Stray electric field energy harvesting technology using MEMS switch from insulated AC power line

A new energy harvesting technology that extracts energy from the stray electric field around a three-wire AC power line is presented. It is observed that when 20 cm of the insulated power line is surrounded with a conductive sheet, about 20 mJ of energy is harvested in 15 min with a 1 μF storage capacitor. An autonomous harvesting circuit was designed and built adopting an MEMS switch as a low leakage, low power consumption and hysteretic switch. It is demonstrated that the harvested energy is utilised to drive a commercial Zigbee-based wireless sensor module autonomously. Since it is easy and safe to install, the proposed stray electric field harvesting technology should greatly expand the field in which wireless sensors are required, such as home automation, smart grid, building energy management and structural health monitoring, as long as power lines are available nearby.