Research On Single-phase Active Distribution Network Based On Solid State Transformer

Energy shortage is a major challenge facing the development of today’s society.With the rapid development of China’s economy and the continuous advancement of urban and rural integration,the electricity consumption in urban and rural areas has continued to increase,and higher requirements have been placed on the reliability and quality of power supply.According to the rich characteristics of renewable energy in urban and rural areas,the development of an active distribution network with distributed power generation units can effectively alleviate energy pressure.China’s urban and rural distribution network mostly uses low-voltage three-phase distribution network.The low-voltage distribution network has the problem of excessive low-voltage power supply radius,long low-voltage line and large line loss,resulting in energy waste and increasing energy supply pressure.The single-phase distribution network developed in developed countries can effectively reduce the length of the low-voltage lines in the distribution network,reduce the power supply radius of the distribution transformer,and reduce the loss and investment of the entire power grid.Therefore,this paper takes the single-phase active distribution network as the research object,and studies the voltage stability under the island state.This topic first describes the advantages of single-phase active distribution network based on solid-state transformers.The voltage stability problem based on master-slave control is analyzed based on single-phase active distribution network islanding.The singlephase three-stage solid-state transformer used in the active distribution network was introduced,and the main isolation stage was theoretically analyzed and modeled.Secondly,the impedance models of the master and slave are established respectively.The impedance criterion is used to analyze the system voltage stability caused by the change of the number of slaves in the system.The theoretical analysis is verified by MATLAB/simulink simulation platform.Thirdly,the related concepts of mixed sensitivity algorithm are introduced,and the master model is established.The mixed sensitivity algorithm is used to design a robust controller for the master,which can maintain the system voltage stability when the number of slaves changes.Then the simulation scheme of the proposed scheme is verified by MATLAB/simulink simulation platform.Finally,the DAB experimental platform was built,and the hardware design was introduced.The theoretical analysis of the isolation level was verified by the experimental platform.Based on the RTDS-based hardware-in-the-loop experimental platform,the hardware-in-the-loop experimental verification scheme for the voltage stability of the island active distribution network is verified by hardware-in-the-loop experiments,and the effectiveness of the proposed strategy is proved.