Device fault diagnosis method, system and equipment based on phase current and zero sequence voltage

Abstract

The present application relates to the field of device fault diagnosis, and provides a device fault diagnosis method, system and equipment based on phase current and zero sequence voltage, comprising calculating phase current steady-state value and phase current fault transient value, and constructing single-phase open circuit fault flag; when the single-phase open circuit fault flag indicates that there is single-phase open circuit fault, obtaining fault phase flag quantity through phase current intensity coefficient; constructing first inverter fault flag through zero sequence voltage, when the first inverter fault flag indicates that there is fault, constructing second inverter fault flag through phase current unit value, obtaining inverter fault flag through the first inverter fault flag and the second inverter fault flag, determining device positioning threshold, constructing inverter fault positioning flag based on the device positioning threshold, positive current intensity and negative current intensity; obtaining final fault positioning flag, thereby diagnosing device fault of the device.

Description

Technical Field

[0001] This invention relates to the field of device fault diagnosis technology, and in particular to device fault diagnosis methods, systems and devices based on phase current and zero-sequence voltage. Background Technology

[0002] Inverters are widely used in various device drive systems. Their power switching devices operate under harsh conditions of high frequency, high voltage, and high current for extended periods, making them prone to open-circuit faults due to poor heat dissipation, overcurrent surges, and insulation aging. Currently, existing inverter open-circuit fault diagnosis methods can be mainly divided into three categories: analytical model-based, signal processing-based, and data-driven. Analytical model-based methods identify faults by constructing a mathematical model of the system and performing residual analysis. This method is fast-responding but highly dependent on physical parameters, making it prone to misjudgment under system parameter disturbances or external interference. Data-driven methods utilize artificial intelligence algorithms to train massive amounts of sample data to achieve pattern recognition. They have strong adaptability but heavily rely on high-quality, complete training datasets, making practical engineering deployment difficult and resulting in poor real-time performance. Signal processing-based methods focus on waveform transformation of electrical signals such as current or voltage to extract hidden fault features. These methods eliminate the reliance on precise models. Among them, current signal-based diagnostic methods have received widespread attention due to their advantages of requiring no additional sensors, low cost, and ease of implementation. However, these methods still have certain limitations in practical applications: for example, the average value method is easily affected by load changes and it is difficult to distinguish between open circuit in the winding and open circuit in the device. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention provides a device fault diagnosis method, system, and device based on phase current and zero-sequence voltage, enabling accurate and rapid identification of device faults.

[0004] This invention provides a device fault diagnosis method based on phase current and zero-sequence voltage, comprising: S1: Measure the phase current, calculate the steady-state value of the phase current and the instantaneous value of the phase current during a fault, and construct a single-phase open-circuit fault flag based on the phase current, the steady-state value of the phase current, and the instantaneous value of the phase current during a fault. S2: When the single-phase open circuit fault flag indicates that a single-phase open circuit fault exists, calculate the phase current intensity coefficient and obtain the fault phase flag quantity through the phase current intensity coefficient. S3: Calculate the zero-sequence voltage, construct the first inverter fault flag bit through the zero-sequence voltage, when the first inverter fault flag bit indicates that there is a fault, calculate the per-unit value of the phase current, construct the second inverter fault flag bit through the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. S4: Calculate the positive and negative current intensities, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity, and negative current intensity; S5: Obtain the final fault location flag by using the fault phase flag, inverter fault flag bit, and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

[0005] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S1, the steady-state value of the phase current and the instantaneous value of the phase current fault are calculated, and the phase current is compared with the steady-state value of the phase current and the instantaneous value of the phase current fault. When the value of the phase current is between the steady-state value of the phase current and the instantaneous value of the phase current fault, the value of the single-phase open-circuit fault flag is 1.

[0006] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S2, intermediate variables of device parameters are calculated, and the phase current intensity coefficient including the first phase current intensity coefficient, the second phase current intensity coefficient and the third phase current intensity coefficient are calculated through the intermediate variables of device parameters.

[0007] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S2, the minimum value of phase current intensity is determined, and an algebraic difference judgment standard is established through the phase current intensity coefficient. The fault phase marker quantity is obtained according to the minimum value of phase current intensity and the algebraic difference judgment standard.

