Research On Access And Inverter Control Based On10kV Distribution Micro-grid

With the progress of science and technology, the development of economic and the increasingly high demand of the environment, the traditional power system can no longer meet the increasing demand for electricity. In order to improve the supply and the demand of the electricity market, the Distributed Generation (DG) is introduced and quickly absorbed into the power grid distribution system. However, due to the Distributed Generation’s own characteristics, its generating capacity is very unstable and very scattered, which leads to many problems in the management of Distributed Generation, such as Distributed Generation into the grid, Distributed Generations parallel, Distributed Generation energy management and so on. Because of the existing of these problems, the Distributed Generation’s positive affection on the diversification demand for electricity is limited seriously.Distributed Generation unit connected into grid and Distributed Generation units in parallel operation are mainly strudied in this thesis. Firstly, based on the study of common distributed powers and their mathematical models, a basic mathematical model of distributed power is designned. At the same time different control strategies for different Distributed Generation units are researched. A nonlinear control method is presented in order to achieve the control on the basic model of distributed power. With the research on the design of Distributed Generation unit interface model and the principle of sag control made, a kind of Distributed Generation unit controller is designed. The process of the controller internal voltage current control loop and the external power control circuit are analyzed in details, which makes the grid-connected Distributed Generation units realized effectively.Secondly, the research on the technology of Distributed Generation units connecting into grid is made. Detailed analysis of circulation between Distributed Generation units in parallel with each other is conducted. At the same time a variety of possible control methods are made to eliminate the circulation hazards. With detailed research on the inverter technology of Distributed Generation units in parallel, an inverter with a filtering function for Distributed Generation units in parallel grid and grid-connected is simply designed. Meanwhile an idea of Distributed Generation unit energy management in summary is put forward for subsequent research.Finally, simulation analysis on the control strategies of Distributed Generation units and the grid presented in this thesis is made on the PSCAD/EMTDC simulation platform.