Investigation on free relaxation process influencing energy harvesting performance of dielectric elastomer generators in intermittent motion

Due to the difference of dielectric elastomer (DE) material properties such as viscosity and conductivity, the existing research results on whether the free relaxation process is introduced into the triangular harvesting scheme to improve the energy harvesting performance of DE generators (DEGs) are completely opposite. In this paper, we quantitatively investigate the performance of DEGs with varied viscosity and conductivity under two types of triangular schemes for converting the intermittent motion. One type is without the free relaxation process and the other includes the free relaxation process. By the comparison of two types of triangular schemes, the results on when to introduce the free relaxation process and how to design the triangular scheme can be achieved. In addition, the effect of the deformation rate during the non-free relaxation process and the transfer capacitor in the energy harvesting circuit on the performance of DEGs is also analyzed. Conclusions can help to select the triangular scheme of DEGs for performance improvement.