Mass tuning technique for a broadband piezoelectric energy harvester array

Converting the wasted ambient vibration to electric power, using a piezoelectric energy harvester, is a promising strategy for powering a sensor network for medical and industrial applications. The designed harvester must satisfy the wideband natural frequency of ambient vibration. Conventional array harvester generates peak power at the cantilever's resonance frequencies and low power between them. This challenge can be managed by controlling the inclination angle of the tip masses (alpha). It is observed that the range of a from 45 degrees to 53.3 degrees generates an output power of 2 -3mW in the frequency range of 19 to 29Hz. For the second mode shape, the output power has been measured to be 9mW in the frequency range from 290 to 330 Hz. Comparing the proposed design with conventional designs, the working bandwidth broadband is increased by a factor of 26, and the output power is increased by a factor of 31. The proposed approach is modeled using finite element analysis and analytical methods. The FEM model is validated by experimental results.