A traction motor fault diagnosis method and system

Abstract

The present invention provides a traction motor fault diagnosis method and system. The method includes: injecting harmonic current to obtain the motor current fluctuation amplitude, motor speed fluctuation amplitude, and motor voltage fluctuation amplitude, then performing surface fitting on each of these fluctuations to obtain a fitted surface. When diagnosing a fault, the harmonic current is injected to obtain the real-time fluctuation amplitude. After obtaining the corresponding fluctuation amplitude based on the fitted surface, the two systems are compared. If any of the fluctuation amplitudes are inconsistent, the traction motor is deemed to have a fault. The present invention utilizes harmonic current and surface fitting methods to perform traction motor fault diagnosis, enabling multi-dimensional fault diagnosis and improving diagnostic accuracy and reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of motor fault diagnosis, and in particular to a fault diagnosis method and system for a traction motor. Background Art

[0002] Traction motors are widely used, such as in mainline electric locomotives, industrial and mining electric locomotives, electric-drive diesel locomotives, and various electric vehicles (such as battery-powered vehicles, new energy vehicles, urban trams, and subway electric vehicles). Traction motors include traction motors, traction generators, and auxiliary motors.

[0003] Traction motor fault diagnosis methods vary, and their application helps promptly detect and address motor faults, ensuring proper operation. Common traction motor fault diagnosis methods include current analysis, vibration detection, temperature monitoring, vibroacoustic diagnostics, special electrical laboratory diagnostic techniques, stator current analysis, and direct observation. However, these methods focus on a single dimension, resulting in limited diagnostic accuracy and reliability. Summary of the Invention

[0004] The present invention provides a traction motor fault diagnosis method and system, which perform fault diagnosis from multiple dimensions to improve diagnostic accuracy and reliability.

[0005] This specification discloses a method for diagnosing a fault of a traction motor, comprising:

[0006] Based on different motor currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor current caused by the change is measured respectively, which is recorded as the motor current fluctuation amplitude;

[0007] Based on different motor speeds, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor speed caused by the change is measured, which is recorded as the motor speed fluctuation amplitude;

[0008] Based on different motor voltages, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor voltage caused by the change is measured respectively, which is recorded as the motor voltage fluctuation amplitude;

[0009] The motor current is used as a row vector and the harmonic current is used as a column vector to form a matrix, and then the motor current fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a first fitting surface;

[0010] The motor speed is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor speed fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a second fitting surface;

[0011] The motor voltage is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor voltage fluctuation amplitude is imported and a surface fitting operation is performed to obtain a third fitting surface;

[0012] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed and real-time motor voltage, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any of the fluctuation amplitudes are inconsistent, it is considered that the traction motor has a fault.

[0013] In this specification, based on different motor vibration frequencies, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor vibration frequency caused by the change is measured respectively, which is recorded as the motor vibration frequency fluctuation amplitude;

[0014] The motor vibration frequency is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor vibration frequency fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fourth fitting surface;

[0015] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor vibration frequency, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor vibration frequency, the first fitting surface, the second fitting surface, the third fitting surface and the fourth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor vibration frequency fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0016] In this specification, based on different motor temperatures, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor temperature caused by the change is measured respectively, which is recorded as the motor temperature fluctuation amplitude;

[0017] The motor temperature is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor temperature fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fifth fitting surface;

[0018] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor temperature, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor temperature, the first fitting surface, the second fitting surface, the third fitting surface and the fifth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor temperature fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0019] In this specification, based on different motor operating noises, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor operating noise caused by the changes is measured respectively, which is recorded as the motor operating noise fluctuation amplitude;

[0020] The motor operating noise is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor operating noise fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a sixth fitting surface;

[0021] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor operating noise, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor operating noise, the first fitting surface, the second fitting surface, the third fitting surface and the sixth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor operating noise fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0022] In this specification, based on different motor stator currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor stator current caused by the change is measured respectively, which is recorded as the motor stator current fluctuation amplitude;

