110 圧電コンポジットを利用した振動発電装置のエネルギー変換効率に関する考察 : 第三報,振動入力エネルギーと発電効率の評価

Abstract

In the previous authors' study, the vibration energy harvester of the piezoelectric bimorph cantilever type was proposed for vibration condition monitoring applications of rotating machinery. Proposed energy harvester consists of the surface bonded two Macro-Fiber Composites (MFCs). In this study, theoretical maximum energy transfer efficiency was derived from the energy balance equation during the natural period of the proposed vibration energy harvester. The maximum AC power through 227.3 Kilo-Ohm resistor which includes instruments internal resistances experimentally obtained 246.1 microwatt when subjected to vibration source input magnitude of 0.71(mm/s rms) at the resonant frequency of the harvester (29.31 Hz). The impedance matching between MFCs and the electrical resistive load was effective for maximizing both AC and DC power transfer of the vibration energy harvester. Theoretical maximum energy transfer efficiency was 18.25%. However, the theoretically estimated energy transfer from mechanical system to electrical system did not obtain the good agreement with the experimentally evaluated maximum AC power during the natural period of the vibration energy harvester.