Design and Research on a Nonlinear 2DOF Electromagnetic Energy Harvester With Velocity Amplification

Abstract

In order to power the microelectronic devices of the Internet of Things in the low-frequency broadband vibration environment, a novel nonlinear 2DOF electromagnetic energy harvester was proposed based on the magnetic levitation structure and velocity amplification mechanism. The electromechanical coupling model was established and numerically simulated to analyze the generating characteristics. A prototype was fabricated and tested to verify the theoretical model. The influences of the key parameters, including the gap between the suspended magnet and the lower spring, excitation acceleration, spring stiffness, mass of copper cylinder, on the generating characteristics were studied. When it was subjected to a harmonic excitation with acceleration amplitude of 0.8g, the measured open-circuit voltage reached peaks of 3.13 V at 8 Hz and 2.93 V at 13.5 Hz, respectively. The optimal output power at 8 Hz was 10.18 mW with the matched load resistance of 250 Ω. Both the experimental and theoretical results demonstrated that this novel electromagnetic energy harvester had obvious advantages in increasing the output power and widening the bandwidth. INDEX TERMS Electromagnetic energy harvester, low frequency, velocity amplification, broadband.

Nonlinear Dynamics and Energy Harvesting of a Two-Degrees-of-Freedom Electromagnetic Energy Harvester near the Primary and Secondary Resonances

“…Liu et al [22] proposed a two-degrees-of-freedom harvester based on magnetic levitation. The effects of the key variables, such as the distance between the lower spring and the suspended magnet, excitation acceleration, spring stiffness, and the copper cylinder mass on the generated properties, were investigated.…”

A Magnetically Coupled Electromagnetic Energy Harvester with Low Operating Frequency for Human Body Kinetic Energy

“…These energy conversion technologies can avoid the aforementioned disadvantages of chemical battery power and reduce the dependence of small electronic devices on batteries [3][4][5]. According to the conductive mechanism, the conversion can be divided into piezoelectric [6][7][8][9], electromagnetic [10][11][12][13][14], and electrostatic [15][16][17][18]. The electromagnetic vibration energy harvester has simple structure, small internal resistance, high current, and easy processing compared to other types of energy harvesters, thus receiving more and more research and attention [19][20][21][22].…”