Effect of collisions in vibration energy harvester utilizing diamagnetic levitation on the output performance of piezoelectric cantilever beams

Abstract The vibration energy harvester based on diamagnetic levitation can increase the amplitude of the floating magnet by adjusting the natural frequency of the diamagnetic levitation structure. However, due to size constraints, the floating magnet frequently collides with the shell. To collect the energy generated by the collision and improve the output performance of the harvester, we introduce piezoelectric cantilever beams into the shell of the vibration energy harvester. The piezoelectric cantilever beam comprises a structural layer, a piezoelectric layer (PZT-5H) and a seismic block. This structure exhibits high energy density and excellent structural stability. The collision provides the initial velocity for the vibration of the piezoelectric cantilever beam, thereby enhancing its output voltage. The simulation results show that collision between the floating magnet and the shell can increase the output voltage of the piezoelectric cantilever beam by more than 10 times. Experimental results show that when the resonance frequency is 3.8 Hz and the external amplitude is 5 mm, the effective output voltage of the piezoelectric cantilever beam is 3034 mV, and the error between the simulation and experiment results is 8.7%. Following the addition of piezoelectric cantilever beams, the output performance of the vibration energy harvester is increased by 7.15 times. This research provides an effective solution for collecting energy generated by impacts and collisions.