A PMSM driving system inverter open-circuit fault diagnosis method

Abstract

The application discloses a PMSM driving system inverter open-circuit fault diagnosis method, belongs to the motor driving system fault diagnosis technical field, including: through the pre-constructed mixed logic dynamic model of the inverter in the PMSM driving system, obtain ideal current value;Through the pre-constructed improved superhelix slip film observer, obtain observed current value;The ideal current value and the observed current value are subtracted to obtain three-phase current residual error;According to the three-phase current residual error, a fault diagnosis classification variable is obtained;The three-phase current residual error is averaged on each cycle to obtain three-phase residual error average;According to the relationship between the three-phase residual error average and the preset threshold, a fault diagnosis detection variable is obtained;The fault position of the switching tube can be obtained through the corresponding values of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table.The application overcomes the problem that the introduction of sensors leads to an increase in the failure rate, and can realize accurate positioning of various fault types.

Description

Technical Field

[0001] This invention relates to the field of motor drive system fault diagnosis technology, and in particular to a method for diagnosing open-circuit faults in the inverter of a PMSM drive system. Background Technology

[0002] As a key energy conversion and power control device, the permanent magnet synchronous motor (PMSM) drive system, as one type of motor drive system, has increasingly higher requirements for safety and reliability. The inverter, as the most fragile component in the motor drive system, will threaten the safe operation of the entire permanent magnet synchronous motor drive system if it fails.

[0003] In motor drive systems, inverter faults are classified into short-circuit faults and open-circuit faults. When a short circuit occurs in the inverter, the current in the corresponding branch will be much greater than the rated value, thereby triggering the fast-acting fuse of the branch to generate a rapid protection action, converting the short-circuit fault into an open-circuit fault.

[0004] Currently, analytical model methods for inverter open-circuit fault diagnosis offer high reliability, fast diagnosis speed, and low computational cost. However, the hybrid logic dynamic model method is susceptible to external interference. The sliding diaphragm observer in the state observer method boasts robustness and high observation accuracy, but system chattering issues limit its application. Existing analytical model methods for inverter open-circuit fault diagnosis primarily focus on the quantitative relationship of three-phase current residuals in single-phase and single-phase double-phase open-circuit faults to determine fault location. However, no more effective strategy has been proposed for handling current residuals in two-phase double-phase open-circuit faults. Summary of the Invention

[0005] The purpose of this invention is to provide a method for diagnosing open-circuit faults in PMSM drive system inverters. This method derives classification variables for fault diagnosis based on the three-phase current residuals, and detection variables based on the relationship between the mean of the three-phase residuals and a set threshold. By looking up the values ​​of the classification and detection variables in a fault table, the location of the switching transistor fault can be determined, enabling precise location of various fault types. This invention is achieved through the following technical solutions.

[0006] In a first aspect, the present invention provides a method for diagnosing open-circuit faults in a PMSM drive system inverter, comprising the following:

[0007] Based on the stator resistance and inductance, the ideal current value is obtained through the hybrid logic dynamic model of the inverter in the pre-built PMSM drive system;

[0008] Based on the actual three-phase current, the observed current value is obtained through a pre-constructed improved super-helical sliding diaphragm observer;

[0009] The three-phase current residual is obtained by subtracting the ideal current value from the observed current value.

[0010] The fault diagnosis classification variables are obtained based on the three-phase current residuals.

[0011] The mean value of the three-phase current residuals is obtained by taking the mean value of the three-phase current residuals in each cycle.

[0012] The fault diagnosis detection variables are obtained based on the relationship between the mean value of the three-phase current residuals and the preset threshold.

[0013] The fault location of the switching transistor can be obtained by using the corresponding values ​​of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table.

[0014] In this practical application, the inverter fault diagnosis strategy of this invention proceeds as follows: First, based on the traditional super-spiral sliding film algorithm, an improved super-spiral sliding film observer model is designed to observe the actual current of the motor. Specifically, the hyperbolic function F(s) is used to replace the sign function sign(s), thereby effectively reducing system chattering. A schematic diagram of the hyperbolic function F(s) is shown below. Figure 3 As shown; secondly, the ideal current value output by the inverter hybrid logic dynamic model is subtracted from the observed current value of the improved super-spiral sliding diaphragm observer to obtain the three-phase current residual; then, the mean value of the three-phase current residual and the fault type are calculated using the three-phase current residual; at the same time, the corresponding detection variables are set according to the relationship between the mean value of the three-phase residual and the given threshold, and the classification variables are set according to the quantitative relationship of the three-phase current residual; finally, the fault switch is located according to the correspondence between the values ​​of the detection variables and the classification variables in the fault table.

