Highly generalizable converter open-circuit fault diagnosis method for motor drive systems

Abstract

This invention discloses a highly generalizable method for diagnosing open-circuit faults in multi-transistor converters of motor drive systems. This method addresses open-circuit faults in power devices caused by overcurrent surges, poor heat dissipation, and other factors, preventing damage to the motor and power grid equipment caused by output current distortion and increased torque ripple. The method analyzes the retention characteristics of the positive and negative regions of the three-phase stator current under steady-state operating conditions to construct a fault location function, and combines auxiliary variables to accurately distinguish between single-power and dual-power device open-circuit faults. This invention enables rapid location and accurate identification of complex open-circuit faults such as those in opposite phases on the same side or in opposite phases on opposite sides. It offers advantages such as high diagnostic accuracy, strong ability to distinguish mixed faults, and non-invasiveness, making it suitable for motor drive systems with high requirements for operational reliability and fault tolerance.

Description

Technical Field

[0001] This invention belongs to the field of fault diagnosis technology for motor drive systems, and specifically relates to a highly generalizable method for diagnosing open-circuit faults in multi-tube converters of motor drive systems. Background Technology

[0002] Inverters are widely used in various motor drive systems. Their internal power devices operate under complex and harsh conditions for extended periods, making them highly susceptible to open-circuit faults. Currently, existing methods for diagnosing inverter open-circuit faults can be mainly categorized into three types: analytical model-based, signal processing-based, and data-driven. Signal processing-based methods focus on waveform transformation of electrical signals to extract hidden fault characteristics, thus eliminating the reliance on precise models.

[0003] Diagnostic methods based on the retention characteristics of the positive and negative regions of steady-state stator current have attracted widespread attention due to their advantages such as no need for additional sensors, low cost, and ease of implementation. However, existing diagnostic methods based on current signals still have significant limitations when dealing with mixed open-circuit faults: on the one hand, single-tube open-circuit faults and out-of-phase bridge arm double-tube open-circuit faults have both overlapping and different current characteristics, making it difficult for traditional diagnostic methods to effectively distinguish between these two types of faults, which easily leads to misdiagnosis; on the other hand, the influence of controller regulation can cause the fault current trajectory to present multiple possibilities, resulting in insufficient generalization accuracy of conventional diagnostic algorithms. Summary of the Invention

[0004] In view of the above, the present invention provides a highly generalizable method for diagnosing open-circuit faults in multi-tube converters of motor drive systems. It can quickly locate and accurately identify complex open-circuit faults such as cross-phase same-side bridge arms and cross-phase cross-side bridge arms. It has the advantages of high diagnostic accuracy, strong ability to distinguish mixed faults, and non-invasiveness.

[0005] A highly generalizable method for diagnosing open-circuit faults in multi-tube converters of motor drive systems includes the following steps: (1) Under stable operating conditions, the stator current under healthy and fault conditions is analyzed separately, and the retention characteristics of the positive and negative regions of the stator current are calculated. (2) Define fault diagnosis variables based on the characteristic quantities of the retention of stator current in the positive and negative regions. and r This is used to diagnose the type of fault in the converter; (3) Define auxiliary diagnostic variables for heterogeneous dual-tube fault types and This allows for precise location of faulty power devices in the converter.

[0006] Furthermore, in step (1), the retention characteristic of the stator current in the positive and negative regions is calculated using the following formula:

[0007]

[0008] in: for x Characteristic quantity of retention of positive and negative regions of phase-positive stator current. for x Characteristic quantity of retention of phase negative stator current in positive and negative regions. for x Phase stator current, x =a,b,c.

[0009] Furthermore, in step (2), the fault diagnosis variables The expression is as follows:

[0010]

[0011] in: , , This indicates that the average value is taken within the fundamental period. This refers to the stator current amplitude. c The threshold value is used.

[0012] Furthermore, in step (2), the fault diagnosis variables r The expression is as follows:

[0013]

[0014] in: for x Phase fault current, i.e., the current after the fault x Phase stator current, This indicates that the average value is taken within the fundamental period.

[0015] Furthermore, in step (2), fault diagnosis variables are first detected. ,like This means determining that there is an open-circuit fault in the power device of the converter; then further detecting fault diagnosis variables. r ,like r >2 indicates that the converter has an open-circuit fault in two out-of-phase transistors; if r If the value is ≤2, it indicates that the converter has an open circuit fault in a single-phase power device.

