A Multi-Harvester architecture with hybrid storage devices and smart capabilities for low power systems

The increasing attention on energy autonomous sensing and computing systems which can operate unattended tens of years, have made energy harvesting and power conversion techniques key technologies for the future. The goal is to power systems nearly perpetually if the scavenger is exposed to reasonable environmental energy conditions. However, the system is still threatened to run out of energy, if a prolonged lack of energy intake happens. The last frontiers of perpetual operating systems is combining cutting edge technologies for energy generation from the environment and long-term and green energy supply using small factor fuel cells with few cm3. In this paper we introduce an hybrid power architecture which improves embedded systems power availability. We present a Smart Power Unit (SPU) that is a power supply architecture which manages both energy harvesting and novel fuel cells technologies. SPU provide an efficient air-flow and solar energy harvesting stage and a hydrogen micro fuel cell interface. Each harvester stores energy in a local supercapacitor and, when full, a lithium-ion battery is charged. Micro fuel cell acts as reservoir source for recharging battery in low environmental power condition. The core of the SPU is the microcontroller based power manager that exploits MPPT, energy prevision, battery monitoring and communications with user node.