Research And Design Of Multi-directional Wide-band Piezoelectric Vibration Energy Harvester

The energy supply of wireless sensor network nodes has become a major bottleneck restricting the development of wireless sensor networks.As more and more sensors are deployed in different applications,if the traditional chemical battery is used for power supply,more and more staff will be required to replace and charge the battery from time to time,which will greatly increase the labor cost.There are many new ways of sensor power supply,such as solar cell power supply,thermal power supply,wind power supply,vibration power supply and so on.Since vibration energy is widely present in the environment,vibration energy power supply is less susceptible to environmental impact than other power supply methods,and is more suitable for wireless sensor networks.There are many kinds of vibration energy in the environment,which has the characteristics of wide frequency band and randomness.However,the traditional piezoelectric vibration energy harvester has the disadvantages of narrow working frequency band and single vibration direction,so it can not make full use of the vibration energy in the environment,so it can not solve the energy supply problem of wireless sensor network nodes.In this paper,aiming at the shortcomings of traditional piezoelectric vibration energy harvester,a new multi-directional wide-band piezoelectric vibration energy harvester is designed.The energy harvester consists of eight single piezoelectric cantilever beams and a fixed base.Firstly,the mathematical model of single piezoelectric cantilever is established,and the relationship between the length,width and mass of single piezoelectric cantilever and its natural frequency is determined through numerical analysis,which provides a reference for the design of multi-directional wide-band piezoelectric vibration energy harvester;Then,the finite element model of the multi-directional wide-band piezoelectric vibration energy harvester is established by the ANSYS finite element simulation software.The influence of the length and width of the piezoelectric vibrator on the voltage is determined by the static analysis,and the influence of the length,width and mass of the piezoelectric vibrator on the natural frequency is determined by the modal analysis,so as to determine the optimal piezoelectric vibrator Structural dimensions;Finally,the actual measurement analysis of the energy harvester is carried out.The actual measurement results of the energy harvester show that the working frequency band of the energy harvester designed in this paper under the excitation of x direction or y direction is 20Hz?40Hz,the best matching resistance is 16k?,and the maximum output power is 4m W.The comparative analysis of the performance of the energy harvester shows that the energy harvester designed in this paper has superior performance in terms of multi-directionality,widened working frequency band and output power,so it has good application value.