Centrifugal Disk Magnetically Plucking Piezoelectric Beam for Broadband Energy Harvesting in Low-Speed Environments

Abstract In this paper, a broadband piezoelectric energy harvester based on an eccentric disk with frequency self-tuning for magnetic plucking in low-speed rotating environments is presented. The eccentric disk swings a large swing angle and magnetically plucks the piezoelectric beam. The plucking causes a transient vibration and generates power due to the piezoelectric effect. The mathematical model (equations of motion) for eccentric disk and piezoelectric beam is derived and solved numerically. The nonlinear dynamic analysis reveals that the eccentric disk exhibits frequency self-tuning, i.e., the frequency self-tuning disk is always in resonance within some rotational velocity range. This capability further magnifies the power output and broadens the bandwidth of the piezoelectric energy harvesting (PEH). The prototype of PEH as well as the experimental setup is developed for measurements. The numerical solutions agree well with the experimental data, showing that the validity of the model has been ensured. The proposed PEH can generate a power greater than 0.1 mW with a bandwidth ranging from 100 rpm (1.67 Hz) to 200 rpm (3.33 Hz).