Nonlinear Oscillation for a Millimeter-Sized Vibrational Energy Harvester with Ethylene Tetrafluoroethylene Electret

Kazuyoshi ONO  Norio SATO  Alexander YU  Yujiro TANAKA  Tomomi SAKATA  Yoshito JIN  Yasuhiro SATO  Hiroshi KOIZUMI  

IEICE TRANSACTIONS on Communications   Vol.E99-B   No.8   pp.1677-1686
Publication Date: 2016/08/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2015CCP0011
Type of Manuscript: Special Section PAPER (Special Section on Advanced Information and Communication Technologies and Services in Conjunction with Main Topics of APCC2015)
Category: Energy in Electronics Communications
energy harvest,  electret,  nonlinear,  vibration,  MEMS,  ETFE,  Internet of Things,  

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A demonstration of power enhancement by nonlinear oscillation in a millimeter-sized electrostatic vibrational energy harvester for the future Internet of Things is presented. To enable nonlinearity in microelectromechanical system (MEMS) devices, we selected a gold spring as a component of the MEMS structure for its lower Young's modulus than conventional materials, a ductile characteristic, and an electrical conductivity. The mechanical characteristics of the fabricated MEMS device related to the nonlinear phenomenon were examined. The charging characteristics of an ethylene tetrafluoroethylene copolymer (ETFE) electret film for electrostatic induction were also evaluated. Nonlinear oscillation for the millimeter-sized energy harvester with the ETFE electret was confirmed experimentally by applying external vibration. The oscillation resulted in a bandwidth two times broader than that by linear oscillation. The normalized harvester effectiveness of the nonlinear oscillation was 5.1 times higher than that of the linear one.