Design of Power Supply System for Field Wireless Sensor Network Nodes

A simple power supply solution with solar energy photovoltaic cells is put forward for low-power field devices like wireless sensor network (WSN) nodes for environmental surveillance. In order to reduce the system´s power loss and improve the efficiency of solar energy photovoltaic cells, the battery´s output characteristics and the leakage current of supercapacitor (SC) are investigated and the power system with matching SCs and solar cells is designed. Then the two-stage energy storage structure including SCs and NIMH batteries are used to store electric power, and the output voltages and currents of power supply are analyzed. The experimental results show that the system can reserve enough energy and meet the long-term power supply requirements of wireless sensor network nodes in the field.