Piezoelectric energy harvester for rolling bearings with capability of self-powered condition monitoring

Rotational energy harvesting for powering low-power electronic devices and wireless sensors has attracted increasing attention in recent years. This paper proposes an energy harvester to scavenge rotational energy from rotating machines by installing an arc-shaped piezoelectric sheet between the outer race of rolling bearing and bearing pedestal. The proposed piezoelectric energy harvester cannot only supply power to sensors but also has the capability of bearing fault detection. The structural design and working principle are initially demonstrated, where an electromechanical coupling model is developed to explain the working principle of energy harvester. Then, a prototype of the energy harvester is fabricated and mounted on a rotor test rig, on which experiments are carried out to evaluate the output performance of energy harvester. The effects of rotating speed, rotor weight, shaft span and matched resistances on energy harvester performance are comprehensively evaluated. It is revealed that a single piezoelectric section of the energy harvester can generate RMS voltage of 25 V, and RMS power of 60–131 μW under the rotating speed range from 600 to 1200 r/min. Finally, the applications of the proposed energy harvester for bearing fault detection and self-powered wireless sensing are demonstrated to manifest its capability of bearing condition monitoring.