Energy harvesting properties of the d₃₁ type piezoelectric cantilever harvester

As a possible alternative to provide a continuous power supply for small and low-power devices, piezoelectric energy harvesting technology has attracted wide attention in the last decade. This paper developed a kind of flexible d₃₁ type piezoelectric macro fiber composite (MFC) and the MFC cantilever harvester. The vibration energy harvesting properties of the harvester were discussed. The research results show that the MFC cantilever harvester has a good voltage response to the excitation signal, and the largest open circuit voltage amplitude appears at the resonance frequency. The open circuit voltage amplitude of the harvester is sensitive to the vibration acceleration, which increases nearly linearly with increasing the vibration acceleration when the vibration acceleration is less than 2.0 g. The increase of the piezoelectric ceramic fiber volume fraction in the MFC can improve the open circuit voltage of the harvester, but increases the stiffness of the harvester, which is disadvantageous to the long-term operational reliability of the harvester. The desired open circuit voltage or short circuit current can be achieved in practical application by connecting multiple MFCs in series or parallel.