Study of micro piezoelectric vibration generator with added mass and capacitance suitable for broadband vibration

Abstract

This study proposes an optimized frequency adjustment method that uses a micro-cantilever beam-based piezoelectric vibration generator based on a combination of added mass and capacitance. The most important concept of the proposed method is that the frequency adjustment process is divided into two steps: the first is a rough adjustment step that changes the size of the mass added at the end of cantilever to adjust the frequency in a large-scale and discontinuous manner; the second step is a continuous but short-range frequency adjustment via the adjustable added capacitance. Experimental results show that when the initial natural frequency of a micro piezoelectric vibration generator is 69.8 Hz, then this natural frequency can be adjusted to any value in the range from 54.2 Hz to 42.1 Hz using the combination of the added mass and the capacitance. This method simply and effectively matches a piezoelectric vibration generator’s natural frequency to the vibration source frequency.

Output Performance Analysis on a Two-degrees-of-Freedom Bistable Piezoelectric Vibration Generator

“…It becomes difficult to convert the low-amplitude vibration energy in the real environment into electrical energy for a single-degree-of-freedom piezoelectric vibration generator. [1][2][3][4][5][6][7] The authors designed a two-degrees-of-freedom bistable piezoelectric vibration generator based on the structures of the single-degree-of-freedom bistable piezoelectric vibration generator by adding an amplitude amplifier. The improved structure retains the bistable characteristics of the single-degree-of-freedom bistable piezoelectric vibration generator and also magnifies the amplitude of the excitation source.…”