Design and experimental study of a piezoelectric energy harvester embedded in a rotating spindle excited by magnetic force

Abstract

A piezoelectric energy harvester based on rotational motion is a promising technique to generate unlimited electrical energy. However, the necessity for an effective harvester that can be mounted on a rotating system has become an important issue as a support for self-powered wireless sensor systems. The purpose of this study is to develop a novel magnetically impelled piezoelectric rotating energy harvester integrated into a rotating spindle, which is excited by multiple magnetic pairs between symmetrically opposed stationary and spinning magnets on the surface of piezoelectric discs. The theoretical examination of the magnetic excitation on a harvester system is provided to determine magnetic the force and torque, while the voltage and power generation capability of a magnetically impelled piezoelectric rotational energy harvester under various series and parallel configurations, and spindle speed excitations were examined experimentally. The experimental results are in line with the analytical model of magnetic force, which showed that the resistance torque can be decreased significantly. A maximum instantaneous output voltage of -15–19 V and 7.5–8 V was achieved at series and parallel connection respectively. The maximum power can be obtained at parallel connection and the RMS and peak power are 870 µW and 3500 µW, respectively and a high power density of 9.67 µW/mm3. The harvester can also charge the capacitors with voltage and power saturation of 6 V and 327 µW respectively. These results showed that the suggested harvester has high durability and the potential to power wireless sensors that are integrated into spindle machines.