Three-phase inverter power tube open circuit fault positioning method, device and equipment

Abstract

The application discloses a three-phase inverter power tube circuit breaking fault positioning method and relates to the technical field of inverter fault diagnosis. The application mainly aims at three-phase three-bridge-arm inverter power tubes, when a three-phase bridge-arm power tube fails, the fault phase current is clamped at zero in an electric cycle; the fault feature is utilized to realize detection and positioning of the three-phase bridge-arm power tube fault. The application establishes an intermediate variable, reconstructs the intermediate variable discrete point current, integrates the intermediate variable about the position angle, and establishes a fault identification code, so that the detection is more accurate, the robustness is stronger, and the cost is lower.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fault diagnosis of inverters, in particular to a three-phase inverter power tube open-circuit fault positioning method, device and equipment. BACKGROUND

[0002] As an important branch of energy and power field, power electronics technology has an important role in electrical energy conversion. However, in the process of energy conversion, the aging, overheating, overload operation caused by excessive load and other factors of the key components such as power tubes of the inverter often have a great impact, and even cause the equipment to be paralyzed. In the draft of the national power system fault diagnosis standard, the failure of sensors, power switching tubes, capacitors and other failures is classified as a fatal failure. According to the survey results, 34% of the faults occur in semiconductor devices.

[0003] Therefore, it is necessary to use more perfect fault diagnosis technology to detect and accurately locate the faults of the inverter system, so as to minimize the system failure rate, which has great significance. For this reason, we propose a three-phase inverter power tube open-circuit fault positioning method, device and equipment. SUMMARY

[0004] The purpose of the present application is to provide a three-phase inverter power tube open-circuit fault positioning method, device and equipment, which uses the fault feature that the fault phase current is clamped to zero in an electrical cycle when the three-phase bridge arm power tube fails to realize the detection and positioning of the three-phase bridge arm power tube failure.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a three-phase inverter power tube open-circuit fault positioning method, comprising:

[0006] The three-phase current value is subjected to Park transformation to obtain the current value in the synchronous rotating dq coordinate system, thereby obtaining the phase current module value;

[0007] The three-phase current is subjected to normalization processing, and the normalized phase current and its absolute value are respectively operated to obtain intermediate variables s n , d n ;

[0008] The average value calculation of the integral of s n with respect to the position angle θ is performed, that is and the fixed length window of 2π is equally divided into fixed X parts, and the discrete calculation of s is performed;

[0009] The s n and θ collected at k and k-1 moments are used to reconstruct the missing sn Discrete points

[0010] The reconstructed s n Discrete points are subjected to sliding window summation calculation to obtain real-time diagnostic variables S N Numerical values, and similarly, the same calculation process is used to obtain real-time diagnostic variables D N Numerical values

[0011] The obtained S N and D N Data are subjected to fault identification coding processing for quickly obtaining fault information of three-phase bridge arm power tubes.

[0012] Further, the phase current modulus can be specifically represented as: In the formula, i d and i q are d-q axis currents.

[0013] Further, the normalized phase current Can be specifically represented as:

[0014]

[0015] In the formula, i n is a stator phase current, and n=a, b, c.

[0016] Further, the sum operation of the phase current And its absolute value Obtains an intermediate variable s n , which is specifically:

[0017] Further, the difference operation of the phase current And its absolute value Obtains an intermediate variable d n , which is specifically:

[0018] Further, the discrete calculation of Is specifically:

[0019]

[0020] Wherein, s n is an intermediate variable, is a normalized stator phase current, n=a, b, c; diagnostic variable S N is the average value of s n , N=A, B, C; j=0, 1,..., X-1, X takes a value that can be divided by 360.

[0021] Further, the s n and θ are reconstructed to obtain the missing s n discrete points, specifically:

[0022] When then in the closed interval of θ k to θ k-1 , there are Y s n discrete points, wherein, is the integer part of ; θ k is the position angle at the k moment, and the missing discrete point value is solved by using the following formula:

[0023]

[0024] wherein, θ j-z is the position angle of the j-zth s n discrete point;

[0025] Further, the S N and D N data are subjected to fault identification code processing, specifically as follows:

[0026] Taking S A and D A as an example:

[0027]

[0028]

[0029] Similarly, the other two phases δ and γ can be obtained, and the fault identification code is set as:

[0030] ζ = 2 5 δ A + 2 4 δ B + 2 3 δ C + 2 2 γ A + 2 1 γ B + 2 0 γ C .

