Nonlinear Electromagnetic Energy Harvester–Structure System under Seismic Excitation: Vibration Mitigation and Energy Scavenging

Abstract

This study investigates the use of electromagnetic (EM) energy harvesters for the dual purpose of energy scavenging and vibration mitigation of seismically isolated structures during earthquake excitation. Specifically, the study examines the transient seismic response of a harvester–structure system, with emphasis on the electromechanical coupling. The behavior of the structure is nonlinear with bilinear hysteretic characteristics, whereas the harvester includes a standard energy harvesting circuit, which induces circuit nonlinearity. To characterize the nonlinear response of the coupled harvester–structure system, the study employs dimensional analysis and considers both trigonometric pulse-type ground motions and historical earthquake records. The results revealed the (dimensionless) parameters that are critical (e.g., the short-circuit damping coefficient and resistance ratio of the electronic load to the coil of the harvester, among others), and others that are immaterial (e.g., the yield displacement of the isolator and the forward voltage drop of the circuit when sufficiently small) to the seismic performance of the coupled system. In general, the analysis shows that flexible and low characteristic strength seismically isolated structures allow for higher energy harvesting. Furthermore, the study investigates the optimal design of the energy harvesting circuit. It recommends a harvester with a high short-circuit damping ratio because it can produce more output energy, and at the same time, suppress the structural vibration and reduce the forces acting on the structure. The analysis also shows that the circuit nonlinearity should be considered for accurate output energy estimation. Overall, the results herein indicate that EM energy harvesters are a promising alternative for reducing the structural response while simultaneously scavenging energy from the seismically induced vibration.