Delta connection PMSM (permanent magnet synchronous motor) stator winding resistive unbalance fault diagnosis method

Abstract

The invention discloses a delta connection PMSM (permanent magnet synchronous motor) stator winding resistive unbalance fault diagnosis method, and the method comprises the following steps: S1, building the relation between zero sequence currents and a resistance deviation and the relation between phase currents and the resistance deviation, deducing the relation formula of the mean value of the zero sequence currents and the resistance deviation and the relation formula of the phase currents and the resistance deviation; S2, injecting three different DC signals into a direct-axis reference current in a two-phase rotating coordinate system, and recording the phase current and zero sequence current of a PMSM after each injection of the signals; S3, respectively calculating the mean values of phase currents and zero sequence currents recorded at three times, and estimating the deviations of stator winding resistance: delta Ra, delta Rb and delta Rc; S4, judging whether there is a resistive unbalance fault or not: judging that the A phase of the PMSM has the resistive unbalance fault if delta Ra is greater than zero; judging that the B phase of the PMSM has the resistive unbalance fault if delta Rb is greater than zero; judging that the C phase of the PMSM has the resistive unbalance fault if delta Rc is greater than zero.

Description

technical field [0001] The invention relates to the technical field of fault diagnosis, in particular to a method for diagnosing the resistive unbalance fault of the stator winding of a delta-connected permanent magnet synchronous motor. Background technique [0002] Permanent magnet synchronous machine (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-tech applications such as electric vehicles and CNC machine tools. [0003] In permanent magnet synchronous motor stator winding faults, stator winding resistive imbalance is a common fault. When an early unbalanced fault occurs, the motor can still continue to run, but if it cannot be detected in time and the severity of the fault is aggravated, it will cause the motor speed t...

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, in the case of multi-phase failure, Most of the existing methods cannot judge the fault phase and fault degree of the resistive unbalance fault

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