Method for diagnosing open-circuit fault of inverter of PMSM (permanent magnet synchronous motor) driving system

Abstract

The invention discloses a PMSM driving system inverter open-circuit fault diagnosis method, and belongs to the technical field of motor driving system fault diagnosis, and the method comprises the steps: obtaining an ideal current value through a pre-constructed hybrid logic dynamic model of an inverter in a PMSM driving system; obtaining an observation current value through a pre-constructed improved super-spiral sliding mode observer; subtracting the ideal current value from the observation current value to obtain a three-phase current residual error; obtaining a fault diagnosis classification variable according to the three-phase current residual error; averaging the three-phase current residual errors in each period to obtain a three-phase residual error average value; obtaining a fault diagnosis detection variable according to the relationship between the three-phase residual mean value and a preset threshold value; and obtaining the fault position of the switching tube through the corresponding values of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table. According to the method, the problem that the fault rate is increased due to introduction of a sensor is solved, and accurate positioning of various fault types can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of motor drive system fault diagnosis, in particular to a PMSM drive system inverter open circuit fault diagnosis method. BACKGROUND

[0002] As a kind of key energy conversion and power control device, permanent magnet synchronous motor (PMSM) drive system as a kind of motor drive system, the safety and reliability of motor drive system is more and more high, and inverter as the most fragile component in motor drive system, once fault will threaten the safe operation of the entire permanent magnet synchronous motor drive system.

[0003] In motor drive system, the fault type of inverter is divided into short circuit fault and open circuit fault. When the inverter occurs short circuit, the current of corresponding branch will be much larger than the rated value, so as to trigger the fast fuse of branch to produce fast protection action, and convert short circuit fault into open circuit fault.

[0004] At present, the reliability of inverter open circuit fault diagnosis using analytical model method is high, the diagnosis speed is fast, and the calculation cost is low, but the hybrid logic dynamic model method in it is easy to be affected by external interference and other factors. The sliding membrane observer in state observer method has the advantages of good robustness and high observation accuracy, but the system chattering problem limits its application. The existing technology using analytical model method for inverter open circuit fault diagnosis is mostly aimed at the three-phase current residual quantity relationship of single tube open circuit and single-phase double tube open circuit fault, and the fault position is judged, but the current residual for double-phase double tube open circuit fault has not yet proposed a more effective processing strategy. SUMMARY

[0005] The purpose of the present application is to provide a PMSM drive system inverter open circuit fault diagnosis method, according to the three-phase current residual, the classification variable of fault diagnosis is obtained, according to the relationship between three-phase residual mean value and set threshold, the detection variable of fault diagnosis is obtained, through the value of fault classification variable and fault detection variable, the fault table is inquired to obtain the fault position of switch tube, which can realize accurate positioning of various fault types. The present application is realized by the following technical scheme.

[0006] In the first aspect, the present application provides a PMSM drive system inverter open circuit fault diagnosis method, including the following contents:

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

[0008] According to the actual three-phase current, the observed current value is obtained through the pre-built improved super spiral synovial observer;

[0009] Subtracting the ideal current value from the observed current value to obtain a three-phase current residual;

[0010] Obtaining a fault diagnosis classification variable according to the three-phase current residual;

[0011] Calculating the average of the three-phase current residuals in each cycle to obtain a three-phase current residual mean;

[0012] Obtaining a fault diagnosis detection variable based on a relationship between the three-phase current residual mean and a preset threshold;

[0013] The fault position of the switch tube is 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 the present invention is as follows: first, based on the traditional super-spiral synovial algorithm, an improved super-spiral synovial 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 the chattering of the system. The schematic diagram of the hyperbolic function F(s) is shown in FIG. 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 film observer to obtain the three-phase current residual; then the three-phase current residual is used to calculate the three-phase current residual mean and detect the fault type, and at the same time, the corresponding detection variable is set according to the size relationship between the three-phase residual mean and the given threshold, and the classification variable is set according to the quantitative relationship corresponding to the three-phase current residual; finally, the faulty switch tube is located according to the corresponding relationship between the detection variable and the classification variable in the fault table.

[0015] Optionally, the hybrid logic dynamic model of the inverter is expressed as:

[0016] ,

[0017] Where, is the ideal current value, is the differential of the ideal current value, is the three-phase voltage, and are all third-order diagonal matrices, The diagonal elements of are the opposite of the ratio of stator resistance R to stator inductance L. The diagonal elements of are the opposite of the reciprocal of the stator inductance L. is the third-order identity matrix, is a third-order matrix with diagonal elements equal to 2 and off-diagonal elements equal to -1. is a three-phase counter electromotive force.