[0023] The motor stator current is used as a row vector, the harmonic current is used as a column vector, a matrix is constructed, and then the motor stator current fluctuation amplitude is imported and a surface fitting operation is performed to obtain the seventh fitting surface;

[0024] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor stator current, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor stator current, the first fitting surface, the second fitting surface, the third fitting surface and the seventh fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor stator current fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0025] In this specification, when diagnosing a fault, different harmonic currents are injected into the traction power supply system of the traction motor successively to obtain the corresponding real-time motor current, real-time motor speed and real-time motor voltage, and measure the corresponding real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude. Based on the injected different harmonic currents, the corresponding real-time motor current, real-time motor speed and real-time motor voltage, as well as the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are obtained respectively, and compared with the corresponding real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any of the fluctuation amplitudes are inconsistent, it is considered that the traction motor has a fault.

[0026] In this specification, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor current is gradually increased or decreased, the resulting harmonic voltage is measured, and the first harmonic impedance is calculated;

[0027] Based on the injected harmonic current, motor current and first harmonic impedance, a surface fitting method is used to obtain the first harmonic impedance fitting surface;

[0028] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated; and a first harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor current, and the first harmonic impedance fitting surface;

[0029] Compare the real-time harmonic impedance with the first harmonic impedance reference value. If they are inconsistent, and the motor current fluctuation amplitude obtained by the first fitting surface is inconsistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has a fault.

[0030] If the real-time harmonic impedance is consistent with the first harmonic impedance reference value, and the motor current fluctuation amplitude obtained by the first fitting surface is consistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has no fault;

[0031] If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

[0032] In this specification, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor speed is gradually increased or decreased. The resulting harmonic voltage is measured and the second harmonic impedance is calculated;

[0033] Based on the injected harmonic current, motor speed and second harmonic impedance, the surface fitting method is used to obtain the second harmonic impedance fitting surface;

[0034] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated. A second harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor speed, and the second harmonic impedance fitting surface.

[0035] Compare the real-time harmonic impedance with the second harmonic impedance reference value. If they are inconsistent, and the motor speed fluctuation amplitude obtained by the second fitting surface is inconsistent with the real-time motor speed fluctuation amplitude, it is considered that the traction motor has a fault.

[0036] If the real-time harmonic impedance is consistent with the second harmonic impedance reference value, and the motor speed fluctuation amplitude obtained by the second fitting surface is consistent with the real-time motor speed fluctuation amplitude, then it is considered that the traction motor has no fault;

[0037] If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

[0038] In this specification, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor voltage is gradually increased or decreased. The resulting harmonic voltage is measured and the third harmonic impedance is calculated;

[0039] Based on the injected harmonic current, motor voltage and third harmonic impedance, the third harmonic impedance fitting surface is obtained using the surface fitting method;

[0040] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated. A third harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor voltage, and the third harmonic impedance fitting surface.

[0041] Compare the real-time harmonic impedance with the third harmonic impedance reference value. If they are inconsistent, and the motor voltage fluctuation amplitude obtained by the third fitting surface is inconsistent with the real-time motor voltage fluctuation amplitude, it is considered that the traction motor has a fault.

[0042] If the real-time harmonic impedance is consistent with the third harmonic impedance reference value, and the motor voltage fluctuation amplitude obtained by the third fitting surface is consistent with the real-time motor voltage fluctuation amplitude, then it is considered that the traction motor has no fault;

[0043] If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

[0044] This specification also discloses a traction motor fault diagnosis system for implementing any one of the above-mentioned traction motor fault diagnosis methods. The traction motor fault diagnosis system includes:

[0045] Data acquisition module, used to:

[0046] Based on different motor currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor current caused by the change is measured respectively, which is recorded as the motor current fluctuation amplitude;

[0047] Based on different motor speeds, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor speed caused by the change is measured, which is recorded as the motor speed fluctuation amplitude;

