relation: https://khub.utp.edu.my/scholars/3666/ title: Improved energy harvesting from low frequency vibrations by resonance amplification at multiple frequencies creator: Ashraf, K. creator: Md Khir, M.H. creator: Dennis, J.O. creator: Baharudin, Z. description: This paper reports on an electromagnetic vibration energy harvester that utilizes a novel method of energy pumping based frequency up-conversion to effectively harvest energy from a broad range of low frequency (<18 Hz) ambient vibrations. Energy from low frequency vibrations is absorbed by a low frequency bounded resonator and subsequently pumped, in the form of pulses, to a high frequency resonator. The mechanical energy of the high frequency resonator is then transferred to the electrical domain by electromagnetic induction. The test results proved that the energy pumping based mechanical frequency up-conversion gets benefit from the resonance amplification phenomenon at multiple frequencies corresponding to higher order of resonances. Resonance amplification at multiple frequencies can improve the efficiency of harvesting energy from broadband vibrations and from sources where energy is distributed in different harmonics. For a 1 g excitation at the third order resonance frequency of 10.3 Hz, the fabricated harvester generated a peak voltage of 7.92 V and RMS voltage of 3.88 V across an optimal load of 3 kΩ and delivered a peak power of 20.9 mW with an average power of 5.02 mW. The harvester is capable of working at as high acceleration as 1 g and produces a usable amount of power (26 μW) from as low acceleration as 50 mg. © 2013 Elsevier B.V. All rights reserved. date: 2013 type: Article type: PeerReviewed identifier: Ashraf, K. and Md Khir, M.H. and Dennis, J.O. and Baharudin, Z. (2013) Improved energy harvesting from low frequency vibrations by resonance amplification at multiple frequencies. Sensors and Actuators, A: Physical, 195. pp. 123-132. ISSN 09244247 relation: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876215940&doi=10.1016%2fj.sna.2013.03.026&partnerID=40&md5=900845bbd1440bedfaf83d98254fe89a relation: 10.1016/j.sna.2013.03.026 identifier: 10.1016/j.sna.2013.03.026