A novel tri-stable piezoelectric vibration energy harvester with an elastic boundary

A novel vibration-based tri-stable piezoelectric energy harvester with an elastic boundary (TPEH-EB) is conceived in this paper to pursue high-efficiency energy scavenging. The TPEH-EB mainly includes two subsystems, namely a piezoelectric energy harvester (PEH) subsystem and an elastic boundary (EB) subsystem. The PEH subsystem consists of a flexible piezoelectric beam with a tip magnet and a PZT patch boned on the surfaces of the flexible beam. The EB subsystem includes two magnet-mass-spring oscillators, which lowers the potential energy threshold and broadens the inter-well bandwidth of the TPEH-EB. The governing equations of the TPEH-EB are derived, and the potential energy distribution is analyzed. A comprehensive comparative experimental study of the TPEH-EB for different initial positions is conducted with a traditional tri-stable piezoelectric harvester with a rigid boundary (TPEH-RB) to highlight the TPEH-EB’s superiority. Furthermore, the insights of the spring stiffness and magnet spacing of the elastic boundary into the energy harvesting performance are revealed. The results show that the introduction of the EB subsystem significantly enhances the output voltage and inter-well bandwidth of TPEH-EB for all three initial positions under a small excitation amplitude (0.6g). The RMS voltage, maximum output voltage, and bandwidth of the TPEH-EB are 452% ∼ 630%, 471% ∼ 600%, and 1120% ∼ 6030% higher than those of the TPEH-RB in the frequency band of inter-well motion for different initial positions, respectively. The introduction of the elastic boundary is beneficial in reducing the sensitivity of different initial positions to nonlinear dynamic responses.