Research on Improving System Stability in Photovoltaic Power Plants Based on Feed-Forward Power Decoupling Control

Under the trend of new energy power system construction and green low-carbon development, photovoltaic power plants rely on a large number of power electronics to be connected to the grid, and new energy gradually replaces conventional synchronous units to pose new challenges to the stable operation of the grid. Grid-connected PV inverters present characteristics such as non-linear coupling and dynamic interaction with the grid, which bring new disturbance factors and safety and stability problems to the grid; based on the characteristics of grid-connected PV inverter power double-loop decoupling control, the anti-disturbance capability of the grid-connected system can be improved by additional control. This paper derives the mechanism of additional control to provide positive damping torque for a PV plant operating in parallel with a synchronous machine, and designs a damping control strategy for grid-connected inverters based on Feedforward power decoupling control (FPD), which smoothes out the power oscillations of the system by reasoning and adjusting the controller parameters with the damping torque coefficient method. Taking an actual operating PV plant as an example, the modeling of the PV plant integrated into a 4-machine, 2-area grid is completed based on the Digsilent platform, and the accuracy of the proposed method is verified by simulation.