[0008] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S3, the zero-sequence voltage is calculated to determine the normal voltage of the inverter. When the value of the zero-sequence voltage is not within the range of the normal voltage of the inverter, the first inverter fault flag bit is set to 1, otherwise it is -1.

[0009] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S3, a diagnosis threshold is determined, a detection flag bit is obtained according to the diagnosis threshold and the per-unit value of the phase current, and the detection flag bit is sampled multiple times to calculate the average value to obtain the second inverter fault flag bit.

[0010] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, step S4 further includes: S41: Calculate the positive half-cycle current of the device based on the phase current to obtain the positive current intensity; calculate the negative half-cycle current of the device based on the phase current to obtain the negative current intensity; and determine the device positioning threshold. S42: Compare the positive current intensity and negative current intensity with the device positioning threshold respectively to obtain the positive inverter fault positioning flag and the negative inverter fault positioning flag, and obtain the inverter fault positioning flag through the positive inverter fault positioning flag and the negative inverter fault positioning flag.

[0011] According to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention, in step S5, the fault phase flag quantity and the inverter fault location flag are weighted and summed, and then multiplied by the inverter fault flag to obtain the final fault location flag.

[0012] The present invention also provides a device fault diagnosis system based on phase current and zero-sequence voltage, including: a single-phase open-circuit fault flag module: used to measure phase current, calculate the steady-state value of phase current and the instantaneous value of phase current fault, and construct a single-phase open-circuit fault flag based on phase current, steady-state value of phase current and instantaneous value of phase current fault; Fault Phase Flag Module: When the single-phase open circuit fault flag indicates the presence of a single-phase open circuit fault, it calculates the phase current intensity coefficient and obtains the fault phase flag quantity through the phase current intensity coefficient. Inverter fault flag module: used to calculate the zero-sequence voltage, construct the first inverter fault flag bit based on the zero-sequence voltage, calculate the per-unit value of the phase current when the first inverter fault flag bit indicates a fault, construct the second inverter fault flag bit based on the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. Inverter fault location flag module: used to calculate the positive current intensity and negative current intensity, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity and negative current intensity; Fault diagnosis module: Used to obtain the final fault location flag through the fault phase flag, inverter fault flag bit and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

[0013] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the device fault diagnosis method based on phase current and zero-sequence voltage as described above.

[0014] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: The device fault diagnosis method, system, and equipment based on phase current and zero-sequence voltage provided by this invention can screen for the minimum value of the periodic phase current intensity, thereby determining the phase where the fault occurs, and using phase current intensity characteristics to describe the fault characteristics. By analyzing the similarity and difference between the characteristics of stator winding open-circuit faults and inverter single-phase open-circuit faults, zero-sequence voltage is used as a characteristic signal to distinguish between device winding open-circuit faults and inverter open-circuit faults. Finally, the positive and negative current intensities are calculated, and the faulty device is located based on the positive and negative current intensities, thereby accurately, effectively, and quickly characterizing various device faults.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart of the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention.

[0018] Figure 2 This is a schematic diagram of the current and voltage changes in a winding open-circuit fault using the device fault diagnosis method based on phase current and zero-sequence voltage provided by this invention.

[0019] Figure 3 This is a schematic diagram of the current and voltage changes in an inverter open-circuit fault according to the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention.

[0020] Figure 4 This is a schematic diagram of the device fault diagnosis system based on phase current and zero-sequence voltage provided by the present invention.

[0021] Figure 5 This is a schematic diagram of the device fault diagnosis device based on phase current and zero-sequence voltage provided by the present invention.

[0022] Figure label: 100. Single-phase open-circuit fault flag module; 200. Fault phase flag module; 300. Inverter fault flag module; 400. Inverter fault location flag module; 500. Fault diagnosis module; 810. Processor; 820. Communication interface; 830. Memory; 840. Communication bus. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but cannot be used to limit the scope of this invention.

