An annularly-distributed poly-stable array for broadband vibrational energy

Abstract

Harvesting the ambient broadband vibrational energy is the ultimate objective of multi-stable vibration energy harvesters. The potential energy of a multi-stable system has more potential wells corresponding stable equilibrium states than a linear energy harvester, and the lower excitation energy is required to overcome the potential barriers to broaden the working bandwidth. However, for traditional multi-stable harvesters, increasing the number of stable equilibrium states to improve energy harvesting efficiency in random frequency bands is difficult. Without the need of external magnets generating static magnetic field, we propose an annularly-distributed poly-stable array which makes stable equilibrium states grow exponentially in maximum number. The experiments indicate that, comparing with a corresponding linear energy harvester, the working frequency bandwidth widened to 283%, the power density increased by a factor of 577 and the electric field energy raised to 133%. The proposed array shows the superiority in broadband vibrational energy harvesting and provides a solution collecting the abundant energy renewable in nature.