A hybrid storage system for wireless sensor nodes powered with energy harvesting

With the recent development of Internet of Things (IoT) and Wireless Sensor Networks (WSN), research and industry have been increasingly focusing on the opportumty of collecting the energy arising from the environment. The Energy Harvesting provides the possibility to supply devices which are placed out of reach or in hazardous spots, e.g. the Wireless Sensor Nodes. Among the different parts belonging to an Energy Harvesting system, the power management network represents a challenging topic. In this paper a Hybrid Energy Storage System (HESS) usable for a WSN powered with Energy Harvesting, based on a battery-capacitor integration, is presented. The experimental results concerning the assembled buck-boost power converter are shown as well. The proposed prototype is based on the up-to-date technology of Gallium-Nitride (GaN) MOSFETs, ensuring reliable and fast operations, as well as small dimensions, appropriate for embedded target loads. The system is compliant with a storage system based on a 12 V battery, consisting of four series rechargeable coin-cell 3 V lithium batteries, and a multilayer chip ceramic capacitor rated for maximum 16 V.