“Miniature 3V-to-500V Converter for Capacitive Actuators”
Scott Sun, S.B. ’18, electrical engineering
Advisor: Gu-Yeon Wei, Robert and Suzanne Case Professor of Electrical Engineering and Computer Science
Dielectric elastomer actuators (DEA) are capacitive materials that mechanically deform under high voltage. The actuators have many applications in the design of soft robots and wearable technology. The lack of efficient, small, high voltage converters for powering these materials is a major limitation preventing their adoption. Sun sought to develop a miniaturized circuit that could drive a DEA at 500V from a 3.7V lithium polymer battery. He built a circuit on a two-layer printed circuit board, using an inductive charging method that allows bidirectional energy transfer between the battery and the actuator. This design is capable of reaching up to 550V. The circuit Sun developed is highly flexible, with the ability to drive other types of capacitive actuators, such as the piezoelectric actuators that are utilized in many miniature robots today.
“The success of this project opens up new applications for materials that require such high voltages. These range from miniature crawling robots with self-contained power supplies to designing light wearables that aren’t inhibited by the need to carry around a bulky power supply,” he said. “The low power nature of such circuits, coupled with appropriate user isolation, means that these high voltage materials can see safe adoption in applications involving human contact. The reverse energy recovery nature of this circuit’s design also opens up possibilities for energy harvesting, whereby actuator materials can be embedded in fabrics or roads and generate recoverable energy as they are deformed.”