A method for diagnosing inter-turn short-circuit faults in stators of doubly-fed asynchronous wind turbines

Abstract

The present invention is a method for diagnosing inter-turn short-circuit faults of the stator of a doubly-fed asynchronous wind turbine. Step 1: establish a mathematical model for short-circuit fault diagnosis of a doubly-fed asynchronous generator on the abc coordinate system, and convert the mathematical model from the abc coordinate system to the dq coordinate system, obtain the voltage and flux linkage equations of the DFIG, and then express the voltage and flux linkage equations as the state space equation of the DFIG; Step 2: According to the state space of the DFIG obtained in Step 1 Equation, based on the MATLAB / SIMULINK software platform to build a fault diagnosis circuit model of a doubly-fed asynchronous generator, and obtain the time-domain waveforms of the stator current corresponding to different μ values ​​through the circuit model simulation; Step 3: Compare μ=0 and μ≠0 respectively The amplitude variation characteristics of the time-frequency spectrogram are extracted to extract the fault characteristics of the stator inter-turn short circuit, which is used for short-circuit diagnosis of the doubly-fed asynchronous generator. The invention ensures the integrity of the overall structure of the motor and the reliability of the diagnosis results.

Description

technical field [0001] The invention relates to a method for diagnosing a short-circuit fault between turns of a stator of a doubly-fed asynchronous wind power generator, and belongs to the technical field of state detection and fault diagnosis of a drive motor. Background technique [0002] Damage to the insulation layer of the adjacent turns or several turns of the stator winding of the doubly-fed asynchronous generator will cause a short circuit fault between the turns of the stator. The probability of this kind of fault accounts for more than 15% of all fault types of the motor, and it is one of the main types of motor faults. . A small turn-to-turn fault will form a short-circuit current in the short-circuit ring, which will cause the short-circuit of the motor to become hotter and hotter, damage the adjacent insulation layer and cause a greater coil short-circuit hazard. Therefore, it must be dealt with in time to avoid more serious motor failures in the later stage. ...

AI Technical Summary

Problems solved by technology

Scholars Mirzoian and Williamson first proposed an online monitoring method for stator winding faults of induction motors in 1985; Jensen B.B. and Popa L.M., scholars at the Timisoara University of Technology in Romania, used experimental methods to simulate short-circuit faults between turns of stator windings with parallel reactance on stator windings, and monitored them in real time. Stator and rotor currents were analyzed accordingly; Scholars Rossi C and Stefani A of the University of Bologna in Italy and Scholars Yazidi A of the University of Picardie in France detected stator winding faults by analyzing rotor current modulation signals; Scholars Nandi S and Shah D of Victoria University in Canada proposed a method based on The method of detecting coil voltage and rotor current harmonics to diagnose short-circuit faults between stator turns is ideal; Dinkhauser V and other scholars aim at the identification of motor faults, build a state observer to reconstruct the internal state of DFIG for diagnosis, the method is novel but difficult to build

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