[0031] According to one aspect of the present application, the present application provides a three-phase inverter power tube open circuit fault positioning device, comprising:

[0032] A conversion module is configured to convert the three-phase current value through Park transformation to obtain the current value in the synchronous rotating dq coordinate system, thereby obtaining the phase current module value;

[0033] a processing module for normalizing the three-phase current and performing operations on the normalized phase currents and their absolute values respectively to obtain intermediate variables s n , d n ;

[0034] a first calculation module for performing average value calculation on the integral of the position angle θ with respect to s n , i.e. and dividing the fixed length window of 2π into fixed X parts to perform discrete calculation on s ;

[0035] a reconstruction discrete point module for reconstructing the missing s n discrete points by using s n and θ collected at k and k-1 moments;

[0036] a second calculation module for performing sliding window summation calculation on the reconstructed s n discrete points to obtain real-time diagnostic variable S N value after each sampling, and by using the same calculation process, real-time diagnostic variable D N value is obtained;

[0037] a fault identification module for performing fault identification coding processing on the obtained S N and D N data to quickly obtain the fault information of the three-phase bridge arm power tube.

[0038] According to another aspect of the present application, the present application provides a terminal device comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the memory stores a computer program capable of running on the processor, and when the processor loads and executes the computer program, the three-phase inverter power tube circuit breaking fault positioning method is adopted.

[0039] The present application has at least the following beneficial effects:

[0040] 1. The technical solution of the present application has strong robustness and will not misdiagnose in the case of variable speed and variable torque;

[0041] 2. The technical solution of the present application does not need to install additional voltage sensors, and the real value of the center point voltage to ground can be obtained by using known current;

[0042] 3. The technical solution of the present application can realize positioning of a total of 21 kinds of faults including single tube fault, single-phase double tube fault, different same side double tube fault and different phase different side double tube fault.

[0043] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of inverter open-circuit fault diagnosis based on current signals.

[0045] Figure 2 Here is a flowchart of the current reconstruction calculation process;

[0046] Figure 3 For the reconstruction of s n Flowchart for discrete point summation calculation;

[0047] Figure 4 For low speed s a Current reconfiguration;

[0048] Figure 5 The waveform for diagnosing an open circuit fault in tube T1;

[0049] Figure 6 The waveforms for diagnosing open circuit faults in transistors T1 and T2. Detailed Implementation

[0050] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0051] Please see Figure 1 This invention provides a technical solution: a method for locating open-circuit faults in the power transistors of a three-phase inverter, comprising:

[0052] The three-phase current values ​​are transformed by Park to obtain the current values ​​in the synchronous rotating dq coordinate system, thereby obtaining the phase current magnitude.

[0053] The three-phase currents are normalized, and the normalized phase currents are then processed. Its absolute value The intermediate variable s is obtained by performing the calculations separately. n d n ;

[0054] Using about s n The integral over the position angle θ is averaged, i.e. And divide the window of fixed length 2π into fixed parts of X, and... Perform discretization calculations;

[0055] Using s collected at times k and k-1n and θ, reconstruct the missing s n discrete points;

[0056] reconstruct the s n discrete points, and then perform a sliding window summation calculation to obtain the real-time diagnostic variable S N value, and similarly, using the same calculation process, the real-time diagnostic variable D N value is obtained.

[0057] The obtained S N and D N data are processed for fault identification coding to quickly obtain the fault information of the three-phase bridge arm power tube.

