Stability analysis and parameter coordination of the grid-connected wind farm with heterogeneous PMSGs

Abstract

Improper setting of phase-locked loop (PLL) control parameters is one of the key factors for the adverse dynamic interaction between wind turbine generators, resulting in the oscillation instability of wind power systems. In this study, considering the spatial distribution characteristics and dynamic heterogeneity of multiple PMSGs, the PLL-induced instability mechanism of the grid-connected PMSG wind farm is studied and a stability criterion is proposed to guide the parameter coordination of the PLL for multiple PMSGs. First, based on the dynamic equivalent modeling method of the homogeneous multi-agent system, a reduced-order model of the homogeneous wind farm dominated by PLL is proposed. The parameter region of PLL control to ensure stability was analytically examined based on the proposed stability criterion. Then, the stability of heterogeneous wind farm is analyzed by constructing an equivalent homogeneous wind farm that has the same dominant oscillation mode as the heterogeneous wind farm; that is, the stability is equivalent. Furthermore, the stability criterion of the heterogeneous wind farm is deduced, and the parameter coordination method of PLL control for multiple PMSGs is proposed. Modal analysis and nonlinear simulation were conducted to confirm the accuracy of the theoretical analysis.

Keywords

• Oscillation stability
• Parameter coordination
• Heterogeneous wind farm
• PMSG
• PLL