Research On TheDesign And Control Strategy Of MGCC

Micro-grid systems fully integrate the advantages of each distributed power, weakening its adverse impact on the power system, so that the distributed power generation system rejuvenated. The main different aspects between the micro-grid system and distributed generation system is that:micro-grid system can not only run islanding without power grid, but also can be operationed with large power grid.Therefore the micro-grid systems’s control and smooth transformation between the two modes is crucial to ensure the micro-grid to achieve safe and stable operation. In this paper, we research the islanding mode and grid-connected mode’s voltage and frequency control; and the pre-synchronization control which change the system from islanding mode to grid-connected mode and the change from grid-connected mod to islanding mode; the main contents are as follows:(1)First, it introduces the background and development of micro-grid, followed by the concept and characteristics of micro-grid, then introduced the development of the each country. Finally, the paper analyzed the micro-grid system’s three control structure:the peer control architecture, the master-slave control structure, the hierarchical control structure; it introduced four control strategies of micro-grid system:they are the VF control, the PQ control, the VSG control and the Droop control;(2)In the paper, it analysis the bicyclic inverter, and get the equivalent circuit of the inverter; While the Micro-grid is islanding mode, it analysis the MGCC’s voltage and frequency control;(3)In the paper, the grid-connected mode’s control are analyzed, and improved the traditional droop control strategies, so that the system’s power output remains constant; Finally, in order to achieve smooth transformation between the two modes,it designed a new pre-synchronization algorithm;(4)At last, we design the MGCC, wich includes the communication mechanisms, connections mode and methods of diaplay and so on; The functions of MGCC include the secondary voltage modulation, the secondary frequency modulation, the pre-synchronization control, the smooth transformation between two modes; Then it in Matlab/Simulink environment do the simulation analysis and also in the experiment platform do the experimental verification. The simulation and experimental results show that the algorithm of MGCC is effectiveness and feasibility for the micro-grid systems;...