Power estimation for piezoelectric energy harvesters in flexure mode with large displacement amplitude

We propose a new method to estimate the output power from piezoelectric energy harvesters using flexure mode of the cantilever. In the energy harvester, displacement amplitude is too large for Bernoulli-Euler hypothesis to hold true. Hence, it is not easy to derive a theoretical solution of output power. In this study, applying the correction coefficient which is a function of flexure rigidity to a conventional theoretical solution, simple equation to estimate the output power was derived. This equation was applied to design a practical (K,Na)NbO₃ based energy harvester. Measured output from the harvester was in good agreement with the calculated value.