scholarly journals Power Efficiency of Energy Harvester Driven by Harmonic Excitation with Amplitude Perturbation

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Krzysztof Kucab ◽  
Grzegorz Górski
Keyword(s):  
Output Power ◽  
Power Efficiency ◽  
Energy Harvester ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Mean Value ◽  
Mean Power ◽  
Stochastic Force ◽  
Stochastic Excitations ◽  
Frequency Regime

In this paper, we examine the influence of the background’s stochastic excitations on an output power generated by using an energy harvester. The harvester is composed of two magnets attached to a piezoelastic oscillators separated by a distance Δ from the static magnets fastened directly to the device. We also introduce the parameter α which describes the mass ratio of moving magnets. We examine the output power for different excitation frequencies, different values of α, and different amplitudes δ0 of the stochastic force. We also analyze the influence of δ0 and Δ on the effective output power (EOP), the mean value of output power averaged over the considered frequencies, produced by using the harvester. We have observed that increasing δ0 causes the growth of generated mean power, especially in the low-frequency regime, while the maximum power near the resonance frequency remains unchanged. The EOP also grows with increasing δ0 for all examined values of α. The environment’s stochastic behavior improves slightly the harvester’s efficiency as compared to the purely harmonic case. Analyzing the dependence of EOP on Δ, we observed the maximum which appears at values of Δ corresponding to the situation when the system starts to work in the unsynchronized regime.

scholarly journals Study of the Properties of a Hybrid Piezoelectric and Electromagnetic Energy Harvester for a Civil Engineering Low-Frequency Sloshing Environment

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Nan Wu ◽  
Yuncheng He ◽  
Jiyang Fu ◽  
Peng Liao
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Civil Engineering ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Electromagnetic Energy ◽  
Maximum Output ◽  
Piezoelectric Film ◽  
Hybrid Energy ◽  
Level Height

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring.

scholarly journals Experimental Study and Parameter Optimization of a Magnetic Coupled Piezoelectric Energy Harvester

2018 ◽  
Vol 8 (12) ◽  
pp. 2609 ◽  
Author(s):  
Xiaobo Rui ◽  
Yibo Li ◽  
Yue Liu ◽  
Xiaolei Zheng ◽  
Zhoumo Zeng
Keyword(s):  
Flux Density ◽  
Parameter Optimization ◽  
Energy Harvester ◽  
Fiber Composite ◽  
Electrical Power ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Lumped Parameter Model ◽  
Peak Output Power ◽  
Piezoelectric Energy

Piezoelectric energy harvesting is a promising way to develop self-sufficient systems. Structural design and parameter optimization are key issues to improve the performance in applications. This paper presents a magnetic coupled piezoelectric energy harvester to increase the output and bandwidth. A lumped parameter model considering the static position is established and various modes are simulated. This paper focuses on the “Low frequency repulsion mode”, which is more practical. The experiment platform is built with the Macro Fiber Composite (MFC) material, and the results are consistent with the analytical simulation. The optimization process of some key parameters, such as magnets spacing and flux density, is carried out. The results show that there is a corresponding optimal spacing for each flux density, which is positive correlated. With the optimized parameter design, the system achieves peak electrical power of 3.28 mW under the harmonic excitation of 4 m/s2. Compared with the conventional single cantilever harvester, the operated bandwidth is increased by 66.7% and the peak output power is increased by 35.0% in experiment.

Periodic Solutions of an Impact-Driven Frequency Up-Conversion Piezoelectric Harvester

2019 ◽  
Vol 29 (10) ◽  
pp. 1930029 ◽  
Author(s):  
Amin Abedini ◽  
Saeed Onsorynezhad ◽  
Fengxia Wang
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Periodic Solutions ◽  
Output Power ◽  
Power Efficiency ◽  
Low Frequency ◽  
Base Excitation ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
The Impact

Frequency up-conversion has been proved to be an effective approach to increase the output power of a piezoelectric energy harvester (PEH). The proposed system can convert low-frequency vibration from ambient sources to the resonant vibration of the PEH hence can improve the output power efficiency. Frequency up-conversion technologies are introduced via impact or nonimpact magnetic forces to initiate the repeated free oscillations of the piezoelectric generator. No matter impact- or nonimpact-driven PEHs, most studies focus on either finite element simulation or experimental demonstration of PEHs electric power generations. Few, if any, study the effects of the impact-induced discontinuous dynamics on power generation efficiency. In this work, the energy harvesting performance of a piezoelectric beam upon interaction with a softer driving beam was studied. The discontinuous dynamics behind this impact-driven PEH was investigated, and strategies exploited to further improve the power efficiency of the frequency up-conversion process. Based on the linear elastic and linear mechanical-electrical constitutive laws, the lumped parameter models were built for both the driving beam and the piezoelectric driven beam. The numerical solution of the output power is obtained based on the vibration amplitude, frequency, and the electrical load. The soft beam is subjected to a sinusoidal base excitation, and the piezoelectric beam was excited via impacting with the soft driving beam. Based on the discontinuous dynamics theory, the performance of the energy harvesting of the impact-driven system was studied for period-1 and period-2 motions. Based on the stability and bifurcation analysis of periodic solutions, bifurcation diagrams of impact velocities, times, displacements and harvested power versus the frequency of the base excitation were also obtained, and compared to the power generation of a piezoelectric beam with base excitation.

