Energy harvesting with a cymbal type piezoelectric transducer from low frequency compression

In this paper a piezoelectric energy harvester based on a Cymbal type structure is presented. A piezoelectric disc ∅35 mm was confined between two convex steel discs ∅35 mm acting as a force amplifier delivering stress to the PZT and protecting the harvester. Optimization was performed and generated voltage and power of the harvester were measured as functions of resistive load and applied force. At 1.19 Hz compression frequency with 24.8 N force a Cymbal type harvester with 250 μm thick steel discs delivered an average power of 0.66 mW. Maximum power densities of 1.37 mW/cm³ and 0.31 mW/cm³ were measured for the piezo element and the whole component, respectively. The measured power levels reported in this article are able to satisfy the demands of some monitoring electronics or extend the battery life of a portable device.