Output optimization of piezoelectric monitoring system considering loss impedance and spatial arrangement under traffic load

Abstract

A widely adoption of stacked piezoelectric transducers in roads or railways health monitoring is limited by a lack of matching quantitative impedance analysis and optimal spatial arrangement. This paper proposes an equivalent circuit model of the stacked piezoelectric transducer considering loss impedance to quantify the output electrical energy. Assisted by laboratory tests, variation in loss impedance as loading amplitude and frequency is obtained, and then, is incorporated into the proposed model to calculate output of piezoelectric transducers. A numerical model is further established to assess effect of spatial arrangement on output of piezoelectric transducers combining with theoretical model and laboratory tests. It is observed that energy output of layered arrangement increases by 300% than that of flat arrangement. An increase in the transducers number not only reduces the matching impedance but also the corresponding output of piezoelectric transducers under the same traffic load. Moreover, a field test is carried out to study the external impedance output power of a stacked piezoelectric energy harvesting system. A closed comparison between theoretical and test results verifies that the proposed model with special consideration on the loss impedance can predict the output of piezoelectric transducers reasonably well, which provides a reference for optimizing the self-power health monitoring system used in roads or railways.