[0018] Optionally, the expression of the improved super-twisted sliding mode observer is:

[0019] ,

[0020] wherein, is the improved super-twisted sliding mode observer, is a differential of the observed current, is the observed current, is an actual current, and are both sliding mode coefficients greater than 0, is a sliding mode surface, is a disturbance term, represents a state variable of the PMSM driving system, represents a differential of F(s), and F(s) is a hyperbolic function of a boundary layer positive gain m = 2.

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

[0022] ,

[0023] wherein, is the three-phase current residual, is an ideal current value, is the observed current.

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

[0025] ,

[0026] wherein, is the fault diagnosis classification variable, , and are current residuals of a phase a, a phase b and a phase c in three phases, respectively; = 1 indicates that a single-phase single-tube open circuit fault or a single-phase double-tube open circuit fault occurs, = 2 indicates that a double-phase different side double-tube open circuit fault or a double-phase same side double-tube open circuit fault occurs.

[0027] Optionally, the expression of the three-phase current residual average is:

[0028] ,

[0029] wherein, is the three-phase current residual average, is an angular frequency.

[0030] Optionally, the expression of the fault diagnosis detection variable is obtained according to the relationship between the three-phase current residual mean value and the preset threshold value, and is as follows:

[0031]

[0032] In the formula, is a fault diagnosis detection variable, is a three-phase current residual mean value, is a preset threshold value, represents that the corresponding current residual mean value is positive, represents that the corresponding current residual mean value is zero, represents that the corresponding current residual mean value is negative, and the fault number is determined by the fault diagnosis detection variable The value of the three phases determines the fault number, which is the number of the fault switch when the inverter fails.

[0033] Optionally, the method further comprises, when the inverter has a single-phase double-tube open circuit fault, identifying a single-phase double-tube fault phase according to an auxiliary diagnosis variable, and the expression of the auxiliary diagnosis variable is as follows:

[0034]

[0035] In the formula, is a diagnosis variable, and are current residuals of a phase, a b phase and a c phase in the three phases, =1 represents that the current residual of the a phase is the largest, indicating that the a phase has a single-phase double-tube open circuit fault; =2 represents that the current residual of the b phase is the largest, indicating that the b phase has a single-phase double-tube open circuit fault; =3 represents that the current residual of the c phase is the largest, indicating that the c phase has a single-phase double-tube open circuit fault.

[0036] The present application relates to four types of faults, a single-phase single-tube open circuit fault, a single-phase double-tube open circuit fault, a double-phase different-side double-tube open circuit fault and a double-phase same-side double-tube open circuit fault. The single-phase double-tube open circuit fault is relatively special, because when the inverter has a single-phase double-tube open circuit fault, the fault cannot be directly identified according to the relationship between the three-phase residual mean value and the preset threshold value, and an auxiliary diagnosis variable needs to be added for identification.

[0037] In the second aspect, the present application provides a computer readable storage medium, which stores a computer program / instruction, and the computer program / instruction is executed by a processor to realize the steps of the PMSM driving system inverter open circuit fault diagnosis method according to the first aspect.

[0038] ​​​In a third aspect, the present application provides a computer program product comprising computer programs / instructions, characterized in that the computer programs / instructions, when executed by a processor, implement the steps of the PMSM drive system inverter open-circuit fault diagnosis method according to the first aspect.

[0039] Advantages

[0040] (1) The PMSM drive system inverter open-circuit fault diagnosis method provided by the present application uses the characteristic that the mean value of three-phase current residuals will change rapidly and stabilize in the corresponding range when the inverter has an open-circuit fault, and the detection variable defined according to this range can reflect the fault type and fault position of the switch tube, thereby solving the problem that the general hybrid logic dynamic model method has a relatively fuzzy threshold value judgment for double-phase faults, while having a good threshold value judgment for single-tube and single-phase faults of the inverter.

[0041] (2) The PMSM drive system inverter open-circuit fault diagnosis method provided by the present application further suppresses system chattering by improving the super-spiral sliding membrane observer and using hyperbolic functions instead of traditional sign functions.

