequency range, low frequency and has multi-resonance frequencies. Each mechanical system operates at difference frequency where each system is attached with electromagnetic transducer components. the device is developed based on the parameter factors of vibration transmissibility from external vibration sources into the device through mathematical modelling. A prototype was tested by using vibration exciter and normal human walking. the fabricated device had showed multi-resonant behavior at 4.26 and 8.34 Hz during test. From experiment results, they have showed capability to operate at wide bandwidth frequency from 1.9 until 18.5 Hz at a periodic excitation of 0.04 g. the highest amount of rms voltage that has been produced about 108 mV with a maximum 78 µW average power across the 150 Ω load resistance. So, it has proven the dual-moving mechanical concept with low damping value in system has increased the operating bandwidth frequency and also increased the amount of output voltage from device.

Finite element based system simulation for piezoelectric vibration energy harvesting devices

We present a system simulation approach for piezoelectric vibration energy harvesting devices. Accurate modeling of the electromechanical structure is achieved by the finite element method. For consideration of power electronic circuits as a means of energy extraction, the finite element model is iteratively coupled to electric circuits via Simulink. The high computational cost of conventional finite element calculations is overcome by a specialized modal truncation method for general linear piezoelectric structures. In doing so, the simulation approach allows efficient prediction of mechanical quantities (e.g. displacements, stresses) as well as electric potentials in the continuum under the influence of arbitrary electrical circuits. Several examples are studied to validate the truncation approach against analytical models and full finite element models. The applicability of the method is demonstrated for a piezoelectric vibration energy harvester in conjunction with a power electronic circuit.

Energy Harvesting and Magneto-Inductive Communications With Molecular Magnets on Vibrating Graphene and Biomedical Applications in the Kilohertz to Terahertz Band

Magneto-inductive (MI) Terahertz (THz) wireless channels provide significant theoretical performances for MI communications (MIC) and wireless power transmission (WPT) in nanoscale networks. Energy harvesting (EH) and signal generation are critical for autonomous operation in challenging medium including biomedical channels. State of the art electromagnetic (EM) vibrational devices have millimeter dimensions while targeting low frequency EH without any real-time communications. In this article, graphene resonators are combined with single molecule magnets (SMMs) to realize nanoscale EH, MIC and WPT with novel modulation methods achieving simultaneous wireless information and PT (SWIPT). Unique advantages of graphene including atomic thickness, ultra-low weight, high strain and resonance frequencies in the Kilohertz to Terahertz band are combined with high and stable magnetic moments of Terbium(III) bis(phthalocyanine) SMMs. Numerical analyses provide tens of nanowatts powers and efficiencies of $10^4 \, W/m^3$ in acoustic and ultrasound frequencies comparable with vibrational EH devices while millimeter wave carrier generation is numerically analyzed. Proposed model and communication theoretical analysis present a practical framework for challenging applications in the near future by promising simple mechanical design. Applications include nanoscale biomedical tagging including human cells, sensing and communication for diagnosis and treatment, EH and modulation for autonomous nano-robotics, and magnetic particle imaging (MPI).

Power and frequency bandwidth improvement of piezoelectric energy harvesting devices using phase-shifted synchronous electric charge extraction interface circuit

This article presents a new way to control the synchronous electric charge extraction interface circuit, which was formerly developed to improve the performances of piezoelectric vibration energy harvesting devices. An analytical model for energy harvesting systems including this new technique, called phase-shift synchronous electric charge extraction, is proposed. This model is then used to study the properties of this new control scheme in the cases of low and high electromechanical coupling. Contrary to the synchronous electric charge extraction technique which exhibited significant improvements in terms of harvested power for piezoelectric devices with low electromechanical coupling, the phase-shift synchronous electric charge extraction technique shows capability to increase the harvested power up to the theoretical limit for piezoelectric devices with high electromechanical coupling. In addition, the presented theoretical results show that the frequency bandwidth of piezoelectric energy harvesting devices may be substantially increased.

Double-induced-mode integrated triboelectric nanogenerator based on spring steel to maximize space utilization

Integrated multilayered triboelectric nanogenerators (TENGs) are an efficient approach to solve the insufficient energy problem caused by a single-layered TENG for achieving high output power density. However, most integrated multilayered TENGs have a relatively large volume. Here, a double-induced-mode integrated triboelectric nanogenerator (DI-TENG) based on spring steel plates is presented as a cost-effective, simple, and high-performance device for ambient vibration energy harvesting. The unique stackable rhombus structure, in which spring steel plates act both as skeletons and as electrodes, can enhance the output performance and maximize space utilization. The DI-TENG with five repeated units in a volume of 12 cm × 5 cm × 0.4 cm can generate a short-circuit current of 51 μA and can transfer charges of 1.25 μC in a half period. The contrast experiment is conducted systematically and the results have proved that the DI-TENG has a great advantage over the single-induced-mode TENG (SI-TENG) with only one side of a friction layer on its electrode. Besides, the DI-TENG can easily power a commercial calculator and can be used as a door switch sensor.

