| Abstract [eng] |
For typical piezoelectric energy harvester designs maximum generated power is achieved when natural frequency of harvester matches dominant vibration frequency of environment it operates in. If resonant frequency of harvester does not match that of its’ operating environment, level of harvester generated power decreases dramatically. It is quite difficult to tune real environment excitation and resonant frequencies of harvester (random vibrations are prevalent in most environments), thus very few harvesters are applied in practice. This dissertation presents design of vibro-impacting piezoelectric energy harvester that would ensure effective electrical energy generation under varying mechanical excitation conditions. Developed configuration of piezoelectric energy harvester is based on incorporation of rigid support, location of which coincides with the nodal points of vibration modes (0.78L or 0.87L), and rational substrate shape - simplified optimal cantilever configuration, which is obtained by thickening the cantilever at particular point of cross section (0.24L). This allows self-excitation of higher harvester vibration modes when harvester is operating in vibro-impacting mode and, thus, increase in harvester generated voltages as well as efficiency of harvester. |
