A Study of Control Modal Interaction and Internal Resonance of DFIG

With the transformation of the national energy structure and the implementation of the “dual-carbon” strategy, large-scale wind power continues to be connected to the power system, which brings problems such as interactive resonance and converter drive stability to the system. By studying the influence of the control parameters of the machine-side converter and the outer ring of the grid-side converter control on the stability of doubly-fed asynchronous wind turbines, it is found that the parameter stabilization zones of the outer ring of the machine-side converter control are located in the lower left plane, and that the parameter stabilization zones of the outer ring of the grid-side converter control are located in the lower right plane, and that there exists a band of parameter risk areas between the parameter stabilization zones and the instability zones. When increasing the proportional and integral coefficients of the grid-side converter controllers, the system damping will be enhanced, but in a certain interval, a strong interaction and thus internal resonance will occur, leading to system destabilization. For the strong interaction between the controllers of the grid-side converter, Particle Swarm Optimization (PSO) is introduced to optimize the parameters of the PI controllers of the grid-side converter, and the optimization shortens the DC voltage recovery speed by half a cycle and reduces the overshooting amount by 40%.