A comprehensive study of non-linear air damping and “pull-in” effects on the electrostatic energy harvesters

• Published in: Energy conversion and management Vol. 203; p. 112264
• Main Authors: Guo, Xinge, Zhang, Yulong, Fan, Kangqi, Lee, Chengkuo, Wang, Fei
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2020; Elsevier Science Ltd
• Subjects: Air damping; Computer simulation; Damping; Design optimization; Electrostatic; Electrostatic properties; Energy; Energy harvester; Energy harvesting; Mathematical models; Microelectromechanical systems; Non-linearity; Parameters; Pull-in effect; Vibration; Pull-in effect; Non-linearity; Air damping; Energy harvester; Electrostatic
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2019.112264

•A comprehensive dynamic model has been proposed for electrostatic energy harvester.•Non-linear air damping force is studied in the model with various geometry.•“Pull-in” effect has been observed during vibration for the first time.•All the simulation from the model has shown good agreement with experimental results. In this paper, a new comprehensive model is presented to optimize the design of vibration based electrostatic energy harvester working in standard atmosphere. This model considers the non-linear air damping force induced by the movement of proof mass as well as the “pull-in” effect from the electrostatic force. Important parameters such as the height of stoppers on the bottom plate, the initial gap between the bottom plate and proof mass and the surface potential of the electret layer have been investigated. With the microelectromechanical system (MEMS) technology, a series of energy harvesters have been fabricated with various parameters. The measurements of devices show excellent agreement with the simulations. For the first time, the “pull-in” phenomenon has been observed during the harvesting test as our expectation. The model provides a promising optimization route for the electrostatic energy harvester with broad bandwidth, decent power output while avoiding the “pull-in” effect.