[0024] In the description of the embodiments of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0026] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0027] The following is combined Figures 1 to 5 Specific embodiments of the present invention are described below. Figure 1 A flowchart illustrating the device fault diagnosis method based on phase current and zero-sequence voltage provided by the present invention includes: S1: Measure the phase current, calculate the steady-state value of the phase current and the instantaneous value of the phase current during a fault, and construct a single-phase open-circuit fault flag based on the phase current, the steady-state value of the phase current, and the instantaneous value of the phase current during a fault. Furthermore, the objective of this stage is to construct a single-phase open-circuit fault flag based on the phase current, the steady-state value of the phase current, and the instantaneous value of the phase current during a fault. Specifically, in step S1, the steady-state value of the phase current and the instantaneous value of the phase current during a fault are calculated, and the phase current is compared with the steady-state value of the phase current and the instantaneous value of the phase current during a fault. When the value of the phase current is between the steady-state value of the phase current and the instantaneous value of the phase current during a fault, the single-phase open-circuit fault flag is set to 1.

[0028] The specific implementation method for the above steps in this embodiment is as follows: First, it's necessary to measure the phase current of each phase of the device. This device can be a three-phase motor, where the inverters are inverter switches. Taking phase a of the motor as an example, assume both inverters in phase a experience open-circuit faults, meaning the entire phase a is open-circuited, and this fault occurs at an electrical angle of 0. After the fault, the phase current of phase a is approximately zero. Since current cannot change abruptly, there is a transient recovery process between the phase currents of phases b and c, occurring during the recovery half-cycle, between the fault occurrence and the subsequent steady state. Under the same load and speed, assuming the motor torque remains constant before and after the fault, the current components in the d- and q-axis coordinate systems will also remain constant. Therefore, the steady-state value of the phase current of phase b... steady-state value of phase current of phase c for: Where θ is the electrical angle. This represents the phase current amplitude under healthy conditions.

[0029] Since the current cannot change abruptly, it will gradually change from the instantaneous value at the moment of the fault to the steady-state value of the phase current. The instantaneous value of the phase current of phase b at the time of the fault is... Instantaneous value of phase current fault in phase c for: For a single inverter open-circuit fault, assuming the fault occurs on phase a at a current angle of 0, the three-phase current trend during the current angle (0, π) phase is consistent with that of a two-inverter open-circuit fault. The difference is that during the current angle (π, 2π), the current path does not pass through the faulty inverter, the system operates normally, and the current gradually recovers to normal under the controller's regulation. Under the controller's regulation, the phase current approaches the amplitude of the phase current in the healthy state until it fully recovers to the healthy state. Therefore, for the motor's q-axis current, its steady-state phase current value is the phase current amplitude in the healthy state, and the instantaneous value of the q-axis phase current during a fault is twice the phase current amplitude in the healthy state.

[0030] Therefore, when the phase current value is between the steady-state phase current value and the instantaneous phase current value during a fault, and the phase current of each phase or q-axis changes from the instantaneous phase current value during a fault to the steady-state phase current value, the single-phase open-circuit fault flag can be set to 1. When the single-phase open-circuit fault flag is set to 1, it indicates that a single-phase open-circuit fault has occurred, meaning that the phase is open. For the single-inverter open-circuit fault current recovery process, when the excitation voltage equals the steady-state q-axis voltage value, the three-phase current can be the normal value of the three-phase current plus the transient component of the q-axis current at this time.

[0031] S2: When the single-phase open circuit fault flag indicates that a single-phase open circuit fault exists, calculate the phase current intensity coefficient and obtain the fault phase flag quantity through the phase current intensity coefficient. Furthermore, the objective of this stage is to calculate the phase current intensity coefficient, and obtain the fault phase indicator quantity through the phase current intensity coefficient. Specifically, in step S2, intermediate variables of device parameters are calculated, and the phase current intensity coefficient, including the first phase current intensity coefficient, the second phase current intensity coefficient, and the third phase current intensity coefficient, is calculated through the intermediate variables of device parameters.

[0032] In step S2, the minimum value of the phase current intensity is determined, and an algebraic difference judgment standard is established through the phase current intensity coefficient. The fault phase indicator quantity is obtained based on the minimum value of the phase current intensity and the algebraic difference judgment standard.

