Method for diagnosing turn-to-turn short circuit faults of permanent magnet synchronous motor in delta connection mode

Abstract

The invention discloses a method for diagnosing turn-to-turn short circuit faults of a permanent magnet synchronous motor in a delta connection mode. The method is used for detecting the turn-to-turn short circuit faults of the permanent magnet synchronous motor in the delta connection mode. According to the technical scheme, the method comprises the steps that firstly, the amplitude and phase are calculated, wherein the amplitude and the initial phase of fundamental waves in a zero-sequence current, the amplitude of third harmonics in the zero-sequence current, and the initial phase of fundamental waves in a three-phase current are calculated by a coordinate transformation theory; secondly, whether the turn-to-turn short circuit faults occur or not is judged, wherein if Fs is greater than thr, the turn-to-turn short circuit faults occur, and if not, the turn-to-turn short circuit faults do not occur; finally, the fault phase is judged, wherein under the circumstance of a turn-to-turn short circuit, the fault phase is diagnosed according to a difference between the initial phase of the fundamental waves in the zero-sequence current and the initial phase of the fundamental waves in the three-phase current. According to the method, no extra sensor is needed, calculation is easy, the method is easy to implement, and the turn-to-turn short circuit faults can be diagnosed in real time.

Description

technical field [0001] The invention belongs to the technical field of fault diagnosis, in particular to a method for diagnosing a short-circuit fault between turns of a permanent magnet synchronous motor with delta connection. Background technique [0002] Permanent magnet synchronous machine (PMSM) has the advantages of high power density, high efficiency, large torque inertia ratio, and wide speed range. In recent years, it has been widely concerned and used in high-power applications such as wind power generation and elevator drives, as well as high-performance applications such as electric vehicles and CNC machine tools. [0003] During the long-term operation of the permanent magnet synchronous motor, some components will gradually fail or be damaged due to the influence of the load condition and the operating environment. Its typical faulty components include stator windings, converters, motor bearings, and key sensors of the control system, among which 38% of faults...

AI Technical Summary

Problems solved by technology

However, there are certain deficiencies in the existing methods. On the one hand, the existing methods are mostly aimed at star-connected permanent magnet synchronous motors, and are not suitable for delta-connected permanent magnet synchronous motors.

On the other hand, the signal analysis techniques used in existing methods include Fast Fourier Transform (FFT), Short-Time Fourier Transform (Short-Time Fourier Transform, STFT), and Wigner-Ville Distribution (Wigner-Ville Distribution). , WVD), wavelet transform, empirical mode decomposition (Empirical Mode Distribution, EMD) and order ratio analysis, etc. These technologies require a large amount of calculation and are not easy to perform real-time fault diagnosis

In addition, most of the existing methods cannot judge the faulty phase of inter-turn short circuit.

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