Inverter fault diagnosis method and related equipment

Abstract

The present application provides an inverter fault diagnosis method and related equipment; the method includes: determining a normal current trajectory according to a three-phase AC circuit topology; determining a first fault phase current expression of a fault phase in a single-tube open-circuit fault and a first adjacent phase current expression of a faulty phase, based on which a first adjacent phase current trajectory for the single-tube open-circuit fault is determined; determining a second fault phase current expression of a fault phase in a double-tube open-circuit fault and a second adjacent phase current expression of a faulty phase, based on which a second adjacent phase current trajectory for the double-tube open-circuit fault is determined; determining a third fault phase current expression of a fault phase in a current sensor fault, and determining a third adjacent phase current trajectory of a faulty phase; using the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory to identify the current current trajectory of each phase current in the current inverter, and determine the current working condition of the inverter.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of circuit fault diagnosis, and more particularly to an inverter fault diagnosis method and related equipment. Background Art

[0002] The single-tube open-circuit fault, double-tube open-circuit fault and current sensor zero output fault in the inverter have very similar manifestations in some cases. The relevant methods for diagnosing and distinguishing them are often limited to three types of methods: model-based, signal-based, and data-based. Among them, the difficulty of the signal-based method is that it requires the three-phase current, voltage signal or control signal to be fully monitored, which puts high requirements on the deployment of sensors and other devices; the difficulty of the data-based and model-based methods is that the data and training samples that meet the model training requirements need to be sufficient, but qualified training samples are often difficult to obtain.

[0003] Based on this, a solution is needed that can effectively identify and diagnose single-tube and double-tube power tube and current sensor zero output faults without relying on the above-mentioned methods, so as to solve the problems of misdiagnosis or missed diagnosis of faults. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide an inverter fault diagnosis method and related equipment.

[0005] Based on the above purpose, the present application provides an inverter fault diagnosis method, including:

[0006] Under a fault-free working condition, according to a normal current expression of each phase current in a three-phase AC circuit topology structure of the inverter, a normal current trajectory formed by two adjacent phase currents is determined;

[0007] Determine a first adjacent phase current expression of a faulty phase according to a first fault phase current expression of the faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression;

[0008] Determine a second adjacent phase current expression of a phase adjacent to the fault according to a second fault phase current expression of the fault phase in the double-tube open-circuit fault of the inverter, and determine a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression;

[0009] Determine the third adjacent phase current trajectory of the faulty phase in the current sensor failure according to the third fault phase current expression of the faulty phase of the inverter in the current sensor failure;

[0010] The first adjacent phase current trajectory is determined according to the first fault trajectory model, and the second adjacent phase current trajectory is determined according to the second fault trajectory model. In a preset current trajectory identification mechanism, the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory are used to identify the current current trajectory of each phase current in the current inverter, and the operating condition of the current inverter is determined according to the identification result.

[0011] Further, according to the normal current expression of each phase current in the three-phase AC circuit topology of the inverter, a normal current trajectory formed by two adjacent phase currents is determined, including:

[0012] The normal current expression of each phase current in the three-phase AC circuit topology is constructed as follows:

[0013]

[0014] According to the normal current expression, in the first coordinate system, the normal current trajectory is expressed as:

[0015]

[0016] and

[0017] in, and They respectively represent the normal current of each phase in the three-phase AC circuit under normal working conditions without faults, and Respectively represent the normal current amplitude of the normal current of each phase, represents the phase difference between the two adjacent phase currents, x and y represent the abscissa and ordinate of the first coordinate system respectively, and ω represents a preset frequency.

[0018] Further, according to a first fault phase current expression of a fault phase in a single-tube open-circuit fault of the inverter, a first adjacent phase current expression of a fault adjacent phase is determined, and according to the first adjacent phase current expression, a first fault trajectory model for the single-tube open-circuit fault is determined, including:

[0019] The first fault phase current expression is constructed as follows:

[0020]

[0021] According to the first fault phase current expression, the first adjacent phase current expression of the fault adjacent phase in the single-tube open circuit fault is constructed as the following formula:

[0022]

[0023]

[0024] Among them, i a (t) represents the fault phase current, i b (t) and i b (t) represents the fault adjacent phase current, represents the current amplitude of the fault adjacent phase, φ represents the phase difference between the fault phase and the fault adjacent phase;

[0025] According to the first adjacent phase current expression, the first fault trajectory model is expressed as follows:

[0026]