[0015] Optionally, the expression for the hybrid logic dynamic model of the inverter is:

[0016] ,

[0017] In the formula, For ideal current value, The derivative of the ideal current value, It is a three-phase voltage. and All are third-order diagonal matrices. The diagonal elements are the negatives of the ratio of stator resistance R to stator inductance L. The diagonal elements are the opposite of the reciprocal of the stator inductance L. It is a third-order identity matrix. It is a 3x3 matrix with 2 elements on the diagonal and -1 elements off the diagonal. It is a three-way back electromotive force.

[0018] Optionally, the expression for the improved superspiral gliding membrane observer is:

[0019] ,

[0020] In the formula, For the improved superhelical gliding membrane observer, To observe the differential of the current, To observe the current, This is the actual current. and All are synovial coefficients greater than 0. For the synovial surface, For the disturbance term, Represents the state variables of the PMSM drive system. express The derivative of F(s) is a hyperbolic function of the boundary layer positive gain m = 2.

[0021] Optionally, the expression for the three-phase current residual is:

[0022] ,

[0023] In the formula, For three-phase current residuals, For ideal current value, To observe the current.

[0024] Optionally, the expression for the fault diagnosis classification variable is:

[0025] ,

[0026] In the formula, For the fault diagnosis classification variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates a single-phase single-pipe open circuit fault or a single-phase double-pipe open circuit fault. =2 indicates a two-phase open-circuit fault on opposite sides or a two-phase open-circuit fault on the same side.

[0027] Optionally, the expression for the average value of the three-phase current residuals is:

[0028] ,

[0029] In the formula, This represents the average of the three-phase current residuals. ω is the angular frequency.

[0030] Optionally, the expression for the fault diagnosis detection variable can be obtained based on the relationship between the mean of the three-phase current residuals and the preset threshold:

[0031] ,

[0032] In the formula, For fault diagnosis detection variables, This represents the average of the three-phase current residuals. For the preset threshold, This indicates that the mean of the corresponding current residual is positive. This indicates that the mean of the corresponding current residual is zero. This indicates that the mean of the corresponding current residual is negative, and the variable is detected through fault diagnosis. The three-phase values ​​determine the fault number, which is the number of the fault switch when the inverter malfunctions.

[0033] Optionally, the method further includes, when a single-phase two-transistor open-circuit fault occurs in the inverter, identifying the faulty single-phase two-transistor phase based on auxiliary diagnostic variables, wherein the expression for the auxiliary diagnostic variables is:

[0034] ,

[0035] In the formula, As a diagnostic variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates that the current residual of phase a is the largest, which means that a single-phase double tube open circuit fault has occurred in phase a; =2 indicates that the current residual of phase b is the largest, which means that a single-phase double tube open circuit fault has occurred in phase b. =3 indicates that the current residual of phase c is the largest, which means that a single-phase double-tube open circuit fault has occurred in phase c.

[0036] This invention relates to four fault types: single-phase single-tube open-circuit fault, single-phase double-tube open-circuit fault, two-phase opposite-side double-tube open-circuit fault, and two-phase same-side double-tube open-circuit fault. The single-phase double-tube open-circuit fault type is special because when the inverter experiences a single-phase double-tube open-circuit fault, the fault cannot be directly identified based on the relationship between the three-phase residual mean and a preset threshold. An auxiliary diagnostic variable needs to be added for identification.

[0037] In a second aspect, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, characterized in that, when the computer program / instruction is executed by a processor, it implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method as described in the first aspect.

[0038] Thirdly, the present invention provides a computer program product, including a computer program / instruction, characterized in that, when the computer program / instruction is executed by a processor, it implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method as described in the first aspect.

