A High-Efficiency MEMS Energy Harvester for Stochastic Environmental Vibrations

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K15038
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: The University of Tokyo
• Principal Investigator: Honma Hiroaki 東京大学, 生産技術研究所, 特任助教 (70833747)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: MEMS / エナジーハーベスタ / 振動発電 / 広帯域化 / 非定常振動 / IoT

Outline of Final Research Achievements

A design strategy is presented to simultaneously enhance the bandwidth and the sensitivity of electrostatic vibrational energy harvester without excessively depending on the velocity amplification through mechanical resonance. Instead, the new design uses comb-electrodes of very short-stroke that are finished with an extremely high density electret film, thereby enhancing the mechano-electric power conversion efficiency, leading to a 3.6-fold expansion of frequency bandwidth from 18 Hz to 64 Hz around a center frequency of around 100 Hz when the electret potential is 1.5-fold enhanced from -200 V to -300 V. Normalized power density as large as 0.7 mW/cm3/G2 is confirmed.

Free Research Field

電子工学

Academic Significance and Societal Importance of the Research Achievements

従来の振動発電素子において帯域拡張手法は、素子が肥大化し微小振動への応答性も劣化していた。一方、本研究が提案する手法では、素子面積は変えずにエレクトレット密度の増強により帯域幅を拡張でき、製作した非定常型振動発電素子は世界最高クラスの出力性能と帯域幅を併せ持つ。
よって、提案する帯域拡張手法と非定常振動型発電素子により、非定常な環境振動下でも無線センサ端末の設置場所を選ばないIoT(Internet of Things)センサネットワークの構築が可能となる。