Transient synchronization instability in doubly fed induction generator (DFIG)-based wind turbines during grid faults remains a critical research challenge. Conventional analysis assumes dynamic decoupling between the current loop and phase-locked loop (PLL) under sufficiently fast current response

suggesting that transient synchronization stability depends primarily on PLL dynamics. However

this study finds that even under ideal fast current response conditions

indirectly controlled stator current dynamics still significantly influence transient synchronization through multi-timescale coupling. Theoretical analysis decouples stator current dynamics into fast and slow timescales. The former changes the initial conditions of the PLL through the cumulative effect of state variables

while the latter exhibits strong nonlinear interactions with the PLL to affect the transient energy. Therefore

this paper develops a reduced-order transient model that accurately characterizes the influence of stator current dynamics through initial value correction and equivalent circuit method

and quantifies the coupling effects of both fast and slow stator current dynamics on transient synchronization stability. Based on this model

the relationship between the PLL control parameters

magnetic inductance

and the impact of stator current dynamics is revealed. Finally

the correctness of the theoretical analysis is validated by hardware-in-the-loop experiments.