[0039] Beneficial effects

[0040] (1) The PMSM drive system inverter open circuit fault diagnosis method proposed in this invention utilizes the characteristic that the mean value of the three-phase current residual will change rapidly and stabilize within the corresponding range when an open circuit fault occurs in the inverter. Based on the detection variable defined by this range, it can reflect the fault type and fault location of the switching transistor. This solves the problem that the general hybrid logic dynamic model method only has a good threshold judgment for single-transistor and single-phase faults in the inverter, but the threshold judgment for two-phase faults is relatively vague.

[0041] (2) The PMSM drive system inverter open circuit fault diagnosis method proposed in this invention improves the super-helical sliding film observer and uses hyperbolic function to replace the traditional sign function, thereby further suppressing system chattering on the original basis.

[0042] (3) The PMSM drive system inverter open circuit fault diagnosis method proposed in this invention uses an improved super-spiral sliding film observer to observe the actual three-phase current, which overcomes the problem of increased failure rate caused by the introduction of sensors. It is beneficial to improve the robustness of inverter fault diagnosis in actual operation of motor drive system and can achieve accurate location of multiple fault types. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the PMSM drive system inverter open-circuit fault diagnosis method of the present invention;

[0044] Figure 2 This is a schematic diagram of the PMSM drive system topology of the present invention;

[0045] Figure 3 This is a schematic diagram of the hyperbolic function of the present invention;

[0046] Figure 4 This is a schematic diagram of the three-phase current residual waveform when the fault switch T1 of the present invention is open-circuited;

[0047] Figure 5 This is a schematic diagram of the three-phase current residual waveform when fault switches T1 and T2 of the present invention are open-circuited;

[0048] Figure 6 This is a schematic diagram of the three-phase current residual waveform when fault switches T1 and T4 of the present invention are open-circuited.

[0049] Figure 7This is a schematic diagram of the three-phase current residual waveform when fault switches T1 and T3 of the present invention are open-circuit faults. Detailed Implementation

[0050] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details. In this description, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0051] Example 1

[0052] This embodiment provides a method for diagnosing open-circuit faults in the inverter of a PMSM drive system, including the following:

[0053] Based on the stator resistance and inductance, the ideal current value is obtained through the hybrid logic dynamic model of the inverter in the pre-built PMSM drive system;

[0054] Based on the actual three-phase current, the observed current value is obtained through a pre-constructed improved super-helical sliding diaphragm observer;

[0055] The three-phase current residual is obtained by subtracting the ideal current value from the observed current value.

[0056] The fault diagnosis classification variables are obtained based on the three-phase current residuals.

[0057] The average value of the three-phase current residuals is obtained by taking the mean value of the three-phase current residuals in each cycle.

[0058] The fault diagnosis detection variables are obtained based on the relationship between the mean of the three-phase residuals and the preset threshold.

[0059] The location of the switch tube fault can be obtained by using the corresponding values ​​of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table.

[0060] In this practical application, the inverter fault diagnosis strategy of this invention proceeds as follows: First, based on the traditional super-spiral sliding film algorithm, an improved super-spiral sliding film observer model is designed to observe the actual current of the motor. Specifically, the hyperbolic function F(s) is used to replace the sign function sign(s), thereby effectively reducing system chattering. A schematic diagram of the hyperbolic function F(s) is shown below. Figure 3As shown; secondly, the ideal current value output by the inverter hybrid logic dynamic model is subtracted from the observed current value of the improved super-spiral sliding diaphragm observer to obtain the three-phase current residual; then, the mean value of the three-phase current residual and the fault type are calculated using the three-phase current residual; at the same time, the corresponding detection variables are set according to the relationship between the mean value of the three-phase residual and the given threshold, and the classification variables are set according to the quantitative relationship of the three-phase current residual; finally, the fault switch is located according to the correspondence between the values ​​of the detection variables and the classification variables in the fault table.

