Micromachines 2019, 10(1), 44; https://doi.org/10.3390/mi10010044
A Theory for Energy-Optimized Operation of Self-Adaptive Vibration Energy Harvesting Systems with Passive Frequency Adjustment
Chair of Measurement and Control Systems, Center of Energy Technology (ZET), Universität Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany
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Received: 15 November 2018 / Revised: 29 December 2018 / Accepted: 4 January 2019 / Published: 9 January 2019
(This article belongs to the Section A:Physics)
Abstract
Self-adaptive vibration energy harvesting systems vary their resonance frequency automatically to better exploit changing environmental conditions. The energy required for the adjustment is taken from the energy storage of the harvester module. The energy gained by an adjustment step has to exceed the energy expended on it to justify the adjustment. A smart self-adaptive system takes this into account and operates in a manner that maximizes the energy output. This paper presents a theory for the optimal operation of a vibration energy harvester with a passive resonance-frequency adjustment mechanism (one that only requires energy for the adjustment steps proper, but not during the hold phases between the steps). Several vibration scenarios are considered to derive a general guideline. It is shown that there exist conditions under which a narrowing of the adjustment bandwidth improves the system characteristics. The theory is applied to a self-adaptive energy harvesting system based on electromagnetic transduction with narrowband resonators. It is demonstrated that the novel optimum mode of operation increases the energy output by a factor of 3.6. View Full-TextKeywords:
vibration energy harvesting; frequency tuning; electromagnetic; microgenerator; self-adaptive
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Mösch, M.; Fischerauer, G. A Theory for Energy-Optimized Operation of Self-Adaptive Vibration Energy Harvesting Systems with Passive Frequency Adjustment. Micromachines 2019, 10, 44.
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