الفهرس 
صفحة العنوانOnly 14 pages are availabe for public view
 |  | from | 116 |  |  |
| | | from | 116 | | |
Abstract
At present, the power consumption reduction of the electronic devices had led to an open space for energy harvesting as an alternating power source. Vibrations are attractive source for energy scavenging. Piezoelectric energy harvesters are considered more compatible with electronic devices. In practical applications, the available vibration sources are irregular frequency peaks. These features in vibration sources limited the output performance and applicability of the conventional vibration energy harvester system due to the harvester operation at a fixed frequency.
In this thesis, a new piezoelectric energy harvester structure is designed for controlling the resonant frequency without changing harvester structure volume. The design is simulated using Comsol Multiphysics 5. The proposed structure idea is based on split the piezoelectric material into multiple segments. By changing the length of each segment, the resonant frequency can be changed. This proposed structure is used in array construction to widen the bandwidth of the harvester system. After then, an optimization for the proposed structure and the conventional structure using a genetic algorithm are performed.
The simulation results indicate that the proposed structure design can control the resonant frequency of the structure without changing the total volume of structure. The resonant frequency is changed from 75 to 84 Hz. Also, building an array of this proposed structure that has the same cantilever beams size provided a continuous bandwidth from 74 to 86 Hz. Finally, the optimization results of both conventional and proposed equally split piezoelectric material structure indicate that the proposed equally split piezoelectric material structure gives a higher output power bandwidth product with lower volume which makes the proposed equally split piezoelectric material structure is a promising design.