scholarly journals Experimental Characterization of Optimized Piezoelectric Energy Harvesters for Wearable Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7042
Author(s):  
Petar Gljušćić ◽  
Saša Zelenika
Keyword(s):  
Sensor Networks ◽  
Kinetic Energy ◽  
Average Power ◽  
Wearable Devices ◽  
Specific Power ◽  
Medical Systems ◽  
Power Sources ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Power Outputs

The development of wearable devices and remote sensor networks progressively relies on their increased power autonomy, which can be further expanded by replacing conventional power sources, characterized by limited lifetimes, with energy harvesting systems. Due to its pervasiveness, kinetic energy is considered as one of the most promising energy forms, especially when combined with the simple and scalable piezoelectric approach. The integration of piezoelectric energy harvesters, generally in the form of bimorph cantilevers, with wearable and remote sensors, highlighted a drawback of such a configuration, i.e., their narrow operating bandwidth. In order to overcome this disadvantage while maximizing power outputs, optimized cantilever geometries, developed using the design of experiments approach, are analysed and combined in this work with frequency up-conversion excitation that allows converting random kinetic ambient motion into a periodical excitation of the harvester. The developed optimised designs, all with the same harvesters’ footprint area of 23 × 15 mm, are thoroughly analysed via coupled harmonic and transient numerical analyses, along with the mostly neglected strength analyses. The models are validated experimentally via innovative experimental setups. The thus-proposed f = 50 mm watch-like prototype allows, by using a rotating flywheel, the collection of low-frequency (ca. 1 to 3 Hz) human kinetic energy, and the periodic excitation of the optimized harvesters that, oscillating at their eigenfrequencies (~325 to ~930 Hz), display specific power outputs improved by up to 5.5 times, when compared to a conventional rectangular form, with maximal power outputs of up to >130 mW and average power outputs of up to >3 mW. These power levels should amply satisfy the requirements of factual wearable medical systems, while providing also an adaptability to accommodate several diverse sensors. All of this creates the preconditions for the development of novel autonomous wearable devices aimed not only at sensor networks for remote patient monitoring and telemedicine, but, potentially, also for IoT and structural health monitoring.

scholarly journals Ensuring the sustainability of real-time embedded system under both QoS and Energy Constraints

2019 ◽  
Vol 281 ◽  
pp. 04006
Author(s):  
Maissa Abdallah ◽  
Nadine Abdallah ◽  
Maryline Chetto
Keyword(s):  
Sensor Networks ◽  
Embedded System ◽  
Sensor Nodes ◽  
Electronic Systems ◽  
Periodic Tasks ◽  
Energy Aware ◽  
Power Sources ◽  
Energy Harvesters ◽  
Aperiodic Tasks ◽  
Energy Constraints

Nowadays, wireless sensor networks (WSNs) are more and more used in applications such as environment monitoring, healthcare monitoring, etc...The challenge in sensor networks is to ensure the sustainability of the system by guaranteeing the required performance level. However, with the limited capacity of finite power sources and the need of guaranteeing a long lifetime of those systems, it is suitable to use energy harvesting which allows to supply low-power electronic systems by converting ambient energy into electric power. Hence, our study is concerned with the problem of soft periodic and aperiodic tasks scheduling in sensor nodes powered by energy harvesters. In this paper, we address this issue by proposing three energy-aware schedulers, namely BG-Green-RTO, BG-Green-BWP and Green-AWP which aim to improve the responsiveness of aperiodic tasks while still guaranteeing the execution of periodic tasks considering their timing and energy constraints. Such algorithms allow to gracefully cope with processing overload and energy starvation. Moreover, a simulation study permits to show their performance.

Analysis of energy harvesters for highway bridges

2011 ◽  
Vol 22 (16) ◽  
pp. 1929-1938 ◽  
Author(s):  
S. F. Ali ◽  
M. I. Friswell ◽  
S. Adhikari
Keyword(s):  
Average Power ◽  
Highway Bridges ◽  
Point Load ◽  
Structural Vibration ◽  
Energy Scavenging ◽  
Single Degree Of Freedom ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Bridge Model ◽  
Single Vehicle

