Analysis of the Key Factors Affecting the Capability and Optimization for Magnetostrictive Iron-Gallium Alloy Ambient Vibration Harvesters

Working characteristics of a magnetostrictive vibration energy harvester for rotating car wheels

The practice of harvesting vibration energy from machine tools, windmill blades, etc., and converting it into electric energy to power low-power electronic circuits has attracted wide attention from experts and scholars. Abundant vibrations that exist in the moving vehicle can be harvested to power sensors in tire pressure monitoring. In this paper, for the first time, a device is proposed to harvest the rotational vibration energy with the iron-gallium alloy (magnetostrictive material) as the core material. Such a device utilizes the coupling characteristics of Villarreal effect and Faraday electromagnetic effect to convert the vibration energy generated by the moving vehicle into electric energy. Upon completion of the design of the magnetostrictive rotational vibration energy harvester, the influence law of key factors, including substrate material, substrate size, and pre-magnetization field arrangement on the harvesting capability of the device, was studied in detail through experiments. An electric motor and vibration exciter were used to apply varied excitation forms to the harvester, and the output patterns of the harvester under conditions of wheel rotation, road bumps, and random vibration were fully analyzed. In addition, the correlation between the deformation of the cantilever beam and harvester performance was also investigated. The results have shown that at the acceleration of 9.6 g and the rotational speed of 90 r/min, the harvester can reach the output voltage of 1.22 V. Consequently, it demonstrates the feasibility of employing the magnetostrictive harvester to gather rotational vibration energy and provides theoretical guidance for further and deeper research on the harvester.

On the Possibility of Developing Magnetostrictive Fe-Co/Ni Clad Plate with Both Vibration Energy Harvesting and Mass Sensing Elements

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) has spread rapidly around the world. In order to prevent the spread of infection, city blockades and immigration restrictions have been introduced in each country, but these measures have a severe serious impact on the economy. This paper examines the possibility of both harvesting vibration energy and detecting mass by using a magnetostrictive alloy. Few efforts have been made to develop new magnetostrictive biosensor materials. Therefore, we propose magnetostrictive Fe-Co/Ni clad steel vibration energy harvesters with mass detection, and we numerically and experimentally discuss the effect of the proof mass weight on the frequency shift and output voltage induced by bending vibration. The results reveal that the frequency and output voltage decrease significantly as the mass increases, indicating that the energy harvesting device is capable of mass detection. In the future, device miniaturization and the possibility of virus detection will be considered.

Research on an Electromagnetic Actuator for Vibration Suppression and Energy Regeneration

This paper proposes an electromagnetic actuator that concurrently realizes two working functions of vibration suppression and energy regeneration. The actuator consists of four permanent magnetic rings, three soft iron rings, three coils, and three springs. The design of the electromagnetic actuator is based on finite element method (FEM) analysis, and the prototype is based on this analysis. Based on the prototype, the characteristics of the electromagnetic actuator, which has an output force–current coefficient of 39.49 N/A, are explored. A control algorithm with a position controller and an acceleration controller are applied to the actuator. When an impulse excitation is input to the electromagnetic actuator, the acceleration of the controlled object decreases from 114.26 m/s2 to 3.14 m/s2 here. Moreover, when the sinusoidal excitation with a 3 mm amplitude and 5 Hz frequency is input to the electromagnetic actuator, the vibration amplitude of the controlled object is 0.045 mm, suppressed within 1.46% when compared with the input signal. The peak value of the regenerated electromotive force is 1.97 V here, and the actuator efficiency for regenerating energy is 11.59%. The experimental results with multiple frequencies and amplitudes also show that the amplitude of the controlled object can be suppressed within 5.5%, and that the ratio of the electromotive force (EMF) to the input amplitude is 0.13. The results indicate that this electromagnetic actuator can suppress vibrations effectively and regenerate energy from vibrations.