[0016] Furthermore, in step (3), the auxiliary diagnostic variables and The expression is as follows:

[0017]

[0018]

[0019] in: , , This indicates that the average value is taken within the fundamental period. This refers to the stator current amplitude. The threshold value is used.

[0020] Furthermore, in step (3), if the auxiliary diagnostic variables , Then determine S a1 and S b1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S b1 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S b2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S b1 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S b2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S b2 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S b1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S b2 and S c1 Open circuit fault; Wherein: S a1 and S a2 S represents the power devices of the upper and lower arms of phase a of the converter, respectively. b1 and S b2 S represents the power devices of the upper and lower arms of phase b of the converter, respectively. c1 and S c2 These represent the power devices of the upper and lower arms of the C-phase converter, respectively.

[0021] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the above-described highly generalizable method for diagnosing open-circuit faults in multi-tube converters of a motor drive system.

[0022] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned highly generalizable method for diagnosing open-circuit faults in multi-tube converters of a motor drive system.

[0023] Based on the above technical solution, the present invention has the following beneficial technical effects: 1. This invention establishes a dual-tube open-circuit fault model that considers the controller's regulatory effect, thereby achieving a quantitative characterization of unmodeled dynamics and laying a theoretical foundation for high-generalization-accuracy dual-tube open-circuit fault diagnosis.

[0024] 2. The fault type identification method based on the retention characteristics of the positive and negative regions of stator current in this invention can accurately identify fault types, has high reliability, and the periodicity characteristics make the algorithm more robust.

[0025] 3. The fault device location method based on the retention characteristics of the positive and negative regions of stator current in this invention has strong speed, can quickly detect faults and quickly locate faulty devices, requires few signals, is simple in method, is easy to apply in engineering, and can effectively improve the generalization accuracy of diagnostic algorithms. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the method for diagnosing open-circuit faults in the converter of a motor drive system according to the present invention.

[0027] Figure 2 This is a schematic diagram of the circuit topology of a two-level motor drive system.

[0028] Figure 3 For power devices S a1 and S a2 Simultaneously, the three-phase fault current diagram after the circuit is opened is shown, where (a) corresponds to the fault current waveform of phase a, (b) corresponds to the fault current waveform of phase b, and (c) corresponds to the fault current waveform of phase c.

[0029] Figure 4 For power devices S b1 A schematic diagram of the three-phase fault current after the circuit is opened, where (a) corresponds to the fault current waveform of phase a, (b) corresponds to the fault current waveform of phase b, and (c) corresponds to the fault current waveform of phase c.

[0030] Figure 5 For power devices S a1 and S b2 A schematic diagram of three-phase fault current under open-circuit conditions.

[0031] Figure 6 This is a schematic diagram of the fault diagnosis algorithm in an embodiment of the present invention.

[0032] Figure 7 This is a schematic diagram of the experimental waveforms for fault diagnosis of two open-circuit tubes on the same side of different sides in an embodiment of the present invention, where the horizontal axis represents time. t The vertical axis represents the per-unit value. Detailed Implementation

[0033] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 1 As shown, this embodiment provides a highly generalizable method for diagnosing open-circuit faults in the converter of a motor drive system, including the following steps: (1) By analyzing the stator current under healthy and fault conditions respectively, the characteristics of the retention of the positive and negative regions of the stator current under the single-phase double tube open circuit condition, the characteristics of the open circuit fault of the power device of the same side arm of the double phase, and the characteristics of the open circuit fault of the power device of the opposite side arm of the double phase are obtained.

[0035] S11: Calculate the steady-state current value after the fault by utilizing the equivalent relationship of the conservation of average torque before and after the fault.

[0036] The circuit topology of a two-level motor drive system is as follows: Figure 2 As shown, assume the initial phase of phase a current is 0 and the amplitude is... I m The rotor position angle is i The expression for the three-phase stator current under healthy conditions is:

[0037] In the formula: x ∈{a, b, c}, , , .

