Stability Improvement of Grid-Connected Renewable Energy Generations Based on Virtual Bus Voltage Control

In order to improve the grid-connected stability of renewable energy power generation multi-machine system, this paper proposes a stability optimization method of renewable energy power generation system based on virtual bus voltage. This method moves the grid-connected point of the information collected by the phase-locked loop to the grid direction by means of control, which mathematically reduces the distance of the transmission line, which is equivalent to reducing the grid impedance of the grid-connected point, thus increasing the grid strength of the grid-connected point of the renewable energy station. The influence of optimization strategy and control parameters on system stability is analyzed by eigenvalue analysis. It is found that the virtual bus voltage control has a good effect on improving the stability of the doubly-fed wind turbine under the weak grid, and in the appropriate range, increasing the compensation factor k of the virtual bus voltage control and reducing the time constant tau are helpful to further improve the stability of the doubly-fed wind turbine connected to the weak grid. Finally, the effectiveness of the control method is verified in time domain simulation.