[0027] Further, according to the second fault phase current expression of the fault phase in the double-tube open-circuit fault of the inverter, a second adjacent phase current expression of the fault adjacent phase is determined, and according to the second adjacent phase current expression, a second fault trajectory model for the double-tube open-circuit fault is determined, including:

[0028] The second fault phase current expression is constructed as follows:

[0029] i a (t)=0ωt∈[2kπ,2kπ+2π)

[0030] According to the second fault phase current expression, the second adjacent phase current expression of the fault adjacent phase in the double-tube open circuit fault is constructed as the following formula:

[0031]

[0032] i c (t) = -i b (t)ωt∈[2kπ,2kπ+2π)

[0033] According to the second adjacent phase current expression, the second fault trajectory model is expressed as follows:

[0034]

[0035] Further, according to the third fault phase current expression of the fault phase of the inverter in the current sensor fault, determining the third adjacent phase current trajectory of the fault adjacent phase in the current sensor fault includes:

[0036] The third fault phase current expression is constructed as follows:

[0037]

[0038] Among them, t F Indicates the time when the current sensor failure occurs;

[0039] According to the third fault phase current expression, the third adjacent phase current trajectory is determined as a trajectory with irregular changes.

[0040] Further, determining a first adjacent phase current trajectory according to the first fault trajectory model, and determining a second adjacent phase current trajectory according to the second fault trajectory model, includes:

[0041] According to the first fault trajectory model, the first adjacent phase current trajectory is expressed in the second coordinate system as:

[0042]

[0043] Wherein, m and n represent the abscissa and ordinate of the second coordinate system respectively;

[0044] According to the second fault trajectory model, the second adjacent phase current trajectory is expressed in the second coordinate system as:

[0045]

[0046] Further, the current current trajectory of each phase current in the current inverter is identified by using the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory, and the working condition of the current inverter is determined according to the identification result, including:

[0047] Determining, according to the first adjacent phase current trajectory, that a first trajectory feature of the first adjacent phase current trajectory is a trajectory in which, in the second coordinate system, the center and / or the center of mass deviates from the coordinate origin and changes regularly;

[0048] According to the second adjacent phase current trajectory, determining that a second trajectory feature of the second adjacent phase current trajectory is a trajectory with a center of mass at the coordinate origin and symmetric about the center;

[0049] According to the normal current trajectory, determining that a normal trajectory feature of the normal current trajectory is an ellipse with a center located at a coordinate origin and a fixed inclination angle;

[0050] and determining the third trajectory feature of the third adjacent phase current trajectory as an irregular feature;

[0051] The current current trajectory is identified by using the preset current trajectory identification mechanism, and in response to the current current trajectory having the first trajectory feature, it is determined that the current inverter is the single-tube open circuit fault;

[0052] In response to the current current trajectory having the second trajectory feature, determining that the current inverter is the double-tube open-circuit fault;

[0053] In response to the current current trajectory having the third trajectory feature, determining that the current inverter is faulty in the current sensor;

[0054] In response to the current current trajectory having the normal trajectory feature, it is determined that the current inverter does not have a single-tube open-circuit fault, a double-tube open-circuit fault, or a current sensor fault.

[0055] Based on the same inventive concept, the present application also provides an inverter fault diagnosis device, including: a normal current trajectory determination module, a first fault trajectory model determination module, a second fault trajectory model determination module, a third adjacent phase current trajectory determination module and an identification and diagnosis module;

[0056] The normal current trajectory determination module is configured to determine the normal current trajectory formed by two adjacent phase currents according to the normal current expression of each phase current in the three-phase AC circuit topology structure of the inverter under no fault conditions;

[0057] The first fault trajectory model determination module is configured to determine a first adjacent phase current expression of a faulty adjacent phase according to a first fault phase current expression of a faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression;

[0058] The second fault trajectory model determination module is configured to determine a second adjacent phase current expression of a faulty adjacent phase according to a second fault phase current expression of the faulty phase in a double-tube open-circuit fault of the inverter, and determine a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression;

[0059] The third adjacent phase current trajectory determination module is configured to determine the third adjacent phase current trajectory of the faulty adjacent phase in the current sensor failure according to the third fault phase current expression of the faulty phase of the inverter in the current sensor failure;

[0060] The identification and diagnosis module is configured to determine a first adjacent phase current trajectory according to the first fault trajectory model, and determine a second adjacent phase current trajectory according to the second fault trajectory model, and in a preset current trajectory identification mechanism, use the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory to identify the current current trajectory of each phase current in the current inverter, and determine the operating condition of the current inverter according to the identification result.