[0033] The specific implementation method for the above steps in this embodiment is as follows: When the single-phase open-circuit fault flag indicates a single-phase open-circuit fault, it will cause the phase current to be completely lost or its instantaneous value to become zero within half a fundamental cycle. The phase current intensity of phase x is defined as follows. for: in, ω It is the fundamental angular frequency of the current. T s The sampling time interval, Represents the phase current of phase x. j The sampled value at time t, ceil() represents the rounding up function.

[0034] To calculate the phase current intensity coefficient for each phase, it is necessary to first calculate the intermediate variables of the device parameters. : Where R is the stator resistance. It is the q-axis inductance.

[0035] The first-phase current intensity coefficient of phase a can then be calculated. Phase b second phase current intensity coefficient and the third phase current intensity coefficient of phase c : The phase current intensity coefficient includes the first phase current intensity coefficient, the second phase current intensity coefficient, and the third phase current intensity coefficient.

[0036] Taking an open-circuit fault in phase a as an example, the algebraic difference between the phase current intensity of phase a and the phase current intensity of the other two phases satisfies the algebraic difference judgment criterion: in, The controller adjustment coefficient, To restore the initial value of the q-axis current for half a cycle, This is the difference between the algebraic mean values ​​of the phase currents of phase b and phase a. This is the difference between the algebraic mean of the phase currents in phase c and phase a. The algebraic difference criterion also applies to other phases experiencing faults. Furthermore, after a phase faults, the phase current intensity flowing through that phase is the minimum of all phase current intensities. When the phase current intensity of a phase meets the algebraic difference criterion and is the minimum of all phase current intensities, the fault phase indicator can be obtained. F p Specifically, F p = F a +2 F b +4 F c ,in, F a For phase a, the fault discrimination quantity is... F b For phase b, the fault discrimination quantity, F c Let be the fault discrimination value for phase c, and when a fault occurs in this phase, the fault discrimination value for this phase is set to 1, thus: When an open-circuit fault occurs in phase a F p =1; When an open circuit fault occurs in phase b F p =2; When an open circuit fault occurs in phase C F p =4.

[0037] S3: Calculate the zero-sequence voltage, construct the first inverter fault flag bit through the zero-sequence voltage, when the first inverter fault flag bit indicates that there is a fault, calculate the per-unit value of the phase current, construct the second inverter fault flag bit through the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. Furthermore, the objective of this stage is to construct a first inverter fault flag bit and a second inverter fault flag bit, thereby obtaining the inverter fault flag bit. Specifically, in step S3, the zero-sequence voltage is calculated to determine the inverter normal voltage. When the value of the zero-sequence voltage is not within the range of the inverter normal voltage, the first inverter fault flag bit is set to 1; otherwise, it is -1.

[0038] In step S3, a diagnostic threshold is determined, and a detection flag bit is obtained based on the diagnostic threshold and the phase current per unit value. The detection flag bit is sampled multiple times and the average value is calculated to obtain the second inverter fault flag bit.

[0039] The specific implementation method for the above steps in this embodiment is as follows: When an open-circuit fault occurs, it could also be due to an open circuit in the stator winding. To distinguish this situation, let's take a fault in phase A as an example. Assume the three-phase back electromotive forces are balanced, since the sum of the three-phase currents is zero. Under healthy conditions, the zero-sequence voltage... for: in, This is the DC bus voltage. For the bridge arm switch indication function of phase a, For the bridge arm switch indication function of phase b, This is the indicator function for the bridge arm switch of phase c. Therefore, it can be seen that the zero-sequence voltage under healthy conditions has four possible levels. , , 0, which is the normal voltage of the inverter.

[0040] When an open-circuit fault occurs in the inverter of phase a, there will be a discontinuous current state, at which point: in, This refers to the discontinuous voltage of phase a, which exhibits a sinusoidal change when the inverter is disconnected. This will result in the presence of voltages other than those specified in the original text. , , Levels other than 0, such as Figure 3 As shown, where i a This refers to the phase current of phase a. When the zero-sequence voltage value is outside the normal inverter voltage range, the first inverter fault flag bit is activated. Finv1 A value of 1 indicates an inverter open-circuit fault; otherwise, -1 indicates a winding open-circuit fault. In this case, because the circuit is completely open, no current flows through phase a, therefore the zero-sequence voltage will not exist outside the normal inverter voltage. Figure 2 As shown, Figure 2 and Figure 3 The blue dashed line in the image indicates the moment the fault occurred.

