Improving the performance of a tri-stable energy harvester with a staircase-shaped potential well

Scavenging energy from ambient vibration by tri-stable energy harvesters (TEHs) has been focused in recent years. Generally, classical TEHs adopt a design of symmetric potential wells. To improve the harvesting efficiency, a TEH with a staircase-shaped potential well (TEH-SSP) is proposed. This staircase-shaped potential well is established by adjusting the distances from the fixed magnets to the axis of symmetry. The distributed model of the proposed energy harvester is established, and the dynamical equations are derived by using the energy approach method. The nonlinear characteristics are explored theoretically and validated by experiments. Compared with the classical TEH with symmetric potential (TEH-SP), the proposed TEH-SSP could execute snap-through from a low frequency, and can obviously enlarge the frequency bandwidth of snap-through. Thus it can create a more dense high output voltages under weak random excitation. Both the theoretical analysis and experimental results prove the effectiveness of the proposed asymmetric design and vindicate that it is very beneficial for harvesting energy from the ambient vibration excitation. This work may serve as a novel insight into the design of more efficient harvesters with a broad bandwidth.