NONLINEAR EFFECTS IN PIEZOELECTRIC VIBRATION HARVESTERS WITH HIGH COUPLING FACTORS

The nonlinear effects of piezoelectric coupling on piezoelectric harvesters are experimentally examined and compared to the approximate solutions of a simple nonlinear model. In this paper we apply a nonlinear version of the piezoelectric equations proposed in (1) to model the nonlinear behavior of a piezoelectric harvester. It turns out that the general nonlinear effects, i.e. the dependence of the resonance frequency on the amplitude, as well as the non-constant voltage-to-excitation ratio can be explained by this model, but the overall behavior of the harvester suggests that the model must be modified to accurately describe the experiment.