[0061] Based on the same inventive concept, the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the inverter fault diagnosis method as described in any one of the above items is implemented.

[0062] Based on the same inventive concept, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the inverter fault diagnosis method as described above.

[0063] From the above, it can be seen that the inverter fault diagnosis method and related equipment provided by the present application are based on the single-tube open-circuit fault, double-tube open-circuit fault and current sensor fault of the inverter, and comprehensively consider the different current expressions of the faulty phase under different faults, and simultaneously consider the current expressions of the corresponding faulty adjacent phases to determine the faulty adjacent phase current trajectory under each fault, so that different faults can reflect different adjacent phase current trajectories, thereby effectively distinguishing the single-tube open-circuit fault, double-tube open-circuit fault and current sensor fault of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0065] Figure 1 This is a flow chart of an inverter fault diagnosis method according to an embodiment of the present application;

[0066] Figure 2 A common circuit topology diagram of an inverter according to an embodiment of the present application;

[0067] Figure 3 A circuit topology diagram of a VT1 fault in an embodiment of the present application;

[0068] Figure 4 This is a schematic diagram of the first adjacent phase current trajectory of an embodiment of the present application;

[0069] Figure 5 This is a schematic diagram of the first adjacent phase current trajectory of an embodiment of the present application;

[0070] Figure 6 This is a schematic diagram of the structure of an inverter fault diagnosis device according to an embodiment of the present application;

[0071] Figure 7 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0072] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0073] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0074] As described in the background technology section, the related inverter fault diagnosis method is still difficult to meet the needs of diagnosing and distinguishing various inverter faults in actual work.

[0075] In the process of implementing the present application, the applicant discovered that the main problem with the relevant inverter fault diagnosis method is that the single-tube open-circuit fault, double-tube open-circuit fault and current sensor zero output fault in the inverter manifest themselves very similarly in some cases, and the methods for diagnosing and distinguishing them are often limited to three types of methods: model-based, signal-based, and data-based. Among them, the signal-based method is difficult in that it requires that the three-phase current, voltage signal or control signal can be fully monitored, which puts high requirements on the deployment of sensors and other devices; and the data-based and model-based methods are difficult in that the data and training samples that meet the model training requirements need to be sufficient, and qualified training samples are often difficult to obtain.

[0076] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0077] refer to Figure 1 , an inverter fault diagnosis method according to an embodiment of the present application comprises the following steps:

[0078] Step S101: Under no-fault conditions, a normal current trajectory formed by two adjacent phase currents is determined according to a normal current expression of each phase current in a three-phase AC circuit topology structure of the inverter.

[0079] In the embodiments of the present application, Figure 2 The inverter used in the train shown is used as a specific example. Figure 2The commonly used circuit topology of the inverter is shown, in which VT1, VT2, VT3, VT4, VT5 and VT6 are insulated gate bipolar transistor modules with anti-parallel diodes. By controlling the alternating conduction of the insulated gate bipolar transistor modules, the DC input voltage u dc It is converted into three-phase alternating current that can be used by the train motor M, where A, B and C represent phase A, phase B and phase C of the three-phase alternating current respectively.

[0080] Among them, the phase current i a and i b The phase current i is measured by the current sensor. c It is calculated through the other two phase currents.

[0081] It can be seen that based on Figure 2 The commonly used circuit topology of the inverter shown in the figure is a 、i b and i c They are the three-phase currents, and correspond to phase A, phase B and phase C in sequence. When there is no fault, the three-phase currents are sinusoidal waves with equal amplitudes and 120 degrees phase difference. Therefore, the normal current of each phase can be expressed in the time domain as shown below:

[0082]

[0083] In this embodiment, and They represent the normal currents of phase A, phase B and phase C in a three-phase AC circuit under normal working conditions without faults. and Respectively represent the normal current amplitude of each phase normal current, It represents the phase difference between the two adjacent phase currents of phase A and phase B, and ω represents the preset frequency.

[0084] Furthermore, based on the above-mentioned normal current expression form, the normal current trajectories of two adjacent phases can be expressed in a preset first coordinate system, that is, an xy coordinate system as follows:

[0085]

[0086] and

[0087] Wherein, x and y represent the abscissa and ordinate of the first coordinate system respectively.

[0088] Based on the above expression of the normal current trajectory, it can be seen that under fault-free conditions, two adjacent phases can form an elliptical trajectory with the center located at the first coordinate origin and a fixed inclination angle in the first coordinate system, and use it as the normal trajectory feature, where the first coordinate origin is the coordinate origin of the xy coordinate system.