This article investigates the possibility of piezoelectric energy harvesters as energy scavenging devices in highway bridges. The structural vibration due to the motion of a load (vehicle) on the bridge is considered as the source of energy generation for the harvester. The energy generated in this way can be useful for wireless sensor networks for structural health monitoring of bridges by reducing or even eliminating the need for battery replacement/recharging. A highway bridge model with a moving point load is investigated and a linear single-degree-of-freedom model is used for the piezoelectric energy harvester. Two types of harvesters, namely, the harvesting circuit with and without an inductor, have been considered and the energy generated for a single vehicle has been estimated. These results may be used, together with traffic statistics, to obtain the variation of average power and thus, for a given application, help to design the energy management system.

scholarly journals Acoustic Energy Harvesting Through Multilayer Piezoelectric Harvester Model

2020 ◽  
Vol 9 (3) ◽  
pp. 1848-1856
Keyword(s):  
Energy Harvesting ◽  
Low Power ◽  
Mechanical Energy ◽  
Scaling Analysis ◽  
Ambient Vibrations ◽  
Specific Element ◽  
Power Sources ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Effective Transfer

Low-power requirements of contemporary sensing technology attract research on alternate power sources that can replace batteries. Energy harvesters’ function as power sources for sensors and other low-power devices by transducing the ambient energy into usable electrical form. Energy harvesters absorbing the ambient vibrations that have potential to deliver uninterrupted power to sensing nodes installed in remote and vibration rich environments motivate the research in vibrational energy harvesting. Piezoelectric bimorphs have been demonstrating a pre-eminence in converting the mechanical energy in ambient vibrations into electrical energy. Improving the performance of these harvesters is pivotal, as the energy in ambient vibrations is innately low. In this paper, we propose a mechanism namely MultilayerPEHM (Piezoelectric Energy Harvester Model) which helps in converting the waste or unused energy into the useful energy. Multilayer-PEHM contains the various layer, which is placed one over the other, each layer is placed with specific element according to their properties and size, the size of the layer plays an important part for achieving efficiency. Furthermore, this paper presents an audit of the energy available in a vibrating source and design for effective transfer of the energy to harvesters, secondly, design of vibration energy harvesters with a focus to enhance their performance, and lastly, identification of key performance metrics influencing conversion efficiencies and scaling analysis for these acoustic harvesters. Typical vibration levels in stationary installations such as surfaces of blowers and ducts, and in mobile platforms such as light and heavy transport vehicles, are determined by measuring the acceleration signal. The frequency content in the signal is determined from the Fast Fourier Transform.

Concurrent vibration attenuation and low-power electricity generation in a locally resonant metastructure

2022 ◽  
pp. 1045389X2110725
Author(s):  
Mohid Muneeb Khattak ◽  
Christopher Sugino ◽  
Alper Erturk
Keyword(s):  
Vibrational Energy ◽  
Laser Doppler Vibrometer ◽  
Total Power ◽  
Main Beam ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Vibration Attenuation ◽  
Electrodynamic Shaker ◽  
Electrical Loads ◽  
Power Outputs

We investigate piezoelectric energy harvesting on a locally resonant metamaterial beam for concurrent power generation and bandgap formation. The mechanical resonators (small beam attachments on the main beam structure) have piezoelectric elements which are connected to electrical loads to quantify their electrical output in the locally resonant bandgap neighborhood. Electromechanical model simulations are followed by detailed experiments on a beam setup with nine resonators. The main beam is excited by an electrodynamic shaker from its base over the frequency range of0–150 Hz and the motion at the tip is measured using a laser Doppler vibrometer to extract its transmissibility frequency response. The formation of a locally resonant bandgap is confirmed and a resistor sweep is performed for the energy harvesters to capture the optimal power conditions. Individual power outputs of the harvester resonators are compared in terms of their percentage contribution to the total power output. Numerical and experimental analysis shows that, inside the locally resonant bandgap, most of the vibrational energy (and hence harvested energy) is localized near the excited base of the beam, and the majority of the total harvested power is extracted by the first few resonators.

