Abstract:
The dielectric elastomer generator (DEG) is an emerging technology with great potential for generating electrical power from large oscillating motion. A DEG’s soft and elastic nature makes it unique, enabling access to energy sources that have thus far remained untapped due to limitations of traditional technology. A DEG is a variable capacitor. In order to generate power, the highly elastic DEG needs to be charged to a few kilovolts when stretched. Relaxing the DEG generates high voltage electrical power which needs to be recovered for use. Traditionally, the DEG is charged and discharged by controlling the DEG’s charge, voltage, or electric field. The necessary sensor, controller, and converter electronics will consume power and can be large and complex. Such electronics will not work for small low-power DEGs where the power consumption can exceed power generation resulting in an overall power loss. Furthermore, high voltage power is not suitable for powering most consumer devices. This thesis introduces a new method for obtaining useful low-voltage power from a DEG. A selfpriming circuit generates high-voltage power and the self-powered converter converts some of the high-voltage energy into low voltage. The electronics work passively and have very low standby power consumption. The self-powered converter has been analysed and pathways toward improved performance are discussed. In preliminary experiments, the DEG system produced 0.8mW at 3V. The DEG had 20g of active material and was oscillated at 1Hz. The self-powered converter was capable producing more than 250mW of power at 5V from 914V with 43% efficiency. A technique for efficient charging and discharging of DEGs has also been introduced in this thesis. The technique transfers high-voltage energy between DEGs and capacitors while retaining its high voltage form. The energy can be returned to the DEG when stretched while avoiding the large power losses incurred from large voltage conversions. This work has enabled the practical use of DEG energy harvesters to produce useful low-voltage power. Steps have been taken to commercialise the new technology. With this new technology and its unique properties, the world can tap into renewable energy sources that have previously remained untouched.