Vibration-based piezoelectric energy harvesting system for rotary motion applications

The modeling and design of a piezoelectric flexible beam that can be used as an energy scavenger for rotary motion applications is investigated in this thesis. The energy harvester consists of a piezoelectric cantilever beam with a tip mass mounted on a rotating hub. Dynamic model of the harvester is derived using Euler-Bernoulli beam equation and considering the effect of the piezoelectric transducer. Equations of motion are derived using Lagrangian approach followed by relationships describing the harvested power. In particular, expressions describing the optimum load resistance and the maximum power that can be harvested using the proposed system are derived. Effect of parameters on the harvester dynamics is analyzed. Fabrication of the prototype is presented further. The model is verified for resonance and off-resonance operation comparing to the experimental results. It is shown that by proper parameter selection the output power of the harvester is sufficient to power wireless sensors.