Large Disturbance Stability Analysis of Full DC Wind Power Generation System Based on Mixed Potential Function

Full DC wind power generation can effectively solve the problems of harmonics and losses generated in the process of grid integration of large-scale wind power, but the complex interactions between the DC devices lead to outstanding transient stability problems of this system under large disturbances. First compares different full DC wind power generation schemes and concludes that the “DC convergence - AC transmission” scheme is more feasible in the context of large-scale wind power grid integration. Then, according to the topology of the “DC convergence-AC transmission” system, analyze the operation and control characteristics of each sub-module and establish an equivalent model of the system. Based on the Brayton-Moser's hybrid potential function theory. Constructing a model of the system's energy function. Derivation of a stability criterion for full DC systems. Calculate the critical power point for stable operation of the system. And analyze the effect of large disturbances with power at the grid side on the voltage and current at the DC convergence point. Finally, the theoretical analysis was verified by simulation software