Energy harvesting using a piezoelectric "cymbal" transducer in dynamic environment

In this study, we investigated the capability of harvesting the electrical energy from mechanical vibrations in a dynamic environment through a "cymbal" piezoelectric transducer. Targeted mechanical vibrations lie in the range of 50-150Hz with force amplitude in the order of 1 kN (automobile engine vibration level). It was found that under such severe stress conditions the metal-ceramic composite transducer "cymbal" is a promising structure. The metal cap enhances the endurance of the ceramic to sustain high loads along with stress amplification. In this preliminary study, the experiments were performed at the frequency of 100 Hz on a cymbal with 29 mm diameter and I mm thickness under a force of 7.8 N. At this frequency and force level, 39mW power was generated from a cymbal measured across a 400kQ resistor. A DC-DC converter was designed which allowed the transfer of 30 mW power to a low impedance load of 5 kOmega with a 2% duty cycle and at a switching frequency of 1 kHz.