[0061] Example 2

[0062] This embodiment takes a three-phase surface-mounted permanent magnet synchronous motor drive system as an example. Based on the PMSM drive system inverter open circuit fault diagnosis method provided by the present invention, the inverter is diagnosed under four open circuit fault conditions: single-phase single-tube open circuit fault, single-phase double-tube open circuit fault, two-phase opposite-side double-tube open circuit fault, and two-phase same-side double-tube open circuit fault. Figure 2 This is a topology diagram of the PMSM drive system. Figure 2 Middle,U dc This is the DC side voltage. T1-T6 are the six switching transistors of the inverter. n is the neutral point, and o is the ground point. The parameters of the three-phase surface-mounted permanent magnet synchronous motor are shown in Table 1.

[0063] Table 1 Basic Parameters of PMSM

[0064]

[0065] Based on Example 1, this example describes the specific implementation process of a PMSM drive system inverter open-circuit fault diagnosis method, such as... Figure 1 As shown, it specifically includes the following:

[0066] In one specific embodiment of the present invention, the expression of the hybrid logic dynamic model of the inverter is:

[0067] ,

[0068] In the formula, For ideal current value, The derivative of the ideal current value, It is a three-phase voltage. and All are third-order diagonal matrices. The diagonal elements are the negatives of the ratio of stator resistance R to stator inductance L. The diagonal elements are the opposite of the reciprocal of the stator inductance L. It is a third-order identity matrix. It is a 3x3 matrix with 2 elements on the diagonal and -1 elements off the diagonal. It is a three-way back electromotive force.

[0069] In one specific embodiment of the present invention, the expression for the improved superspiral synovial observer is:

[0070] ,

[0071] In the formula, For the improved superhelical gliding membrane observer, To observe the differential of the current, To observe the current, This is the actual current. and All are synovial coefficients greater than 0. For the synovial surface, For the disturbance term, Represents the state variables of the PMSM drive system. express The derivative, F(s), is a hyperbolic function of the boundary layer positive gain m = 2. A schematic diagram of the hyperbolic function F(s) is shown below. Figure 3 As shown.

[0072] F(s) is a hyperbolic function, and its expression is:

[0073] ,

[0074] In the formula, m represents the positive gain of the hyperbolic function's boundary layer. By adjusting the value of m, the chattering of the hyperbolic function near zero can be adjusted. Considering both factors, the hyperbolic function with m = 2 is chosen as the switching function to improve convergence speed and reduce chattering.

[0075] In one specific embodiment of the present invention, the expression for the three-phase current residual is:

[0076] ,

[0077] In the formula, This represents the three-phase current residual. For ideal current value, To observe the current.

[0078] In one specific embodiment of the present invention, the expression for the fault diagnosis classification variable is:

[0079] ,

[0080] In the formula, For the fault diagnosis classification variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates a single-phase single-pipe open circuit fault or a single-phase double-pipe open circuit fault. =2 indicates a two-phase open-circuit fault on opposite sides or a two-phase open-circuit fault on the same side.

[0081] In one specific embodiment of the present invention, the expression for the average value of the three-phase current residuals is:

[0082] ,

[0083] In the formula, Angular frequency, This represents the average residual value of the three-phase current.

[0084] In one specific embodiment of the present invention, the expression for the fault diagnosis detection variable is obtained based on the relationship between the average value of the three-phase current residuals and a preset threshold:

[0085] ,

[0086] In the formula, For fault diagnosis detection variables, This represents the average residual value of the three-phase current. For the preset threshold, This indicates that the mean of the corresponding current residual is positive. This indicates that the mean of the corresponding current residual is zero. This indicates that the mean of the corresponding current residual is negative, and the variable is detected through fault diagnosis. The three-phase values ​​determine the fault number, which is the number of the fault switch when the inverter malfunctions.

[0087] In one specific embodiment of the present invention, the method further includes, when a single-phase dual-transistor open-circuit fault occurs in the inverter, identifying the faulty single-phase dual-transistor phase based on auxiliary diagnostic variables, wherein the expression of the auxiliary diagnostic variables is:

[0088] ,

[0089] In the formula, As a diagnostic variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates that the current residual of phase a is the largest, which means that a single-phase double tube open circuit fault has occurred in phase a; =2 indicates that the current residual of phase b is the largest, which means that a single-phase double tube open circuit fault has occurred in phase b. =3 indicates that the current residual of phase c is the largest, which means that a single-phase double-tube open circuit fault has occurred in phase c.

