Piezoelectric Energy Harvesting Systems—Essentials to Successful Developments

In recent years, industrial and academic research units have focused on harvesting energy from mechanical vibrations using piezoelectric transducers. These efforts have provided research guidelines and have brought to light the problems and limitations of piezoelectric systems. There are three major phases associated with piezoelectric energy harvesting: (i) mechanical–mechanical energy transfer, including mechanical stability of the piezoelectric transducer under large stresses, and mechanical impedance matching, (ii) mechanical–electrical energy transduction, relating to the electromechanical coupling factor in the composite transducer structure, and (iii) electrical–electrical energy transfer, including electrical impedance matching, such as a direct current (DC/DC) conversion to transfer the energy to a rechargeable battery. This Review starts from the historical background of piezoelectric energy harvesting, followed by several misconceptions by current researchers. The main part deals with step-by-step detailed energy flow analysis energy harvesting systems with lead zirconate titanate (PZT)-based devices to provide comprehensive strategies on how to improve the efficiency of the harvesting system.