This article discusses how a nonhomogeneous magnetic field with a nonconstant flux gradient affects the behavior of electromagnetic vibration energy harvesters. Based on simulations, the authors show that this nonlinearity enables to increase the output power and bandwidth but not to effectively limit the oscillator vibration amplitude. The impact, however, depends on various system parameters, especially the mechanical damping. Comparing the results to an energy-harvesting prototype, one can conclude that, in practice, the linear model based on a homogeneous magnetic field provides a good estimate. The authors finally give suggestions about magnetic fields that are beneficial for energy harvesting.
BartonDAWBurrowSG (2011) Numerical continuation in a physical experiment: investigation of a nonlinear energy harvester. Journal of Computational and Nonlinear Dynamics6: 011010.
2.
BartonDAWBurrowSGClareLR (2010) Energy harvesting from vibrations with a nonlinear oscillator. Journal of Vibration and Acoustics132: 021009.
3.
CepnikCRadlerORosenbaumS. (2011) Effective optimization of electromagnetic energy harvesters through direct computation of the electromagnetic coupling. Sensors and Actuators A167: 416–421.
4.
ChallaVRPrasadMGShiY. (2008) A vibration energy harvesting device with bidirectional resonance frequency tunability. Smart Materials and Structures17: 015035–015044.
5.
CottoneFVoccaHGammaitoniL (2009) Nonlinear energy harvesting. Physical Review Letters102(8): 080601.
6.
KaramiMAInmanDJ (2011) Equivalent damping and frequency change for linear and nonlinear hybrid vibrational energy harvesting systems. Journal of Sound and Vibration330: 5583–5597.
7.
MannBPOwensBA (2010) Investigations of a nonlinear energy harvester with a bistable potential well. Journal of Sound and Vibration329(9): 1215–1226.
8.
MannBPSimsND (2009) Energy harvesting from the nonlinear oscillations of magnetic levitation. Journal of Sound and Vibration319: 515–530.
9.
NguyenDSHalvorsenE (2010) Analysis of vibration energy harvesters utilizing a variety of nonlinear springs. In: Proceedings of PowerMEMS, Leuven, Belgium, 30 November–3 December 2010, pp.331–334.
SnellerAJMannBP (2010) On the nonlinear electromagnetic coupling between a coil and an oscillating magnet. Journal of Physics D: Applied Physics43: 295005.
12.
SpreemannDFolkmerBMaurathD. (2006a) Tunable transducer for low frequency vibrational energy scavenging. In: Proceedings of eurosensors, 17–20September2006, pp.M2C–P2.
13.
SpreemannDManoliYFolkmerB. (2006b) Non-resonant vibration conversation. Journal of Micromechanics and Microengineering16: 169–173.
14.
XingXLouJYangGM. (2009) Wideband vibration energy harvester with high permeability magnetic material. Applied Physics Letters95: 134103-1–134103-3.
15.
ZhuDRobertsSTudorMJ. (2010) Design and experimental characterization of a tunable vibration-based electromagnetic micro-generator. Sensors and Actuators A: Physical158(2): 284–293.