[0048] Based on different motor voltages, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor voltage caused by the change is measured respectively, which is recorded as the motor voltage fluctuation amplitude;

[0049] Surface fitting module, used for:

[0050] The motor current is used as a row vector and the harmonic current is used as a column vector to form a matrix, and then the motor current fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a first fitting surface;

[0051] The motor speed is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor speed fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a second fitting surface;

[0052] The motor voltage is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor voltage fluctuation amplitude is imported and a surface fitting operation is performed to obtain a third fitting surface;

[0053] The fault diagnosis module is used to inject harmonic current into the traction power supply system of the traction motor during fault diagnosis, obtain real-time motor current, real-time motor speed and real-time motor voltage, and measure the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are respectively obtained, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0054] This manual can at least achieve the following beneficial effects:

[0055] By injecting harmonic currents, the motor current, motor speed, and voltage fluctuation amplitudes are measured. Surface fitting is then performed on each of these fluctuations to obtain fitted surfaces. During fault diagnosis, harmonic currents are injected to obtain real-time fluctuation amplitudes. The corresponding fluctuation amplitudes are then compared based on the fitted surfaces. If any of the fluctuation amplitudes are inconsistent, the traction motor is considered faulty. Utilizing harmonic currents and surface fitting for traction motor fault diagnosis allows for multi-dimensional fault diagnosis, improving diagnostic accuracy and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 It is a flowchart of the fault diagnosis method of the traction motor involved in the present invention. DETAILED DESCRIPTION

[0058] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0059] The disclosure below provides many different embodiments or examples for implementing different structures of the embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. In addition, the embodiments of the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0060] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0061] like Figure 1 As shown, this specification discloses a fault diagnosis method for a traction motor, comprising:

[0062] Based on different motor currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor current caused by the change is measured respectively, which is recorded as the motor current fluctuation amplitude;

[0063] Based on different motor speeds, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor speed caused by the change is measured, which is recorded as the motor speed fluctuation amplitude;

[0064] Based on different motor voltages, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor voltage caused by the change is measured respectively, which is recorded as the motor voltage fluctuation amplitude;

[0065] The motor current is used as a row vector and the harmonic current is used as a column vector to form a matrix, and then the motor current fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a first fitting surface;

[0066] The motor speed is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor speed fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a second fitting surface;

[0067] The motor voltage is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor voltage fluctuation amplitude is imported and a surface fitting operation is performed to obtain a third fitting surface;

[0068] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed and real-time motor voltage, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any of the fluctuation amplitudes are inconsistent, it is considered that the traction motor has a fault.

[0069] In some embodiments, based on different motor vibration frequencies, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor vibration frequency caused by the change is measured respectively, which is recorded as the motor vibration frequency fluctuation amplitude;

[0070] The motor vibration frequency is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor vibration frequency fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fourth fitting surface;

[0071] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor vibration frequency, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor vibration frequency, the first fitting surface, the second fitting surface, the third fitting surface and the fourth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor vibration frequency fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0072] In some embodiments, based on different motor temperatures, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitudes of the motor temperature changes caused thereby are measured and recorded as the motor temperature fluctuation amplitudes;

[0073] The motor temperature is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor temperature fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fifth fitting surface;

[0074] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor temperature, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor temperature, the first fitting surface, the second fitting surface, the third fitting surface and the fifth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor temperature fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0075] In some embodiments, based on different motor operating noises, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor operating noise caused thereby is measured and recorded as the motor operating noise fluctuation amplitude;

[0076] The motor operating noise is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor operating noise fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a sixth fitting surface;

[0077] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor operating noise, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor operating noise, the first fitting surface, the second fitting surface, the third fitting surface and the sixth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor operating noise fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0078] In some embodiments, based on different motor stator currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor stator current caused by the changes is measured respectively, which is recorded as the motor stator current fluctuation amplitude;

[0079] The motor stator current is used as a row vector, the harmonic current is used as a column vector, a matrix is constructed, and then the motor stator current fluctuation amplitude is imported and a surface fitting operation is performed to obtain the seventh fitting surface;

[0080] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor stator current, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor stator current, the first fitting surface, the second fitting surface, the third fitting surface and the seventh fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor stator current fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0081] In summary, there are three situations in which different and / or the same harmonic currents are injected, taking motor current as an example.

