Asking for piezoelectric energy extraction

Discussion in 'General Electronics Chat' started by bundit_b, Feb 5, 2013.

  1. bundit_b

    Thread Starter New Member

    Jul 30, 2012
    Hi all,

    I'm doing research on piezoelectric energy harvesting.
    My piezoelectric device is bulk type as shown in the attached file. The device is tested by impact force by a metal bar with force frequency around 1 Hz.

    The output voltage is a pulse-liked with peak amplitude around 50-60 V when no load or resistive load(1k ohm and greater) is connected.
    But when I connected it with AC-DC rectifier circuit + a storage capacitor(10 uF or greater) the peak voltage across the piezo device is dramatically dropped down to about 1-2 V. The harvested energy are therefore only a little.

    I have reviewed the previous literatures for techniques for efficiency enhancement,how ever, most are the methods for piezoelectric cantilever type.
    Can anyone suggest for techniques or interface circuit to harvest energy from this device efficiently?

    Thank you.
  2. #12


    Nov 30, 2010
    Ten Characters.
  3. Audioguru

    New Member

    Dec 20, 2007
    How are you activating your piezo sensor? With a hammer?
    Of course your harvested energy is very low, your generating time is only a single short-duration pulse. 60V into 1k ohm is only 60mA. A cheap solar garden light charges its battery continuously at 60mA ALL DAY LONG! Then it has the energy to dimmly light a single LED for a few hours at night. You would need millions of hits on your piezo sensor to equal the power from the cheap little solar panel.

    Energy harvesting is done with a sidewalk covered with piezo sensors and many people walking or running on them.
    Or a piezo sensor in your shoe then you go for a long walk or run.
    Then the piezo has thousands of activations but they are soft so the voltage produced is low. Then the ICs shown in the attachments boost the voltage and charge a capacitor.

    The harvested energy is very low, slightly more than NOTHING. Maybe enough to power your cell phone for a few seconds if the harvesting is done for many minutes.

    Hee, hee. There was a thread where a kid used a computer fan as a windmill generator on his bicycle. Of course the wind resistance of the fan caused the kid to pedal harder. The energy produced was slightly more than NOTHING.
  4. bundit_b

    Thread Starter New Member

    Jul 30, 2012
    Thanks for all comments.