Abstract
In this paper is presented an extensive theoretical study and some experimental results regarding an electromagnetic generator based on levitated magnet, designated to harvest energy from ambient vibrations. Generator optimization for achieving the maximum values of transmissibility and electrical power was performed by considering a resonance frequency different from the natural frequency that is usually used in literature. The step response of the system, described analytically, is useful in the analysis of generators subject to sudden variations of the random vibration amplitude. The obtained experimental results indicate the possibilities of optimization and increase of the device power depending on the frequency and amplitude of external vibrations. The generator with levitated magnet studied in this paper, provided a maximum power of 27 mW when working as a quasi-linear oscillator and of 64 mW, respectively, when working as a non-linear oscillator.