Dynamic Analysis of DFIG Fault Detection and Its Suppression Using Sliding Mode Control

In this paper, a fault detection method based on chaos is proposed for doubly-fed induction generator (DFIG). Firstly, the nonlinear differential equation of the DFIG is established by the stator flux-oriented vector control method, and then the motion state of the DFIG is proved by the 0-1 test algorithm. Secondly, the motion state of the DFIG is analyzed under normal and fault conditions. Due to some failures that may occur in the normal operation of the DFIG, the motion state of the DFIG system may enter chaos from the cycle, which is mainly manifested by the violent oscillation of the rotor current and speed. At this time, the system is in an extremely unstable operating condition. Thereby, a new sliding mode control rate is mentioned to suppress chaotic behavior. Its stability is analyzed by constructing the Lyapunov function to ensure that the system state can quickly and stably converge to the given value. After that, the simulation model of the system is built. The simulation results show that sliding mode control can make the DFIG get out of the chaotic state quickly. And, the sliding mode control has the characteristics of fast fault elimination and high control accuracy. In addition, the traditional sliding mode approach rate is compared with the proposed new sliding mode approach rate. It proves that the proposed new approach rate can achieve better control effect.