A piezoelectric wave energy harvester equipped with a sequential-drive rotating mechanism and rotary piezoelectric harvesting component

This study developed a sequential rotary-driven piezoelectric wave energy harvester (SRD-PWEH), comprising a cylindrical buoy, sequential-drive rotating mechanism based on a pair of one-way bearings, and rotary piezoelectric harvesting component. The harvesting component was based on a circumferentially arranged piezoelectric composite cantilever beam array. The one-way bearings converted the repetitive rotary motion of an input shaft into a unidirectional rotational motion without reverse rotation to drive the rotary piezoelectric harvesting component. Considering that the rotary-driven process is kind of noncontact-driven, it can effectively reduce the risk of damage to the piezoelectric composite cantilever beam structure. The SRD-PWEH was tested in a wave flume under two wave amplitudes and five wave periods. Results showed that the experimental condition of the wave amplitude and period of 75 mm and 0.9 s, respectively, achieved the highest electrical power. The root-mean-square voltage and maximum average power with the fault diagnosis rate filter circuit were 2.46 V and 0.49 mW, respectively.