[0042] (3) The PMSM drive system inverter open-circuit fault diagnosis method provided by the present application uses the improved super-spiral sliding membrane observer to observe the three-phase actual current, thereby overcoming the problem of increased failure rate caused by the introduction of sensors, and being conducive to improving the robustness of inverter fault diagnosis in the actual operation of the motor drive system, and enabling accurate positioning of various fault types. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flowchart of the PMSM drive system inverter open-circuit fault diagnosis method of the present application;

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

[0045] Figure 3 is a diagram of the hyperbolic function of the present application;

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

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

[0048] Figure 6 is a diagram of the three-phase current residual waveform when the fault switches T1 and T4 are open-circuited according to the present application;

[0049] Figure 7is a schematic diagram of three-phase current residual waveform when the fault switches T1 and T3 are open-circuit faults of the application. DETAILED DESCRIPTION

[0050] Further described below in combination with the drawings and specific embodiments. In the description of the application, it is understood that the terms "first", "second", etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second", etc. can be explicitly or implicitly included one or more of the features.

[0051] Embodiment 1 The embodiment provides an inverter open-circuit fault diagnosis method of a PMSM driving system, and includes the following contents:

[0052] According to the stator resistance and inductance, the ideal current value is obtained through the pre-constructed hybrid logic dynamic model of the inverter in the PMSM driving system;

[0053] According to the three-phase actual current, the observed current value is obtained through the pre-constructed improved super-spiral sliding film observer;

[0054] The three-phase current residual is obtained by subtracting the ideal current value from the observed current value;

[0055] The fault diagnosis classification variable is obtained according to the three-phase current residual;

[0056] The three-phase residual mean value is obtained by averaging the three-phase current residual in each cycle;

[0057] The fault diagnosis detection variable is obtained according to the relationship between the three-phase residual mean value and the preset threshold value;

[0058] The switch tube fault position can be obtained through the corresponding values of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table.

[0059] In the practical application, the steps of the inverter fault diagnosis strategy of the application are as follows: first, an improved super-spiral sliding film observer model is designed based on the traditional super-spiral sliding film algorithm to observe the actual current of the motor, specifically, the hyperbolic function F(s) is used instead of the sign function sign(s), thereby effectively reducing the chattering of the system, and a schematic diagram of the hyperbolic function F(s) is as follows: Figure 3As shown in Fig. 1, firstly, the ideal current value outputted by the hybrid logic dynamic model of the inverter is calculated; secondly, the ideal current value outputted by the hybrid logic dynamic model of the inverter is subtracted from the observed current value outputted by the improved super-spiral sliding mode observer to obtain three-phase current residuals; then, the three-phase current residual mean value is calculated by using the three-phase current residuals, and the fault type is detected, meanwhile, the corresponding detection variable is set according to the size relationship between the three-phase residual mean value and the given threshold value, and the classification variable is set according to the corresponding number relationship of the three-phase current residuals; finally, the fault switch tube is located according to the corresponding relationship between the values of the detection variable and the classification variable in the fault table.

[0060] Embodiment 2 In this embodiment, the three-phase surface-mounted permanent magnet synchronous motor driving system is taken as an example, and the inverter open-circuit fault diagnosis method provided by the present application is used to diagnose the inverter open-circuit fault in four conditions, i.e., single-phase single-tube open-circuit fault, single-phase double-tube open-circuit fault, double-phase different side double-tube open-circuit fault and double-phase same side double-tube open-circuit fault. Figure 2 The topology diagram of the PMSM driving system is shown in Fig. 2. Figure 2 In Fig. 2, U is the DC side voltage, T1-T6 are six switch tubes of the inverter, n is the neutral point, and o is the grounding point. dc The parameters of the three-phase surface-mounted permanent magnet synchronous motor are shown in Table 1.

[0061] Table 1 Basic parameters of PMSM

[0062] Based on the embodiment 1, this embodiment introduces a specific implementation process of the inverter open-circuit fault diagnosis method of the PMSM driving system, as shown in Fig. 3, which specifically includes the following contents. Figure 1

[0063] In one specific embodiment of the present application, the expression of the hybrid logic dynamic model of the inverter is as follows:

[0064]

[0065] In the formula, i is the ideal current value, is the differential of the ideal current value, is the three-phase voltage, and are all three-order diagonal matrices, the diagonal elements of are the inverse numbers of the ratio of the stator resistance R to the stator inductance L, the diagonal elements of are the inverse numbers of the reciprocal of the stator inductance L, is a three-order unit matrix, is a three-order matrix with 2 as the diagonal elements and -1 as the non-diagonal elements, is the three-phase counter electromotive force.

