Analysis effects on operating frequency range by geometrical nonlinearity in electromagnetic vibration energy harvesters

Abstract

The paper aims to analyze and verify how geometrical nonlinearity of the microstructure affect the bandwidth of the vibration energy harvesters (EVEHs). In the paper, an electromagnetic energy harvester which has three nonlinear vibration pickup systems is analyzed and measured. Different degrees of geometric nonlinearity under certain condition can be shown by vibration pickup systems which are composed different folded beams in the EVEH. By using static simulation and numerical calculation methods, the nonlinear degree of each vibration pickup system is estimated, and the relationship between the nonlinear degree and the working bandwidth of each vibration pickup system is simulated and analyzed. The principle prototype is measured. The results show that the geometrical nonlinerity of vibration pickup systems is proportional to the excitation acceleration, and the bandwidth increases with increasing geometrical nonlinearity the bandwidth. Meanwhile, the results indicate that the vibration pickup system with greater geometrical nonlinearity has better frequency broad ability in low frequency vibration environment. The measured results and analytical results exhibit excellent agreement and the analysis method of structural nonlinearity in the paper may be helpful in designing structures of micro vibration energy harvesters.