Design, modelling and experimental verification of a tunable electromagnetic generator for multi-directional vibration energy harvesting

R. Ebrahimi and S. Ziaei-Rad

Journal of the Brazilian Society of Mechanical Sciences and Engineering, Volume 46, February 2024, 117

ABSTRACT

Environmental vibrations as the renewable energy sources are random in directions and broadband. So, the design of vibration energy harvesters puts much emphasis on capturing energy from vibration in multiple directions and frequency tuning capability over the past few years. In this paper, a novel tunable multi-directional vibration energy harvester using electromagnetic conversion is proposed. The electromechanical equations are developed by the Faraday’s law of electromagnetic induction, Kirchoff voltage law and Lagrange’s equations. The electromechanical equations are solved using the Runge–Kutta method. The energy harvesting performance is then discussed with regard to the input amplitude, direction of the excitation, assembly angle and resistive load. In order to validate theoretical simulations, experimental measurements have been carried out. Good correlation between the experimental and theoretical results was found. The results showed that the harvester is not only capable of capturing energy from vibrations in multiple directions but also has the advantage of the resonant frequency tuning. A positive or negative frequency shift can be obtained by changing the assembly angle. The increase in the amplitude of the shaker acceleration and assembly angle have a direct effect on the output voltage of the system. Also, it was found that, depending on the direction of the excitation, increasing of the amplitude of the shaker acceleration can either increase or decrease the resonant frequency of the harvester. The results of this study can provide a design methodology to optimize system parameters according to different low-frequency environment vibrations.

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