Dielectric Elastomer Generator with a Voltage-Difference-Type Output Circuit Considering Leakage Currents

Abstract

The use of environmental vibrations as a power source for IoT devices has been attracting increasing attention. Dielectric elastomer generators (DEG) convert the mechanical energy to the electrical one by utilizing the capacitance change according to its deformation, and are expected for the generators for low-frequency vibrations. The self-priming circuit (SPC) that boosts the voltage of the DEG is widely used. For the power source for the IoT devices, voltage step-down elements such as Zener diodes can be introduced, however, the energy loss will deteriorate the efficiency. Moreover, for quick voltage boosts, the use of small capacitance condensers in the SPC is required, which will make the generators sensitive to the leakage currents. This study proposes a DEG circuit that utilizes a rectifier as the output circuit elements connected between the DEG and SPC, instead of the step-down elements connected parallel to them. The current flow to the load is governed by the voltage difference between the DEG and SPC, thus, we can choose larger capacitance condensers for the SPC. We first derive the formulae for the charge increments in a cycle, then the properties of the proposed circuit are precisely discussed. To see the property under the existence of the leakage current, experiments are conducted, which show the effectiveness of the proposed circuit.