Multi-Source Energy Harvesting for Wireless Sensor Nodes.

The past few years have seen an increasing interest in the development of wireless sensor networks. But the unsatisfactory or limited available energy source is one of the major bottlenecks which are limiting the wireless sensor technology from mass deployment. Ambient energy harvesting is the most promising solution towards autonomous sensor nodes by providing low cost, permanent, and maintenance-free energy source to wireless sensor nodes. In this paper, we first invested available energy source such as solar, vibration, thermal and other potential energy sources, and described the mathematical model of each energy source. Secondly, a novel adaptive topology maximum point power tracking method is proposed. This method is that changes the solar cells array from series to parallel or series-parallel mixed way to find out a best array that output the maximum power. This method also can be used in other energy source. At last, we purchased the matured energy generator: vibration, thermal, and solar panels to measure and verify the output power of each energy source. The experimental result showed that the conversion efficiency of this novel MPPT method can reach 60%-80% in outdoor and it is able to supply sufficient power to wireless sensor nodes