Research On The Control Technology Of Micro-grid

With the development of economy and improvement of living standards,people’s dependence on electricity is increasing.The power supply mode is also gradually changed from the centralized power supply to the power supply mode both with centralized power supply and distributed power supply.In order to improve the quality and reliability of power grids,reduce environmental pollution,increase the use of renewable energy,and alleviate the shortage of non-renewable energy sources,scholars have proposed the concept of micro-grids and conducted extensive research on them.The paper focuses on the stability of the micro-grid and micro-grid control.The work is as follows:First,the paper introduced the commonly micro source control method and commonly Control strategy of micro-grid system,and compared the advantages and disadvantages of each control method and discussed the suitable range of the method.A micro-grid model is built on the idea of peer-to-peer control.The parameters and structures of the filter,controller,inverter and other modules of the micro grid system are designed.A simulation model is built on the Matlab/Simulink platform to verify the simulation.Secondly,based on the principle of small signal stability,Small signal modeling was built and stability of micro-grid was analysed.The influence of the droop coefficient change and load change on the stability of the micro-grid is analyzed.The eigenvalue and damping coefficient are established through analysis and establishment of the relationship between the resistance and the droop coefficient in which range of change is determined to enable the system to have better dynamic performance and good stability.Finally,for the unbalanced power caused by unequal line impedances in the traditional droop control,the droop controller is improved,and the effectiveness of the improved scheme is verified by simulation.