[0038] S a1 and S a2 Simultaneously, the three-phase current after the circuit is opened is as follows: Figure 3 As shown, Figure 3 In the diagram, (a) corresponds to the fault current waveform of phase a, (b) corresponds to the fault current waveform of phase b, and (c) corresponds to the fault current waveform of phase c. i xf_H and i xf_L Fault current i xf The steady-state value and the limiting minimum value.

[0039] Single-phase power device S a1 and S a2 The steady-state current value under open-circuit fault is:

[0040] S12: Using the concept of limits, analyze the limit value of the stator current after the fault, and establish a stator current model that can characterize the regulating effect of the controller.

[0041] The current cannot change abruptly; it will change from the moment the fault occurred. i bf Gradually increase to i bf_H The required time depends on the time constant and control parameters. Maintaining the instantaneous value of the phase b current at the moment of the fault as a limiting state is denoted as... i bf_L Its expression is:

[0042] When S a1 After an open circuit fault occurs, the current in phase A will become 0, and the currents in phases B and C will be opposites. The current in phase B will become at the zero-crossing point. i =π / 2. Similarly, we can conclude that... i ∈(2π / 3, 5π / 3] stage, i b >0. If only S b1 An open circuit fault occurs when S b1 After an open circuit fault occurs, in a healthy state i b The phase b current, which is greater than 0, will become 0. The phase a current and the phase c current are opposites, and the zero-crossing point of the phase a current will be... i =π becomes i =7π / 6, S b1 The three-phase current after the circuit is opened is as follows Figure 4 As shown, Figure 4 In the diagram, (a) corresponds to the fault current waveform of phase a, (b) corresponds to the fault current waveform of phase b, and (c) corresponds to the fault current waveform of phase c.

[0043] Based on the above analysis, we obtain the health status and S. a1 Open circuit state and S b1 The polarities of phase a current and phase b current under open-circuit conditions are shown in Table 1: Table 1

[0044] S a1 The effect of an open-circuit fault on the polarity of the stator current can be summarized as follows: the positive polarity current of phase a in a healthy state becomes zero; the current of phase b in the interval (π / 2, 2π / 3) changes from negative to positive.

[0045] S b1 The effect of an open-circuit fault on the polarity of the stator current can be summarized as follows: the positive polarity current of phase b in a healthy state becomes zero; the current of phase a in the interval (π, 7π / 6) changes from negative to positive.

[0046] As the above analysis shows, when an open-circuit fault occurs in the power device of the upper bridge arm of the inverter, only the positive current range of the faulty phase will be affected, and the positive current will become zero. If S a1 and S b1 exist i If an open-circuit fault occurs simultaneously at time 0, then: exist i In the stage ∈(0, π / 2], only S a1 Open circuit faults affect system operation; In S a1 Under the influence of an open-circuit fault, the positive polarity region of the phase b current expands to [π / 2, 5π / 3]. Therefore, in i After =π / 2, S a1 Opening the road and S b1 Opening a circuit also affects system operation; If S b1 No malfunction occurred. i After =π, S a1 Open circuits no longer affect system operation; however, S b1 An open-circuit fault will cause the positive polarity range of phase a current to expand to (π, 7π / 6], still requiring S a1 Participate in system operation; and due to S a1 open circuit, i a It cannot be greater than 0, therefore i a =0 will continue until i =7π / 6; exist i After =7π / 6, only S b1 An open circuit fault affects system operation until... i =5π / 3, S a1 and S b1 They no longer participate in system operations, and the system gradually returns to normal.

[0047] Based on the above analysis, S a1 and S b1 The polarities of phase a and phase b currents under simultaneous open-circuit fault conditions are shown in Table 1, which can be divided into four stages. The changes in the three-phase currents are as follows: Figure 5 As shown.

[0048] Phase 1: i ∈(0, π / 2] exist i In the time interval ∈(0, π / 2], only S a1 An open-circuit fault affects the system, and in this case:

[0049]

[0050]

[0051] During this period, all three-phase currents are unipolar, that is... i af =0, i bf <0, i cf >0.

[0052] Phase 2: i ∈(π / 2, 7π / 6) At this stage, S a1 Opening the road and S b1 An open circuit fault affects system operation; the currents in phases a and b are both zero. Since the sum of the three-phase currents is zero, therefore... i af =0, i bf =0, i cf =0.