[0082] The first case: different harmonic currents are injected and combined with different motor currents, and the fluctuation amplitude of the motor current under different combinations is measured.

[0083] The second case: inject the same harmonic current and combine it with different motor currents, and measure the fluctuation amplitude of the motor current under different combinations.

[0084] The third case is a combination of the first and second cases (in no particular order), that is, first injecting different harmonic currents, combining them with different motor currents, and measuring the fluctuation amplitude of the motor current under different combinations; then injecting the same harmonic current, combining it with different motor currents, and measuring the fluctuation amplitude of the motor current under different combinations.

[0085] For the descriptions of other parameters, refer to the above.

[0086] The motor current, motor speed, motor voltage, motor vibration frequency, motor temperature, motor operating noise and motor stator current, as well as the schemes of the first fitting surface to the seventh fitting surface can be used in combination to form a comprehensive embodiment, that is, seven fluctuation amplitudes are compared. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0087] In some embodiments, when diagnosing a fault, different harmonic currents are injected into the traction power supply system of the traction motor successively to obtain the corresponding real-time motor current, real-time motor speed and real-time motor voltage, and measure the corresponding real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude. Based on the injected different harmonic currents, the corresponding real-time motor current, real-time motor speed and real-time motor voltage, as well as the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are obtained respectively, and compared with the corresponding real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any of the fluctuation amplitudes are inconsistent, it is considered that the traction motor has a fault.

[0088] Based on this embodiment, in the embodiments of motor vibration frequency, motor temperature, motor operating noise and motor stator current, as well as the fourth to seventh fitting surfaces, this embodiment can also be used in combination. That is, in the corresponding embodiments of the fourth to seventh fitting surfaces, during fault diagnosis, different harmonic currents are successively injected into the traction power supply system of the traction motor, and then the corresponding fluctuation amplitudes are compared respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0089] In some embodiments, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor current is gradually increased or decreased, and the harmonic voltage generated thereby is measured to calculate the first harmonic impedance;

[0090] Based on the injected harmonic current, motor current and first harmonic impedance, a surface fitting method is used to obtain the first harmonic impedance fitting surface;

[0091] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated; and a first harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor current, and the first harmonic impedance fitting surface;

[0092] Compare the real-time harmonic impedance with the first harmonic impedance reference value. If they are inconsistent, and the motor current fluctuation amplitude obtained by the first fitting surface is inconsistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has a fault.

[0093] If the real-time harmonic impedance is consistent with the first harmonic impedance reference value, and the motor current fluctuation amplitude obtained by the first fitting surface is consistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has no fault;

[0094] If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

[0095] In some embodiments, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor speed is gradually increased or decreased, and the harmonic voltage generated thereby is measured to calculate the second harmonic impedance;

[0096] Based on the injected harmonic current, motor speed and second harmonic impedance, the surface fitting method is used to obtain the second harmonic impedance fitting surface;

[0097] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated. A second harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor speed, and the second harmonic impedance fitting surface.

[0098] Compare the real-time harmonic impedance with the second harmonic impedance reference value. If they are inconsistent, and the motor speed fluctuation amplitude obtained by the second fitting surface is inconsistent with the real-time motor speed fluctuation amplitude, it is considered that the traction motor has a fault.