[0090] This invention involves four fault types: single-phase single-tube open-circuit fault, single-phase double-tube open-circuit fault, two-phase opposite-side double-tube open-circuit fault, and two-phase same-side double-tube open-circuit fault. The single-phase double-tube open-circuit fault type is particularly unique because when this fault occurs in the inverter, it cannot be directly identified based on the relationship between the average three-phase residual and a pre-set threshold; auxiliary diagnostic variables need to be added for identification. Table 2 below shows the single-phase fault tables for single-phase single-tube open-circuit and single-phase double-tube open-circuit faults in the motor drive system of this embodiment, and Table 3 shows the two-phase fault tables for two-phase opposite-side double-tube open-circuit faults and two-phase same-side double-tube open-circuit faults in the motor drive system of this embodiment.

[0091] Table 2 Single-phase fault table (l=1)

[0092]

[0093] , and These are the current residuals for phases a, b, and c in the three-phase system, respectively.

[0094] (1) When an open circuit fault occurs in T1, ,therefore This indicates that the fault type represented by l=1 is valid.

[0095] In Table 2, when , , When this occurs, it indicates that a single-phase single-tube open circuit fault has occurred in fault switch T1. This indicates that the mean residual of phase a current is positive. This indicates that the mean of the phase b current residual is negative. This indicates that the mean of the residual current in phase c is negative, such as... Figure 4 The diagram shown illustrates the three-phase current residual waveforms when the fault switch T1 of this invention is open-circuited. When the inverter is not faulty, the three-phase current residuals and their mean values ​​are close to zero.

[0096] (2) When both T1 and T2 experience open-circuit faults, although , and The waveforms all fluctuate around 0, but since the three-phase current residual waveform can still be regarded as a sine wave with equal upper and lower amplitudes, it can be approximated as 0 over one cycle. .

[0097] In Table 2, when , and When using auxiliary variables To determine the location of the fault, such as when When this occurs, it indicates that fault switches T1 and T2 have experienced a single-phase double-tube open-circuit fault.

[0098] When a single-phase dual-transistor open-circuit fault occurs in the inverter, the residual waveforms of the currents in both the faulty and non-faulty phases are close to sine waves, and the quantitative relationship also satisfies that the residual current of the faulty phase is equal to negative twice the residual current of the non-faulty phase. Figure 5 As shown.

[0099] Table 3 Two-phase fault table 2 (l=2)

[0100]

[0101] (3) When both T1 and T4 experience open-circuit faults, due to ≥ 0, ≤ 0, therefore > 0, < 0. And Although the sign is unknown, because its amplitude is very small and fluctuates around 0, it can be approximated as such over one period. ≈ 0. However, when a two-phase open-circuit fault occurs in the inverter, the relationship that the residual current of the faulted phase is equal to negative twice the residual current of the non-faulted phase does not exist, indicating that the fault type represented by l=2 is valid.

[0102] In Table 3, when , , When this occurs, it indicates that fault switches T1 and T4 have experienced a two-phase open circuit fault on opposite sides.

[0103] This indicates that the mean residual of phase a current is positive. This indicates that the mean of the phase b current residual is negative. This indicates that the mean residual of the c-phase current is 0, such as Figure 6 The diagram shown illustrates the three-phase current residual waveforms when fault switches T1 and T4 are open-circuited according to the present invention. When the inverter is not faulty, the three-phase current residuals and their mean values ​​are close to zero.

[0104] (4) When both T1 and T3 experience open-circuit faults, due to ,so .and ,so > 0, > 0. When a dual-phase open-circuit fault occurs in both sides of the inverter, the relationship that the residual current of the faulted phase is equal to negative twice the residual current of the non-faulted phase does not exist, indicating that the fault type represented by l=2 is valid.

[0105] In Table 3, when , , When this occurs, it indicates that fault switches T1 and T3 have experienced a double-sided double-tube open-circuit fault.

[0106] This indicates that the mean residual of phase a current is positive. This indicates that the mean of the phase b current residual is positive. This indicates that the mean of the residual current in phase c is negative, such as... Figure 7 The diagram shown illustrates the three-phase current residual waveforms when fault switches T1 and T3 are open-circuited according to the present invention. When the inverter is not faulty, the three-phase current residuals and their mean values ​​are close to zero.

