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.

Fractal-Inspired Multifrequency Structures for Piezoelectric Harvesting of Ambient Kinetic Energy

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
D. Castagnetti
Keyword(s):  
Energy Harvesting ◽  
Kinetic Energy ◽  
Fractal Geometry ◽  
Electrical Energy ◽  
Piezoelectric Energy Harvesting ◽  
Charge Generation ◽  
Piezoelectric Energy ◽  
Bending Strain ◽  
Noticeable Improvement ◽  
Energy Harvesting Devices

Energy harvesting devices capable of converting freely-available ambient energy into electrical energy have received significant attention recently. Ambient kinetic energy is particularly attractive for conversion since it is almost ubiquitous and easily accessible. Piezoelectric energy harvesting devices are promising due to their simple configuration and high conversion efficiency. This paper studies multifrequency structures for piezoelectric energy harvesting of ambient kinetic energy, inspired by fractal geometry. Identifying such structures that are simple and efficient is challenging. We propose four fractal-inspired structures and we examine them at both micro and macroscales. We calculate their frequency response up to 100 Hz with computational modeling, and we also examine the effect of the fractal geometry iteration level. We use a cantilever plate example as a reference to validate computational results against analytical ones. A quantitative criterion to assess the harvesting efficiency of the proposed structures is introduced using the bending strain associated with each mode shape. Results show that a large number of eigenfrequencies is obtained, evenly distributed below 100 Hz, particularly in the macroscale. In addition, the iteration level of the fractal geometry affects the number and distribution of eigenfrequencies in the range of interest. Comparison with a conventional batch of cantilevers of the same size as the proposed structures shows noticeable improvement in electric charge generation.

scholarly journals A Feasibility Study of Fabrication of Piezoelectric Energy Harvesters on Commercially Available Aluminum Foil

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2797 ◽  
Author(s):  
Chongsei Yoon ◽  
Buil Jeon ◽  
Giwan Yoon
Keyword(s):  
Energy Harvesting ◽  
Elevated Temperatures ◽  
Aluminum Foil ◽  
Cost Effective ◽  
Device Fabrication ◽  
Point Of View ◽  
Plastic Substrate ◽  
Device Performance ◽  
Piezoelectric Energy ◽  
Energy Harvesting Devices

In this paper, we present zinc oxide (ZnO)-based flexible harvesting devices employing commercially available, cost-effective thin aluminum (Al) foils as substrates and conductive bottom electrodes. From the device fabrication point of view, Al-foils have a relatively high melting point, allowing for device processing and annealing treatments at elevated temperatures, which flexible plastic substrate materials cannot sustain because of their relatively low melting temperatures. Moreover, Al-foil is a highly cost-effective, commercially available material. In this work, we fabricated and characterized various kinds of multilayered thin-film energy harvesting devices, employing Al-foils in order to verify their device performance. The fabricated devices exhibited peak-to-peak output voltages ranging from 0.025 V to 0.140 V. These results suggest that it is feasible to employ Al-foils to fabricate energy-efficient energy harvesting devices at relatively high temperatures. It is anticipated that with further process optimization and device integration, device performance can be further improved.

Topology Optimization of Piezoelectric Energy Harvesting Devices Subjected to Stochastic Excitation

2010 ◽  
Author(s):  
Zheqi Lin ◽  
Hae Chang Gea ◽  
Shutian Liu
Keyword(s):  
Topology Optimization ◽  
Energy Harvesting ◽  
Electrical Energy ◽  
Ambient Vibration ◽  
Piezoelectric Energy Harvesting ◽  
The Past ◽  
Piezoelectric Energy ◽  
Random Responses ◽  
Pseudo Excitation ◽  
Energy Harvesting Devices

Converting ambient vibration energy into electrical energy using piezoelectric energy harvester has attracted much interest in the past decades. In this paper, topology optimization is applied to design the optimal layout of the piezoelectric energy harvesting devices. The objective function is defined as to maximize the energy harvesting performance over a range of ambient vibration frequencies. Pseudo excitation method (PEM) is applied to analyze structural stationary random responses. Sensitivity analysis is derived by the adjoint method. Numerical examples are presented to demonstrate the validity of the proposed approach.

A Low-order Model for the Design of Piezoelectric Energy Harvesting Devices

2008 ◽  
Vol 20 (5) ◽  
pp. 495-504 ◽  
Author(s):  
Jeffrey L. Kauffman ◽  
George A. Lesieutre
Keyword(s):  
Energy Harvesting ◽  
Design Tool ◽  
Mode Shapes ◽  
Piezoelectric Energy Harvesting ◽  
Coupling Coefficients ◽  
Order Model ◽  
Power Sources ◽  
Piezoelectric Energy ◽  
Energy Harvesting Devices ◽  
Low Order

Piezoelectric energy harvesting devices are an attractive approach to providing remote wireless power sources. They operate by converting available vibration energy and storing it as electrical energy. Currently, most devices rely on mechanical excitation near their resonance frequency, so a low-order model which computes a few indicators of device performance is a critical design tool. Such a model, based on the assumed modes method, develops equations of motion to provide rapid computations of key device parameters, such as the natural frequencies, mode shapes, and electro-mechanical coupling coefficients. The model is validated with a comparison of its predictions and experimental data.

scholarly journals On Piezoelectric Energy Harvesting from Human Motion

2019 ◽  
Vol 07 (01) ◽  
pp. 155-164 ◽  
Author(s):  
Chunhua Sun ◽  
Guangqing Shang ◽  
Hongbing Wang
Keyword(s):  
Energy Harvesting ◽  
Human Motion ◽  
Piezoelectric Energy Harvesting ◽  
Piezoelectric Energy

Demonstrating the effects of elastic support on power generation and storage capability of piezoelectric energy harvesting devices

2018 ◽  
Vol 30 (2) ◽  
pp. 323-332 ◽  
Author(s):  
Mohammad Reza Zamani Kouhpanji
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Elastic Properties ◽  
Elastic Support ◽  
Physical Parameters ◽  
Piezoelectric Energy Harvesting ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
Energy Harvesting Devices ◽  
And Storage

This study represents effects of an elastic support on the power generation and storage capability of piezoelectric energy harvesting devices. The governing equations were derived and solved for a piezoelectric energy harvesting device made of elastic support, multilayer piezoelectric beam, and a proof mass at its free end. Furthermore, a Thevenin model for a rechargeable battery was considered for storage of the produced power of the piezoelectric energy harvesting device. Analyzing the time-domain and frequency-domain responses of the piezoelectric energy harvesting device on an elastic support shows that the elastic deformation of the support significantly reduces the power generation and storage capability of the device. It was also found that the power generation and storage capability of the piezoelectric energy harvesting device can be enhanced by choosing appropriate physical parameters of the piezoelectric beam even if the elastic properties of the support are poor relative to elastic properties of the piezoelectric beam. These results provide an insightful understanding for designing and material selection for the support in order to reach the highest possible power generation and storage capability for piezoelectric energy harvesting devices.

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