Numerical Optimization Approach of the Gap between the Magnet and Coil for Electromagnetic Vibration Energy Harvesters Design

2015 ◽  
Vol 645-646 ◽  
pp. 1214-1222
Author(s):  
Yi Ming Lei ◽  
Zhi Yu Wen

In the design of the micro electromagnetic vibration harvester, an important goal is maximization of the magnetic flux linkage gradient, which directly determines the induced voltage and output power of the electromagnetic vibration harvester. This paper established a numerical model based on structure of the electromagnetic vibration energy harvester. An analytic expression for the magnetic field of rectangular permanent magnets is used to build up an electromagnetic coupling model. The magnetic field distribution of the rectangular permanent magnet was analyzed. The effects of the gap between the magnet and the coil on the load voltage of the electromagnetic vibration energy harvester were investigated. According to the formula, the magnetic flux linkage and flux gradient were calculated to optimize the geometrical parameter of the magnet and coil. The method and boundary conditions of optimizing the gap between the magnet and coil were presented. The maximum output voltage can be obtained by optimizing the gap between the magnet and the coil. A simple prototype was fabricated and measured to validate the theoretical deducing and the feasibility of method.

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2710 ◽  
Author(s):  
Zhuang Lu ◽  
Quan Wen ◽  
Xianming He ◽  
Zhiyu Wen

The performance of vibration energy harvesters is usually restricted by their frequency bandwidth. The double-clamped beam with strong natural nonlinearity is a simple way that can effectively expand the frequency bandwidth of the vibration energy harvester. In this article, a nonlinear electromagnetic vibration energy harvester with monostable double-clamped beam was proposed. A systematic analysis was conducted and a distributed parameter analytical model was established. On this basis, the output performance was estimated by the analytical model. It was found that the nonlinearity of the double-clamped beam had little influence on the maximum output, while broadening the frequency bandwidth. In addition, the resonant frequency, the frequency bandwidth, and the maximum output all increased following the increase of excitation level. Furthermore, the resonant frequency varies with the load changes, due to the electromagnetic damping, so the maximum output power should be gained at its optimum load and frequency. To experimentally verify the established analytical model, an electromagnetic vibration energy harvester demonstrator was built. The prediction by the analytical model was confirmed by the experiment. As a result, the open-circuit voltage, the average power and the frequency bandwidth of the electromagnetic vibration energy harvester can reach up to 3.6 V, 1.78 mW, and 11 Hz, respectively, under only 1 G acceleration, which shows a prospect for the application of the electromagnetic vibration energy harvester based on a double-clamped beam.


2022 ◽  
Vol 253 ◽  
pp. 115146
Author(s):  
Yifeng Wang ◽  
Peigen Wang ◽  
Shoutai Li ◽  
Mingyuan Gao ◽  
Huajiang Ouyang ◽  
...  

Author(s):  
S. D. Moss ◽  
L. A. Vandewater ◽  
S. C. Galea

This work reports on the modelling and experimental validation of a bi-axial vibration energy harvesting approach that uses a permanent-magnet/ball-bearing arrangement and a wire-coil transducer. The harvester’s behaviour is modelled using a forced Duffing oscillator, and the primary first order steady state resonant solutions are found using the homotopy analysis method (or HAM). Solutions found are shown to compare well with measured bearing displacements and harvested output power, and are used to predict the wideband frequency response of this type of vibration energy harvester. A prototype harvesting arrangement produced a maximum output power of 12.9 mW from a 12 Hz, 500 milli-g (or 4.9 m/s2) rms excitation.


Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2410 ◽  
Author(s):  
Bei Zhang ◽  
Qichang Zhang ◽  
Wei Wang ◽  
Jianxin Han ◽  
Xiaoli Tang ◽  
...  

A novel bistable electromagnetic vibration energy harvester (BEMH) is constructed and optimized in this study, based on a nonlinear system consisting mainly of a flexible membrane and a magnetic spring. A large-amplitude transverse vibration equation of the system is established with the general nonlinear geometry and magnetic force. Firstly, the mathematical model, considering the higher-order nonlinearities given by nonlinear Galerkin method, is applied to a membrane with a co-axial magnet mass and magnetic spring. Secondly, the steady vibration response of the membrane subjected to a harmonic base motion is obtained, and then the output power considering electromagnetic effect is analytically derived. On this basis, a parametric study in a broad frequency domain has been achieved for the BEMH with different radius ratios and membrane thicknesses. It is demonstrated that model predictions are both in close agreement with results from the finite element simulation and experiment data. Finally, the proposed efficient solution method is used to obtain an optimizing strategy for the design of multi-stable energy harvesters with the similar flexible structure.


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