A high-efficiency dual-channel photovoltaic power system for nonvolatile sensor nodes

With the development of the Internet of things, battery maintaining of trillion sensor nodes becomes prohibitive both in time and costs. Power system with energy harvesting provides a promising solution. However, conventional energy harvesting systems with storage suffer from low efficiency because of conversion loss, storage leakage and so on. Direct supply systems without an energy buffer can achieve high efficiency, but fail to satisfy quality of service due to mismatches between energy harvesting and workloads. This paper proposes a novel dual-channel photovoltaic power system which hybrids a direct power path and a conventional supercapacitor power path. A power management unit is developed to control the channels according to real time solar condition. The nonvolatile processor enables the node system to run reliably and efficiently under varying solar profiles. We develop a simulation platform with real component parameters to validate the proposed techniques. Experimental results demonstrate up to 31.87% energy efficiency improvement under same design cost against the conventional architecture.