[0053] Phase 3: i ∈(7π / 6, 5π / 3) At this time, only S b1 Open circuit faults affect system operation. i af It will gradually increase in the negative direction. i bf It is still zero, and during this period there are:

[0054]

[0055]

[0056] According to the above formula, the three-phase current during this period is still unipolar, that is... i af <0, i bf =0, i cf >0.

[0057] Phase 4: i ∈(5π / 3, 2π] exist i After ≥5π / 3, the phase b current is no longer positive. i bf It will gradually increase in the negative direction, and all three-phase currents can flow normally, and the system enters the recovery phase; i At time =5π / 3, we have:

[0058]

[0059] For ease of description, the critical region is extended, and the range of three-phase currents during the recovery phase can be expressed as:

[0060]

[0061]

[0062] During this period, there are i af <0, i bf <0, i cf >0.

[0063] S13: Using mathematical statistical transformation, based on the stator current model in step S12, establish a stator current positive and negative region retention characteristic model that can characterize the controller's regulation effect, and calculate the characteristic differences between health and fault, and between different faults.

[0064] Under healthy conditions, the polarity of the stator current changes periodically. Different types of faults can lead to the presence of DC currents with different polarities in the three-phase current. i x A waveform greater than 0 is called a waveform. x The retention degree of positive and negative regions of the phase stator current will i x A waveform with a value less than 0 is called a waveform. x The retention degree of the positive and negative regions of the phase-negative stator current. Characteristic quantities are constructed to facilitate fault feature extraction. T x , G x ,Will i x The positive and negative stator current regions are kept separate. T x , G x The expressions are as follows:

[0065]

[0066] Let the current position of the motor rotor be... i e1 Then, the average retention rates of the positive and negative stator currents in the positive and negative regions can be expressed as follows:

[0067]

[0068] From the expression of three-phase current under healthy conditions and T x , G x The expression yields the average retention rates of the three-phase positive and negative stator currents in a healthy state as follows:

[0069]

[0070] Based on the above analysis, after an open-circuit fault occurs in the power devices of the opposite bridge arm, all three phase currents are unipolar currents. Specifically, if the upper bridge arm fails, the currents of the two faulted phases are both negative, and the current of the healthy phase is positive; if the lower bridge arm fails, the currents of the two faulted phases are both positive, and the current of the healthy phase is negative.

[0071] Substituting the three-phase current ranges of the four stages into the equation for the average value of the retention of the positive and negative stator currents in the positive and negative regions, the average value range of the negative half-wave of phase a current can be obtained as follows:

[0072] The average range of the retention degree of the positive and negative regions of the phase b negative stator current is:

[0073] The average range of the retention rate of the positive and negative regions of the c-phase positive stator current is:

[0074] By solving for the average range of the retention rate in the positive and negative regions of the three-phase stator current, the S values ​​of the power devices in the bridge arms on opposite sides can be obtained. a1 and S b1 The retention characteristics of stator current in both positive and negative regions after an open-circuit fault are as follows:

[0075]

[0076]

[0077] Combination Figure 5 It can be seen that the retention rates of the positive and negative regions of the phase a positive stator current, the phase b positive stator current, and the phase c negative stator current are all zero, that is:

[0078]

[0079]

[0080] The following uses S a1 and S b2 Taking the simultaneous occurrence of open circuit faults as an example, we analyze the retention characteristics of the stator current in the positive and negative regions of open circuit faults in power devices of different phases and sides of the bridge arm. The fault current can still be divided into 4 stages.

[0081] The analysis method for the characteristics of open-circuit faults in power devices of different phases and different sides of bridge arms is similar to that for open-circuit faults in power devices of the same side of bridge arms of different phases, and will not be elaborated further. The difference is that after an open-circuit fault occurs in a power device of a different phase and different side of bridge arms, the two-phase currents of the fault are unipolar currents: after the upper bridge arm is open, the current of the faulty phase is negative; after the lower bridge arm is open, the current of the faulty phase is positive; while the current of the non-faulty phase is an alternating current.

[0082] We can obtain S. a1 and S b2 The retention characteristics of the positive and negative regions of the three-phase positive stator current under the condition of simultaneous open-circuit fault are as follows:

[0083]

[0084]

[0085] The retention characteristics of negative stator current in both positive and negative regions are as follows:

[0086]

[0087]

[0088] (2) Based on the retention characteristics of the positive and negative regions of stator current, the fault location variables are redefined to distinguish the fault diagnosis of single and dual phase bridge arms with open tubes.

