Coherence resonance of nonlinear piezoelectric energy harvester under broadband random excitation

With the development of micro electromechanical systems, many researchers focus their attention on nonlinear energy harvesting device. The stochastic equivalent linearization method is used to analyze an energy harvesting system under ambient noise. First, according to the bistability of beam axially loaded, a model of bistable nonlinear vibration energy harvester under the stochastic condition is proposed. A close-form approximation expression for the ensemble average of harvested power is derived and the numerical simulation of the system shows stochastic resonance. The results show that it is possible to optimally design system such that the harvest power is maximized for a given density or variance of random excitation.