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Subject: search.filters.subject.Piezoelectric energy harvester

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    Item type:Publication,
    Design and evaluation of double-stage energy harvesting floor tile
    (2019-10-01)
    Isarakorn, Don
    ;
    Jayasvasti, Subhawat
    ;
    Panthongsy, Phosy
    ;
    Janphuang, Pattanaphong
    ;
    Hamamoto, Kazuhiko
    This paper introduces the design and characterization of a double-stage energy harvesting floor tile that uses a piezoelectric cantilever to generate electricity from human footsteps. A frequency up-conversion principle, in the form of an overshooting piezoelectric cantilever, plucked with a proof mass is utilized to increase energy conversion efficiency. The overshoot of the proof mass is implemented by a mechanical impact between a moving cover plate and a stopper to prevent damage to the plucked piezoelectric element. In an experiment, the piezoelectric cantilever of a floor tile prototype was excited by a pneumatic actuator that simulated human footsteps. The key parameters affecting the electrical power and energy outputs were investigated by actuating the prototype with a few kinds of excitation input. It was found that, when actuated by a single simulated footstep, the prototype was able to produce electrical power and energy in two stages. The cantilever resonated at a frequency of 14.08 Hz. The output electricity was directly proportional to the acceleration of the moving cover plate and the gap between the cover plate and the stopper. An average power of 0.82 mW and a total energy of 2.40 mJ were obtained at an acceleration of 0.93 g and a gap of 4 mm. The prototype had a simple structure and was able to operate over a wide range of frequencies.
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    Performance and behavior analysis of piezoelectric energy harvesting floor tiles
    (2019-07-01)
    Panthongsy, Phosy
    ;
    Isarakorn, Don
    ;
    Hamamoto, Kazuhiko
    ;
    Janphuang, Pattanaphong
    This paper presents the performance and behavior analysis of two unlike piezoelectric energy harvesting floor tiles in which they are functioned with different frequency up-conversion strategies to achieve the high energy conversion efficiency from low and variable-frequency vibration as the human footstep. One of such strategies is to convert the frequency of piezoelectric bimorph up through the magnetic interaction between a permanent magnet and an iron plate, while another one is achieved on that through the mechanical impact between a cover plate and a wall of the floor tile. Experimentally, the floor tiles having one piezoelectric bimorph inside of them are prototyped and then mounted to their individual input-exciting kit to investigate the energy harvesting performance. The input-exciting kits are employed to simulate the human footstep on floor tiles. The results show that the floor tile with frequency up-converting mechanism based on mechanical impact should be a better option for energy harvesting from human footstep due to the low-profile structure and good energy harvesting performance. Moreover, its operational way can result in long-lasting piezoelectric bimorph. When a cover plate is actuated to move down with the velocity of 54.13 mm/s and then released, the floor tile can produce the average power of 0.82 mW at load resistance approximately of 55.68 kΩ.