A monostable hybrid energy harvester for capturing energy from low-frequency excitations

2019 ◽  
Vol 30 (18-19) ◽  
pp. 2716-2732 ◽  
Author(s):  
Kangqi Fan ◽  
Jiayu Hao ◽  
Qinxue Tan ◽  
Meiling Cai
Keyword(s):  
Power Unit ◽  
Energy Harvester ◽  
Low Frequency ◽  
Theoretical Models ◽  
Harmonic Excitation ◽  
Hybrid Energy ◽  
Hybrid Energy Harvester ◽  
Electromagnetic Power ◽  
The Individual ◽  
Reliability And Robustness

Efficient energy extraction from ubiquitous low-frequency excitations is still an open problem due to the high challenge in constructing an energy harvester with sufficiently low resonant frequency. To address this problem, this article reports a monostable hybrid energy harvester that consists of a piezoelectric power unit and an electromagnetic power unit. The proposed hybrid energy harvester can capture energy simultaneously from one excitation through the two power units. Theoretical models for the monostable hybrid energy harvester are established, and theoretical results fit well with the experimental measurements. Under a harmonic excitation with amplitude of 0.5 g ( g = 9.8 m/s2), the power output of the monostable hybrid energy harvester is experimentally measured to be 0.39 mW, which is obviously higher than that (piezoelectric unit: 0.25 mW; electromagnetic unit: 0.3 mW) produced by the individual power units when they work separately. More importantly, compared with the linear hybrid energy harvester, the monostable hybrid energy harvester has an operating frequency range that is shifted toward the lower frequency and achieves a slightly enhanced peak power, making the monostable hybrid energy harvester well suited for harnessing low-frequency excitations. In addition, employing two transduction mechanisms to synchronously and parallelly generate electricity from ambient excitations, the monostable hybrid energy harvester may also enjoy improved reliability and robustness.

Piezoelectric MEMS Energy Harvester for Low-Frequency Vibrations With Wideband Operation Range and Steadily Increased Output Power

2011 ◽  
Vol 20 (5) ◽  
pp. 1131-1142 ◽  
Author(s):  
Huicong Liu ◽  
Cho Jui Tay ◽  
Chenggen Quan ◽  
Takeshi Kobayashi ◽  
Chengkuo Lee
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Low Frequency ◽  
Piezoelectric Mems

scholarly journals Research on piezoelectric vibration energy harvester with variable section circular beam

2020 ◽  
pp. 146134842091840
Author(s):  
Tianbing Ma ◽  
Yongjing Ding ◽  
Xiaodong Wu ◽  
Nannan Chen ◽  
Menghan Yin
Keyword(s):  
Output Power ◽  
Electromechanical Coupling ◽  
Energy Harvester ◽  
Orthogonal Experiment ◽  
Low Frequency ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Variable Section ◽  
Piezoelectric Vibration Energy Harvester ◽  
Piezoelectric Vibration

In order to reduce the natural frequency of the piezoelectric vibration energy harvester, improve performance of the piezoelectric vibration energy harvester, and meet the requirements of energy acquisition in the low-frequency vibration environment, a variable-section circular piezoelectric vibration energy harvester is presented. The dynamic model and electromechanical coupling model of variable-section circular piezoelectric vibration energy harvester are established. The main factors affecting the output performance of piezoelectric vibration energy harvester are analyzed. The structure parameters of piezoelectric vibration energy harvester are optimized by orthogonal experiment. An experimental platform is built to test output voltage and output power of piezoelectric vibration energy harvester. The experimental results show that when the number of energy harvester is 4 and the external load is 180KΩ, the parallel output power can reach 0.213mW, which can meet the requirements of micro-power device power supply.

scholarly journals Orthogonal Piezoelectric Energy Harvester for Low Frequency Applications: Modeling and Experimental Validation

2019 ◽  
Vol 8 (4) ◽  
pp. 6268-6274
Keyword(s):  
Piezoelectric Material ◽  
Output Power ◽  
Experimental Validation ◽  
Energy Harvester ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Galvanized Steel ◽  
Rotational Inertia ◽  
Acceptable Error ◽  
Piezoelectric Energy