[0099] If the real-time harmonic impedance is consistent with the second harmonic impedance reference value, and the motor speed fluctuation amplitude obtained by the second fitting surface is consistent with the real-time motor speed fluctuation amplitude, then it is considered that the traction motor has no fault;

[0100] If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

[0101] In some embodiments, different harmonic currents are injected into the traction power supply system of the traction motor, and the motor voltage is gradually increased or decreased, and the resulting harmonic voltage is measured to calculate the third harmonic impedance;

[0102] Based on the injected harmonic current, motor voltage and third harmonic impedance, the third harmonic impedance fitting surface is obtained using the surface fitting method;

[0103] During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated. A third harmonic impedance reference value is obtained based on the real-time injected harmonic current, the real-time motor voltage, and the third harmonic impedance fitting surface.

[0104] Compare the real-time harmonic impedance with the third harmonic impedance reference value. If they are inconsistent, and the motor voltage fluctuation amplitude obtained by the third fitting surface is inconsistent with the real-time motor voltage fluctuation amplitude, it is considered that the traction motor has a fault; (If both are inconsistent)

[0105] If the real-time harmonic impedance is consistent with the third harmonic impedance reference value, and the motor voltage fluctuation amplitude obtained by the third fitting surface is consistent with the real-time motor voltage fluctuation amplitude, then it is considered that the traction motor has no fault; (the case of both being consistent)

[0106] If any of the two conditions are inconsistent, it is considered that the traction motor may be faulty. (Any inconsistent condition)

[0107] Based on the above-mentioned motor current, motor speed and motor voltage, the corresponding harmonic impedance embodiments (i.e., the above-mentioned three embodiments), in the motor vibration frequency, motor temperature, motor operating noise and motor stator current, as well as the embodiments of the fourth fitting surface to the seventh fitting surface, this embodiment can also be used in combination, that is, in the corresponding embodiments of the fourth fitting surface to the seventh fitting surface, harmonic impedance calculation is performed, and surface fitting is performed to obtain the corresponding harmonic impedance fitting surface. When diagnosing a fault, the corresponding harmonic impedance comparison is performed. If they are all inconsistent, it is considered that the traction motor is faulty. If they are all consistent, it is considered that the traction motor is not faulty. If any one is inconsistent, it is considered that the traction motor may be faulty.

[0108] That is, based on the harmonic impedance fitting surface, the motor current, motor speed, motor voltage, motor vibration frequency, motor temperature, motor operating noise, and motor stator current can each have an embodiment, for a total of seven embodiments; and the first to third fitting surfaces are each an embodiment, and the fourth to seventh fitting surfaces are each an embodiment, for a total of five embodiments. These seven embodiments and five embodiments can be used in combination or together, and similarly, they can also be used in combination or together with the embodiment of "injecting different harmonic currents into the traction power supply system of the traction motor in sequence during fault diagnosis." In summary, all embodiments of this specification can be freely combined and used, and the combined solutions are all part of this specification.

[0109] When used in combination, the diagnosis results may include "traction motor failure", "traction motor no failure" and "traction motor may have a failure" at the same time. In this case, the diagnosis results can be merged according to conventional logic. If the diagnosis result is "traction motor failure", then regardless of other results, the final diagnosis result of the combined use embodiment is traction motor failure; if the diagnosis results include "traction motor may have a failure" and "traction motor no failure", then the final diagnosis result of the combined use embodiment is that the traction motor may have a failure.

[0110] In this specification, errors are allowed. For example, if the motor current fluctuation amplitude obtained by the first fitting surface is 1mA and the real-time motor current fluctuation amplitude is 1.1mA, the error is 0.1mA, and they can be considered consistent. The specific error can be set according to actual needs.

