Research And Design On The Micro-Grid Central Controller

Micro-grid system integrates the advantages of distributed power supply and weakens its adverse effects on the power system.The advantage is that micro-grid system can not only operate without the large grid island,but also operate with large power grid and network.Therefore,the control of the micro-grid system in these two modes and the smooth switching between the two modes are the key to ensure the safe and stable operation of the micro-grid.This thesis studies the voltage and frequency control of the micro grid system in the islanding mode and the grid operation mode and the pre-synchronization control of the islanding and the grid and the control of the grid and island.Firstly,this thesis introduces the generation and development of micro-grid,describes the research significance and the current research situation and analyzes the function of the micro-grid central controller and the hierarchical control structure.Secondly,this thesis introduces the control strategy and principle of the micro gird inverter,analyzes the operation of the system and improves the power control structure based on the traditional control to maintain constant output power.In order to achieve an island mode no difference adjustment of voltage and frequency in the island mode,this thesis adopts the quadratic voltage regulation and frequency control algorithm to track the given value,designs a pre-synchronization control method based on the adaptive controller for the smooth switching between the two modes,and derivates the unit distribution coefficient formula in the process.Thirdly,this thesis designs the micro-grid central controller according to requirements of the system communication mechanism,connection,configuration interface and other aspects,so as to ensure that the various functions of the micro-grid system can be realized.Finally,this thesis constructed the simulation platform and conducts the simulated analysis and verification on the control function and control effect of the micro-grid under the MATLAB/Simulink,and designed the hardware platform,software platform as well as the corresponding platform.The simulation results show that the control algorithm is effective and feasible.