Theoretical model and analysis of an electromagnetic vibration energy harvester with nonlinear damping and stiffness based on 3D MEMS coils

Abstract

This paper presents a micro electromagnetic vibration energy harvester (VEH) that uses complementary metal-oxide-semiconductorcompatible 3D micro-electromechanical system coils and a ferromagnetic core to improve efficiency and output power. A systematic model is proposed to describe the nonlinear electromagnetic damping coefficient and nonlinear attraction between the magnet and the ferromagnetic core. The nonlinear model agrees well with the finite element calculation results. Then, a vibration model is established by considering nonlinear stiffness and damping coefficient to obtain the dynamic characteristics and output performance of the system. Furthermore, a numerical method is conducted to systematically investigate the influence of air gap and initial magnet offset under different excitation amplitudes. The simulation results indicate that with a smaller air gap, the output power is higher. Moreover, there is an optimal initial magnet offset in relation to the air gap to maximise the output power of the system. These conclusions and analysis models can be generalised and can be used as a guidance for the designs of similar structural devices. The results also show that the structure proposed in this study can significantly enhance the energy harvesting performance compared with published data of conventional VEHs.

Parametric study on circularly abrupt magnetic flux density changes of electromagnetic energy harvesters via simulation

“…Wang et al [2] presented multiple segments of coils with alternating winding directions, which improved the induced voltage and power of the EMEH. Tao et al [3] utilized a ferromagnetic core and micro-electromechanical system coils to make an EMEH for improving power. Kim et al [4] designed a cylindrical model based on different the aspect ratio for optimizing the output power.…”

Wearable Ball-Impact Piezoelectric Multi-Converters for Low-Frequency Energy Harvesting from Human Motion

“…Furthermore, depending on the available environmental energy forms, different harvesting principles have been employed, including electro-magnetic [ 20 , 21 , 22 ], photovoltaic [ 23 ], triboelectric [ 24 ], pyroelectric [ 25 ] and piezoelectric [ 26 , 27 , 28 , 29 , 30 ] principles.…”

Novel Structure for Electromagnetic Micro-Power Harvester

“…Consequently, flux loss is minimized and the major part of the electromagnetic field is passed through the coil cross-section. Utilizing the magnetic core, the magnetic field path is corrected and the output power density is maximized [18]- [20].…”