A Distributed Parameter Electromechanical Model for Cantilevered Piezoelectric Energy Harvesters

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
A. Erturk ◽  
D. J. Inman
Keyword(s):  
Electromechanical Coupling ◽  
Mechanical Response ◽  
Exact Analytical Solution ◽  
Short Circuit ◽  
Open Circuit ◽  
Distributed Parameter ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Cantilevered Beams ◽  
Power Outputs

Cantilevered beams with piezoceramic layers have been frequently used as piezoelectric vibration energy harvesters in the past five years. The literature includes several single degree-of-freedom models, a few approximate distributed parameter models and even some incorrect approaches for predicting the electromechanical behavior of these harvesters. In this paper, we present the exact analytical solution of a cantilevered piezoelectric energy harvester with Euler–Bernoulli beam assumptions. The excitation of the harvester is assumed to be due to its base motion in the form of translation in the transverse direction with small rotation, and it is not restricted to be harmonic in time. The resulting expressions for the coupled mechanical response and the electrical outputs are then reduced for the particular case of harmonic behavior in time and closed-form exact expressions are obtained. Simple expressions for the coupled mechanical response, voltage, current, and power outputs are also presented for excitations around the modal frequencies. Finally, the model proposed is used in a parametric case study for a unimorph harvester, and important characteristics of the coupled distributed parameter system, such as short circuit and open circuit behaviors, are investigated in detail. Modal electromechanical coupling and dependence of the electrical outputs on the locations of the electrodes are also discussed with examples.

Efficient and Sensitive Energy Harvesting Using Piezoelectric MEMS Compliant Mechanisms

2015 ◽  
Author(s):  
Xiaokun Ma ◽  
Hong Goo Yeo ◽  
Christopher D. Rahn ◽  
Susan Trolier-McKinstry
Keyword(s):  
Proof Mass ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Average Power ◽  
Low Frequency ◽  
Human Movement ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Rigid Frame ◽  
The Time Domain

Piezoelectric energy harvesters typically perform poorly in the low frequency, low amplitude, and intermittent excitation environment of human movement. In this paper, a piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a PZT unimorph clamped at the base and attached to a compliant mechanism at the tip. The compliant mechanism has two flexures that amplify the tip displacement to produce large motion of a proof mass and a low frequency first mode with an efficient (nearly quadratic) shape. The compliant mechanism is fabricated as a separate, relatively rigid frame with flexure hinges, simplifying the fabrication process and surrounding and protecting the PZT unimorph. The bridge structure of the PCM also introduces an axial tensioning nonlinearity that self-limits the response to large amplitude impacts, improving the robustness of the device. Comparing the time domain performance based on realistic wrist acceleration data, the PCM produces 6 times more average power than a proof mass cantilever with the same unimorph area and natural frequency.

scholarly journals Kinetic Energy Harvesting for Wearable Medical Sensors

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4922 ◽  
Author(s):  
Petar Gljušćić ◽  
Saša Zelenika ◽  
David Blažević ◽  
Ervin Kamenar
Keyword(s):  
Energy Harvesting ◽  
Kinetic Energy ◽  
Human Motion ◽  
Optimal Operation ◽  
Specific Power ◽  
Medical Applications ◽  
Piezoelectric Energy ◽  
Medical Sensors ◽  
Wearable Medical ◽  
Energy Harvesting Devices

The process of collecting low-level kinetic energy, which is present in all moving systems, by using energy harvesting principles, is of particular interest in wearable technology, especially in ultra-low power devices for medical applications. In fact, the replacement of batteries with innovative piezoelectric energy harvesting devices can result in mass and size reduction, favoring the miniaturization of wearable devices, as well as drastically increasing their autonomy. The aim of this work is to assess the power requirements of wearable sensors for medical applications, and address the intrinsic problem of piezoelectric kinetic energy harvesting devices that can be used to power them; namely, the narrow area of optimal operation around the eigenfrequencies of a specific device. This is achieved by using complex numerical models comprising modal, harmonic and transient analyses. In order to overcome the random nature of excitations generated by human motion, novel excitation modalities are investigated with the goal of increasing the specific power outputs. A solution embracing an optimized harvester geometry and relying on an excitation mechanism suitable for wearable medical sensors is hence proposed. The electrical circuitry required for efficient energy management is considered as well.

scholarly journals Electromechanical Performance Analysis of the Hybrid Piezoelectric-Electromagnetic Energy Harvester under Rotary Magnetic Plucking Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Hongyan Wang ◽  
Jiarui Hu ◽  
Gang Sun ◽  
Liying Zou
Keyword(s):  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Average Power ◽  
Load Resistance ◽  
Electromagnetic Energy ◽  
Lumped Parameter Model ◽  
Model Parameters ◽  
Piezoelectric Energy ◽  
Power Inputs ◽  
Power Outputs