[0041] Furthermore, because the anti-parallel diodes of the power devices continue to operate after a fault, an intermittent current path will still exist, and the fault phase current will fluctuate around 0. In contrast, the current after a winding open-circuit fault is always 0.

[0042] To reduce the load dependency of the fault diagnosis algorithm, it is also necessary to determine the diagnosis threshold th and calculate the per-unit value of the phase current. : in, Let x be the phase current of phase x.

[0043] Subsequently, when the per-unit value of the phase current is greater than or equal to the diagnostic threshold, the detection flag is set to 1; otherwise, it is set to 0. To avoid noise interference, the detection flag is sampled multiple times and the average value is calculated. If the average value of the multiple samples of the detection flag is not 0, then the second inverter fault flag is set. F inv2 The first inverter fault flag is set to 1, indicating an open-circuit fault in the inverter; otherwise, the second inverter fault flag is set to -1, indicating an open-circuit fault in the winding. Finally, the average of the sum of the first and second inverter fault flags is calculated to obtain the inverter fault flag values. F inv Furthermore, when F inv When the value is 0.5, an early warning of an open-circuit fault in the inverter is triggered; when... F inv When =1, an inverter open-circuit fault is determined; when F inv When = -0.5, an open circuit fault in the warning winding is detected; when F inv When the value is -1, an open-circuit fault in the winding is confirmed.

[0044] S4: Calculate the positive and negative current intensities, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity, and negative current intensity; Furthermore, the objective of this stage is to construct an inverter fault location flag based on the device location threshold, forward current intensity, and negative current intensity. Specifically, step S4 further includes: S41: Calculate the positive half-cycle current of the device based on the phase current to obtain the positive current intensity; calculate the negative half-cycle current of the device based on the phase current to obtain the negative current intensity; and determine the device positioning threshold. S42: Compare the positive current intensity and negative current intensity with the device positioning threshold respectively to obtain the positive inverter fault positioning flag and the negative inverter fault positioning flag, and obtain the inverter fault positioning flag through the positive inverter fault positioning flag and the negative inverter fault positioning flag.

[0045] The specific implementation method for the above steps in this embodiment is as follows: The half-cycle of the fundamental frequency when the phase current is greater than 0 is called the positive half-cycle of that phase, and the half-cycle when the phase current is less than 0 is called the negative half-cycle of that phase. Furthermore, the current intensity obtained by considering only the positive half-cycle current of phase x is defined as the forward current intensity. The current intensity obtained by considering only the negative half-cycle current of phase x is defined as the negative current intensity. Therefore: When different devices in the same phase fail, the average value of the phase current at the fault will differ. Taking a phase a fault as an example, when the first inverter in phase a fails, the forward current intensity of phase a will be... and negative current intensity have: When the second inverter fails, then: Therefore, if an open-circuit fault occurs simultaneously, no current will flow through that phase. Thus, the forward current intensity of phase a is... and negative current intensity All are 0.

[0046] The device positioning threshold can then be determined by calculating the positive and negative current intensities using the above formula. This allows us to obtain the fault location flag for the x-phase forward inverter. and the fault location flag of the negative inverter in phase x : Thus, when the first inverter of phase x fails, r xp =1、 r xn =0; when the second inverter of phase x fails. rxp =0、 r xn =1; When the first and second inverters of phase x fail simultaneously. r xp =1、 r xn =1. This allows us to obtain the inverter fault location flag for phase x. : When a winding is open-circuited, the inverter fault location flag is directly set to 3.

[0047] S5: Obtain the final fault location flag by using the fault phase flag, inverter fault flag bit, and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

[0048] Furthermore, the objective of this stage is to obtain the final fault location marker, which is then used to diagnose device faults. Specifically, in step S5, the fault phase marker and the inverter fault location marker are weighted and summed, and then multiplied by the inverter fault marker to obtain the final fault location marker.

