Analysis of vibration characteristics of inter-turn short circuit fault of double-fed asynchronous wind turbine generator rotor
Aiming at the problem that the fault vibration mechanism of rotor inter-turn short circuit in doubly-fed induction generator is not clear,and it cannot provide a theoretical basis for fault diagnosis,the vibration characteristics of rotor inter-turn short circuit in doubly-fed induction generator are analyzed.Firstly,combined with finite element simulation and analytical derivation,the air gap magnetic density law of doubly-fed induction generator under rotor inter-turn short circuit is analyzed,and the unbalanced magnetic tension force of the rotor is obtained.Secondly,a nonlinear dynamic model of the rotor-bearing system of doubly-fed induction generator considering the rotor unbalanced magnetic tension is constructed,and the vibration simulation signal of the system under rotor inter-turn short circuit is obtained by using the nonlinear dynamic simulation.Finally,the rotor inter-turn short circuit experiment is carried out on the doubly-fed induction generator fault simulation bench,and the validity of the nonlinear dynamic simulation results is verified by experimental analysis.The results of nonlinear dynamics simulation and experimental analysis show that the spectrum of the vibration signal of rotor-bearing system of doubly-fed induction generator has the harmonic component of frequency conversion under rotor inter-turn short circuit,and rotor inter-turn short circuit of doubly-fed induction generator can be diagnosed by detecting the harmonic component of the rotating frequency.This study effectively reveals the fault vibration mechanism of the rotor inter-turn short circuit in doubly-fed induction generator.