A Flexible Doubly Clamped Beam Energy Harvester with a Standard Rectifier Electric Circuit

While wearable electronics are rapidly developing nowadays, it is greatly limited by the power solutions. Flexible piezoelectric energy harvester presents advantages of high energy density, compact architecture, and easy integration with MEMS, which provides an attractive prospect to power these next generation electronics. Since the flexible devices are usually devised with wavy, island-bridge, and precisely controlled buckling structures, the doubly clamped beam structure for energy harvesting application is analytically studied in this paper. Combine with Euler-Bernoulli beam theory and separation variable method, the analytical expression for output voltage is derived. By conducting the analytical simulation, it is found that the output power is related with the geometry dimensions, external excitation and load resistances. For further validation, experiment is systematically studied. By connecting the standard rectifier electric circuit with the energy harvesting device, it is found that a 0.1uF capacitor can be fully charged in 0.15 s, and the charged output voltage is about 2.5 V, which are successfully used for powering LEDs.