On the energy localization in weakly coupled oscillators for electromagnetic vibration energy harvesting

The present paper investigates the implementation of the energy localization phenomenon for enhancing the output harvesting performance. Also in this paper, a linear electromagnetic vibration energy harvester with weakly-magnetic coupling is proposed. The designed device is two degree-of-freedom oscillators, which functionalizes the energy localization phenomenon via a spring-magnet array. The proposed concept is made up of moving magnets held by elastic springs and coupled by a repulsive magnetic force with a very low mechanical damping. The energy localization is achieved by mistuning the mass of one of the moving magnets. The experimental and theoretical results showing the benefits of the energy localization phenomenon are reported. The maximal average power density harvested by functionalizing the energy localization is $P_{avg}=0.8\mu W{cm}^{-3}{g}^{-2}{Hz}^{-2}$ for a magnetic coupling β = 0.015. (letter)