A new design to improve bandwidth of piezoelectric energy harvester

This study proposed a unique wideband energy harvester with a spiral metal plate design which has the potential to harvest vibrational energy over a broad range of ambient frequencies. In this design, metal shim with various length was integrated with piezoceramic rings in a spiral form as the cochlea. Spiral form metal shims with various radius leaves were integrated with piezoelectric ceramic. Each metal leaves has its resonance frequency that is slightly different than its neighboring ones. Parametric studies such as split structure, the radius of the metal shim, brass thickness, and tip mass and clamped area were performed to investigate the energy harvester structure. From the results, the buzzer form energy harvesting unit is designed to split leaf form, resonance frequency shifts to lower frequency. In split structure design for various leaf radius, every leaf keeps their resonance frequencies. This designed structure was resonated on the broader frequency range. Radius difference for neighbor leaves provided wider effective energy harvesting frequency range. Thicker brass shim led to higher stress on piezoelectric ceramic, more significant peak to peak output voltage at own resonance frequency.