The optimal design of a piezoelectric energy harvester for smart pavements

Abstract

The traffic environment contains tremendous mechanical energy due to the dynamic loads of moving vehicles which can be converted into electricity by using piezoelectric materials. Considering the road environmental characteristics, we propose here a piezoelectric energy harvester (PEH) consisting of piezoelectric ceramics that are encapsulated in epoxy resin filler between the MC nylon protective plates. As an illustration, periodic traffic loading is considered and is simulated by a controlled MTS loading, using which the effects of various system parameters on the efficiency of energy harvesting are examined. A theoretical electromechanical model is also developed to predict the energy harvesting behavior of the PEH device. The theoretical predictions agree very well with the experimental measurements, and they both suggest that various load, material, and circuit factors will have diverse effects on output power. To figure out the best collection of all factors and their simultaneous effect on the output performance, we also establish a simple and universal scaling law to reveal the underlying mechanism of the correlation between various systematic parameters. The normalized output power depends only on the normalized intrinsic impedance that consists of all material properties, geometrical, electrical circuit, and loading condition parameters. The optimization strategy may provide a useful tool to guide the design of the PEH device for enhancing the efficiency of energy harvesting by properly selecting the system parameters.