scholarly journals Piezoelectric Performance of a Symmetrical Ring-Shaped Piezoelectric Energy Harvester Using PZT-5H under a Temperature Gradient

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 640
Author(s):  
Nannan Zhou ◽  
Rongqi Li ◽  
Hongrui Ao ◽  
Chuanbing Zhang ◽  
Hongyuan Jiang

With the rapid development of microelectronics technology, low-power electronic sensors have been widely applied in many fields, such as Internet of Things, aerospace, and so on. In this paper, a symmetrical ring-shaped piezoelectric energy harvester (SR-PEH) is designed to provide energy for the sensor to detect the ambient temperature. The finite element method is used by utilizing software COMSOL 5.4, and the electromechanical coupling model of the piezoelectric cantilever is established. The output performance equations are proposed; the microelectromechanical system (MEMS) integration process of the SR-PEH, circuit, and sensor is stated; and the changing trend of the output power density is explained from an energy perspective. In the logarithmic coordinate system, the results indicate that the output voltage and output power are approximately linear with the temperature when the resistance is constant. In addition, the growth rate of the output voltage and output power decreases with an increase of resistance under the condition of constant temperature. In addition, with an increase of temperature, the growth rate of the output power is faster than that of the output voltage. Furthermore, resistance has a more dramatic effect on the output voltage, whereas temperature has a more significant effect on the output power. More importantly, the comparison with the conventional cantilever-shaped piezoelectric energy harvester (CC-PEH) shows that the SR-PEH can improve the output performance and broaden the frequency band.

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.


2019 ◽  
Vol 136 ◽  
pp. 02017
Author(s):  
Min Liu ◽  
Hui Xia ◽  
Guoqiang Liu ◽  
Dong Xia

A finite element fluid-solid coupling model for ocean energy harvester based on piezoelectric vortex-induced vibration(VIV) is established. Given that the Karman Vortex Street is generated after the fluid passes through the vibrator. The model includes the conversion of water flow energy to VIV energy and the capture of electrical energy by piezoelectric devices. And the output voltage curve is obtained by coupling with piezoelectric beam. Based on the fluid-solid coupling calculation, the dynamic response characteristics of the oscillator under different parameters such as shape of oscillators and fluid velocity are studied. The voltage output of piezoelectric beam in cylindrical, semi-cylindrical and regular triangular oscillators is analyzed. Simulation results show that the output voltage and pressure difference are largest in regular triangular oscillator system compared with the cylindrical and semi-cylindrical system. When changing fluid velocity, it is found that the higher the velocity of the water fluid be, the higher the output voltage be. When the given fluid velocity reaches 1 m/s, the maximum output voltage of cylindrical, semi-cylindrical and regular triangular piezoelectric energy harvesters reaches 0.045V, 0.08V, and 0.085V respectively. Under the same fluid velocity, change the ratio of height and width of oscillator, and find that the higher ratio of height and width of oscillator is more suitable to harvest the energy of VIV.


Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3203 ◽  
Author(s):  
Zhenlong Xu ◽  
Hong Yang ◽  
Hao Zhang ◽  
Huawei Ci ◽  
Maoying Zhou ◽  
...  

The approach to improve the output power of piezoelectric energy harvester is one of the current research hotspots. In the case where some sources have two or more discrete vibration frequencies, this paper proposed three types of magnetically coupled multi-frequency hybrid energy harvesters (MHEHs) to capture vibration energy composed of two discrete frequencies. Electromechanical coupling models were established to analyze the magnetic forces, and to evaluate the power generation characteristics, which were verified by the experimental test. The optimal structure was selected through the comparison. With 2 m/s2 excitation acceleration, the optimal peak output power was 2.96 mW at 23.6 Hz and 4.76 mW at 32.8 Hz, respectively. The superiority of hybrid energy harvesting mechanism was demonstrated. The influences of initial center-to-center distances between two magnets and length of cantilever beam on output power were also studied. At last, the frequency sweep test was conducted. Both theoretical and experimental analyses indicated that the proposed MHEH produced more electric power over a larger operating bandwidth.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2387
Author(s):  
Quan Wang ◽  
Kyung-Bum Kim ◽  
Sang-Bum Woo ◽  
Yooseob Song ◽  
Tae-Hyun Sung

Piezoelectric energy harvesters have attracted much attention because they are crucial in portable industrial applications. Here, we report on a high-power device based on a magneto-mechanical piezoelectric energy harvester to scavenge the AC magnetic field from a power-line cable for industrial applications. The electrical output performance of the harvester (×4 layers) reached an output voltage of 60.8 Vmax, an output power of 215 mWmax (98 mWrms), and a power density of 94.5 mWmax/cm3 (43.5 mWrms/cm3) at an impedance matching of 5 kΩ under a magnetic field of 80 μT. The multilayer energy harvester enables high-output performance, presenting an obvious advantage given this improved level of output power. Finite element simulations were also performed to support the experimental observations. The generator was successfully used to power a wireless sensor network (WSN) for use on an IoT device composed of a temperature sensor in a thermal power station. The result shows that the magneto-mechanical piezoelectric energy harvester (MPEH) demonstrated is capable of meeting the requirements of self-powered monitoring systems under a small magnetic field, and is quite promising for use in actual industrial applications.


