Prototype of energy harvester designed for ultra-low excitation frequency

This paper presents a design of a piezoelectric energy harvester prototype. The electrical power generating performance of the prototype was also analyzed. The prototype consists of four thin circular piezoelectric diaphragms. The aim of this work is using the prototype to convert ultra-low frequency dynamic compression force, such as compression force between foot and floor resulting from human walking, into useful electrical energy. It was found that at excitation force of about 1Hz, which is nearly the frequency of human step, the maximum generated power was about 530 mu W and depended on the electrical connection of the piezoelectric elements and the connected load.