Double Beam Energy Harvester Based on PZT Piezoelectrics

This work presents a new design and performance evaluation of an energy harvester. The generator was built in the form of a double beam mechanical structure on which eight piezoelectric elements were glued and subjected to cyclic tensile and compression loads. Electrical energy is converted from mechanical vibrations generated by machines, by means of a piezoelectric material based on Lead Zirconium Titanate (PZT). Geometric dimensions of the beam structure were optimized by a finite element analysis prior to the practical construction of the device. Simulated and experimental results regarding the generator dynamics and the generated electric voltage are presented and compared. The device was evaluated for different excitations and vibration amplitudes at a frequency of 60 Hz in order to capture vibrational energy from machines at this frequency. Additionally, the generator's performance was evaluated when operating under two different real-world conditions: First, the device mounted on a condenser of an air conditioner, then on a three-phase motor pump. As a load for the piezoelectric generator, an RF circuit transmitted the ambient temperature information to a nearby computer. Correct reception of the ambient temperature value validated the ability to generate electrical power suitable for a low-power circuit. As contribution to the literature, this study demonstrates the ability of a novel piezoelectric generator design, to provide sufficient power for a circuit transmitting information from a sensor. This allows monitoring the state of a machine, using energy dissipated by mechanical vibrations in order to power the electronic systems responsible for sensing.