[0089] In an embodiment of the present application, based on the above-mentioned inverter, the following fault diagnosis steps are performed on the single-tube open-circuit fault of the power tube (which may also be referred to as "single-tube open-circuit fault" in this embodiment), the double-tube open-circuit fault of the power tube (which may also be referred to as "double-tube open-circuit fault" in this embodiment) and the current sensor zero output fault (which may also be referred to as "current sensor fault" in this embodiment) in the inverter fault.

[0090] Specifically, it is necessary to first determine the fault trajectory model of the adjacent phase in the cases of single-tube open-circuit fault, double-tube open-circuit fault and current sensor fault, and then determine the trajectory of the adjacent phase current and its trajectory characteristics in each fault situation based on the fault trajectory model.

[0091] Step S102: Determine a first adjacent phase current expression of a faulty phase according to a first fault phase current expression of a faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression.

[0092] In the embodiment of the present application, for a single-tube fault, the first fault trajectory model may be determined according to the characteristics of the single-tube fault.

[0093] Specifically, when a single-tube open-circuit fault occurs in the power tube, the current of the faulty phase can be considered to be equal to 0 within half a cycle, and if the single-tube open-circuit fault occurs in the upper bridge arm power tube, the current value of the faulty phase is non-positive, and if the single-tube open-circuit fault occurs in the lower bridge arm power tube, the current value of the faulty phase is non-negative.

[0094] Further, Figure 2 Phase A in the figure is taken as the fault phase. If a single tube open circuit fault of VT1 occurs in phase A, the Figure 2 The commonly used circuit topology under normal working conditions shown is approximately equivalent to Figure 3 The single-tube open-circuit fault circuit topology shown in the figure is Figure 3 In the figure, the structure drawn with non-solid black lines is the structure where a single-tube open-circuit fault occurs. Figure 3 In this example, the single-tube open-circuit fault occurring in phase A is referred to as VT1 fault.

[0095] Furthermore, combined with the above normal current expression, the current of the fault phase A can be expressed as:

[0096]

[0097] Among them, i a (t) represents the fault phase current, i.e., the current of phase A when VT1 fails. b (t) and i b (t) represents the two adjacent phase currents of the fault phase.

[0098] Furthermore, taking the VT1 fault of phase A as an example, the changing trend of the current of the phases adjacent to the fault, that is, the current changing trend of phases B and C, can be analyzed.

[0099] It can be seen that in the interval of ωt∈[2kπ, 2kπ+π), the three-phase inverter under the condition of VT1 fault can be approximately regarded as the normal condition of the single-phase inverter. Therefore, the B-phase current can be expressed as the first adjacent phase current expression as shown below:

[0100]

[0101] in, represents the current amplitude of the phase adjacent to the fault when VT1 fails, that is, the current amplitude of phase B, and φ represents the phase difference between the fault phase and the phase adjacent to the fault. In this embodiment, considering that there may be other unknown influencing factors under the working condition of VT1 failure, therefore, the amplitude can be is considered as a time variable.

[0102] It should be noted that the above first adjacent phase current expression can also be obtained by calculation. And, φ=-5π / 6 to determine the expression.

[0103] Furthermore, the first adjacent phase current expression also includes another fault adjacent phase, that is, phase C. In this embodiment, the current of phase C can be expressed as:

[0104]

[0105] Furthermore, in the interval of ωt∈[2kπ+π, 2kπ+2π), since the current of phase A returns to normal, the currents of phases B and C will change toward normal.

[0106] It can be seen that according to the above analysis, a model of the current trajectory when VT1 fails can be obtained, which is used as the first fault trajectory model in this embodiment and expressed by the following formula:

[0107]

[0108] It should be noted that, due to the motor M, under the condition of VT1 fault, the B phase current may still contain certain harmonics, so the above-mentioned first adjacent phase current expression and the first fault trajectory model expression may be different from the actual situation.

[0109] Step S103: Determine a second adjacent phase current expression of the faulty phase in the double-switch open-circuit fault of the inverter according to a second fault phase current expression of the faulty phase, and determine a second fault trajectory model for the double-switch open-circuit fault according to the second adjacent phase current expression.

[0110] In the embodiment of the present application, for the case of a double-tube fault, the second fault trajectory model may be determined according to the characteristics of the double-tube fault.