Lead-free Mn-doped (K0.5,Na0.5)NbO3 piezoelectric thin films for MEMS-based vibrational energy harvester applications

Lead-free Mn-doped (K0.5, Na0.5)NbO3 (KNN) thin films were fabricated by the chemical solution deposition method. The addition of small concentration of Mn dopant effectively reduced the leakage current density and enhanced the piezoelectric properties of the films. The leakage current density of 0.5 mol. % Mn-doped KNN film showed the lowest value of ∼10-7 A/cm2 at 10 V compared to the films with other doping concentrations and the piezoelectric d33 and e31 coefficients of this film were ∼90 pm/V and −8.5 C/m2, respectively. The maximum power and power density of the lead-free thin film-based vibrational energy harvesting device were 3.62 μW and 1800 μW/cm3 at the resonance frequency of 132 Hz and the acceleration of 1.0 G. The results prove that the 0.5 mol. % Mn-doped KNN film is an attractive candidate transducer layer for the piezoelectric MEMS energy harvesting device applications with a small volume and a long-lasting power source.

Combined Effect of Bistability and Mechanical Impact on the Performance of a Nonlinear Electromagnetic Vibration Energy Harvester

This paper presents the design, modeling, fabrication, and characterization of a nonlinear bistable electromagnetic vibrational energy harvesting device. A folded cantilever structure based on low Young's modulus FR4 material reduces the operating frequency, while keeping the device footprint relatively small. The bistability is introduced into the system by a pair of repulsively oriented NdFeB permanent magnets. A second nonlinear mechanism, i.e., mechanical impact between the oscillator and the base, is also taken into account. Analytical expressions are derived to obtain the restoring force and potential energy for such a system. The model was further numerically simulated and validated with experimental results of the fabricated device. The device generated maximum power of 19.3 μW at 1.5-g acceleration across an optimum resistive load of 1 kΩ, which was further improved by almost 70% with an optimized prototype. Both the numerical simulation and experimental results show broadening of the operational frequency range of the nonlinear bistable device by up to 4.35 Hz at 0.6-g acceleration with respect to the linear counterpart. At higher input vibration, the harvester oscillates with large amplitude and collides with the base, which abruptly changes the system dynamics. At an acceleration of 1.5 g, this impact induced change in dynamics increases the peak power frequency and widens the bandwidth even further up to 8 Hz (22% of the peak power frequency). Thus, the effects of both bistability and mechanical impact are incorporated into a single device to obtain a fairly wideband operation.

The MEMS four-leaf clover wideband vibration energy harvesting device: design concept and experimental verification

In this contribution, we discuss a novel design concept of a high-performance wideband MEMS vibration energy harvester (EH), named four-leaf clover (FLC EH-MEMS) after its circular shape featuring four petal-like mass-spring systems. The goal is to enable multiple resonant modes in the typical range of vibrations scattered in the environment (i.e., up to 4---5 kHz). This boosts the FLC conversion capability from mechanical into electrical energy exploiting the piezoelectric effect, thus overcoming the common limitation of cantilever-like EHs that exhibit good performance only in a very narrow band of vibration (i.e., fundamental resonant mode). The FLC concept is first discussed framing it into the current state of the art, highlighting its strengths. Then, after a brief theoretical introduction on mechanical resonators, the FLC EH-MEMS device is described in details. Finite Element Method (FEM) analyses are conducted in the ANSYS Workbench™ framework. A suitable 3D model is built up to perform modal simulations, aimed to identify mechanical resonant modes, as well as harmonic analyses, devoted to study the mechanical and electrical behaviour of the FLC EH-MEMS (coupled field analysis). The work reports on experimental activities, as well. Physical samples of the FLC EH-MEMS device are fabricated within a technology platform that combines surface and bulk micromachining. Thereafter, specimens are tested both with a laser doppler vibrometer measurement setup as well as with a dedicated shaker-based setup, and the results are compared with simulations for validation purposes. In conclusion, the FLC EH-MEMS exhibits a large number of resonant modes scattered in the tested range of vibrations (up to 15 kHz) already starting from frequencies as low as 200 Hz, and expected levels of converted power better than 10 µW.

Analysis and efficiency measurement of electromagnetic vibration energy harvesting system

This paper deals with the efficiency analysis of developed electromagnetic vibration energy harvesting systems. The efficiency analysis of this energy harvesting system is specified and a linear model of the vibration energy harvesting system is simulated to determine theoretical limits. The influence of individual parameters of vibration energy harvesters is evaluated by the simulation model. Three vibration energy harvesting devices, developed at Brno University of Technology, were measured and their efficiencies were consecutively calculated from the measured data. Vibration tests of these harvesters were done with a lightweight vibrating structure of a steel beam where the effect of the vibration energy harvester operation is noticeable. The effects of used electronics and power management circuit for different levels of excited mechanical vibrations are presented. Realized analyses and measurements will be used for future improvement of vibration energy harvester design; mainly in applications of lightweight vibrating structures where the vibration energy harvester can affect mechanical vibrations in feedback.

