Study on the energy conversion mechanism and working characteristics of a new energy harvester with magnetic liquid

Abstract

This paper carries out a numerical analysis and an experimental investigation of the output characteristics of an electromagnetic vibration energy harvester with magnetic liquid. In the proposed prototype device, the suspension magnet is subject to the nonlinear restoring force of the fixed magnet, and the magnetic liquid is mainly used to reduce the friction between the suspension magnet and the tube wall and prevent the deflection of the suspension magnet. The purpose of this study is to investigate the feasibility of adding magnetic liquid to assess the potential of these devices to collect energy from vibration. To this end, we analyze the second-order buoyancy characteristics of the magnetic liquid and developed a nonlinear mathematical model of the new energy harvester. The accuracy of the model is verified by comparing the simulation results with the experimental results. Additionally, the simulation results show that the mass and damping ratio of the suspended part can effectively change the amplitude of the output power, and the distance between the suspended magnet and the fixed magnet mainly affects the working frequency corresponding to the peak output power. Meanwhile, the experimental results show that compared with the energy harvester without magnetic liquid, the output peak power of the proposed energy harvester is 3.46 mW at 9 Hz, which is significantly increased by 149%, and the normalized power density is 108 μW/(cm3g2). To sum up, the new structure of energy harvester and the established model can provide a new solution for enhancing the output power performance of such devices.