[0089] To facilitate the differentiation between open circuits in two-phase power devices and fault characteristics in single-phase power devices, a fault differentiation threshold is calculated based on the characteristic differences in step S13.

[0090] Single-phase bridge arm single-tube open-circuit faults and two-phase bridge arm dual-power device open-circuit faults have both overlaps and differences. Therefore, when diagnosing faults, it is still necessary to distinguish between the two types of faults to avoid misdiagnosis. Because x After a single-tube open-circuit fault occurs, only i xf It is a unipolar current, that is:

[0091] When power devices in opposite phases and on the same side of the bridge experience simultaneous open-circuit faults, all three-phase currents become unipolar currents; when power devices in opposite phases and on opposite sides of the bridge experience simultaneous open-circuit faults, the two-phase currents of the fault become unipolar currents. Let:

[0092]

[0093] Based on the above analysis, we can conclude that: In a healthy state, r →0; When both power devices in a two-phase bridge arm experience an open-circuit fault simultaneously r >2; The solution is performed using Matlab. After a single-tube open-circuit fault occurs, 1 < r ≤2; x After a two-phase tube fault, the fault phase current fluctuates around 0, and its average value is... →0 and Less than ,Right now r x <1; The currents of the non-faulty phases are opposites of each other, and their average value also tends to 0; It can be assumed that under steady-state conditions, regardless of whether a single-phase single-tube open-circuit fault or a single-phase double-tube open-circuit fault occurs, there is always... r ≤2; according to r >2 and r A value of ≤2 can distinguish between open-circuit faults in in-phase power devices and open-circuit faults in two-phase power devices.

[0094] (3) Establish auxiliary criteria based on the difference in polarity of the three-phase current after the fault to distinguish between single-phase single tube and double-phase double tube bridge arm power device open circuit mixed fault diagnosis.

[0095] Based on the feature differences identified in step S13, a fault location threshold is calculated; as long as the feature quantity is less than the threshold... c Then it can be determined that a fault has occurred, that is:

[0096]

[0097] Taking phase a and phase b power devices as examples, the retention characteristics of stator current in the positive and negative regions under two types of open-circuit faults in two-phase bridge arm power devices—open-circuit faults in power devices on the same side of different phases and open-circuit faults in power devices on opposite sides of different phases—were analyzed. Based on the above analysis, the fault characteristics of other power devices after open-circuit faults can be obtained similarly, as shown in Table 2: Table 2

[0098] To facilitate differentiation from fault characteristics of single-phase power devices, the fault location variables are redefined, namely:

[0099]

[0100] In the formula r 1 is the diagnostic threshold under steady-state conditions. r 1. Should satisfy:

[0101] Based on this, a fault location function is constructed:

[0102] The fault location functions corresponding to different devices after being open-circuited are shown in Table 3: Table 3

[0103] Based on the above analysis Figure 6 The fault diagnosis process based on the stator current retention rate in positive and negative regions is given: After a fault is detected, the first step is to determine... r The fault type is identified by whether the value is greater than 2; then, the faults are identified according to the diagnostic process.

[0104] In this embodiment, the parameters of the converter open-circuit fault test platform and the surface-mounted permanent magnet synchronous motor are shown in Table 4. Table 4

[0105] The power device S of the two-level converter a1 Taking an open-circuit fault as an example for diagnosis, the results show that: characteristic markings F The calculation results are consistent with those in Table 3, verifying the correctness of the theoretical analysis. The converter open-circuit fault diagnosis method based on the retention degree of stator current in the positive and negative regions has a good diagnostic effect on multi-tube open-circuit faults under different control parameters.