Piezoelectric Vibration Energy Harvesting Device Combined with Damper

Piezoelectricity is a type of material that enables mechanical energy and electrical energy to be interchangeable, which can be divided into positive piezoelectric effect and inverse piezoelectric effect. The positive piezoelectric effect is that the electric dipole moment of material generates changes when the piezoelectric material is subjected to pressure, resulting in electrical energy. Conversely, the inverse piezoelectric effect is the process of electrical energy converted into mechanical energy.

A Silicon Disk with Sandwiched Piezoelectric Springs for Ultra-low Frequency Energy Harvesting

Exploiting the sporadic availability of energy by energy harvesting devices is an attractive solution to power wireless sensor nodes and many other distributed modules for much longer operation duration and much lower maintenance cost after they are deployed. MEMS energy harvesting devices exhibit unique advantageous of super-compact size, mass productivity, and easy-integration with sensors, actuators and other integrated circuits. However, MEMS vibration energy harvesting devices are rather difficult to be used practically due to their poor response to most of the ambient vibrations at ultra-low frequency range. In this paper, a micromachined silicon disk with sandwiched piezoelectric springs was successfully developed with resonant frequency of 15.36∼42.42 Hz and quality factor of 39∼55 for energy harvesting. Footprint size of the device was 6 mm × 6 mm, which is less than half of the piezoelectric cantilevers, while the device can scavenge reasonably high power of 0.57 μW at the acceleration of 0.1 g. The evaluation results also suggested that the device was quite sensitive as a sensor for selective monitoring of vibrations at a certain frequency.

Powering autonomous sensors with miniaturized piezoelectric based energy harvesting devices operating at very low frequency

Harvesting energy from ambient mechanical vibrations is a smart and efficient way to power autonomous sensors and support innovative developments in IoT (Internet of Things), WSN (Wireless Sensor Network) and even implantable medical devices. Beyond the environmental operating conditions, efficiency of such devices is mainly related to energy source properties like the amplitude of vibrations and its spectral contain and some of these applications exhibit a quite low frequency spectrum where harvesting surrounding mechanical energy make sense, typically 5-50Hz for implantable medical devices or 50Hz-150Hz for industrial machines. Harvesting such low frequency vibrations is a challenge since it leads to adapt the resonator geometries to the targeted frequency or to use out-off band indirect harvesting strategies. In this paper we present a piezoelectric based vibrational energy harvesting device (PEH) which could be integrated into a biocompatible package to power implantable sensor or therapeutic medical devices. The presented architecture is a serial bimorph laminated with ultra-thinned (ranging from 15μm to 100μm) outer PZT “skins” that could operate at a “very low frequency”, below 25Hz typically. The core process flow is disclosed and performances highlighted with regards to other low frequency demonstrations.

An infrasonic vibration energy harvester using pendulum impact

This paper presents experiments and finite element (FE) analyses of an infrasonic vibration energy harvesting device in which a low-frequency pendulum impacts a cantilever beam type energy harvester. The experiments demonstrate that the energy harvester operates in the frequency range of 2~8 Hz and has output power of several microwatts under 0.1 g excitation acceleration. Moreover, a finite element model with a coupling of impact, vibration, piezoelectricity and circuit is established and used to analyze the output voltage and power. The frequency response characteristics at different pendulum lengths and the distances between the pendulum ball and cantilever beams are measured and calculated, respectively. Useful guidelines for designing the energy harvester are obtained.

Assessment of MEMS Vibration Energy Harvesting for High Temperature Sensing Applications

Distributed electronics for improving the accuracy of sensing in harsh high temperature environments, such as aero-engine and down-well is a growing field, where reduced power input requirements in cabling and batteries is viewed a key enabler for accelerating the adoption of high temperature electronics. Although batteries are available that can operate up to 200°C, they offer limited life at high temperatures and are bulky, increasing the costs of deployment and maintenance. Cabling also adds weight and takes up space in limited access applications. Energy harvesting in-situ offers the opportunity to make a step change in the design of high temperature electronics modules and in expanding their possible range of applications; for example, in sensor systems for combustor and turbine monitoring in aero-engines. This paper covers an assessment of MEMS vibration energy harvesting technology for high temperature sensing applications. MEMS devices based on the principle of parametric resonance, using AlN on Silicon have been designed and fabricated, along with sourcing of high temperature components for rectification, impedance matching and energy storage. The MEMS devices have been packaged into ceramic chip carriers and measured for energy output from a random vibration profile representative of an aerospace application. The measured output from the MEMS vibration energy harvester is capable of providing sufficient power to be of interest for autonomous sensing applications. This paper reports on the performance of the MEMS vibration energy harvesting devices and their associated circuitry at room temperature and at temperatures of up to 150°C. The challenges remaining to develop robust energy harvesting devices that could be applied in aero-engine, down-well and other high temperature applications are described. This work has been carried out under the Innovate UK supported project HI-VIBE, in a collaboration between GE Aviation Systems – Newmarket and the University of Cambridge.