Modeling and Control of Lozenge-Shaped Dielectric Elastomer Generators

Abstract

Dielectric Elastomers (DEs) are a very promising technology for the development of energy harvesting devices based on the variable-capacitance electrostatic generator principle. As compared to other technologies, DE Generators (DEGs) are solid-state energy conversion systems which potentially feature: 1) large energy densities, 2) good energy conversion efficiency that is rather independent of cycle frequency, 3) easiness of manufacturing and assembling, 4) high shock resistance, 5) silent operation, 6) low cost. Envisioned applications for DEGs are in devices that convert ocean wave energy into usable electricity.This paper introduces the Lozenge-Shaped DEG (LS-DEG) that is a specific type of planar DE transducer with one degree of freedom. A LS-DEG consists of a planar DE membrane that is connected along its perimeter to the links of a parallelogram four-bar mechanism. As the mechanism is put into reciprocal motion, the DE membrane varies its capacitance that is then employed as a charge pump to convert external mechanical work into usable electricity.Specifically, this paper describes the functioning principle of LS-DEGs, and provides a comparison between different hyper-elastic models that can be used to predict the energy harvesting performances of realistic prototypes. Case studies are presented which address the constrained optimization of LS-DEGs subjected to failure criteria and practical design constraints.

Dynamic Model of Dielectric Elastomer Diaphragm Generators for Oscillating Water Column Wave Energy Converters

“…Initially proposed as muscle-like actuators for robots, DEs are now receiving significant attention in energy scavenging applications [2][3][4][5][6], in particular for the development of Wave Energy Converters (WECs) [7][8][9][10][11]. Specifically, DE Generators (DEGs) are foreseen to replace the Power-Take-Off (PTO) systems of traditional WECs, which are currently made of stiff, heavy, shock-sensitive, corrosion-sensitive and costly (metallic and rare-earth) materials.…”

Synthesis of Bottlebrush Polymers with Spontaneous Self-Assembly for Dielectric Generators

“…The relative permittivity of mix - co -P was 3.83 at 20 Hz. After the polar group modification, the dielectric permittivity increased to 5.23, which is higher than the VHB of 4.45–4.48 (1–10 Hz). − Besides, tan δ (ε″/ε′ ratio) revealed that our materials can be operated at frequencies above 1 Hz where tan δ remains lower than 0.1. Additionally, the conductivity of all materials was below 10 –12 S/cm, which is rather low and further confirms the good dielectric properties of our materials.…”

Flexible membrane structures for wave energy harvesting: A review of the developments, materials and computational modelling approaches

“…Oscillating Bodies. The surge converter [117] has seen alternative forms with DEG implementation suggested by SBM [118] and Moretti et al [119,120], replacing the hydraulic pump PTO. In [118], the energy from flap movement is harvested by a vertical stack of DEG films.…”