[0111] Specifically, in the case of a double-tube open-circuit fault, the impact of an open-circuit fault on each power tube can be considered independent of each other. Therefore, when an open-circuit fault occurs on two power tubes, it can be considered as the superposition of an open-circuit fault on a corresponding single power tube, and its current trajectory can be derived according to the logic shown below:

[0112] FAULT_VTi&VTj=FAULT_VTi∩FAULT_VTj

[0113] Among them, VT i and VT j They are two different power tubes in the inverter, FAULT_VT i and FAULT_VT j They represent the current trajectory in the first coordinate system corresponding to the power tube with an open circuit fault, and the symbol ∩ represents the FAULT_VT i The area enclosed by FAULT_VT j The enclosed area intersects, and the boundary trajectory of the area after the intersection is FAULT_VT i &VT j .

[0114] Furthermore, in combination with the above normal current expression, a similar analysis method as in the above step S102 is adopted to determine the current trajectory model during a double-tube open-circuit fault, that is, the second fault trajectory model.

[0115] Specifically, taking the upper bridge arm power tube fault and the lower bridge arm power tube fault occurring on phase A as an example, the current expression of phase A at this time can be determined as follows, that is, the current expression of the second fault phase:

[0116] i a (t)=0ωt∈[2kπ,2kπ+2π)

[0117] It can be seen that at this time, the current of phase A is always 0 in each cycle. Figure 2 The circuit topology shown can be equivalent to the following at any time after the double-tube open-circuit fault occurs: Figure 3 The single-phase inverter shown in FIG. 1 can obtain the current expressions of phases B and C, that is, the current expression of the second adjacent phase, and can be specifically expressed as:

[0118]

[0119] i c (t) = -i b (t)ωt∈[2kπ,2kπ+2π)

[0120] Furthermore, according to the above second adjacent phase current expression, the second fault trajectory model can be determined and expressed as follows:

[0121]

[0122] Step S104: determining a third adjacent phase current trajectory of a faulty adjacent phase in the current sensor failure according to an expression of a third faulty phase current of the faulty phase of the inverter in the current sensor failure.

[0123] In the embodiment of the present application, in the case of a current sensor failure, the third adjacent phase current trajectory may be determined according to the characteristics of the current sensor failure.

[0124] Specifically, when a zero output fault occurs in the current sensor, the current of the corresponding fault phase will approach 0 under the fault.

[0125] In this embodiment, taking the current sensor failure of phase A as an example, combined with the above normal current expression, the current expression of the fault phase A, that is, the third fault phase current expression can be constructed in the following form:

[0126]

[0127] Among them, t F Indicates the time when the current sensor failure occurs.

[0128] It can be seen that after the current sensor failure occurs in phase A, the current characteristics are similar to the double-tube open-circuit failure of the power tube of phase A. However, unlike the double-tube open-circuit failure, when the current sensor failure occurs, the actual current of phase A is not zero. Therefore, in the case of the current sensor failure, the circuit topology cannot be equivalent to Figure 3 Single-phase inverter shown.

[0129] It can be determined that, in the case of a current sensor failure, the B-phase current does not satisfy the second adjacent phase current expression. At the same time, since the A-phase current sensor can always feedback a zero current signal, it is very easy to cause control instability, causing the B-phase and C-phase currents to show irregular changes. Therefore, the third trajectory feature of the current trajectory of the B-phase and C-phase in the current sensor failure, that is, the third trajectory feature of the third adjacent phase current trajectory is an irregularly changing trajectory.

[0130] Step S105, respectively determine the first adjacent phase current trajectory according to the first fault trajectory model, and determine the second adjacent phase current trajectory according to the second fault trajectory model; in a preset current trajectory identification mechanism, use the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory to identify the current current trajectory of each phase current in the current inverter, and determine the operating condition of the current inverter according to the identification result.

[0131] In an embodiment of the present application, the corresponding adjacent phase current trajectories can be determined respectively based on the current trajectory models under various fault conditions determined above. By combining the adjacent phase current trajectories and the normal current trajectory, the fault diagnosis of the current inverter can be performed by extracting the characteristics of each trajectory.

[0132] First, based on Figure 2 The commonly used circuit topology shown in the figure still uses phase A to generate VT i Fault as an example, we can know that in phase A VT i In the case of a fault, the first adjacent phase current expression of phase B and phase C can be further expressed as follows:

[0133]

[0134]

[0135] Furthermore, by transforming the above expression of phase C into (c) (t) Overall right shift This can be determined as:

[0136]

[0137] Furthermore, in the preset second coordinate system, that is, the mn coordinate system, let the horizontal coordinate m=i (b) (t), n = i' (c) (t), according to the above expression, the A phase VT can be expressed in the second coordinate system as i The current trajectory of the adjacent phase of the fault in the next cycle, that is, the current trajectory of the first adjacent phase, is expressed as:

[0138]

[0139] It can be seen that the first adjacent phase current trajectory is composed of multiple elliptical trajectories and circular trajectories.