[0066] ​​​In an embodiment of the present application, the expression of the improved super-twisting sliding mode observer is:

[0067] ,

[0068] wherein, is the improved super-twisting sliding mode observer, is the differential of the observed current, is the observed current, is the actual current, and are sliding mode coefficients greater than 0, is the sliding surface, is the perturbation term, represents the state variable of the PMSM driving system, represents the differential of, F(s) is the hyperbolic function of the positive gain m = 2 of the boundary layer, and a schematic diagram of the hyperbolic function F(s) is shown in Figure 3 .

[0069] F(s) is a hyperbolic function, and its expression is:

[0070] ,

[0071] wherein, m is a positive gain for adjusting the boundary layer of the hyperbolic function. By adjusting the value of m, the dithering of the hyperbolic function near zero can be adjusted. Considering comprehensively, the hyperbolic function with m = 2 is selected as the switching function to improve the convergence speed and reduce the chattering.

[0072] In an embodiment of the present application, the expression of the three-phase current residual error is:

[0073] ,

[0074] wherein, represents the three-phase current residual error, is the ideal current value, is the observed current.

[0075] In an embodiment of the present application, the expression of the fault diagnosis classification variable is:

[0076] ,

[0077] wherein, is the fault diagnosis classification variable, , and are the current residual errors of phase a, phase b and phase c in the three phases, respectively; =1 represents that a single-phase single-tube open-circuit fault or a single-phase double-tube open-circuit fault occurs, =2 represents that a double-phase different-side double-tube open-circuit fault or a double-phase same-side double-tube open-circuit fault occurs.

[0078] In one specific embodiment of the embodiment of the present application, the expression of the three-phase current residual mean value is:

[0079] ,

[0080] In the expression, ω is an angular frequency, is the three-phase current residual mean value.

[0081] In one specific embodiment of the embodiment of the present application, the expression of the fault diagnosis detection variable according to the relationship between the three-phase current residual mean value and a preset threshold value is:

[0082] ,

[0083] In the expression, ω is an angular frequency, is the fault diagnosis detection variable, is the three-phase current residual mean value, is the preset threshold value, represents that the corresponding current residual mean value is positive, represents that the corresponding current residual mean value is zero, represents that the corresponding current residual mean value is negative, and the fault number is determined by the fault diagnosis detection variable The fault number is the number of the fault switch when the inverter fails.

[0084] In one specific embodiment of the embodiment of the present application, the method further comprises, when the inverter fails in a single-phase double-tube open-circuit fault, identifying a single-phase double-tube fault phase according to an auxiliary diagnosis variable, and the expression of the auxiliary diagnosis variable is:

[0085] ,

[0086] In the expression, ω is an angular frequency, is the diagnosis variable, , and are the current residuals of phases a, b and c in the three phases, respectively, =1 represents that the current residual of phase a is the largest, indicating that a single-phase double-tube open-circuit fault occurs in phase a; =2 represents that the current residual of phase b is the largest, indicating that a single-phase double-tube open-circuit fault occurs in phase b; =3 represents that the current residual of phase c is the largest, indicating that a single-phase double-tube open-circuit fault occurs in phase c.

[0087] ​The present application relates to four fault types in total, single-phase single-tube open-circuit fault, single-phase double-tube open-circuit fault, double-phase different-side double-tube open-circuit fault and double-same-side double-tube open-circuit fault. The single-phase double-tube open-circuit fault type is relatively special, because when the inverter has the single-phase double-tube open-circuit fault, the fault cannot be directly identified according to the relationship between the three-phase residual mean value and the pre-set threshold, and an auxiliary diagnostic variable needs to be added for identification. Table 2 below is a single-phase fault table of the motor drive system of the embodiment having the single-phase single-tube open-circuit fault and the single-phase double-tube open-circuit fault, and Table 3 is a double-phase fault table of the motor drive system of the embodiment having the double-phase different-side double-tube open-circuit fault and the double-same-side double-tube open-circuit fault.

[0088] Table 2 Single-phase fault table (l=1)

[0089] 、 and are the current residuals of the a-phase, b-phase and c-phase in the three-phase respectively.

[0090] (1) When T1 has an open-circuit fault, thus , it is indicated that the fault type represented by l=1 is established.

[0091] In Table 2, when , , , it is indicated that the fault switch T1 has the single-phase single-tube open-circuit fault. It is indicated that the a-phase current residual mean value is a positive number, it is indicated that the b-phase current residual mean value is a negative number, it is indicated that the c-phase current residual mean value is a negative number, as shown in Figure 4 , which is a three-phase current residual waveform schematic diagram when the fault switch T1 of the present application has an open-circuit fault. When the inverter does not have a fault, the three-phase current residual and the mean value thereof are close to zero.

