Coordinated Control Strategy Research Of AC Micro-grid Based On Large Scale Energy Storage System

Energy crisis and environmental pollution have attracted wide attention from all over the world.Developing and utilizing renewable energy are one of the effective measures to solve these problems.The output power of the wind and solar power systems has the characteristics of random and intermittent.In order to improve the overall performance and reliability of the system,it is common to use a large-scale energy storage system in the wind and solar power generation system.This paper studies the coordinated control strategy of large-scale energy storage system.The main work is as follows:First of all,the mathematical model of the wind and solar power system and large-scale batteries are built.Secondly,the work characteristics of the wind generator and photovoltaic cells are researched.Thirdly,the basic principle of the wind and solar power generation system maximum power tracking control strategy are analyzed.Then,the control strategy of the wind and solar power generation system interface converter are designed.Finally,the simulation is carried out under the changes of wind speed,light intensity and temperature.Then,this paper presents a kind of two layer coordinated control for large scale energy storage system based on peak and valley load change.The three work modes are divided according to the state of power load,and the bottom control of battery energy storage system and system upper control are given.The simulation research of proposed hierarchical coordination control method is carried out.The proposed research method can be used to realize peak shaving and valley filling.Finally,in view of the traditional droop control without considering the different working state of battery SOC and battery safe operation range,a control strategy of energy storage system based on SOC power allocation is proposed and the three different operation modes of which are divided according to SOC.The basic principle of improved droop control and acquisition method of variable droop factor is given,and the simulation research of proposed improved droop control method is carried out.The simulation results show that the method can effectively avoid the battery get into the over-charging and over-discharging area,and improve the reliability of the system.