The Experts below are selected from a list of 3405 Experts worldwide ranked by ideXlab platform

Wei Wang - One of the best experts on this subject based on the ideXlab platform.

  • energy harvester array using piezoelectric circular diaphragm for rail vibration
    Acta Mechanica Sinica, 2014
    Co-Authors: Wei Wang, Rongjin Huang, Chuanjun Huang, Laifeng Li
    Abstract:

    Generating electric energy from mechanical vibration using a piezoelectric circular membrane array is presented in this paper. The electrical characteristics of the functional array consisted of three plates with varies tip masses are examined under dynamic conditions. With an optimal Load Resistor of 11 kΩ, an output power of 21.4 mW was generated from the array in parallel connection at 150 Hz under a pre-stress of 0.8 N and a vibration acceleration of 9.8 m/s2. Moreover, the broadband energy harvesting using this array still can be realized with different tip masses. Three obvious output power peaks can be obtained in a frequency spectra of 110 Hz to 260 Hz. The results show that using a piezoelectric circular diaphragm array can increase significantly the output of energy compared with the use of a single plate. And by optimizing combination of tip masses with piezoelectric elements in array, the frequency range can be tuned to meet the broadband vibration. This array may possibly be exploited to design the energy harvesting for practical applications such as future high speed rail.

  • vibration energy harvesting using a piezoelectric circular diaphragm array
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 2012
    Co-Authors: Wei Wang, Tongqing Yang, Xurui Chen
    Abstract:

    This paper presents a method for harvesting electric energy from mechanical vibration using a mechanically excited piezoelectric circular membrane array. The piezoelectric circular diaphragm array consists of four plates with series and parallel connection, and the electrical characteristics of the array are examined under dynamic conditions. With an optimal Load Resistor of 160 kω, an output power of 28 mW was generated from the array in series connection at 150 Hz under a prestress of 0.8 N and a vibration acceleration of 9.8 m/s2, whereas a maximal output power of 27 mW can be obtained from the array in parallel connection through a resistive Load of 11 kω under the same frequency, prestress, and acceleration conditions. The results show that using a piezoelectric circular diaphragm array can significantly increase the output of energy compared with the use of a single plate. By choosing an appropriate connection pattern (series or parallel connections) among the plates, the equivalent impedance of the energy harvesting devices can be tailored to meet the matched Load of different applications for maximal power output.

  • vibration energy harvesting using piezoelectric circular diaphragm array
    International Symposium on Applications of Ferroelectrics, 2011
    Co-Authors: Wei Wang, Tongqing Yang, Xurui Chen, Qifa Zhou
    Abstract:

    Harvesting electric energy from mechanical vibration using a mechanically excited piezoelectric circular membrane array is presented in this paper. The piezoelectric circular diaphragm array is consisted of four plates with parallel connection, and the electrical characteristics of the array are examined under dynamic conditions. With an optimal Load Resistor of 11 kΩ, an output power of 27 mW was generated at 150 Hz under a pre-stress of 0.8 N force and a vibration acceleration of 9.8 m/s2. The results show that using a parallel array can increase significantly the output of energy compared with the use of a single plate.

Xiangjian Liu - One of the best experts on this subject based on the ideXlab platform.

  • energy harvesting performance of a dandelion like multi directional piezoelectric vibration energy harvester
    Sensors and Actuators A-physical, 2015
    Co-Authors: Renwen Chen, Long Ren, Huakang Xia, Xingwu Yuan, Xiangjian Liu
    Abstract:

    Abstract To achieve effective harvesting of ambient vibration energy in different directions, this paper proposes a dandelion-like multi-directional piezoelectric vibration energy harvester (MD-PVEH). After theoretical design, analysis and optimization of the device, validation experiments were carried out, which shows that the dandelion-like MD-PVEH can harvest relatively more energy in different excitations, although it harvests less energy from excitation in individual directions (for example, the angle between excitation direction and X axis is π/2 in XZ plane). Overall, this dandelion-like MD-PVEH with a Load Resistor of 8 kΩ can reach its maximum output power of about 0.28 mW and maximum energy conversion efficiency of 3% in the harmonic excitation which the frequency and amplitude are 22 Hz and 0.28 mm, respectively. It can meet the needs of many microelectronic devices.

