Smoothing Power Strategy Of Wind/Photovoltaic/Hybrid Energy Storage System Considering The Battery SOC Safety Range

Human's life tends to be technological and modern.The development of society and the new normal of economy point out a new direction for the utilization and exploitation of renewable energy.lt is of great significance to develop new energy generation methods such as wind,solar and so on,research on the structure and characteristics of hybrid energy storage systems and research smoothing sower strategy.This paper studied the principle and characteristics of wind power generator and solar cells,including the relationship between the variable wind speed and the output power of the wind power generator,and the output characteristic of solar cells under variable light intensity and different temperatures.And the simulation was carried out to study the basic principle and composition of Wind-solar Hybrid Generation System.Finally,the Wind-solar Hybrid Generation System was established by the alternation and complementation of the two generation power in time and space.Hybrid energy storage equipment makes up for the weak state of charge and discharge of single energy storage equipment.This paper studied the hybrid energy storage devices,which uses supercapacitor and lead-acid battery as the core.The combination of the two can give full play to the high energy density of the battery,the high power density and long cycle life of the supercapacitor,then can realize the flexible energy management.The wind/photovoltaic/energy storage hybrid power System was built,and the three-phase voltage source type grid connected inverter was used as the grid connection interface of this system.The power distribution of the hybrid energy storage was done in the way of low pass filter to suppress the power fluctuation of Wind-Solar Hybrid Generation System.A Wind/Photovoltaic/Energy Storage Hybrid Power System was built and simulated on the matlab/Simulink.The simulation results show that the power output was more smooth after the suppression of the hybrid energy storage unit,and there will not be much random and intermittent oscillation,and the DC voltage oscillation was eliminated.The stability of the system is improved.In order to achieve the real-time and accurate tracking of the battery charging state,the Extended Kalman Filter was selected to estimate the SOC,and the space state model of SOC was built On the basis of on-line identification of battery parameters,constant current and equal capacity discharge experiments were carried out to compare and analyze dynamic conditions.and the Simulink simulation module was set up.The results show that the Extended Kalman Filter has strong traceability and adaptability,and the ideal value of battery SOC can be tracked accurately and in real time.On the premise of accurate estimation of the battery SOC,the influence of different filter parameters on the output power was analyzed.Then the principle of filter parameters selection was proposed,and the generation of power reference values with on-line adjustment of filter time constant is given.Finally,the adaptive adjustment module of variable filter time constant was added to the simulation model of Wind-solar Hybrid Storage System,and the simulation study of SOC is carried out at different stages.The simulation results show that when SOC is in its upper limit or lower limit,the method proposed in this paper can slow down the speed of SOC to the upper and lower limits.It prevented the output power of battery energy storage system suddenly switching to zero,and effectively suppresses grid connected power fluctuations.At the end of this paper we proved the feasibility and validity of this model.