Control Strategy Study Of Wind-PV-Battery Micro Grid Island Operation

Micro grid is an effective means of distributed power accessing to power network, has gradually become the research focus of domestic and overseas. There are two main operating modes of micro grid: Grid operation and island operation, Seamless switching between grids connected operation and island operation and stability problem is the key and difficult point of micro grid control research. Distributed power output power through the inverter unit to achieve grid, In the process of system operation, the effective control strategy is directly related to the safe and stable operation of the micro grid and the power grid. Therefore, it is of academic significance and practical value to carry out the research on the control strategy of the island operation of Wind-PV-Battery micro grid.In the thesis, the distributed power control strategy and control system as the research object, the stable operation of micro grid as the goal, the research contents are as follows:(1) Research on control algorithm and control system of Wind-PV-Battery micro grid,and the simulation analysis is carried out by using MATLAB/Simulink. Simulation results show that the permanent magnet wind generator unit output voltage is stable in the range of3.5-4.0m/s variation of wind speed; realize the maximum power tracking of photovoltaic power generation unit; the energy storage unit can keep stable output under the load of resistance, inductive and resistance-inductive.(2) In the thesis, the designed control system is studied based on Wind-PV-Battery micro grid. Experimental results show that the system meets the requirements of the national standard in the condition of resistive, inductive and resistance-inductive load.(3) Aim at the suggested control algorithm and control system, the research that the measured voltage waveform in the experiment has a certain range is carried out. The Droop control strategy of the system is changed into V/f and PQ control strategy, and the simulation is carried out by using MATLAB/Simulink. Simulation results show that after change the control strategy, the output voltage fluctuation range of the system is obviously reduced, verify that the control strategy is effective.