Research On Three-phase To Single-phase Matrix Converter Of Micro-grid

Recently,as an effective measure of integrating distributed generation into the grid,micro-grid has attracted more and more attention.The distribution system general y uses transformers to convert the electric power to household consumers when micro-grid connecting to the grid where the transformer has several disadvantages.This thesis proposes the replacement of transformers by three-phase to single-phase matrix converter in distribution system,and investigates the control strategy which enables the three-phase to single-phase matrix converter to control the voltage stability in household consumers side to build a micro-grid with high power quality for consumers.Firstly,this thesis presents the basic structure of micro-grid system and the basic theory of three-phase to single-phase matrix converter,and then introduces the basic control theory of three-phase to single-phase matrix converter.After the coordinate transformation principle is il ustrated,the control function and method of three-phase to single-phase matrix converter are deduced.Secondly,aiming at the fact that the change of three-phase source voltage amplitude in micro-grid will lead to the change of voltage amplitude in consumer side,a load voltage amplitude phase control method and damping control method are proposed to control the voltage amplitude stability in consumer side;aiming at the fact that the change of threephase source voltage frequency in micro-grid will lead to the change of the voltage frequency in consumer side,a output voltage frequency control method is proposed to control the voltage frequency constant.Thirdly,a simulation model for three-phase to single-phase matrix converter system is built up.Aiming at the change of three-phase source voltage amplitude and load,the load voltage amplitude phase control method and output damping control method are simulated;aiming at the change of three-phase source voltage frequency,the output voltage frequency control method is simulated.The simulation results show that the proposed methods can control the stability of output voltage amplitude and frequency wel.Finally,the experimental system of three-phase to single-phase matrix converter is designed,where its general structure is presented and its hardware design and software design are carried out.The experiment study of proposed method of load voltage amplitude phase control method and output voltage frequency control method has been conducted on this platform.The experimental results verify the correctness of theoretical analysis and the validity of the simulation analysis.