Device control and structure design for high conversion efficiency of MEMS vibratory energy harvesters with high Q-value in a wide band

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K06016
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: Kyoto Institute of Technology
• Principal Investigator: Yamashita Kaoru 京都工芸繊維大学, 電気電子工学系, 教授 (40263230)
• Co-Investigator(Kenkyū-buntansha): 藤田 孝之 兵庫県立大学, 工学研究科, 准教授 (50336830) ; 野田 実 京都工芸繊維大学, 電気電子工学系, 教授 (20294168)
• Research Collaborator: Tanaka Tsunehisa ; Nishiumi Taiki ; Shiomi Jo ; Nishioka Tomoki ; Nakajima Shota ; Hibino Hikaru
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 圧電 / MEMS / 応力 / 共振周波数 / 振動モード / エネルギー変換

Outline of Final Research Achievements

Device control and structure design were investigated on piezoelectric MEMS (micro-electro-mechanical systems) vibratory structures for high efficiency of mechanical-to-electrical energy conversion. A static buckling deflection was introduced in the piezoelectric vibratory structures for high conversion efficiency owning to its nonlinear strain, and converse piezoelectric effect was used to dynamically change the resonant frequency of the vibrators to follow the environmental vibration. Preparation condition of piezoelectric PZT thin films in sol-gel process was optimized form the viewpoints of residual stress dominating the buckling, and piezoelectric property. Converse piezoelectric stress was applied to the buckled structure and vibration behavior was elucidated in its vibration modes and natural frequencies.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

MEMS環境発電素子（エネルギー・ハーベスタ）は来たるIoT (internet of things)社会を支える電源技術として不可欠である。特に人類の活動環境に普遍的に存在する環境振動をエネルギー源とする振動発電素子は重要である。本研究では圧電MEMS型環境発電素子について，環境振動周波数に追従して高効率で発電するための基盤技術となる共振周波数制御方法を追究し，特に単体での振動発電効率を向上する従来にない座屈構造に着目して共振挙動の解明を進めた。