Abstract: The dual-excited synchronous generator (DESG) can control the active and reactive power independently by regulating the magnitude and direction of the excitation magnetomotive force (mmf) so as to enhance its ability for suppressing system oscillations. However, the rotor body damping structures of the DESG will affect the response speed of the excitation mmf, and then affect the dynamic characteristics of the unit. In this paper, the field-circuit coupling time-stepping finite element model of the DESG is established by combining the 2-D transient electromagnetic with the stator and rotor circuit equations. Taking the large disturbance caused by the three-phase sudden short circuit of the system as an example, the influence of the damping structures, such as the rotor slot wedges and the rotor core, on the characteristics of the power tracking excitation control (PTEC) is studied, and the effect law of different damping structures on the characteristics indexes of the low frequency oscillation is revealed. In order to improve the dynamic performance of the DESG, the fuzzy control method is used to optimize the excitation control parameters, and the optimal excitation control parameters suitable for different rotor damping structures are obtained. The research results can provide the theoretical support for the improvement of the dynamic characteristics for the DESG and the increment of the system damping effect.