Piezoelectric Energy Harvesting

The piezoelectric material selection and the circuit design in vibrational energy harvesting are discussed. The performances of the energy-harvesting unimorph devices that captured frequencies of 60 Hz by using piezoelectric PZT-based and BT-based ceramics were evaluated. Output voltages and power from the devices depend on the amplitude and the frequency of the oscillations, and depend on the load resistance. Generally, PZTbased ceramics are superior for piezoelectric energy-harvesting applications. The figures of merit of the materials are discussed in order to provide the guidelines of the piezoelec‐ tric material selections. Piezoelectric voltage coefficient, g31, is considered to be good parameter to predict the maximum voltages. On the other hand, d31g31/tanδ, k31Qm and d31g31 are close to the behavior of the maximum power. Combination of the piezoelectric unimorph and power management circuit produced the constant voltage output, which would be used as the power sources.