Design, Modeling, and Response Analysis of a Nonlinear Rolling Magnet Electromagnetic Energy Harvester

A tunable nonlinear rolling magnet electromagnetic energy harvester is presented in this paper for energy harvesting from ambient vibration. The harvester utilizing the rolling motion of a magnetically suspended permanent magnet possesses a small mechanical damping. Dynamic model of the rolling magnet is established and electrical output of the harvester is predicted through electromagnetic induction combined with finite element simulation. Theoretical results based on harmonic balance method demonstrate that the proposed harvester exhibits strong nonlinearity and could generate considerable output in a wide frequency range. Within a certain frequency range, the harvester under harmonic excitation has multiple solutions and proper initial condition could enable the harvester to achieve high-energy branch. Moreover, numerical output under random excitation indicates that the response frequency band of the harvester significantly depends on the nonlinear restoring force exerted on the rolling magnet.