Bruce E Logan - One of the best experts on this subject based on the ideXlab platform.

  • capturing power at higher voltages from arrays of microbial fuel cells without voltage reversal
    Energy and Environmental Science, 2011
    Co-Authors: Younggy Kim, Marta C Hatzell, Adam J Hutchinson, Bruce E Logan
    Abstract:

    Voltages produced by microbial fuel cells (MFCs) cannot be sustainably increased by linking them in series due to voltage reversal, which substantially reduces stack voltages. It was shown here that MFC voltages can be increased with continuous power production using an electronic circuit containing two sets of multiple capacitors that were alternately charged and discharged (every one second). Capacitors were charged in parallel by the MFCs, but linked in series while discharging to the circuit Load (Resistor). The parallel charging of the capacitors avoided voltage reversal, while discharging the capacitors in series produced up to 2.5 V with four capacitors. There were negligible energy losses in the circuit compared to 20–40% losses typically obtained with MFCs using DC-DC converters to increase voltage. Coulombic efficiencies were 67% when power was generated via four capacitors, compared to only 38% when individual MFCs were operated with a fixed resistance of 250 Ω. The maximum power produced using the capacitors was not adversely affected by variable performance of the MFCs, showing that power generation can be maintained even if individual MFCs perform differently. Longer capacitor charging and discharging cycles of up to 4 min maintained the average power but increased peak power by up to 2.6 times. These results show that capacitors can be used to easily obtain higher voltages from MFCs, allowing for more useful capture of energy from arrays of MFCs.

Aj Flewitt - One of the best experts on this subject based on the ideXlab platform.

  • Air Stable Indium-Gallium-Zinc-Oxide Diodes with a 6.4 GHz Extrinsic Cutoff Frequency Fabricated Using Adhesion Lithography
    2020
    Co-Authors: Wyatt-moon G, Km Niang, Cb Rider, Aj Flewitt
    Abstract:

    © 2019 IEEE. High speed rectifiers that can be fabricated at low cost whilst still maintaining a high performance are of interest for wireless communication applications. In this letter amorphous indium gallium zinc oxide (a-IGZO) has been used with adhesion lithography (a technique to create asymmetric planar electrodes separated by a nanogap) to fabricate high performance Schottky diode rectifiers. The diode area and junction capacitance can be significantly reduced using this technique, improving device cut-off frequencies. Devices of different widths have been fabricated showing rectification ratios between 103-104. Capacitances measured for devices of various sizes were all on the order of 0.1 pF. By applying ac signals to the diode and measuring the output voltage across a Load Resistor a cut-off frequency was found. a-IGZO diodes with an extrinsic cut-off frequency of 6.4 GHz at a 15 dBM input power have been realized. The devices also show good air stability with little change in current-voltage characteristics after 12 months

Flewitt Andrew - One of the best experts on this subject based on the ideXlab platform.

  • Air Stable Indium-Gallium-Zinc-Oxide Diodes with a 6.4 GHz Extrinsic Cutoff Frequency Fabricated Using Adhesion Lithography
    'Organisation for Economic Co-Operation and Development (OECD)', 2020
    Co-Authors: Wyatt-moon Gwenhivir, Km Niang, Rider Christopher, Flewitt Andrew
    Abstract:

    High speed rectifiers that can be fabricated at low cost whilst still maintaining a high performance are of interest for wireless communication applications. In this letter amorphous indium gallium zinc oxide (a-IGZO) has been used with adhesion lithography (a technique to create asymmetric planar electrodes separated by a nanogap) to fabricate high performance Schottky diode rectifiers. The diode area and junction capacitance can be significantly reduced using this technique, improving device cut-off frequencies. Devices of different widths have been fabricated showing rectification ratios between 103-104. Capacitances measured for devices of various sizes were all on the order of 0.1 pF. By applying ac signals to the diode and measuring the output voltage across a Load Resistor a cut-off frequency was found. a IGZO diodes with an extrinsic cut-off frequency of 6.4 GHz at a 15 dBM input power have been realized. The devices also show good air stability with little change in current-voltage characteristics after 12 months