A Novel Piezoelectric Multilayer Stack Energy Harvester With Force Amplification

A piezoelectric lead zirconate titanate (PZT) multilayer stack flextensional energy harvester (PZT-Stack-FEH) was designed and characterized in this paper. An elastic flextensional frame for force amplification was optimally designed to transmit more mechanical energy with high efficiency to the PZT-Stack-FEH. Instead of 31-mode single layer piezoelectric component, a 33-mode piezoelectric PZT multilayer stack was employed to increase mechanical-to-electrical energy conversion efficiency. The power delivery ratio of the electrical power dissipated by resistive load over the total generated electrical power from PZT stack was studied. Theoretical analysis and experiments were carried out. The experiment results show that the mechanical-to-electrical energy conversion efficiency of the PZT-Stack-FEH is 19%, 48.6 times more mechanical energy can be transmitted to PZT-Stack-FEH, and 26.5 times more electrical energy can be generated by using the PZT-Stack-FEH than directly applying force to the PZT multilayer stack. The maximum power delivery ratio can attain 70% when the resistive load matches the impedance of piezoelectric stack. The power generation performance of the PZT-Stack-FEH with a proof mass was also studied. Experiment results show that he peak power/acceleration can attain 2400mW/g when the PZT-Stack-FEH is connected with a proof mass of 200 grams and 3280 mW/g with a proof mass of 500 grams.