A new class of variable capacitance generators based on the dielectric fluid transducer

Abstract

This paper introduces the novel concept of dielectric fluid transducer (DFT), which is an electrostatic variable capacitance transducer made by compliant electrodes, solid dielectrics and a dielectric fluid with variable volume and/or shape. The DFT can be employed in actuator mode and generator mode. In this work, DFTs are studied as electromechanical generators able to convert oscillating mechanical energy into direct current electricity. Beside illustrating the working principle of dielectric fluid generators (DFGs), we introduce different architectural implementations and provide considerations on limitations and best practices for their design. Additionally, the proposed concept is demonstrated in a preliminary experimental test campaign conducted on a first DFG prototype. During experimental tests a maximum energy per cycle of and maximum power of has been converted, with a conversion efficiency up to 30%. These figures correspond to converted energy densities of with respect to the displaced dielectric fluid and with respect to the mass of the solid dielectric. This promising performance can be largely improved through the optimization of device topology and dimensions, as well as by the adoption of more performing conductive and dielectric materials.

Electric power generation using a parallel‐plate capacitor

“…Additionally, breakdown field for dielectric fluids is also higher than that of air. In a recent work, Duranti et al proposed a novel concept of dielectric fluid transducer, which is a variable capacitance electrostatic generator. Such transducers are able to convert mechanical energy into direct current electricity.…”

“…At present, most portable scale electronic devices rely upon chemical cells of rechargeable or single‐use type to store and deliver electrical power on demand. In the era of smartphones and other devices, portable energy generators are high on demand, and these demands support research in the area of energy generation methods, as it is not always possible to find an available power outlet.…”

“…Previously, different types of energy generators covering a very broad range of applications is proposed and discussed . Electrostatic generators have existed for a long time; the Van de Graaff generator from the early 20th century is probably the most famous one.…”

“…Previously, different types of energy generators covering a very broad range of applications is proposed and discussed. [2][3][4][5][6][7][8][9][10] Electrostatic generators have existed for a long time; the Van de Graaff generator 11 from the early 20th century is probably the most famous one. Variable capacitance-based energy generators are strong pillar of energy harvesting industry; some of the early examples of such generators are described by previous studies.…”

Inkjet Printing of Complex Soft Machines with Densely Integrated Electrostatic Actuators

“…[ 33 ] The latter devices reach energy densities in the range of 10 5 –10 6 J m −3 using inextensible polymers that can sustain very high electric fields. Zipping actuators with a liquid dielectric have been applied to different fields, such as microfluidics, [ 34 ] energy harvesting, [ 35 ] or haptic feedback, [ 36 ] thanks to their high displacement and force. Soft electrostatic zipping actuators are therefore interesting candidates to provide embedded electrically controlled deformation and liquid displacement for the actuation of soft machines, and developing a fabrication technique to seamlessly integrate these actuators into soft structures would enable the design of complex multi‐degrees‐of‐freedom devices.…”