Piezoelectric Transducers的能量清除

　　微捕集，或能量清除，依賴于從微小而無處不在的環(huán)境能量中提取能量，如光、熱、rf或振動。利用壓電器件，振動能量可以提供低功率應(yīng)用，如用于設(shè)備或結(jié)構(gòu)監(jiān)測的難以到達(dá)和維護(hù)的無線傳感器。通過以下幾個關(guān)鍵的設(shè)計考慮，工程師可以通過壓電換能器的視差供電的應(yīng)用，測量專業(yè)/謝維茨，和美迪科技和電源管理器件的線性化技術(shù)。

　　與其他微采能相比，振動和運(yùn)動是環(huán)境動力的相對可靠來源（圖1）。例如，放在電機(jī)上，振動驅(qū)動的傳感器可以在電機(jī)運(yùn)行時準(zhǔn)確地獲得功率。在實際應(yīng)用中，壓電換能器可能被用來向高效率存儲設(shè)備充電，而不是直接向應(yīng)用電路供電。例如，一個典型的微收獲可能包括一個專門設(shè)計的電池如在平靜期或超級電容器如伊頓HB系列裝置確保在高峰負(fù)荷期間，無線數(shù)據(jù)傳輸足夠的電力儲存電荷Cymbet EnerChip。

　　Figure 1： Sources of vibration can serve as significant ambient energy sources. （Courtesy of Texas Instruments.）

　　How it works

　　Piezoelectric wafers are fabricated from a ceramic such as lead zirconate titanate （PZT） or fluoropolymer film such as polyvinylidene fluoride （PVDF）。 When subjected to mechanical forces that cause them to flex， these devices produce an ACvoltage proportional to the amplitude of the flexing movement. For use as vibration transducers， these materials are typically mounted in cantilevered structures， mounted to a fixed platform at one end and affixed with a tuning mass at the other （Figure 2）。 For example， the Parallax 605-00004， Measurement Specialties 0-1002794-0， and Mide Technology VR001 all are provided in their own variations of this basic cantilevered design.