2020 ◽  
Vol 87 (9) ◽  
pp. 575-585
Author(s):  
Suresh Kote ◽  
Shankar Krishnapillai ◽  
Sujatha Chandramohan

AbstractIn piezoelectric energy harvesting devices, the relative displacement between the two ends of the harvester beam decides the output power from the piezoelectric patch. A novel four bar mechanism with a helical spring is used as a dynamic magnifier to improve the relative displacement and thereby the output power from the harvester. This dynamic magnifier is placed between the base excitation location and the composite harvester beam to form two degrees of freedom (2DOF) piezoelectric energy harvester. Electromechanical coupled analytical equations for the voltage and output power are derived using a lumped electromechanical model. The model is developed assuming linear transverse vibrations of the harvester. A dynamic magnifier is fabricated for the required frequency range and the suitable dimensions of the harvester beam are estimated using commercially available software. Experiments are conducted for base excitation amplitude of 0.05 mm and the performance of the proposed 2DOF harvester is studied for the output voltage and power. The proposed 2DOF harvester has shown 110 % improvement in output power in first mode and 270 % improvement in second mode compared to the conventional single degree of freedom (SDOF) cantilevered harvester for given identical input conditions. The measured frequencies and output power are validated with analytical solutions and are found to be in good agreement. Further, the effect of mass ratio, stiffness ratio and base excitation amplitude on the output voltage and power is investigated using analytical expressions.


2020 ◽  
Vol 12 (4) ◽  
pp. 506-512
Author(s):  
Ashok Batra ◽  
Almuatasim Alomari ◽  
James Sampson ◽  
Alak Bandyopadhyay ◽  
Mohan Aggarwal

Piezoelectric energy conversion has received considerable attention for vibration-to-electric energy conversion over the past decade. A typical piezoelectric energy harvester is a unimorph or a bimorph cantilever located on a vibrating host structure. This paper presents a comparison between unimorph and bimorph cantilever beam having a number of segmented PMN-PT piezo-elements on the input and output power. The numerical simulation was carried out by applying the finite element analysis (FEA) using COMSOL multi-physics software in order to predict output voltage and power over a frequency range of 60–200 Hz for the first resonant frequencies. The simulation results show maximum output voltage and power harvested of 7.38 V and 135.73 μW, respectively, by the unimorph piezoelectric energy harvester at resonant frequency value of 84 Hz with electromechanical coupling factor (ke) of 77.29%. These results highlight that the highest value of the output electrical power can be obtained when the piezoelectric element is attached on the top of a clamped end of a cantilever piezoelectric beam. Moreover, in an unimorph or bimorph cantilever beam system, increasing the number of piezoelectric elements results in a higher resonant frequency shift and significantly decreasing in the harvested power.


Author(s):  
X. F. Zhang ◽  
S. D. Hu ◽  
H. S. Tzou

Flexoelectricity, the electromechanical coupling of the polarization response and strain gradient, occurs in solid crystalline dielectrics of any symmetry or asymmetric crystals. Different from the piezoelectric energy harvester, an energy harvester based on the direct flexoelectric effect is designed in this study. The energy harvester consists of an elastic ring and a flexoelectric patch laminated on its outer surface. Due to the direct flexoelectric effect, the electric energy induced by the strain gradient of the flexoelectric patch is harvested to power the electric device when the ring is subjected to mechanical excitations. Electromechanical coupling equation of the flexoelectric energy harvesting system in close-loop circuit condition is derived. In this study, dynamic response, output power across the external resistor and energy harvesting results are evaluated when the ring is excited by a harmonic point loading. The output power is a function of the external excitation frequency, the external equivalent resistance, the flexoelectric patch’s thickness and other design parameters. Case studies of those parameters for the flexoelectric energy harvester are presented to optimize the output power. Results show that the optimal excitation frequency is equal to the natural frequency for each mode, and the optimal equivalent resistance is dependent of the equivalent capacitance of the flexoelectric patch and the excitation frequency. Since the output power of the flexoelectric energy harvester is similar to that of the piezoelectric energy harvester, comparison of the two harvesters is also discussed. With all the optimal conditions discussed, it can supply a design principle in the engineering applications.


Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 963
Author(s):  
Chaoqun Xu ◽  
Yuanbo Li ◽  
Tongqing Yang

Piezoelectric energy harvesting technology using the piezoelectric circular diaphragm (PCD) has drawn much attention because it has great application potential in replacing chemical batteries to power microelectronic devices. In this article, we have found a non-uniform strain distribution inside the PCD energy harvester. From the edge to the center of the ceramic disk, its output voltage first increases and then decreases. This uneven output voltage reduces the output power of the PCD energy harvester. Based on this phenomenon, we reduce the ceramic disk diameter and dig a hole in the center, analyzing the effect of removing the ceramic disk’s low output voltage part on the PCD energy harvester. The experimental results show that removing the ceramic disk’s low output voltage part can improve the output power, reduce the resonance frequency, and increase the optimal impedance of the PCD energy harvester. Under the conditions of 10 g proof mass, 9.8 m/s2 acceleration, the PCD energy harvester with a 19-mm diameter and a 6-mm hole can reach a maximum output power of 8.34 mW.


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