Research On Composite Energy Storage System Of Microgrid

In the past two decades,the global economy has developed rapidly,and the electricity consumption of the people's livelihood and the electricity consumption of the industry have increased substantially.The old-fashioned traditional power generation model has been unable to completely deal with the global demand for electricity.Therefore,the power system is developing rapidly.The period of rapid change.On the one hand,the traditional large-scale power generation technology for centralized power generation and long-distance transmission has matured.On the other hand,the emerging way of mixing the micro-grid with the traditional large-scale power grid has become a new development direction of the power system.How to make a good storage of electricity is one of the key technologies that the microgrid needs to deal with.The importance of energy storage technology is reflected in improving the operating characteristics of the microgrid,improving the quality and reliability of power supply,and being able to co-operate with new energy generation technologies.Better collaborative use.This paper is divided into four parts: the present situation of microgrid at home and abroad,the operation and control of microgrid and distributed power supply,the research of battery and supercapacitor,the topology and control strategy of composite energy storage system.In the first chapter,the background and significance of the research on microgrid are explained,the research status of microgrid and its composite energy storage system at home and abroad is introduced,and the main contents of this paper are listed.Then the concept of microgrid and several typical structures of foreign mainstream microgrid are introduced,and their differences and similarities are analyzed.In the second chapter,the development and structure of microgrid in China are introduced,and the microgrid and its components are studied.The operation and control mode of distributed power supply,the mode of communication in microgrid and the protection measures of microgrid.In the third chapter,I focus on the analysis of battery and supercapacitor energy storage methods,give the relevant formulas of the two energy storage modes,and introduce their two commonly used charging and discharging modes.The main circuit diagram and related control block diagram of the charge and discharge are given respectively,and the charge and discharge simulation experiments of supercapacitors are carried out in Matlab/simulink simulation software.Finally,in the fourth chapter,according to the fact that the composite energy storage system is parallel on the AC side or DC side,I study the composite storage composed of several typical supercapacitors and batteries.The topological structure of the energy system is analyzed,the advantages and disadvantages of each topology are analyzed,and the extremely importantbidirectional DC/DC converter in the composite energy storage system is studied.The working principle of boost state and buck state is introduced and the voltage formula at both ends is given.Finally,I select a composite energy storage system topology for detailed analysis,and combined with the battery pack,supercapacitor bank and DC bus power exchange situation,and finally give the control strategy of the composite energy storage system.