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

Dual-Excited Synchronous Generator (DESG) has strong damping effect and high stability due to the two field windings and the corresponding power tracking excitation control (PTEC). However, the rotor damping structures, such as rotor core and slot wedges, also provide damping effect for the DESG. In order to study the PTEC and damping structures on the damping effects of the DESG, the field-circuit-control coupled time-stepping finite element model is established by coupling the finite element method and PTEC strategy, and a small-power DESG is developed to verify the correctness of the model. The dynamic characteristics of the DESG are studied under the individual and combined effects of the PTEC and rotor damping structures. The effect of the different damping structure can result in the variation of the dynamic characteristics. In order to improve the dynamic characteristics of the DESG, a parameter optimization method of the PTEC is proposed according to the active and reactive power deviations and their rates. The results can provide the theoretic basis for enhancing the system damping effect and suppressing the system oscillation.