Linear electromagnetic devices for vibration damping and energy harvesting: Modeling and testing

Over the past decades, the research on structural vibration control has mainly focused on 'energy dissipation' strategy using various dampers for hazard mitigation. This paper proposes a novel application of linear motion electromagnetic (EM) devices, termed linear EM dampers hereinafter, for both vibration damping and energy harvesting. The kinetic energy caused by earthquakes, wind or traffic loads is not only dissipated by EM dampers, but also stored by energy-harvesting electric circuits connected to EM dampers. The green and regenerative energy output may provide an alternative power supply to portable and wireless devices at remote sites. This paper presents a theoretical and experimental study of linear EM dampers connected with four representative circuits. The dynamic characteristics of linear EM dampers, including parasitic damping, EM damping, energy conversion efficiency and output power, are modeled and discussed systematically in each case. The modeling is further verified by a series of dynamic testing of a small-scale linear EM damper, which is cyclically tested on a MTS machine at different frequencies and amplitudes. A good match between the modeling and testing results clearly demonstrates that the described model can predict the performance of the linear EM damper and energy harvesting circuit very well. The promises and challenges of using EM dampers in future civil infrastructure for both vibration damping and energy harvesting are discussed based on the outcome of this study. (C) 2011 Elsevier Ltd. All rights reserved.