Frequency Coupling Characteristic Modeling and Stability Analysis of Doubly Fed Induction Generator

• Published in: IEEE transactions on energy conversion Vol. 33; no. 3; pp. 1475 - 1486
• Main Authors: Xu, Yunyang, Nian, Heng, Wang, Tao, Chen, Liang, Zheng, Taiying
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: analytical modeling; Analytical models; Computer simulation; Control systems; Coupling; Couplings; Doubly fed induction generator (DFIG); Doubly fed induction generators; Electric power generation; frequency coupling; Frequency stability; Impedance; Induction generators; Mathematical models; Phase locked systems; Power system stability; Rotors; Stability analysis; Stability criteria; system stability analysis; Systems stability; Wind power; Wind power generation
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2018.2800043

Impedance-based method is an effective method to analyze the system stability. Based on the impedance stability theory, a doubly fed induction generator (DFIG) based wind power generation system can be decoupled into a positive- and a negative-sequence subsystem. Then, under small-signal operation, each subsystem is assumed to have linear characteristic in the frequency domain. Therefore, a single-in-single-out stability criterion can be applied for each subsystem to analyze the stability of the interconnected system consisted of the DFIG system and the grid. However, when there is frequency coupling in the DFIG system, this linear assumption may lead to wrong conclusion of the system stability analysis. The frequency coupling of DFIG can be caused by the PLL and the asymmetric rotor current control. In this paper, the frequency coupling characteristic of DFIG caused by these two causes will be studied, and an analytical model that describes the frequency coupling of DFIG will be developed and validated by simulations. Based on this derived model, the system stability and the influencing factors of frequency coupling will be analyzed.