Enhanced modeling of resonant frequency of piezoelectric bimorph cantilever energy harvester

With the popular use of wireless sensor networks, the replacement of the batteries becomes more concerned in the research communities. Piezoelectric materials (PZT) can be used to convert ambient vibration energy into electrical energy for use in powering microelectronics. Because the generated power and voltage depend on not only the amplitude and frequency of the ambient vibration, but also the geometric configuration of the piezoelectric bimorph generator, it is of great interest to study the relationships between the harvester's geometric configuration and its resonant frequency, and between the driving frequency and the harvested voltage and power. In this paper, a piezoelectric bimorph cantilever beam with a proof mass on the free end is adopted as the basic configuration, since it is simple and widely used as a low resonance frequency energy harvester. The previous model in the literature is described at the beginning, and then the Euler-Bernoulli beam model is created and calculated numerically. ANSYS simulation is performed to compare the results of the two different models. The results show that the Euler model has better predication of the resonant frequency of the PEH than the model in the literature. Finally, the design optimization of PEH is presented.