[0140] Further, let φ = -5π / 6, And ignore As time goes by, in an ideal situation, the first adjacent phase current trajectory can be shown as Figure 4 The trajectory shown.

[0141] It can be seen that the first trajectory of the first adjacent phase current trajectory under a single-tube open-circuit fault is characterized by a regular but irregular closed figure, which is basically in the shape of an inverted triangle and is mainly located at Figure 4 The centers and centroids of the first, second and fourth regions in the θ deviate from the origin of the second coordinate system.

[0142] In this embodiment, based on Figure 2 The circuit topology shown in the figure still takes the double-tube open-circuit fault of phase A as an example. It can be seen that in the case of a double-tube open-circuit fault of the power tube of phase A, according to the second adjacent phase current expression in the previous step, the expression i of phase C is also converted into (c) (t) Overall right shift The current expression of phase C can be determined as:

[0143]

[0144] Furthermore, in the preset second coordinate system, mn coordinate system, let the horizontal coordinate m=i (b) (t), n = i' (c) (t), combined with the second adjacent phase current expression, the current trajectory of the adjacent phase of the A phase double-tube open-circuit fault in the next cycle, that is, the second adjacent phase current trajectory, can be expressed in the second coordinate system under ideal conditions as follows:

[0145]

[0146] Furthermore, considering is a time-varying variable. The second trajectory characteristic of the second adjacent phase current trajectory is ideally as follows: Figure 5 As shown, it can be a quasi-circular trajectory with its center at the origin of the coordinate system and periodically rotating around the origin of the coordinate system.

[0147] Furthermore, based on the above-determined trajectories under normal operating conditions and faulty operating conditions, a preset current trajectory identification mechanism may be used to identify the current current trajectory of the current inverter to be diagnosed.

[0148] Specifically, the current trajectory identification mechanism can be a classification neural network or support vector machine equipped with pattern recognition technology, or it can be an identification of the current trajectory through trajectory centroid calculation, unsupervised clustering or supervised classification.

[0149] Furthermore, for the current inverter to be diagnosed, if the current current trajectory of any phase thereof has the first trajectory feature, it can be determined that the current inverter has a single-tube open-circuit fault.

[0150] Furthermore, if any current current trajectory has the second trajectory feature, it can be determined that the current inverter has a double-switch open-circuit fault;

[0151] Furthermore, if any current current trajectory has the third trajectory feature, it can be determined that there is a current sensor fault in the current inverter;

[0152] Furthermore, if the current current trajectory has normal trajectory characteristics, it can be determined that the current inverter does not have a single-tube open-circuit fault, a double-tube open-circuit fault, or a current sensor fault.

[0153] It can be seen that the inverter fault diagnosis method of the embodiment of the present application is based on the single-tube open-circuit fault, double-tube open-circuit fault and current sensor fault of the inverter, and comprehensively considers the different current expressions of the faulty phase under different faults, and simultaneously considers the current expressions of the corresponding faulty adjacent phases to determine the faulty adjacent phase current trajectory under each fault, so that different faults can reflect different adjacent phase current trajectories, thereby effectively distinguishing the single-tube open-circuit fault, double-tube open-circuit fault and current sensor fault of the inverter.

[0154] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the described method.

[0155] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0156] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, an embodiment of the present application further provides an inverter fault diagnosis device.

[0157] refer to Figure 6 , the inverter fault diagnosis device comprises: a normal current trajectory determination module 601, a first fault trajectory model determination module 602, a second fault trajectory model determination module 603, a third adjacent phase current trajectory determination module 604 and an identification and diagnosis module 605;

[0158] The normal current trajectory determination module 601 is configured to determine the normal current trajectory formed by two adjacent phase currents according to the normal current expression of each phase current in the three-phase AC circuit topology of the inverter under fault-free conditions.

[0159] The first fault trajectory model determination module 602 is configured to determine a first adjacent phase current expression of a faulty phase according to a first fault phase current expression of a faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression.

[0160] The second fault trajectory model determination module 603 is configured to determine a second adjacent phase current expression of the faulty phase according to a second fault phase current expression of the faulty phase of the inverter in a double-tube open-circuit fault, and determine a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression.

[0161] The third adjacent phase current trajectory determination module 604 is configured to determine the third adjacent phase current trajectory of the faulty adjacent phase in the current sensor failure according to the third faulty phase current expression of the faulty phase of the inverter in the current sensor failure.