This paper presents an analysis of the hybrid piezoelectric-electromagnetic energy harvester (P-EMEH) driven by contactless rotary magnetic plucking. A lumped-parameter model of the hybrid P-EMEH is developed, and the model parameters are determined from the finite element analysis (FEA) method. A parametric study is conducted to investigate the effects of driving force parameters, load resistance, and electromechanical coupling strengths (EMCSs) on the maximal displacements and velocities, average power inputs and outputs, and energy efficiencies of the system for indicating the performance of the hybrid P-EMEH. The results show that the hybrid P-EMEH can obtain the improved power inputs by reducing the gyration radii of the rotary magnet and shortening the gaps between the two magnets. The structural vibrations can be strongly suppressed owing to the optimal piezoelectric power outputs, which can lead to the occurrence of valleys’ power of the electromagnetic element. At weak coupling, the hybrid P-EMEH can achieve higher power outputs than the single piezoelectric energy harvester (PEH) and the single electromagnetic energy harvester (EMEH). At strong coupling, the use of the PEH is more advantageous for energy harvesting due to wider power bandwidths at high dimensionless frequencies when compared with the hybrid P-EMEH. This work provides a fundamental understanding on the effect of load resistance and EMCSs on the dynamic and electrical characteristics of the magnetically plucked hybrid P-EMEH.

Efficient Aeroelastic Energy Harvesting From HVAC Ducts

2015 ◽  
Author(s):  
Xiaokun Ma ◽  
Christopher D. Rahn
Keyword(s):  
Cantilever Beam ◽  
Average Power ◽  
Beam Theory ◽  
Constitutive Law ◽  
Premature Failure ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Higher Power ◽  
Pressure Dynamics ◽  
Euler Bernoulli Beam

Piezoelectric energy harvesters can be used to scavenge energy for unattended sensors in heating ventilation and air conditioning (HVAC) ducts. In this paper, an aeroelastic energy harvester using a pinned-pinned beam is designed, modeled, and analyzed. To obtain the desired model, we use nonlinear Euler-Bernoulli beam theory, a linear piezoelectric constitutive law, and nonlinear pressure dynamics. Compared with the traditional cantilever beam used by previous researchers, the pinned-pinned beam has a higher frequency limit cycle and more efficient mode shape, which ensure higher power output at the same strain level. The pinned-pinned boundary condition also self-limits the response amplitude, limiting strain in the piezoelectric beam and premature failure. Simulation results show that the pinned-pinned beam can harvest at least 4 times more average power than a cantilever beam with the same maximum strain.

Performance of a multipurpose piezoelectric energy harvester

2017 ◽  
Vol 31 (07) ◽  
pp. 1741007 ◽  
Author(s):  
Kangqi Fan ◽  
Liansong Wang ◽  
Yingmin Zhu ◽  
Zhaohui Liu ◽  
Bo Yu
Keyword(s):  
Power Output ◽  
Mechanical Vibration ◽  
Experimental Studies ◽  
Rotation Frequency ◽  
Peak Voltage ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Cantilever ◽  
Power Outputs ◽  
Rotation Motion

Harvesting energy from the surrounding environment through piezoelectric conversion is a promising method for implementing self-sustained low-power devices. To date, most piezoelectric energy harvesters (PEHs) developed can only scavenge energy from the unidirectional mechanical vibration. This deficiency severely limits the adaptability of PEHs because the real-world excitations may involve different mechanical motions and the mechanical vibration may come from various directions. To tackle this issue, we proposed a multipurpose PEH, which is composed of a ferromagnetic ball, a cylindrical track and four piezoelectric cantilever beams. In this paper, theoretical and experimental studies were carried out to examine the performance of the multipurpose PEH. The experimental results indicate that, under the vibrations that are perpendicular to the ground, the maximum peak voltage is increased by 3.2 V and the bandwidth of the voltage above 4 V is expanded by more than 4 Hz by the proposed PEH as compared to its linear counterpart; the maximum power output of 0.8 mW is attained when the PEH is excited at 39.5 Hz. Under the sway motion around different directions on the horizontal plane, significant power outputs, varying from 0.05 mW to 0.18 mW, are also generated by the multipurpose PEH when the sway angle is larger than 5[Formula: see text] and the sway frequency is smaller than 2.8 Hz. In addition, the multipurpose PEH demonstrates the capacity of collecting energy from the rotation motion, and approximately 0.14 mW power output is achieved when the rotation frequency is 1 Hz.

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