M-shaped asymmetric nonlinear oscillator for broadband vibration energy harvesting: Harmonic balance analysis and experimental validation

Bistable generator for vibration energy harvesting is one of the most promising solutions to reach practically enhanced performance. Due to the buckled–spring–mass–specific behavior, the deformation of the piezoelectric transducer is nonlinearly dependent on the displacement, especially in the inter-well motion case. An analytical model is developed using harmonic balance analysis for the buckled–spring–mass generator architecture. Contrary to the usual method, a special doubled frequency voltage solution in the inter-well motion case is assumed in harmonic balance analysis to obtain an accurate predictive model, which is validated by experimental results. The influence of five critical parameters on the performance is thoroughly discussed. Design rules are then deduced: low damping ratio, properly high coupling level, matched load, optimal buckling level, and low characteristic frequency are required to get optimal performance in the inter-well motion case. Besides, we show some interesting results about the parameter optimization study.

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Multiphysics Modelling and Experimental Validation of a Bi-Axial Magnetoelectric Vibration Energy Harvester

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.558.465 ◽

2013 ◽

Vol 558 ◽

pp. 465-476

Author(s):

Joshua E. McLeod ◽

Scott D. Moss

Keyword(s):

Energy Harvesting ◽

Experimental Validation ◽

Ball Bearing ◽

Electrical Energy ◽

Open Circuit ◽

Vibration Energy ◽

The Finite Element Method ◽

Vibration Energy Harvesting ◽

Vibration Energy Harvester ◽

Multiphysics Modelling

This paper reports on the multiphysics modelling of a bi-axial vibration energy harvesting (VEH) approach, with experimental validation of the model predictions. The authors have developed a harvester able to generate voltage under bi-axial vibrations. The harvesting approach is based on a magnetoelectric (ME) transducer that is positioned between a fixed magnet and oscillating ball bearing, which steers a changing magnetic field through the transducer to generate a voltage. The transducer combines magnetostrictive and piezoelectric properties to convert magnetic potential into electrical energy. Analytical modelling of this phenomenon is difficult due to the highly coupled nature of this interaction, so Comsol multiphysics software is used to make predictions of output using the finite element method (FEM). A peak open-circuit harvester voltage of 39.4 V is predicted for a ball bearing oscillating with 4.5 mm amplitude, agreeing reasonably well with measured harvester voltage of approximately 35 V. The modelling is applied to a two-dimensional representation of the system, which is shown to be sufficient for a basic understanding of the highly coupled nature of interactions, and a basis for optimising the magnetoelectric vibration energy harvesting approach.

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