[0092] (2) When T1 and T2 have open-circuit faults at the same time, although , and all fluctuate around 0, because the three-phase current residual waveform can still be regarded as a sine wave with equal amplitude, it can be approximately considered that .

[0093] In Table 2, when , and , the auxiliary variable is used to judge the position of the fault, such as when When , it indicates that the fault switches T1 and T2 have a single-phase double-tube open circuit fault.

[0094] When a single-phase double-tube open-circuit fault occurs in the inverter, the residual current waveforms of the fault phase and the non-fault phase are close to sine waves, and the quantitative relationship also satisfies that the residual current of the fault phase is equal to negative two times the residual current of the non-fault phase, such as Figure 5 shown.

[0095] Table 3 Two-phase fault table 2 (l=2)

[0096] (3) When T1 and T4 have open circuit faults at the same time, due to ≥ 0, ≤ 0, so > 0, < 0. Although the sign is unknown, because its amplitude is very small and fluctuates around 0, it can be approximately considered that ≈ 0. However, when a dual-phase, dual-side open-circuit fault occurs in the inverter, the relationship that the fault phase current residual is equal to negative two times the non-fault phase current residual does not exist, indicating that the fault type represented by l=2 is established.

[0097] In Table 3, when 、 、 When , it indicates that the faulty switches T1 and T4 have a double-phase, double-side open-circuit fault.

[0098] , indicating that the residual mean of phase a current is positive. This indicates that the mean of the residual current of phase b is negative. This indicates that the mean of the residual current of phase C is 0, such as Figure 6 FIG2 is a schematic diagram of the three-phase current residual waveform when the fault switches T1 and T4 are open-circuited. When the inverter is not faulty, the three-phase current residual and its mean are close to zero.

[0099] (4) When T1 and T3 have open circuit faults at the same time, due to ,so .and ,so > 0, > 0. When a dual-side double-switch open-circuit fault occurs in the inverter, the relationship that the fault phase current residual is equal to negative two times the non-fault phase current residual does not exist, indicating that the fault type represented by l=2 is established.

[0100] In Table 3, when 、 、 At this time, it is shown that the fault switches T1 and T3 have the double same side double tube open circuit fault.

[0101] It is shown that the a-phase current residual mean value is positive number, It is shown that the b-phase current residual mean value is positive number, It is shown that the c-phase current residual mean value is negative number, and Figure 7 As shown in the figure, it is a three-phase current residual waveform schematic diagram when the fault switches T1 and T3 have the open circuit fault. When the inverter does not have the fault, the three-phase current residual and the mean value thereof are close to zero.

[0102] Embodiment 3 This embodiment introduces a computer readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the PMSM driving system inverter open circuit fault diagnosis method as introduced in Embodiment 1 or 2 are realized.

[0103] Embodiment 4 This embodiment introduces a computer program product. When the computer program / instruction is executed by a processor, the steps of the PMSM driving system inverter open circuit fault diagnosis method as introduced in Embodiment 1 or 2 are realized.

[0104] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0105] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The device for implementing the functions specified in one or more flows and / or blocks. Figure 1 The device for implementing the functions specified in one or more flows and / or blocks.

[0106] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed embodiments, can be implemented as hardware logic circuits, such as an integrated circuit chip (e.g., an ASIC) or Field Programmable Gate Arrays (FPGAs). In these embodiments, the hardware logic circuits perform the functions of flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed embodiments, can be implemented as hardware logic circuits, such as an integrated circuit chip (e.g., an ASIC) or Field Programmable Gate Arrays (FPGAs). In these embodiments, the hardware logic circuits perform the functions of flow

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions of flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed embodiments, can be implemented as hardware logic circuits, such as an integrated circuit chip (e.g., an ASIC) or Field Programmable Gate Arrays (FPGAs). In these embodiments, the hardware logic circuits perform the functions of flow Figure 1 The functions of a flow or multiple flows and / or a block or multiple blocks in conjunction with the disclosed embodiments, can be implemented as hardware logic circuits, such as an integrated circuit chip (e.g., an ASIC) or Field Programmable Gate Arrays (FPGAs). In these embodiments, the hardware logic circuits perform the functions of flow

[0108] The above embodiments of the present application have been described with reference to the accompanying drawings, wherein the embodiments are merely the preferred embodiments of the present application, and thus are not intended to limit the present application. The ordinary skilled in the art can make many modifications and variations without departing from the scope of the present application, and these modifications and variations should be within the scope of the present application. Therefore, the scope of the present application should be determined by the principles, characteristics, and novel features disclosed in the application rather than by the embodiments.

