Regional analysis and optimization control of static power stable operation of grid-connected converter under weak grid

As photovoltaic energy generation systems are connected to the grid, the strength of the grid will decrease, which will limit the power output capacity of the grid-connected converter (GCC). To solve the above problems, a reactive power compensation optimization control strategy of a grid-connected converter connected to a weak grid is proposed. Firstly, the mechanism of a weak network environment affecting stable output active power of grid-connected converter is revealed. Then, the critical short-circuit ratio of static power stability under the unit power factor is obtained by taking the grid-connected converter output current amplitude and the allowable voltage range of the point of common coupling as constraints. Next, the critical short-circuit ratio of static power stability is obtained when only grid-connected converter capacity is considered and when an external reactive power compensation device is attached. Finally, MATLAB/Simulink is used to verify the correctness and validity of the theoretical analysis.