[0111] This specification also discloses a traction motor fault diagnosis system for implementing any one of the above-mentioned traction motor fault diagnosis methods. The traction motor fault diagnosis system includes:

[0112] Data acquisition module, used to:

[0113] Based on different motor currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor current caused by the change is measured respectively, which is recorded as the motor current fluctuation amplitude;

[0114] Based on different motor speeds, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor speed caused by the change is measured, which is recorded as the motor speed fluctuation amplitude;

[0115] Based on different motor voltages, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor voltage caused by the change is measured respectively, which is recorded as the motor voltage fluctuation amplitude;

[0116] Surface fitting module, used for:

[0117] The motor current is used as a row vector and the harmonic current is used as a column vector to form a matrix, and then the motor current fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a first fitting surface;

[0118] The motor speed is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor speed fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a second fitting surface;

[0119] The motor voltage is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor voltage fluctuation amplitude is imported and a surface fitting operation is performed to obtain a third fitting surface;

[0120] The fault diagnosis module is used to inject harmonic current into the traction power supply system of the traction motor during fault diagnosis, obtain real-time motor current, real-time motor speed and real-time motor voltage, and measure the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are respectively obtained, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

[0121] When implementing the methods of the above embodiments, it is only necessary to add corresponding functional modules.

[0122] It should be noted that the relevant adjustments of motor current, motor speed, motor voltage, motor vibration frequency, motor temperature and motor stator current are existing technologies, and the present invention does not improve them. The adjustment technology can refer to the existing technology.

[0123] It should be understood that the surface fitting operation described above can be performed using existing software tools, such as the CurveFitting tool in Matlab. Each of the aforementioned modules can be an existing data detection (acquisition) / measurement device / sensor or a data reading module of the traction system, which can directly obtain the corresponding data of the traction system.

[0124] It is clear that by obtaining the corresponding data in the traction system in advance through existing equipment, a large amount of test data can be obtained. These test data can be simulation test data in the laboratory or actual measurement or operation data of the traction system in practice.

[0125] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Therefore, changes in illustrative values or substitutions of equivalent components should still fall within the scope of the present invention.

[0126] From the above detailed description, it will be clear to those skilled in the art that the present invention can indeed achieve the aforementioned objectives and is in compliance with the provisions of the Patent Law.

[0127] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as covering the preferred embodiments and all changes and modifications that fall within the scope of the invention. The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

[0128] It should be noted that the above description of the relevant processes is for illustration and purpose only and does not limit the scope of application of this specification. For those skilled in the art, various modifications and changes can be made to the processes under the guidance of this specification. However, such modifications and changes are still within the scope of this specification.

[0129] The basic concepts have been described above. It will be apparent to those skilled in the art after reading this application that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0130] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or more in different places in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0131] In addition, it will be understood by those skilled in the art that various aspects of the present application can be illustrated and described by a number of patentable categories or situations, including any new and useful combination of processes, machines, products or substances, or any new and useful improvements thereto. Therefore, various aspects of the present application can be implemented entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can all be referred to as "units", "modules" or "systems". In addition, various aspects of the present application can take the form of a computer program product embodied in one or more computer-readable media, wherein computer-readable program code is contained therein.

[0132] The computer program code required for the operation of each part of the application can be written in any one or more programming languages, including object-oriented programming languages such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python, conventional procedural programming languages such as C programming language, VisualBasic, Fortran2103, Perl, COBOL2102, PHP, ABAP, dynamic programming languages such as Python, Ruby and Groovy or other programming languages. The program code can be run completely on the user's computer, or run on the user's computer as an independent software package, or run partly on the user's computer and partly on a remote computer, or run completely on a remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any network form, such as a local area network (LAN) or a wide area network (WAN), or be connected to an external computer (such as by the Internet), or in a cloud computing environment, or used as a service such as software as a service (SaaS).

[0133] In addition, unless expressly stated in the claims, the order of the processing elements and sequences described in this application, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this application. Although the above disclosure discusses some embodiments of the invention that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this application. For example, although the implementation of the various components described above can be embodied in a hardware device, it can also be implemented as a pure software solution, for example, installation on an existing server or mobile device.

