Ultra-low frequency energy harvesting using bi-stability and rotary-translational motion in a magnet-tethered oscillator

Abstract

Harvesting ultra-low frequency random vibration, such as human motion or turbine tower oscillations, has always been a challenge, but could enable many potential self-powered sensing applications. In this paper, a methodology to effectively harness this type of energy is proposed using rotary-translational motion and bi-stability. A sphere rolling magnet is designed to oscillate in a tube with two tethering magnets underneath the rolling path, providing two stable positions for the oscillating magnet. The generated magnetic restoring forces are of periodic form with regard to the sphere magnet location, providing unique nonlinear dynamics and allowing the harvester to operate effectively at ultra-low frequencies (< 1 Hz). Two sets of coils are mounted above the rolling path, and the change of magnetic flux within the coils accomplishes the energy conversion. A theoretical model, including the magnetic forces, the electromagnetic conversion and the occurring bi-stability, is established to understand the electromechanical dynamics and guide the harvester design. End linear springs are designed to maintain the periodic double-well oscillation when the excitation magnitude is high. Parametric studies considering different design factors and operation conditions are conducted to analyze the nonlinear electromechanical dynamics. The harvester illustrates its capabilities in effectively harnessing ultra-low frequency motions over a wide range of low excitation magnitudes.

An Ultra-Low Frequency Magnet-Tethered Vibration Energy Harvester for Self-Powered Sensing

“…The variation of forces applied by the tethering magnets on the rolling magnet and the generated potential energy are shown in Fig. 2, using the theoretical model developed in [18]. As shown in Fig.…”

“…This paper introduces an ultra-low frequency energy harvester that utilizes rotary-translational motion of a rolling magnet, applying the theoretical model established in [18]. A prototype is developed, and its performance to exploit ultra-low vibration is explored in a comprehensive experimental study.…”

High-energy orbit sliding mode control for nonlinear energy harvesting

“…In recent years, with the rapid development of low-power communication and microelectronics technologies, more and more low-power consumption sensors are applied widely in a variety of industrial occasions [1][2][3]. As a sustainable energy supply method, the vibration energy harvesting technology has attracted plenty of scholars to investigate the huge potential in many significant occasions, such as mechanical structure health monitoring, vehicle tire pressure monitoring, IoT and human health monitoring [4][5][6][7][8][9][10]. However, the traditional linear structures have a narrow resonance bandwidth under the ambient excitation, which poses a constraint to providing sufficient power for electronics.…”

Ultra-Low Frequency Eccentric Pendulum-Based Electromagnetic Vibrational Energy Harvester

“…Xu et al investigated a pendulum-based cantilever energy harvester and realized few-Hertz multi-direction vibration energy harvesting [ 52 ]. Fu et al introduced a bi-stability rotary-translational-motion energy-converting structure and realized energy harvesting at an ultra-low frequency and low acceleration [ 53 ]. With the excitation of 0.8 Hz and acceleration of 0.6 m/s 2 , the energy harvester reached a root-mean-square output power of 60 µW.…”