Piezoelectric Compliant Mechanism Energy Harvesters Excited Under Large Base Accelerations

2016 ◽  
Author(s):  
Xiaokun Ma ◽  
Susan Trolier-McKinstry ◽  
Christopher D. Rahn
Keyword(s):  
Strain Distribution ◽  
Energy Harvester ◽  
Compliant Mechanism ◽  
Average Power ◽  
Low Frequency ◽  
Uniform Strain ◽  
Bridge Structure ◽  
Energy Harvesters ◽  
Axial Stretching ◽  
Stretching Effect

A piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a polyvinylidene diflouoride, PVDF unimorph clamped at its base and attached to a compliant mechanism at its tip. The compliant hinge stiffness is carefully tuned to approach a low frequency first mode with an efficient (nearly quadratic) shape that provides a uniform strain distribution. A nonlinear model of the PCM energy harvester under large base excitation is derived to determine the maximum power that can be generated by the device. Simulation results show that the PCM bridge structure self-limits the displacement and maximum strain at large excitations compared with the proof mass cantilever, improving the device robustness. The PCM outperforms the cantilever in both average power and power-strain sensitivity at high accelerations due to the PCM axial stretching effect and its more uniform strain distribution.

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.

Heartbeat Energy Harvesting Using the Fan-Folded Piezoelectric Beam Geometry

2015 ◽  
Author(s):  
M. H. Ansari ◽  
M. Amin Karami
Keyword(s):  
Natural Frequency ◽  
Energy Harvester ◽  
Low Frequency ◽  
Mode Shapes ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Mechanical Coupling ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam

A three dimensional piezoelectric vibration energy harvester is designed to generate electricity from heartbeat vibrations. The device consists of several bimorph piezoelectric beams stacked on top of each other. These horizontal bimorph beams are connected to each other by rigid vertical beams making a fan-folded geometry. One end of the design is clamped and the other end is free. One major problem in micro-scale piezoelectric energy harvesters is their high natural frequency. The same challenge is faced in development of a compact vibration energy harvester for the low frequency heartbeat vibrations. One way to decrease the natural frequency is to increase the length of the bimorph beam. This approach is not usually practical due to size limitations. By utilizing the fan-folded geometry, the natural frequency is decreased while the size constraints are observed. The required size limit of the energy harvester is 1 cm by 1 cm by 1 cm. In this paper, the natural frequencies and mode shapes of fan-folded energy harvesters are analytically derived. The electro-mechanical coupling has been included in the model for the piezoelectric beam. The design criteria for the device are discussed.

An Electromagnetic Frequency Increased Vibration Energy Harvester

2011 ◽  
Vol 403-408 ◽  
pp. 4231-4234 ◽  
Author(s):  
Khalid Ashraf ◽  
Mohd Haris Md Khir ◽  
John Ojur Dennis
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Proof Mass ◽  
Excitation Frequency ◽  
Average Power ◽  
Low Frequency ◽  
High Frequency Oscillation ◽  
Vibration Energy ◽  
Frequency Oscillation ◽  
Vibration Energy Harvester

This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.

Efficient Energy Harvesting Using Piezoelectric Compliant Mechanisms: Theory and Experiment

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Xiaokun Ma ◽  
Andrew Wilson ◽  
Christopher D. Rahn ◽  
Susan Trolier-McKinstry
Keyword(s):  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Low Frequency ◽  
Human Movement ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Rigid Frame ◽  
High Power Output ◽  
Piezoelectric Unimorph ◽  
Low Amplitude

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 that consists of a polyvinylidene diflouoride (PVDF) 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 piezoelectric unimorph. The bridge structure of the PCM also self-limits the response to large amplitude impacts, improving the device robustness. Experiments show that the compliant hinge stiffness can be carefully tuned to approach the theoretical high power output and mode shape efficiency.

Nonlinear Characteristics for Rotatable Magnetically Coupling Piezoelectric Energy Harvesters

2014 ◽  
Author(s):  
Junyi Cao ◽  
Shengxi Zhou ◽  
Daniel J. Inman
Keyword(s):  
Inclination Angle ◽  
Nonlinear Dynamic ◽  
Magnetic Force ◽  
Energy Harvester ◽  
Low Frequency ◽  
High Energy ◽  
Nonlinear Characteristics ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Frequency Excitation

This paper investigates the nonlinear dynamic characteristics of a magnetically coupled piezoelectric energy harvesters under low frequency excitation, where the angle of external magnetic field is adjustable. The nonlinear dynamic equation with the identified nonlinear magnetic force is derived to describe the electromechanical interaction of variable inclination angle harvesters. The effect of excitation amplitude and frequency on dynamic behavior is proposed by using the phase trajectory and bifurcation diagram. The numerical analysis shows that a rotatable magnetically coupling energy harvesting system exhibits rich nonlinear characteristics with the change of external magnet inclination angle. The nonlinear route to and from large amplitude high energy motion can be clearly observed. It is demonstrated numerically and experimentally that lumped parameters equations with an identified polynomials for magnetic force could adequately describe the characteristics of nonlinear energy harvester. The rotating magnetically coupled energy harvester possesses the usable frequency bandwidth over a wide range of low frequency excitation by adjusting the angular orientation.