[0058] The specific embodiment steps are as follows:

[0059] (1) The three-phase current is subjected to Park transformation to obtain the current in the synchronous rotating d-q coordinate system, and the phase current modulus value can be expressed as:

[0060]

[0061] In the formula, i d and i q are d-q axis currents

[0062] (2) The three-phase current is subjected to normalization processing to reduce the influence of motor operating condition mutation on the stator current;

[0063]

[0064] In the formula, i n is the stator phase current, and n=a, b, c;

[0065] (3) The normalized phase current and its absolute value are subjected to sum and difference operations to obtain intermediate variables

[0066] (4) Taking S N calculation as an example, the average value calculation of the integral of s n with respect to the position angle θ is performed, that is, the window with a fixed length of 2π is equally divided into a fixed X parts. The discrete calculation of is performed, that is, where s n is the intermediate variable, is the normalized stator phase current, n=a, b, c; and the diagnostic variable S N is the s nThe average value of N = A, B, C; j = 0, 1, ..., X-1. For ease of calculation, X is taken as a value divisible by 360;

[0067] (5) Using the s data collected at times k and k-1 n And θ, reconstruct the missing s n Discrete points, such as Figure 2 As shown;

[0068] (6) When Then at θ k to θ k-1 Within the closed interval, there exist Y s n Discrete points. Among them, To Round down; θ k Let k be the position angle. The missing discrete point values ​​are calculated using the following formula (1):

[0069]

[0070] Where, θ j-z For the jzth s n The position angle of a discrete point;

[0071] (7) Figure 3 The calculation process shown will reconstruct s n By performing a sliding window summation on discrete points, the real-time S after each sampling can be obtained. N Similarly, using the same calculation process, the real-time D can be obtained. N Numerical value, where s n As an intermediate variable, Diagnostic variable D N For d n The average value;

[0072] (8) By analyzing S N and D N The data undergoes fault identification coding to enable rapid acquisition of fault information. Simultaneously, by appropriately setting S... N and D N The fault threshold is used to reduce the fault diagnosis time.

[0073] With S A and D A For example

[0074]

[0075]

[0076] Similarly, the other two phases δ and γ can be obtained, and fault indicators can be set.

[0077] ζ = 2 5 δ A +2 4 δ B +2 3 δ C +2 2 γ A +2 1 γ B +2 0 γ C (4)

[0078] Figure 4 For low-speed current reconstruction, current reconstruction is performed as seen and completely according to theoretical derivation; Figure 5 The waveform for diagnosing open-circuit faults in the pipe is shown; it is not affected by speed and torque changes and has strong robustness. At t = 0.254s, the fault flag = 31, indicating that an open-circuit fault has been detected in the pipe; the fault detection time is 4ms. Figure 6 The waveforms for diagnosing pipe and pipe open circuit faults are shown. In the healthy state, all six fault indicator values ​​are around 2 / π; no false diagnoses occurred. At t = 0.254s, the fault indicator is 31. According to the table, a pipe open circuit fault occurred, and the detection time is 4ms. At t = 0.255s, the fault indicator is 27. The pipe and pipe open circuit faults were detected; the fault detection time is 5ms.

[0079] It should be noted that different fault types correspond to different fault identification codes, as shown in the table below:

[0080] Table 1 Fault Identification Table

[0081] Zeta delta A ]] gamma A ]] delta B ]]> B ]]> ​ delta C ]] gamma C ]] Faulty tube 63 1 1 1 1 1 1 Healthy 62 1 1 1 1 1 0 [CD AT T6] 61 1 1 1 0 1 1 [CD AT T4] 60 1 1 1 0 1 0 [T4 T6] 59 1 0 1 1 1 1 <![CDATA[T2 <!-- 5 -->]]> 58 1 0 1 1 1 0 [T2 T6] 57 1 0 1 0 1 1 [T2 T4] 55 1 1 1 1 0 1 [T5] 54 1 1 1 1 0 0 [T5 T6] 53 1 1 1 0 0 1 [T4 T5] 51 1 0 1 1 0 1 [T2 T5] 47 1 1 0 1 1 1 [CD AT T3] 46 1 1 0 1 1 0 [T3 T6] 45 1 1 0 0 1 1 [T3 T4] 43 1 0 0 1 1 1 [T2 T3] 39 1 1 0 1 0 1 [T3 T5] 31 0 1 1 1 1 1

[00100] T1 30 0 1 1 1 1 0 [T1 T6] 29 0 1 1 0 1 1 [T1 T4] 27 0 0 1 1 1 1 [T1 T2] 23 0 1 1 1 0 1 [T1 T5] 15 0 1 0 1 1 1 [T1T3]

[0082] According to one aspect of the present invention, a three-phase inverter power transistor open-circuit fault location device is provided, comprising:

[0083] The conversion module is used to transform the three-phase current values ​​through Park transformation to obtain the current values ​​in the synchronous rotating dq coordinate system, thereby obtaining the phase current magnitude.

