A rotational piezoelectric energy harvester based on trapezoid beam: Simulation and experiment

Rotational piezoelectric energy harvesters which can directly convert mechanical energy into electrical energy are considered as one of the most attractive harvesters for self-powered rotational wireless monitoring systems. In this paper, a trapezoid piezoelectric cantilever beam is proposed to improve the output of rotational piezoelectric energy harvester. Finite element simulation results indicate that the trapezoid beam harvester can bear higher stress than the rectangle beam harvester near the clamping end and show excellent electrical output properties. The experimental results are consistent with the simulation analysis results, and verify that the rotational piezoelectric energy harvesters are endowed with the characters of up-conversion frequency and ring-down pattern. Experimentally, a prototype trapezoid beam harvester has been fabricated to harvest wind energy, which can generate an average output power density of 0.64 mW/cm2 at the matching impedance of 50 kΩ. Our work has demonstrated that the proposed trapezoid beam harvester is a good potential generator for harvesting flow energies and monitoring conditions of rotating machinery.