[0049] The specific implementation method for the above steps in this embodiment is as follows: Finally, the calculation method for the final fault location flag F is as follows: It is important to note that when When the value is ±0.5, a warning is issued for the fault type, indicating that a fault has occurred, but no fault location is performed; when... When the value is ±1, the fault type is clearly distinguished, and fault location is carried out. Thus, based on the correspondence between fault location markers and faults, as shown in Table 1, the fault can be located. Table 1. Correspondence between fault location markers and faults

[0050] Among them, S a1 For the first inverter of phase a, S a2 For the second inverter of phase a, S b1 For the first inverter of phase b, S b2 For the second inverter of phase b, S c1 For the first inverter of phase c, S c2 This is the second inverter of phase c. As you can see, different fault location markers correspond to different fault positions, allowing for the diagnosis of device faults.

[0051] The device fault diagnosis device based on phase current and zero-sequence voltage provided by the present invention will be described below. The device fault diagnosis device based on phase current and zero-sequence voltage described below can be referred to in correspondence with the device fault diagnosis method based on phase current and zero-sequence voltage described above.

[0052] Figure 4 A schematic diagram of a device fault diagnosis system based on phase current and zero-sequence voltage is shown in the example, such as... Figure 4 As shown, the device fault diagnosis method based on phase current and zero-sequence voltage described above includes: Single-phase open-circuit fault flag module 100: used to measure phase current, calculate steady-state value of phase current and instantaneous value of phase current fault, and construct single-phase open-circuit fault flag based on phase current, steady-state value of phase current and instantaneous value of phase current fault; Fault Phase Flag Module 200: When the single-phase open circuit fault flag indicates the presence of a single-phase open circuit fault, it calculates the phase current intensity coefficient and obtains the fault phase flag quantity through the phase current intensity coefficient. Inverter fault flag module 300: used to calculate the zero-sequence voltage, construct the first inverter fault flag bit through the zero-sequence voltage, calculate the phase current per unit value when the first inverter fault flag bit indicates that a fault exists, construct the second inverter fault flag bit through the phase current per unit value, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. Inverter fault location flag module 400: used to calculate the positive current intensity and negative current intensity, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity and negative current intensity; Fault diagnosis module 500: Used to obtain the final fault location flag through the fault phase flag, inverter fault flag bit and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

[0053] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call a computer program in the memory 830 to execute a device fault diagnosis method based on phase current and zero-sequence voltage, the method including: S1: Measure the phase current, calculate the steady-state value of the phase current and the instantaneous value of the phase current during a fault, and construct a single-phase open-circuit fault flag based on the phase current, the steady-state value of the phase current, and the instantaneous value of the phase current during a fault. S2: When the single-phase open circuit fault flag indicates that a single-phase open circuit fault exists, calculate the phase current intensity coefficient and obtain the fault phase flag quantity through the phase current intensity coefficient. S3: Calculate the zero-sequence voltage, construct the first inverter fault flag bit through the zero-sequence voltage, when the first inverter fault flag bit indicates that there is a fault, calculate the per-unit value of the phase current, construct the second inverter fault flag bit through the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. S4: Calculate the positive and negative current intensities, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity, and negative current intensity; S5: Obtain the final fault location flag by using the fault phase flag, inverter fault flag bit, and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

[0054] Furthermore, when the computer program in the aforementioned memory 830 can be implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0055] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0056] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device fault diagnosis method based on phase current and zero-sequence voltage, characterized in that, include: S1: Measure the phase current, calculate the steady-state value of the phase current and the instantaneous value of the phase current during a fault, and construct a single-phase open-circuit fault flag based on the phase current, the steady-state value of the phase current, and the instantaneous value of the phase current during a fault. S2: When the single-phase open circuit fault flag indicates that a single-phase open circuit fault exists, calculate the phase current intensity coefficient and obtain the fault phase flag quantity through the phase current intensity coefficient. In step S2, intermediate variables of device parameters are calculated, and the phase current intensity coefficient, including the first phase current intensity coefficient, the second phase current intensity coefficient, and the third phase current intensity coefficient, is calculated using the intermediate variables of device parameters. Calculate intermediate variables of device parameters : Where R is the stator resistance. It is the q-axis inductance; Then the first phase current intensity coefficient of phase a is calculated. Phase b second phase current intensity coefficient and the third phase current intensity coefficient of phase c : ； S3: Calculate the zero-sequence voltage, construct the first inverter fault flag bit through the zero-sequence voltage, when the first inverter fault flag bit indicates that there is a fault, calculate the per-unit value of the phase current, construct the second inverter fault flag bit through the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. S4: Calculate the positive and negative current intensities, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity, and negative current intensity; S5: Obtain the final fault location flag by using the fault phase flag, inverter fault flag bit, and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

2. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, In step S1, the steady-state value of the phase current and the instantaneous value of the phase current during a fault are calculated, and the phase current is compared with the steady-state value of the phase current and the instantaneous value of the phase current during a fault. When the value of the phase current is between the steady-state value of the phase current and the instantaneous value of the phase current during a fault, the value of the single-phase open-circuit fault flag is 1.

3. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, In step S2, the minimum value of the phase current intensity is determined, and an algebraic difference judgment standard is established through the phase current intensity coefficient. The fault phase indicator quantity is obtained based on the minimum value of the phase current intensity and the algebraic difference judgment standard.

4. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, In step S3, the zero-sequence voltage is calculated to determine the normal voltage of the inverter. When the value of the zero-sequence voltage is not within the range of the normal voltage of the inverter, the first inverter fault flag bit is set to 1; otherwise, it is -1.

5. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, In step S3, a diagnostic threshold is determined, and a detection flag bit is obtained based on the diagnostic threshold and the phase current per unit value. The detection flag bit is sampled multiple times and the average value is calculated to obtain the second inverter fault flag bit.

6. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, Step S4 further includes: S41: Calculate the positive half-cycle current of the device based on the phase current to obtain the positive current intensity; calculate the negative half-cycle current of the device based on the phase current to obtain the negative current intensity; and determine the device positioning threshold. S42: Compare the positive current intensity and negative current intensity with the device positioning threshold respectively to obtain the positive inverter fault positioning flag and the negative inverter fault positioning flag, and obtain the inverter fault positioning flag through the positive inverter fault positioning flag and the negative inverter fault positioning flag.

7. The device fault diagnosis method based on phase current and zero-sequence voltage according to claim 1, characterized in that, In step S5, the fault phase flag value and the inverter fault location flag are weighted and summed, and then multiplied by the inverter fault flag value to obtain the final fault location flag.

8. A device fault diagnosis system based on phase current and zero-sequence voltage, used to execute the device fault diagnosis method based on phase current and zero-sequence voltage as described in any one of claims 1 to 7, characterized in that, include: Single-phase open-circuit fault flag module: used to measure phase current, calculate steady-state value of phase current and instantaneous value of phase current during fault, and construct single-phase open-circuit fault flag based on phase current, steady-state value of phase current and instantaneous value of phase current during fault; Fault Phase Flag Module: When the single-phase open circuit fault flag indicates the presence of a single-phase open circuit fault, it calculates the phase current intensity coefficient and obtains the fault phase flag quantity through the phase current intensity coefficient. Inverter fault flag module: used to calculate the zero-sequence voltage, construct the first inverter fault flag bit based on the zero-sequence voltage, calculate the per-unit value of the phase current when the first inverter fault flag bit indicates a fault, construct the second inverter fault flag bit based on the per-unit value of the phase current, and obtain the inverter fault flag bit through the first inverter fault flag bit and the second inverter fault flag bit. Inverter fault location flag module: used to calculate the positive current intensity and negative current intensity, determine the device location threshold, and construct the inverter fault location flag based on the device location threshold, positive current intensity and negative current intensity; Fault diagnosis module: Used to obtain the final fault location flag through the fault phase flag, inverter fault flag bit and inverter fault location flag bit, and use the final fault location flag to diagnose device faults.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the device fault diagnosis method based on phase current and zero-sequence voltage as described in any one of claims 1 to 7.

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