A capacitive electric-field energy harvester with double-layer copper foil for 220V power line

Abstract

The output power of electric-field energy harvesting is limited by displacement current produced in the capacitive coupling between the harvester and power line. This paper presents a capacitive electric-field energy harvester (CEFEH) that obtains energy from 220V power line by displacement current. The CEFEH consists of copper foil wound around the power line and ground electrode. In order to improve the output power of CEFEH, a double-layer copper foil is used to enhance the capacitive coupling, thereby increasing the displacement current. With the help of larger displacement current, the harvesting power of CEFEH with double-layer copper foil is 1.6 times higher than that of the single-layer copper foil. However, the electric-field energy around the 220V power line is very weak, which makes wireless sensor node unable to work directly. A power management circuit is designed for CEFEH. The test results show that the proposed CEFEH collects 2.468mJ in 400s and drives the ultra-low power wireless temperature sensor node to operation for 800ms. This CEFEH can be used in wireless sensor node with a short-term ultra-low power.