[0134] Similarly, it should be noted that in order to simplify the presentation of this disclosure and thereby facilitate understanding of one or more of the invention's embodiments, the foregoing descriptions of the embodiments of this disclosure sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this approach should not be interpreted as reflecting an intention that the claimed subject matter requires more features than expressly recited in each claim. Rather, the subject matter of the invention may possess fewer features than the single embodiment described above.

Claims

1. A method for diagnosing a fault of a traction motor, characterized in that: include: Based on different motor currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor current caused by the change is measured respectively, which is recorded as the motor current fluctuation amplitude; Based on different motor speeds, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor speed caused by the change is measured, which is recorded as the motor speed fluctuation amplitude; Based on different motor voltages, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor voltage caused by the change is measured respectively, which is recorded as the motor voltage fluctuation amplitude; The motor current is used as a row vector and the harmonic current is used as a column vector to form a matrix, and then the motor current fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a first fitting surface; The motor speed is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor speed fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a second fitting surface; The motor voltage is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor voltage fluctuation amplitude is imported and a surface fitting operation is performed to obtain a third fitting surface; During fault diagnosis, a harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed and real-time motor voltage, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, the first fitting surface, the second fitting surface and the third fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude and motor voltage fluctuation amplitude are respectively obtained, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude and real-time motor voltage fluctuation amplitude respectively. If any fluctuation amplitude except the motor current fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault; Injecting different harmonic currents into the traction power supply system of the traction motor and gradually increasing or decreasing the motor current, measuring the resulting harmonic voltage, and calculating the first harmonic impedance; Based on the injected harmonic current, motor current and first harmonic impedance, a surface fitting method is used to obtain the first harmonic impedance fitting surface; When diagnosing a fault, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated; and obtaining a first harmonic impedance reference value based on the real-time injected harmonic current, the real-time motor current, and the first harmonic impedance fitting surface; Compare the real-time harmonic impedance with the first harmonic impedance reference value. If they are inconsistent, and the motor current fluctuation amplitude obtained by the first fitting surface is inconsistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has a fault. If the real-time harmonic impedance is consistent with the first harmonic impedance reference value, and the motor current fluctuation amplitude obtained by the first fitting surface is consistent with the real-time motor current fluctuation amplitude, it is considered that the traction motor has no fault; If any of the two conditions are inconsistent, it is considered that the traction motor may be faulty; Among them, multiple diagnostic results are integrated: when the diagnostic result shows that there is a traction motor failure, regardless of other results, the final diagnostic result is a traction motor failure; when the diagnostic result only shows that the traction motor may fail and that the traction motor has no failure, the final diagnostic result is that the traction motor may fail; when the diagnostic result only shows that the traction motor has no failure, the final diagnostic result is that the traction motor has no failure.

2. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Based on different motor vibration frequencies, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor vibration frequency caused by the change is measured respectively, which is recorded as the motor vibration frequency fluctuation amplitude; The motor vibration frequency is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor vibration frequency fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fourth fitting surface; During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor vibration frequency, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor vibration frequency, the first fitting surface, the second fitting surface, the third fitting surface and the fourth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor vibration frequency fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor vibration frequency fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

3. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Based on different motor temperatures, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor temperature caused by the change is measured respectively, which is recorded as the motor temperature fluctuation amplitude; The motor temperature is used as a row vector and the harmonic current is used as a column vector to construct a matrix, and then the motor temperature fluctuation amplitude is imported and a surface fitting operation is performed to obtain a fifth fitting surface; During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor temperature, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor temperature, the first fitting surface, the second fitting surface, the third fitting surface and the fifth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor temperature fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor temperature fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

4. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Based on different motor operating noises, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor operating noise caused by the changes is measured respectively, which is recorded as the motor operating noise fluctuation amplitude; The motor operating noise is used as a row vector, and the harmonic current is used as a column vector to form a matrix, and then the motor operating noise fluctuation amplitude is introduced and a surface fitting operation is performed to obtain a sixth fitting surface; During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor operating noise, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor operating noise, the first fitting surface, the second fitting surface, the third fitting surface and the sixth fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor operating noise fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor operating noise fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

5. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Based on different motor stator currents, different and / or the same harmonic currents are injected into the traction power supply system of the traction motor, and the fluctuation amplitude of the motor stator current caused by the change is measured respectively, which is recorded as the motor stator current fluctuation amplitude; The motor stator current is used as a row vector, the harmonic current is used as a column vector, a matrix is constructed, and then the motor stator current fluctuation amplitude is imported and a surface fitting operation is performed to obtain the seventh fitting surface; During fault diagnosis, harmonic current is injected into the traction power supply system of the traction motor to obtain real-time motor current, real-time motor speed, real-time motor voltage and real-time motor stator current, and the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude are measured. Based on the injected harmonic current, real-time motor current, real-time motor speed, real-time motor voltage, real-time motor stator current, the first fitting surface, the second fitting surface, the third fitting surface and the seventh fitting surface, the corresponding motor current fluctuation amplitude, motor speed fluctuation amplitude, motor voltage fluctuation amplitude and motor stator current fluctuation amplitude are obtained respectively, and compared with the real-time motor current fluctuation amplitude, real-time motor speed fluctuation amplitude, real-time motor voltage fluctuation amplitude and real-time motor stator current fluctuation amplitude respectively. If any fluctuation amplitude is inconsistent, it is considered that the traction motor has a fault.

6. The fault diagnosis method for a traction motor according to claim 1, characterized in that: When diagnosing a fault, different harmonic currents are injected into the traction power supply system of the traction motor successively.

7. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Different harmonic currents are injected into the traction power supply system of the traction motor, and the motor speed is gradually increased or decreased. The resulting harmonic voltage is measured and the second harmonic impedance is calculated. Based on the injected harmonic current, motor speed and second harmonic impedance, the surface fitting method is used to obtain the second harmonic impedance fitting surface; When diagnosing a fault, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated; And based on the real-time injected harmonic current, the real-time motor speed and the second harmonic impedance fitting surface, the second harmonic impedance reference value is obtained; Compare the real-time harmonic impedance with the second harmonic impedance reference value. If they are inconsistent, and the motor speed fluctuation amplitude obtained by the second fitting surface is inconsistent with the real-time motor speed fluctuation amplitude, it is considered that the traction motor has a fault. If the real-time harmonic impedance is consistent with the second harmonic impedance reference value, and the motor speed fluctuation amplitude obtained by the second fitting surface is consistent with the real-time motor speed fluctuation amplitude, then it is considered that the traction motor has no fault; If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

8. The fault diagnosis method for a traction motor according to claim 1, characterized in that: Different harmonic currents are injected into the traction power supply system of the traction motor, and the motor voltage is gradually increased or decreased. The resulting harmonic voltage is measured and the third harmonic impedance is calculated. Based on the injected harmonic current, motor voltage and third harmonic impedance, the third harmonic impedance fitting surface is obtained using the surface fitting method; When diagnosing a fault, harmonic current is injected into the traction power supply system of the traction motor, the resulting harmonic voltage is measured, and the real-time harmonic impedance is calculated; And based on the real-time injected harmonic current, the real-time motor voltage and the third harmonic impedance fitting surface, the third harmonic impedance reference value is obtained; Compare the real-time harmonic impedance with the third harmonic impedance reference value. If they are inconsistent, and the motor voltage fluctuation amplitude obtained by the third fitting surface is inconsistent with the real-time motor voltage fluctuation amplitude, it is considered that the traction motor has a fault. If the real-time harmonic impedance is consistent with the third harmonic impedance reference value, and the motor voltage fluctuation amplitude obtained by the third fitting surface is consistent with the real-time motor voltage fluctuation amplitude, then it is considered that the traction motor has no fault; If either of the two conditions is inconsistent, it is considered that the traction motor may be faulty.

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