• TECHNOLOGIES

    VIBRATION POWER GENERATION WITH PIEZOELECTRIC ELEMENT USING COUPLING WITH CYLINDRICAL SOUND FIELD ENCLOSED BY END PLATES HAVING DIFFERENT THICKNESS

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 9, pg(s) 18-2

    This paper describes the electricity generation characteristics of a new energy-harvesting system with piezoelectric elements.
    The proposed system is composed of a rigid cylinder and thin plates at both ends. The piezoelectric elements are installed at the centers of both plates, and one side of each plate is subjected to a harmonic point force. In this system, vibration energy is converted into electrical energy via electro-mechanical coupling between the plate vibration and piezoelectric effect. In addition, the plate vibration excited by the point force induces a self-sustained vibration at the other plate via mechanical-acoustic coupling between the plate vibration and an internal sound field into the cylindrical enclosure. Therefore, the electricity generation characteristics should be considered as an electro- mechanical-acoustic coupling problem. Actually, the plate on the excitation side is lower than that on the non-excitation side in the natural frequency because of the influence of a vibrator to apply the point force to the plate, so that both natural frequencies are not identical and the effect of mechanical-acoustic coupling is not clarified very well. Then both frequencies are close by tuning the natural frequency due to thinning the plate on the non-excitation side. As a result, it is expected that the electricity generation characteristics are improved by promoting mechanical-acoustic coupling in comparison with the inherent situation.

  • BUSINESS & “INDUSTRY 4.0”

    VIBRATION POWER GENERATION WITH PIEZOELECTRIC ELEMENT USING MECHANICAL-ACOUSTIC COUPLING IN ACTUAL ENVIRONMENT

    Industry 4.0, Vol. 2 (2017), Issue 3, pg(s) 115-118

    This paper describes electricity generation characteristics of the vibration power generator with piezoelectric elements. In general, it is well-known that the above generator has low generation efficiency, having so simple structure. Moreover, vibrations of broad frequency band, which exist in actual environment, bring the characteristics to lower efficiency in comparison with the particular situation in which the host structure is excited by the vibration of the natural frequency. In this study, the vibrations of broad frequency band, i.e. random vibration, attracts attention and mechanical-acoustic coupling with an internal sound field enclosed by the host structures, on which the piezoelectric element is installed, is adopted to improve the electricity generation efficiency. The behavior of mechanical-acoustic coupling is determined by the relationship between the respective characteristics of the host structure vibrations and the internal sound field, so that the electricity generation efficiency depends strongly on those dimensions. Here, the electric power and the electricity generation efficiency are regarded as the representative characteristics of the electricity generation, then the characteristics are considered based on them with changing the dimensions to find the condition in which the efficiency can be improved. As a result, the applicability of such a power generation system in actual environments is mentioned.