Research of the Effect of Different Current Control Structures on the Stability of Wind Turbine Generator

With the increasing proportion of wind power in the power system, the new energy grid-side equipment with power electronic devices as the interface has gradually significant influence on the safe and stable operation of power system. At present, grid-side converters are widely connected to the power grid synchronously through phase-locked loop (PLL), which can interact with the inner current control loop and thus cause the small-signal instability. In addition, the difference of control structures of the inner current control loop will influence the stability as well. In this paper, the small-signal models of grid-side converter with and without feedforward decoupling are all developed to analysis the small-signal stability of the power system, and the differences of stability under the different control structures are compared based on eigenvalue analysis. Then, by comparing the participation factors of eigenvalues under the different control structure and eigenvalue trajectories when the grid strength and control parameters change, the improvement effect of feedforward decoupling on stability is proved. Finally, simulations are built in PowerFactory to verify the results of eigenvalue analysis.