[0162] The identification and diagnosis module 605 is configured to determine the first adjacent phase current trajectory according to the first fault trajectory model, and determine the second adjacent phase current trajectory according to the second fault trajectory model, and in a preset current trajectory identification mechanism, use the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory to identify the current current trajectory of each phase current in the current inverter, and determine the operating condition of the current inverter based on the identification result.

[0163] For the convenience of description, the above devices are described in terms of functions and are divided into various modules. Of course, when implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0164] The device of the above embodiment is used to implement the corresponding inverter fault diagnosis method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0165] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, an embodiment of the present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the inverter fault diagnosis method as described in any of the above embodiments is implemented.

[0166] Figure 7 A more specific schematic diagram of the hardware structure of an electronic device provided in this embodiment is shown, and the device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are connected to each other through the bus 1050 in the device.

[0167] The processor 1010 can be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application.

[0168] The memory 1020 may be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When the technical solution provided in the embodiment of the present application is implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0169] The input / output interface 1030 is used to connect the input / output module to realize information input and output. The input / output module can be configured in the device as a component (not shown in the figure), or it can be externally connected to the device to provide corresponding functions. The input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0170] The communication interface 1040 is used to connect a communication module (not shown) to realize communication interaction between the device and other devices. The communication module can realize communication through a wired mode (such as USB, network cable, etc.) or a wireless mode (such as mobile network, WIFI, Bluetooth, etc.).

[0171] The bus 1050 includes a path that transmits information between the various components of the device (eg, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040).

[0172] It should be noted that, although the above device only shows the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040 and the bus 1050, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include the components necessary for implementing the embodiment of the present application, and does not necessarily include all the components shown in the figure.

[0173] The device of the above embodiment is used to implement the corresponding inverter fault diagnosis method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0174] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the inverter fault diagnosis method described in any of the above embodiments.

[0175] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0176] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the inverter fault diagnosis method described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0177] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0178] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power supply / ground connection with the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application will be implemented (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details (e.g., circuits) to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0179] Although the present application has been described in conjunction with specific embodiments of the present application, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0180] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A method for diagnosing inverter faults, characterized in that: include: Under a fault-free working condition, according to a normal current expression of each phase current in a three-phase AC circuit topology structure of the inverter, a normal current trajectory formed by two adjacent phase currents is determined; Determine a first adjacent phase current expression of a faulty phase according to a first fault phase current expression of the faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression; Determine a second adjacent phase current expression of a phase adjacent to the fault according to a second fault phase current expression of the fault phase in the double-tube open-circuit fault of the inverter, and determine a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression; Determine the third adjacent phase current trajectory of the faulty phase in the current sensor failure according to the third fault phase current expression of the faulty phase of the inverter in the current sensor failure; The first adjacent phase current trajectory is determined according to the first fault trajectory model, and the second adjacent phase current trajectory is determined according to the second fault trajectory model. In a preset current trajectory identification mechanism, the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory are used to identify the current current trajectory of each phase current in the current inverter, and the operating condition of the current inverter is determined according to the identification result.

2. The method according to claim 1, characterized in that The determining of the normal current trajectory formed by two adjacent phase currents according to the normal current expression of each phase current in the three-phase AC circuit topology structure of the inverter comprises: The normal current expression of each phase current in the three-phase AC circuit topology is constructed as follows: According to the normal current expression, in the first coordinate system, the normal current trajectory is expressed as: and in, and They respectively represent the normal current of each phase in the three-phase AC circuit under normal working conditions without faults, and Respectively represent the normal current amplitude of the normal current of each phase, represents the phase difference between the two adjacent phase currents, x and y represent the abscissa and ordinate of the first coordinate system respectively, and ω represents a preset frequency.

3. The method according to claim 1, characterized in that The method of determining a first adjacent phase current expression of a faulty phase in a single-tube open-circuit fault of the inverter according to a first fault phase current expression of the faulty phase, and determining a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression, comprises: The first fault phase current expression is constructed as follows: According to the first fault phase current expression, the first adjacent phase current expression of the fault adjacent phase in the single-tube open circuit fault is constructed as the following formula: Among them, i a (t) represents the fault phase current, i b (t) and i b (t) represents the fault adjacent phase current, represents the current amplitude of the fault adjacent phase, φ represents the phase difference between the fault phase and the fault adjacent phase; According to the first adjacent phase current expression, the first fault trajectory model is expressed as follows:

4. The method according to claim 3, characterized in that The method of determining a second adjacent phase current expression of a faulty phase in a double-tube open-circuit fault of the inverter according to a second fault phase current expression of the faulty phase, and determining a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression, comprises: The second fault phase current expression is constructed as follows: i a (t)=0ωt∈[2kπ,2kπ+2π) According to the second fault phase current expression, the second adjacent phase current expression of the fault adjacent phase in the double-tube open circuit fault is constructed as the following formula: i c (t)=-i b (t)ωt∈[2kπ,2kπ+2π) According to the second adjacent phase current expression, the second fault trajectory model is expressed as follows:

5. The method according to claim 4, characterized in that The step of determining the third adjacent phase current trajectory of the faulty phase in the current sensor failure according to the third fault phase current expression of the faulty phase of the inverter in the current sensor failure comprises: The third fault phase current expression is constructed as follows: Among them, t F Indicates the time when the current sensor failure occurs; According to the third fault phase current expression, the third adjacent phase current trajectory is determined as a trajectory with irregular changes.

6. The method according to claim 5, characterized in that The determining of the first adjacent phase current trajectory according to the first fault trajectory model and the determining of the second adjacent phase current trajectory according to the second fault trajectory model include: According to the first fault trajectory model, the first adjacent phase current trajectory is expressed in a preset second coordinate system as: Wherein, m and n represent the abscissa and ordinate of the second coordinate system respectively; According to the second fault trajectory model, the second adjacent phase current trajectory is expressed in the second coordinate system as:

7. The method according to claim 6, characterized in that The identifying the current current trajectory of each phase current in the current inverter by using the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory, and determining the working condition of the current inverter according to the identification result, includes: Determining, according to the first adjacent phase current trajectory, that a first trajectory feature of the first adjacent phase current trajectory is a trajectory in which, in the second coordinate system, the center and / or the center of mass deviates from the coordinate origin and changes regularly; According to the second adjacent phase current trajectory, determining that a second trajectory feature of the second adjacent phase current trajectory is a trajectory with a center of mass at the coordinate origin and symmetric about the center; According to the normal current trajectory, determining that a normal trajectory feature of the normal current trajectory is an ellipse with a center located at a coordinate origin and a fixed inclination angle; and determining the third trajectory feature of the third adjacent phase current trajectory as an irregular feature; The current current trajectory is identified by using the preset current trajectory identification mechanism, and in response to the current current trajectory having the first trajectory feature, it is determined that the current inverter is the single-tube open circuit fault; In response to the current current trajectory having the second trajectory feature, determining that the current inverter is the double-tube open-circuit fault; In response to the current current trajectory having the third trajectory feature, determining that the current inverter is faulty in the current sensor; In response to the current current trajectory having the normal trajectory feature, it is determined that the current inverter does not have a single-tube open-circuit fault, a double-tube open-circuit fault, or a current sensor fault.

8. An inverter fault diagnosis device, comprising: A normal current trajectory determination module, a first fault trajectory model determination module, a second fault trajectory model determination module, a third adjacent phase current trajectory determination module and an identification and diagnosis module; The normal current trajectory determination module is configured to determine the normal current trajectory formed by two adjacent phase currents according to the normal current expression of each phase current in the three-phase AC circuit topology of the inverter under no fault conditions; The first fault trajectory model determination module is configured to determine a first adjacent phase current expression of a faulty adjacent phase according to a first fault phase current expression of a faulty phase in a single-tube open-circuit fault of the inverter, and determine a first fault trajectory model for the single-tube open-circuit fault according to the first adjacent phase current expression; The second fault trajectory model determination module is configured to determine a second adjacent phase current expression of a faulty adjacent phase according to a second fault phase current expression of the faulty phase in a double-tube open-circuit fault of the inverter, and determine a second fault trajectory model for the double-tube open-circuit fault according to the second adjacent phase current expression; The third adjacent phase current trajectory determination module is configured to determine the third adjacent phase current trajectory of the faulty adjacent phase in the current sensor failure according to the third fault phase current expression of the faulty phase of the inverter in the current sensor failure; The identification and diagnosis module is configured to determine a first adjacent phase current trajectory according to the first fault trajectory model, and determine a second adjacent phase current trajectory according to the second fault trajectory model, and in a preset current trajectory identification mechanism, use the first adjacent phase current trajectory, the second adjacent phase current trajectory, the third adjacent phase current trajectory and the normal current trajectory to identify the current current trajectory of each phase current in the current inverter, and determine the operating condition of the current inverter according to the identification result.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions for causing a computer to execute the method according to any one of claims 1 to 7.

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