A study of power conversion system for energy harvester using a piezoelectric materials

In this paper, the energy harvester with a piezoelectric materials is modeled as the electric equivalent circuit, and performances of a standard DC method and a Parallel-SSHI method are verified through experiment under variable force and load conditions. Piezoelectric generator consists of mass, damper and spring constant, and it is modeled by electrical equivalent circuit with components. Standard DC and Parallel-SSHI are used as power conversion methods, and standard DC consists of full-bridge rectifier and smoothing capacitor. Parallel-SSHI method is composed of L-C resonant circuit, zero-crossing detector and full-bridge rectifier. In case of simulation under 100kΩ load condition, the harvested power is 500μW in Standard DC and 670μW in Parallel-SSHI, respectively. In experiment, the harvested power under 100kΩ load condition is 420μW in standard DC and 602μW in Parallel-SSHI. Harvested power of Parallel-SSHI is improved by approximately 40% more than that of standard DC method. Copyright © The Korean Institute of Electrical Engineers.