Design, Analysis, and Experimental Studies of a Novel PVDF-Based Piezoelectric Energy Harvester With Beating Mechanisms

2014 ◽  
Author(s):  
Kuo-Shen Chen
Keyword(s):  
Natural Frequency ◽  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Low Frequency ◽  
Major Barrier ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Low Frequency Vibration ◽  
High Efficient ◽  
The Future

Wireless sensor networks become increasingly important in modern life for structural health monitoring and other related applications. In these applications, due to their overall sensor populations and possible covered measurement areas, the replacement of batteries becomes a difficult and unrealistic task. As a result, energy harvesters to convert environment wasted vibration energy into electricity for powering those sensor nodes become important and many miniaturized device have been realized by using MEMS technology. In order to achieve optimal performance, the energy harvester must be operated at the resonance frequency. However, the vibration frequencies of environmental vibrations are usually much less than that of those miniaturizing energy harvesters and this fact could be a major barrier for energy harvesting performance. In this paper, a new piezoelectric energy scavenging concept is proposed and demonstrated to convert environmental vibrations into electricity. Unlike previous MEMS-based piezoelectric energy harvesters, which suffer from matching between environmental low frequency vibration and the much higher system natural frequency, this work proposes a novel beating design using polymer piezoelectric materials in collaborating with a beating mechanism. That is, by creating impact force via the low frequency vibration motion from the mechanism, it is possible to excite system natural frequency by the low frequency environmental vibrations and it is possible to operate the entire system at the natural frequency. This work contains details in presenting this idea, designing piezoelectric harvester systems with flexible PVDF elements, exploring their vibration characteristics, and energy accumulating strategies by using a capacitor with a full-bridged rectifiers or a boost conversion. By experimental characterization, the overall harvesting efficiency of the proposed design is much greater than that from the design without the beating mechanism. It indicates that the efficiency is significantly improved and the proposed translational design could potentially improve the future design approach for piezoelectric energy harvesters significantly. In summary, this preliminary study shows that it is a feasible scheme for the application of piezoelectric materials in harvesting electricity from environmental vibrations. Although this work is still in its initial phase, the results and conclusions of this work are still invaluable for guiding the development of high efficient piezoelectric harvesters in the future.

Springless Vibration Energy Harvesters

2010 ◽  
Author(s):  
Mohamed A. E. Mahmoud ◽  
Eihab M. Abdel-Rahman ◽  
Raafat R. Mansour ◽  
Ehab F. El-Saadany
Keyword(s):  
Thin Film ◽  
Energy Harvester ◽  
Low Frequency ◽  
Center Frequency ◽  
Vibration Energy ◽  
Restoring Force ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Thin Film Fabrication ◽  
Film Fabrication

A novel vibration energy harvester (VEH) architecture is developed to eliminate the need for restoring force elements (springs) in the VEH. The architecture can realize VEHs with arbitrarily low center frequency. Two prototypes were fabricated and tested to demonstrate the feasibility of this architecture. The center frequency of the first prototype was found to be 2 Hz demonstrating low frequency operation. The second prototype improve the performance by five times at much smaller footprint using thin film fabrication process and precision alignment.

Modeling and parametric study of a force-amplified compressive-mode piezoelectric energy harvester

2016 ◽  
Vol 28 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Zhengbao Yang ◽  
Jean Zu ◽  
Jun Luo ◽  
Yan Peng
Keyword(s):  
Power Generation ◽  
Energy Harvester ◽  
Low Frequency ◽  
Lumped Parameter Model ◽  
Small Scale ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Compressive Mode

Piezoelectric energy harvesters have great potential for achieving inexhaustible power supply for small-scale electronic devices. However, the insufficient power-generation capability and the narrow working bandwidth of traditional energy harvesters have significantly hindered their adoption. To address these issues, we propose a nonlinear compressive-mode piezoelectric energy harvester. We embedded a multi-stage force amplification mechanism into the energy harvester, which greatly improved its power-generation capability. In this article, we describe how we first established an analytical model to study the force amplification effect. A lumped-parameter model was then built to simulate the strong nonlinear responses of the proposed energy harvester. A prototype was fabricated which demonstrated a superior power output of 30 mW under an excitation of 0.3 g ([Formula: see text] m/s2). We discuss at the end the effect of geometric parameters that are influential to the performance. The proposed energy harvester is suitable to be used in low-frequency weak-excitation environments for powering wireless sensors.

