An octo-generator for energy harvesting based on the piezoelectric effect

Abstract

A renewable energy harvester using the piezoelectric effect is developed for the ocean tidal and wind flow. The harvester is made of connected driving blades to an octo-generator, which has a rotator with n blades and a stator attached by eight mass-spring-piston-cylinder-piezoelectricity devices. The resonance and force magnification are utilized to increase the power output of the harvester. A corresponding mathematical model is developed to calculate the root mean square of the generated electric power. The simulation results indicate that the generated power is largely enhanced when the near-resonant condition is established. The power increases with increases in the magnetic flux density, the large-to-small diameter ratio of the cylinder, the size of magnetic bar face, and decreases in the gap between two magnetic faces and the size of the piezoelectric bar face. A generated power of 5kW is realized by the harvester working under an ocean tidal speed, V=1.75m/s, and its geometric and material properties of driving length L=7.5m, spring constant kv=65000N/m, gap between the two magnets s=0.0015m, large to small diameter ratio of the cylinder z=6, and magnetic flux density Br=1.45T.