[0106] Figure 7 Demonstrated power device S a1 and S b1 The experimental results showed that the motor speed was 1000 r / min and the load torque was 0.5 times the rated torque. After the fault occurred, the fault type identification flag was displayed. r It begins to increase in size, reaching a maximum of around 3; according to diagnostic logic, when r When the value is less than 2, the fault is diagnosed according to the single-phase bridge arm power device open-circuit fault diagnosis algorithm. Since the current in phase b is greater than zero and the current in phase a is less than zero at the time of the fault, S... b1 Open circuit fault characteristics first appear, in t g S is detected at all times b1 Open circuit fault, taking approximately 0.6ms (0.04) T ).exist t f1 At that moment, S a1 Open circuit fault characteristics begin to appear. Gradually decrease, since the current in phase b is less than zero at this time, only S a1An open circuit fault affects system operation, lasting approximately 1.7ms (0.11). T )back, Less than It becomes the minimum value among all eigenvalues. t g1 The time system reported S a1 Open circuit fault. Subsequently... It also began to decrease. r Gradually increase, when r When the value is greater than 2, the fault is located according to the open-circuit fault diagnosis logic of the two-phase bridge arm power device. Based on the diagnosis logic in Table 3, the fault location flag is calculated. F =26, indicating that S a1 and S b1 Open the road at the same time.

[0107] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A method for diagnosing open-circuit faults in multi-tube converters of a motor drive system with high generalization capability, characterized in that, Includes the following steps: (1) Under stable operating conditions, the stator current under healthy and fault conditions is analyzed separately, and the retention characteristics of the positive and negative regions of the stator current are calculated. (2) Define fault diagnosis variables based on the characteristic quantities of the retention of stator current in the positive and negative regions. and ρ This is used to diagnose the type of fault in the converter; (3) Define auxiliary diagnostic variables for heterogeneous dual-tube fault types and This allows for precise location of faulty power devices in the converter.

2. The method for diagnosing open-circuit faults in multi-transistor converters of motor drive systems with high generalization capability according to claim 1, characterized in that, In step (1), the retention characteristics of the stator current in the positive and negative regions are calculated using the following formula: in: for x Characteristic quantity of retention of positive and negative regions of phase-positive stator current. for x Characteristic quantity of retention of phase negative stator current in positive and negative regions. for x Phase stator current, x =a,b,c.

3. The high-generalization-capability converter multi-transistor open-circuit fault diagnosis method for motor drive systems according to claim 2, characterized in that, The fault diagnosis variables in step (2) The expression is as follows: in: , , This indicates that the average value is taken within the fundamental period. This refers to the stator current amplitude. γ The threshold value is used.

4. The method for diagnosing open-circuit faults in multi-transistor converters of motor drive systems with high generalization capability according to claim 1, characterized in that, The fault diagnosis variables in step (2) ρ The expression is as follows: in: for x Phase fault current, i.e., the current after the fault x Phase stator current, This indicates that the average value is taken within the fundamental period.

5. The method for diagnosing open-circuit faults in multi-transistor converters of motor drive systems with high generalization capability according to claim 1, characterized in that: In step (2), the fault diagnosis variables are first detected. ,like This means determining that there is an open-circuit fault in the power device of the converter; then further detecting fault diagnosis variables. ρ ,like ρ >2 indicates that the converter has an open-circuit fault in two out-of-phase transistors; if ρ If the value is ≤2, it indicates that the converter has an open circuit fault in a single-phase power device.

6. The high-generalization-capability converter multi-transistor open-circuit fault diagnosis method for motor drive systems according to claim 2, characterized in that, In step (3), auxiliary diagnostic variables and The expression is as follows: in: , , This indicates that the average value is taken within the fundamental period. This refers to the stator current amplitude. The threshold value is used.

7. The method for diagnosing open-circuit faults in multi-tube converters of a motor drive system with high generalization capability according to claim 6, characterized in that: In step (3), if auxiliary diagnostic variables , Then determine S a1 and S b1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S b1 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S b2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a1 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S b1 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S b2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S b2 and S c2 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S b1 Open circuit fault; If auxiliary diagnostic variables , Then determine S a2 and S c1 Open circuit fault; If auxiliary diagnostic variables , Then determine S b2 and S c1 Open circuit fault; Wherein: S a1 and S a2 S represents the power devices of the upper and lower arms of phase a of the converter, respectively. b1 and S b2 S represents the power devices of the upper and lower arms of phase b of the converter, respectively. c1 and S c2 These represent the power devices of the upper and lower arms of the C-phase converter, respectively.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The processor is used to execute the computer program to implement the highly generalizable method for diagnosing open-circuit faults in multi-tube converters of motor drive systems as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the highly generalizable method for diagnosing open-circuit faults in multi-tube converters of motor drive systems as described in any one of claims 1 to 7.

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