A self-triggered pulsed-mode flyback converter for electric field energy harvesting

Electric Field Energy Harvesting (EFEH) from medium-voltage power lines is an emerging technology to energise the low-cost distributed electronic measurement systems that are needed to monitor vital line parameters for smart grid systems. The challenge with EFEH is to extract energy without requiring a direct connection to the power line conductor. This severely constrains the amount of continuous energy that can be obtained because of the weak capacitive coupling between the power line and the energy harvesting system. This paper addresses this challenge, by using a self-triggered discontinuously operating flyback converter to transform a high voltage DC bus rectified from the weakly coupled AC supply down to useful low voltage levels. The results show that over 20 mW of continuous power can be extracted from a 12.7kV medium-voltage line using this approach. Detailed circuit analysis and matching experimental results are presented to validate the concept.