Flexible, Piezoelectric Aluminium-doped Zinc Oxide Energy Harvesters with Printed Electrodes for Wearable Applications

2021 ◽  
Vol 11 ◽  
Author(s):  
Muhammad Irsyad Suhaimi ◽  
Anis Nurashikin Nordin ◽  
Aliza Aini Md Ralib ◽  
Lai Ming Lim ◽  
Zambri Samsudin
Keyword(s):  
Zinc Oxide ◽  
Output Voltage ◽  
Energy Harvester ◽  
Wearable Sensors ◽  
Low Frequency ◽  
Design Parameters ◽  
Axis Orientation ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Cantilever Structure

Aims: Recent advancements in sensing technology and wireless communications have accelerated the development of the Internet of Things (IoT) which promote the usage of wearable sensors. An emerging trend is to develop self-sustainable wearable devices, thus eliminating the necessity of the user to carry bulky batteries. In this work, the development of a flexible piezoelectric energy harvester that is capable of harvesting energy from low frequency vibrations is presented. The target application of this energy harvester is for usage in smart shoes. Objectives: The objectives of this research is to design, fabricate and test an energy harvester on PET substrate using Aluminum Zinc Oxide as its piezoelectric layer. Methods: The energy harvester was designed as a cantilever structure using PET/AZO/Ag layers in d33 mode which can generate large output voltages with small displacements. The electrodes were designed as an interdigitated structure in which two significant design parameters were chosen, namely the effect of gap between electrodes, g and number of interdigital electrodes (IDE) pairs, N to the output voltage and resonant frequency. Results: The sputtered AZO on PET showed c-axis orientation at 002 peak with 2 values of 34.45° which indicates piezoelectric behaviour. The silver IDE pairs were screen-printed on the AZO thin film. Functionality of the device as an energy harvester was demonstrated by testing it using a shaker. The energy harvester was capable of generating 0.867 Vrms output voltage when actuated at 49.6 Hz vibrations. Conclusion: This indicates that the AZO thin films with printed silver electrodes can be used as flexible, d33 energy harvesters.

A human heartbeat frequencies based 2-DOF piezoelectric energy harvester for pacemaker application

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hygin Davidson Mayekol Mayck ◽  
Ahmed Mohamed Rashad Fath El-Bab ◽  
Evan Murimi ◽  
Pierre Moukala Mpele
Keyword(s):  
Lead Zirconate Titanate ◽  
Energy Harvester ◽  
Low Frequency ◽  
Life Time ◽  
Lead Zirconate ◽  
Secondary Beam ◽  
Average Output ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Self Powered

Abstract In the last decade, piezoelectric energy harvesters have received a significant attention from the scientific community. This comes along with the need of developing self-powered devices such as medical implant to reduce the cost and risk of surgery. This paper investigates a two degree of freedom (2-DOF) piezoelectric energy harvester device to be integrated into a pacemaker. The 2-DOF is designed as a cut-out beam with a secondary beam cut into a primary one. The system is developed to operate in the frequency range of 0–2 Hz, with an acceleration of 1 g (9.8 m/s2) to match the heartbeat frequencies (1–1.67 Hz). The system uses a Lead Zirconate Titanate (PZT) and a Poly Methyl Methacrylate (PMMA) as lead beam to compensate the brittleness of PZT. COMSOL Multiphysics software is used to model and analyze the resonant frequencies of the system, and the stress in the piezoelectric beam. The proposed device has a compact volume of 26 × 11.58 × 0.41 mm, which can fit perfectly in a pacemaker whose battery volume has been reduced by 50%. The output voltage and power are determined through analytical calculus using Matlab. Typical pacemakers require 1 μW to operate. Thus, with a peak power of 30.97 μW at 1.5 Hz and an average output power of 11.05 μW observed from 0.9 to 1.7 Hz, the harvester can power a pacemaker. It is assumed that the energy harvester could extend its life time for 5–10 more years. Furthermore, the harvester operates at extremely low frequency and produces reasonable power, making it suitable for biomedical devices.

Sign in / Sign up

Export Citation Format

Share Document