The use of piezoelectric energy harvesters in low frequency applications is a classic problem due to the high elastic modulus of currently available piezoelectric materials. Furthermore, the output power is proportional to the third power of the excitation frequency. Higher excitation amplitudes or an increase in the piezoelectric material can produce a high output power. However, this is not feasible for weak environmental vibration, and using more piezoelectric material would incur a higher cost so this is not an attractive option. This article proposes an L-shaped piezoelectric energy harvester that amplifies the excitation amplitude with the aid of an extension arm. The effects of bending and rotational inertia are considered when modelling the open-circuit voltage that can be generated by the harvester. Experimental validation is carried out using zinc, aluminium and galvanized steel extension arms. The prediction model provides a good estimation of the results with acceptable error percentages for linear elastic extension arms. It is found that the proposed harvester geometry generates more output voltage for all lengths of extension arm, and the optimum lengths are different for each material. The use of a zinc extension arm generated 290 µW at 49 Hz, which is 55% greater than the power generated by a harvester without an extension arm that had a power density of 1.41 µW/mm3 .

System Parameter Optimization for a Frequency-Up-Conversion Piezoelectric Energy Harvester With Backward Mechanical-Electric Coupling Effect

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Fengxia Wang
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Coupling Effect ◽  
Maximum Output Power ◽  
Harmonic Excitation ◽  
Maximum Output ◽  
Piezoelectric Energy ◽  
Dynamic Damping ◽  
The Galerkin Method ◽  
The Relationship

Abstract In this work, a parametric model for a frequency-up-conversion piezoelectric energy harvester (PEH) was developed based on the Galerkin method. The PEH is composed of a piezoelectric bimorph and a stopper, which was subjected to a harmonic excitation. Although backward coupling results in a structure dynamic damping, models with neglected backward coupling were often adopted to estimate the output power of a piezoelectric energy harvester. The purpose of this work is to examine the effect of backward coupling on the dynamic response and the output power generation for a frequency-up-conversion PEH. With the same base excitations, we compared the dynamics and output energies of two cases: (1) neglecting the backward coupling effect (BCE) in the model and (2) including the BCE in the model. To obtain the optimum gap with maximum output power, we studied the relationship between the output power and the gap of the steady-state solutions. From the analytical results, it was found that the BCE can be neglected as long as there is no impact or the output power is small. However, once impacts get involved, the piezoelectric backward effect dominates the total damping due to small mechanical damping which is true for most PEH. The backward coupling will significantly diminish both the vibration and output power. Therefore, if the BCE is neglected in an impact-driven frequency-up-conversion PEH, the simplified model will exaggerate the output power.

Investigation of Soft and Hard Ceramics and Single Crystals for Resonant and Off-Resonant Piezoelectric Energy Harvesting

2010 ◽  
Author(s):  
Alper Erturk ◽  
Ho-Yong Lee ◽  
Daniel J. Inman
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Resonance Frequency ◽  
Single Crystals ◽  
Energy Harvester ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Resonant Excitation ◽  
Piezoelectric Energy Harvesting ◽  
Piezoelectric Energy

Piezoelectric materials have received the most attention for vibration-to-electricity conversion over the last decade. Harmonic excitation is the most commonly investigated form of excitation in piezoelectric energy harvesting and it can be divided into two subgroups as resonant and off-resonant excitations. Although resonant excitation is preferred for extracting the maximum electrical power output from the device, there are several practical cases where it is not possible to excite the energy harvester at its resonance frequency (e.g. varying frequency excitations or very low frequency excitations where the input frequency is much lower than the fundamental resonance frequency). Several researchers have used soft piezoceramics (e.g. PZT-5A and PZT-5H) for power generation under resonant excitation. Typically, these soft piezoceramics have larger piezoelectric strain constant and larger elastic compliance compared to hard piezoceramics (e.g. PZT-4 and PZT-8). However, it is known that hard piezoceramics can have an order of magnitude larger mechanical quality factor compared to soft piezoceramics. Consequently, hard piezoceramics can generate more power under resonant excitation even though researchers have mostly focused on the soft piezoceramics. On the other hand, soft piezoceramics can generate more power for low frequency excitation below the resonance frequency due to their large effective piezoelectric stress constants. This difference is also the case for soft and hard single crystals (e.g. soft PMN-PZT versus hard PMN-PZT-Mn). In addition, single crystals can generate more power than ceramics at low off-resonant frequencies due to their large dynamic flexibilities (which is related to their large elastic compliances). This work investigates the specific advantages of soft and hard piezoceramics and single crystals for vibration-based energy harvesting. An experimentally validated piezoelectric energy harvester model is used to compare the power generation performances of soft and hard ceramics as well as soft and hard single crystals. The soft and the hard piezoceramics considered in this work are PZT-5H and PZT-8, respectively, while the soft and the hard single crystals considered here are PMN-PZT and PMN-PZT-Mn, respectively.

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