Session: VIB-02-02 Nonlinear Systems, Phenomena and Energy Harvesting

Paper Number: 66940

Start Time: August 17, 02:10 PM

66940 - On the Efficiency of Energy Harvesters Under Large-Amplitude Excitations 

In this research the effects of the excitation conditions on the
efficiency of a vibration energy harvester are evaluated and
discussed. Typically, these discussions focus on the frequency
content of the applied motion in relation to the resonance
frequency of the generator. However, another important quantity
that should be considered in these discussion is the motion ratio.
The motion ratio is a metric that describes the relation between
the amplitude of the applied excitation to the internal
displacement limit of the device. While it has been generally
accepted that the greatest efficiency is achieved when the
generator operates at resonance and is damped such that the
amplitude of the internal motion matches the displacement limit,
it will be shown here that this is not true for all cases. In cases
where the amplitude of the driving motion is greater than the
internal displacement limit, as is typically the case for lowfrequency
vibrations, it was found that the efficiency can be
improved by reducing the damping such that the proof mass
comes in contact with the displacement limits. The power output
that can be obtained by using this approach can exceed that of a
resonant system and therefore allow for a figure of merit greater
than 100%. Furthermore, in a range of conditions the efficiency
can be further increased by adopting a bi-stable system.

Presenting Author: Thijs Blad Delft University of Technology

Authors:

T. W. A. Blad Delft University of Technology
N. Tolou Delft University of Technology