Influence of Different Rotor Damping Structures on Dynamic Characteristic of Dual-Excited Synchronous Generator with Excitation Control

In order to study the effect of the rotor damping structure comprised of the slot wedges and core on the dynamic characteristic of the dual-excited synchronous generator (DESG) with the power tracking excitation control (PTEC), the field-circuit coupled time-stepping finite element model is established by combining the 2-D transient electromagnetic model with the stator and rotor circuit equations. With a 300-MW DESG as an example, the dynamic characteristic indices, such as the amplitude and duration of rotor speed oscillation, are compared in terms of the separate and combined effects of the rotor damping structure and the PTEC. The different rotor damping structures of the DESG result in the large difference of the dynamic characteristic. In order to improve the dynamic characteristic of the DESG with different damping structures, the parameters of the PTEC are optimized in real time by the fuzzy control method (FCM). The optimal parameters of the PTEC are found to match the DESG with different rotor damping structure. The result shows that the DESGs with different rotor damping structures all have better dynamic characteristic indices after the parameter optimization of the PTEC. The results can provide a theoretical basis for improving the dynamic characteristic of the DESG and enhancing the system damping.