A characterization method for identifying the piezoelectric bending beam energy harvesters

This paper presents a characterization method for measuring model parameters of a piezoelectric bending beam energy harvester. In the proposed method, all parameters except coupling coefficient are obtained through a simple electrical test which facilitates the characterization procedure and enhances the accuracy of measurements. In the suggested method, the frequency response of output voltage and current of the beam under short-circuit and open-circuit conditions will be compared with the frequency response of analytical model of the beam. Then, by minimization of the matching error, an estimation of the model parameters including mechanical damping, electrical coupling, beam capacitance, resonant frequency and coupling coefficient will be obtained. The proposed method does not require measurement of the tip deflection of the beam. This feature will simplify the characterization test setup and also it enables characterization of the sealed package devices in which the tip of the beam is not accessible. This performance of the method is verified using an experimental test setup and it is successfully used for characterization of a cm-scale piezoelectric beam.