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Tunable resonant frequency kinetic energy harvester

  • US 8,188,622 B1
  • Filed: 11/12/2009
  • Issued: 05/29/2012
  • Est. Priority Date: 11/12/2009
  • Status: Expired due to Fees
First Claim
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1. An energy harvester comprising:

  • a substrate;

    two magnets coupled to the substrate in close proximity to each other with like magnetic poles facing each other creating a flux gap;

    a coil coupled to the substrate and disposed within the flux gap, wherein the coil and the magnets are coupled to the substrate such that substrate acceleration causes relative elastic motion between the magnets and the coil thereby exposing the coil to a changing magnetic flux;

    a proof mass elastically coupled to the substrate via elastic members, wherein the coil is coupled to the proof mass and the proof mass is elastically coupled to the substrate and wherein the magnets are rigidly coupled to the substrate, wherein the proof mass comprises top and bottom surfaces with top and bottom recesses respectively therein, and the coil comprises top and bottom coils, both coils being wound in the same direction, and wherein the top and bottom coils are mounted in the top and bottom recesses respectively so that both the top and bottom coils are positioned approximately in a null of a magnetic field gradient created by the magnets;

    a resonant frequency tuner coupled to the substrate and configured to adjust the resonant frequency between the coil and the magnets; and

    a force feedback system operatively coupled to the resonant frequency tuner and an output of the top and bottom coils, wherein the force feedback system is configured to monitor the output of the top and bottom coils and adjust the tension in the elastic members via the resonant frequency tuner in real time such that at any given vibration frequency of the substrate, the proof mass vibrates at a resonant frequency with respect to the magnets.

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