[0107] Example 3

[0108] This embodiment describes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method as described in Embodiment 1 or 2.

[0109] Example 4

[0110] This embodiment describes a computer program product. When the computer program / instruction is executed by the processor, it implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method as described in Embodiment 1 or 2.

[0111] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0112] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0113] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0114] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0115] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for diagnosing open-circuit faults in the inverter of a PMSM drive system, characterized in that, include: Based on the stator resistance and inductance, the ideal current value is obtained through the hybrid logic dynamic model of the inverter in the pre-built PMSM drive system; Based on the actual three-phase current, the observed current value is obtained through a pre-constructed improved superspiral sliding diaphragm observer; wherein, the improved superspiral sliding diaphragm observer is obtained by replacing the sign function with a hyperbolic function; The three-phase current residual is obtained by subtracting the ideal current value from the observed current value. The fault diagnosis classification variables are obtained based on the three-phase current residuals. The mean value of the three-phase current residuals is obtained by taking the mean value of the three-phase current residuals in each cycle. The fault diagnosis detection variables are obtained based on the relationship between the mean value of the three-phase current residuals and the preset threshold. The fault location of the switching transistor can be obtained by using the corresponding values ​​of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table. The expression for the fault diagnosis classification variable is: ， In the formula, For the fault diagnosis classification variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates a single-phase single-pipe open circuit fault or a single-phase double-pipe open circuit fault. =2 indicates a two-phase open-circuit fault on opposite sides or a two-phase open-circuit fault on the same side. Based on the relationship between the mean value of the three-phase current residuals and the preset threshold, the expression for the fault diagnosis detection variable is as follows: ， In the formula, For fault diagnosis detection variables, This represents the average residual value of the three-phase current. For the preset threshold, This indicates that the mean of the corresponding current residual is positive. This indicates that the mean of the corresponding current residual is zero. This indicates that the mean of the corresponding current residual is negative, and the variable is detected through fault diagnosis. The three-phase values ​​determine the fault number, which is the number of the fault switch when the inverter malfunctions.

2. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 1, characterized in that, The expression for the hybrid logic dynamic model of the inverter is: ， In the formula, For ideal current value, The derivative of the ideal current value, It is a three-phase voltage. and All are third-order diagonal matrices. The diagonal elements are the negatives of the ratio of stator resistance R to stator inductance L. The diagonal elements are the opposite of the reciprocal of the stator inductance L. It is a third-order identity matrix. It is a 3x3 matrix with 2 elements on the diagonal and -1 elements off the diagonal. It is a three-way back electromotive force.

3. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 1, characterized in that, The expression for the improved superspiral slippery surface observer is: ， In the formula, For the improved superhelical gliding membrane observer, To observe the differential of the current, To observe the current, This is the actual current. and All are synovial coefficients greater than 0. For the synovial surface, For the disturbance term, Represents the state variables of the PMSM drive system. express The derivative of F(s) is a hyperbolic function of the boundary layer positive gain m = 2.

4. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 1, characterized in that, The expression for the three-phase current residual is: ， In the formula, For three-phase current residuals, For ideal current value, To observe the current.

5. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 4, characterized in that, The expression for the average value of the three-phase current residuals is: ， In the formula, This represents the average residual value of the three-phase current. ω is the angular frequency.

6. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 1, characterized in that, The method further includes, when a single-phase two-transistor open-circuit fault occurs in the inverter, identifying the faulty single-phase two-transistor phase based on auxiliary diagnostic variables, wherein the expression for the auxiliary diagnostic variables is: ， In the formula, As a diagnostic variable, , and These are the current residuals for phases a, b, and c in the three-phase system, respectively. =1 indicates that the current residual of phase a is the largest, which means that a single-phase double tube open circuit fault has occurred in phase a; =2 indicates that the current residual of phase b is the largest, which means that a single-phase double tube open circuit fault has occurred in phase b. =3 indicates that the current residual of phase c is the largest, which means that a single-phase double-tube open circuit fault has occurred in phase c.

7. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method according to any one of claims 1-6.

8. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the PMSM drive system inverter open-circuit fault diagnosis method according to any one of claims 1-6.

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