A RING PIEZOELECTRIC ENERGY HARVESTER EXCITED BY MAGNETIC FORCES

摘要

A ring piezoelectric harvester excited by magnetic forces with high excitation frequencies is developed. The harvester is made of a concentric outer ring stator and an inner ring rotator. The stator ring is made of a series of discrete piezoelectric patches with a rectangular shape surface mounted by magnetic ring slabs with the same size. All the piezoelectric patches and the magnetic slabs are placed on an aluminum ring. The rotator ring is made of a serious of magnetic rectangular slabs mounted on an aluminum ring with the exact size of the corresponding piezoelectric patches on the stator. Because of periodic magnetic forces between the stator ring and the rotator ring, a compression is induced to the piezoelectric patches leading to an electric charge for energy harvesting. To describe the energy harvesting process, a mathematical model is used to calculate the output charge and voltage from the piezoelectric patches. The influences of the size of the piezoelectric harvester and the rotating speed of the rotator ring on the root mean square of the generated electric power are discussed. Results show that a power up to 5274.81V can be realized for a practical design of the harvester with a radius around 0.5m.