Study on Method of Vibration Power Generation using Piezoelectric Element

(3rd Report, Examination of Optimal Layer Number of Laminated Piezoelectric Elements)

Abstract

Electrical power generation devices that use piezoelectric lead zirconate titanate (PZT) have been developed to convert mechanical energy given by structural vibration into electrical energy. This paper describes an analytical and experimental study conducted to clarify the power-generation characteristics of the laminated PZT element doped with Nb 1.0 mol% under vibration loads and to examine optimal layer number of the laminated PZT element. In the analytical study, theoretical formulas on the power generation characteristics of the PZT element under the vibrational loads are derived by considering the equivalent circuit model consisting of the laminated PZT element. Optimal layer number deduced from the theoretical formula is 11 layers, and 11-layers PZT elements are produced in order to investigate the power-generation characteristics. In the experimental study, the effects of the number of layers of the laminated PZT element, the loads and frequencies on the power-generation characteristics of the laminated PZT element are evaluated by vibration tests. The experimentally obtained results are in good agreement with the values obtained theoretically and the validity of the theoretical formulas to vibration force of the laminated piezoelectric element was confirmed. Further, the optimal layer number of the laminated PZT element is confirmed to be 11 layers.