Research On Solar Power Management System Of Wireless Sensor Network

With the continuous development of the Internet of things,wireless sensor network has been applied more and more widely,and the power supply of wireless sensor network has gradually become the focus of people’s attention.Solar energy is safe and reliable,inexhaustible and inexhaustible.The use of solar energy to power a wireless sensor network can not only reduce environmental damage,but also ensure the sustainability of power supply and reduce the cost of maintenance and replacement of energy storage devices.In this paper,the overall system architecture is designed according to the load demand of power supply.Selection and capacity calculation of photovoltaic cells,super capacitors and batteries;The structure and characteristics of the power electronic transformation circuit used in the system were compared and analyzed.The half-bridge circuit was selected as the main circuit of the switching power supply,the boost circuit as the maximum power point tracking control circuit of the photovoltaic cell,and the bi-directional dc-dc transformation circuit as the charging and discharging circuit of the energy storage device.According to the working status of photovoltaic cells,batteries and supercapacitors,an energy flow path control strategy is proposed.Through controlling the on-off of dc-dc circuit switch tube,the coordination of three kinds of energy of photovoltaic cells,mixed energy storage device and municipal power is achieved to ensure efficient and stable operation of power supply system and fast response.Secondly,the parameter calculation of main circuit of switching power supply and the design of control and protection circuit are carried out.By comparing and analyzing the principle and characteristics of the existing photovoltaic cell maximum power point tracking method,a three-point adaptive method is proposed for maximum power point tracking.According to the charging and discharging characteristics of the battery and the supercapacitor,the control strategy of the voltage and current double closed loop is used.The battery is charged by the three-phase charging mode,the supercapacitor is charged by the constant voltage charging mode,and the mixed energy storage device is discharged by the constant voltage limiting and discharging mode.The solar power management system designed was modeled and simulated by using MATLAB software.Through the comparison and analysis of the simulation results,it was concluded that the solar power management system could quickly meet the load requirements and provide stable voltage for the load.Finally,the system experimental platform was built.The charging and discharging test showed that the solar power management system can quickly switch energy and ensure the output voltage of 24 V to meet the load demand and achieve the expected effect.