Research and analysis of an energy harvester of piezoelectric cantilever beam based on nonlinear magnetic action.

In this paper, a nonlinear piezoelectric energy harvester is developed based on rotational motion applications. It consists of the pedestal, the piezoelectric beam, the connection mass, the tip magnetic mass, the revolving host, the support frame, and the bolts. This device drives the intermittent magnetic vibration between the magnet and the tip magnetic mass to generate electric energy, avoids mechanical collision and wear, and extends the service life of the device. The working principle and vibration model of the proposed energy harvester are studied theoretically. The displacement state of the piezoelectric beam under a magnetic force is simulated and analyzed. In addition, a series of experiments verify the simulation results. With two driving magnets, 5 g tip magnetic mass, and 10 mm radial excitation distances, a piezoelectric energy harvester can capture energy efficiently. The results demonstrate that the piezoelectric energy harvester produces four resonance frequencies of 4, 11, 15, and 19 Hz. When the rotation frequency is 4 Hz, the maximum open-circuit voltage of the piezoelectric energy harvester is 96.87 V. The piezoelectric energy harvester gets the maximum average power of 8.97 mW when the external resistance is 300 kΩ. At this time, the voltage across the resistance is 51.87 V.