Claims

1. A PMSM drive system inverter open-circuit fault diagnosis method, characterized in that, The method comprises the following steps: According to the stator resistance and inductance, the ideal current value is obtained by pre-building the hybrid logic dynamic model of the inverter in the PMSM driving system; According to the three-phase actual current, the observed current value is obtained by pre-building the improved super-spiral sliding film observer; The three-phase current residual is obtained by subtracting the observed current value from the ideal current value; The fault diagnosis classification variable is obtained according to the three-phase current residual; The three-phase current residual average is obtained by averaging the three-phase current residual in each cycle; The fault diagnosis detection variable is obtained according to the relationship between the three-phase current residual average and the preset threshold value; The switch tube fault position is obtained by the corresponding values of the fault diagnosis classification variable and the fault diagnosis detection variable in the fault table.

2. The PMSM drive system inverter open-circuit fault diagnosis method according to claim 1, characterized by, The expression of the hybrid logic dynamic model of the inverter is: ， wherein is the ideal current value, is the differential of the ideal current value, is the three-phase voltage, and are all three-by-three diagonal matrices, the diagonal elements of which are the negative of the ratio of the stator resistance R to the stator inductance L, the diagonal elements of which are the negative of the inverse of the stator inductance L, is a three-by-three identity matrix, is a three-by-three matrix whose diagonal elements are two and whose off-diagonal elements are minus one, is the three-phase counter-electromotive force.

3. The PMSM drive system inverter open-circuit fault diagnostic method of claim 1, wherein, The expression of the improved super-spiral sliding film observer is: ， wherein is the improved super-turbulence skin observer, is the derivative of the observed current, is the observed current, is the actual current, and are skin coefficients greater than 0, is the skin surface, is the perturbation term, denotes the state variable of the PMSM drive system, denotes the derivative of F(s), F(s) being the hyperbolic function of the boundary layer positive gain m = 2.

4. The PMSM drive system inverter open-circuit fault diagnostic method of claim 1, characterized by, The expression of the three-phase current residual is: ， wherein is a three-phase current residual, is an ideal current value, is an observed current.

5. The PMSM drive system inverter open-circuit fault diagnostic method according to claim 4, characterized by, The expression of the fault diagnosis classification variable is: ， In the formula, is the fault diagnosis classification variable, , and are the current residual errors of the a-phase, b-phase and c-phase in the three-phase respectively; =1 indicates that a single-phase single-tube open circuit fault or a single-phase double-tube open circuit fault occurs, =2 indicates that a double-phase different-side double-tube open circuit fault or a double-phase same-side double-tube open circuit fault occurs.

6. The PMSM drive system inverter open-circuit fault diagnostic method according to claim 4, characterized by, The expression of the three-phase current residual average is: ， wherein is the three-phase current residual mean value, is the angular frequency.

7. The PMSM drive system inverter open-circuit fault diagnostic method of claim 1, wherein, The expression of the fault diagnosis detection variable is obtained according to the relationship between the three-phase current residual average and the preset threshold value: ， wherein, is a fault diagnosis detection variable, is a three-phase current residual mean value, is a preset threshold value, indicates that the corresponding current residual mean value is positive, indicates that the corresponding current residual mean value is zero, indicates that the corresponding current residual mean value is negative, through the fault diagnosis detection variable the value of the three phases determines a fault number, which is the number of the fault switch when the inverter is faulty.

8. The PMSM drive system inverter open-circuit fault diagnostic method according to claim 7, characterized by, The method further comprises, when the inverter occurs single-phase double-tube open circuit fault, identifying the single-phase double-tube fault phase according to the auxiliary diagnosis variable, and the expression of the auxiliary diagnosis variable is: ， In the formula, is a diagnostic variable, , and are current residual errors of phases a, b and c in the three-phase system respectively, =1 indicates that the current residual error of phase a is the largest, which means that a single-phase double-tube open circuit fault occurs in phase a; =2 indicates that the current residual error of phase b is the largest, which means that a single-phase double-tube open circuit fault occurs in phase b; =3 indicates that the current residual error of phase c is the largest, which means that a single-phase double-tube open circuit fault occurs in phase c.

9. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to realize the steps of the PMSM driving system inverter open circuit fault diagnosis method of any one of claims 1-8.

10. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to realize the steps of the PMSM driving system inverter open circuit fault diagnosis method of any one of claims 1-8.

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