Piezoelectric energy harvester converting strain energy into kinetic energy for extremely low frequency operation Appl. Phys. Lett.

In this study, a piezoelectric wind energy harvester was vibrated that aims to convert high-speed wind energy into electrical energy using vibrations caused by centrifugal force. Vibrations induced by centrifugal force enabled effective distortion of the piezoelectric clamped beam and thus produced electric charge through the piezoelectric effect. A clamped beam was used rather than a conventional thin cantilever to harvest the wind energy in the proposed harvester. The centrifugal force was introduced by a pair of rotating eccentric turbines that are installed on two ball bearings on both sides of the piezoelectric unimorph. Benefiting from the rotating eccentric masses of these turbines, the harvester is capable of capturing wind energy in high speed wind environments. A prototype was set up to examine the effects of the wind speed and the structural parameters on the electrical output of the harvester. It is found that the harvester worked efficiently with wind applied from the axial directions in a 20–55 m/s speed range and produced a maximum open-circuit voltage of 47.2 V. When connected to an external load of 50 kΩ, the harvester showed a peak output power of 3.69 mW at a wind speed of 55 m/s.