[0084] The processing module is used to normalize the three-phase currents and process the normalized phase currents. Its absolute value The intermediate variable s is obtained by performing the calculations separately. n d n ;

[0085] The first calculation module is used to employ information about s n The integral over the position angle θ is averaged, i.e. And divide the window of fixed length 2π into fixed parts of X, and... Discretization calculation is performed;

[0086] A discrete point reconstruction module is configured to reconstruct the missing s n and theta by using s n discrete points collected at k and k-1 time points.

[0087] A second calculation module is configured to perform sliding window summation calculation on the reconstructed s n discrete points to obtain a real-time diagnostic variable S N value, and in the same way, the same calculation process is used to obtain a real-time diagnostic variable D N value.

[0088] A fault identification module is configured to perform fault identification and encoding processing on the obtained S N and D N data to quickly obtain fault information of the three-phase bridge arm power tube.

[0089] According to another aspect of the present application, the present application provides a terminal device, comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the memory stores a computer program capable of running on the processor, and when the processor loads and executes the computer program, the three-phase inverter power tube circuit breaking fault positioning method is used.

[0090] The terminal device can be a computer device such as a desktop computer, a notebook computer or a cloud server, and the terminal device comprises but is not limited to a processor and a memory, for example, the terminal device can further comprise an input / output device, a network access device and a bus, etc.

[0091] Further, the processor can be a central processing unit (CPU), of course, according to the actual use, other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), ready programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. can also be used, and the general-purpose processor can be a microprocessor or any conventional processor, etc. The present application does not limit this.

[0092] In addition, the memory can be an internal storage unit of the terminal device, for example, a hard disk or a memory of the terminal device, or an external storage device of the terminal device, for example, a plug-in hard disk, a smart memory card (SMC), a secure digital card (SD), a flash card (FC) or the like equipped on the terminal device, or a combination of the internal storage unit and the external storage device of the terminal device. The memory is used to store a computer program and other programs and data required by the terminal device, and can also be used to temporarily store data that has been output or is to be output, which is not limited in the present application.

[0093] Further, the terminal device stores any one of the three-phase inverter power tube open circuit fault positioning methods in the above embodiments in the memory of the terminal device, and loads and executes the method on the processor of the terminal device, which is convenient to use.

[0094] The embodiments of the present application also disclose a computer readable storage medium, and the computer readable storage medium stores a computer program, wherein the computer program is executed by a processor to adopt any one of the three-phase inverter power tube open circuit fault positioning methods in the above embodiments.

[0095] The computer program can be stored in the computer readable medium, and the computer program includes computer program code, which can be in the form of source code, object code, executable files or some middleware forms, etc. The computer readable medium includes any entity or device, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier wave signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code. It should be noted that the computer readable medium includes but is not limited to the above-mentioned components.

[0096] It should be further noted that the computer readable storage medium stores any one of the three-phase inverter power tube open circuit fault positioning methods in the above embodiments in the computer readable storage medium, and loads and executes the method on the processor, so as to facilitate the storage and application of the method.

[0097] It should be noted that, in the present document, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0098] Those of ordinary skill in the art will appreciate that the above described terms are understood in their specific context within the present application. When an element is referred to as being "mounted," "attached," "connected" or "disposed" on another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can also be present. As used herein the terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used for illustration only and are not intended to be limiting.

[0099] While embodiments of the application have been shown and described, it is to be understood that various modifications, substitutions, combinations, and variations can be made therein and by those of ordinary skill in the art without departing from the spirit and scope of the present application, which is defined by the following claims and their equivalents.

[0100] In the description of the specification, reference can be made to terms such as "one embodiment," "an example," "a specific example," or similar terms. It is understood that such referenced examples can be incorporated into any embodiment of the present disclosure at any place that the context permits, without losing generality. Also, it is understood that the specific features, structures, or characteristics described in the specification can be combined in any manner and / or number in one or more embodiments or examples.

Claims

1. A method for locating open-circuit faults in the power transistors of a three-phase inverter, including: Synchronous rotation is obtained by performing Park transformation on the three-phase current values. dq The current value in the coordinate system is used to obtain the phase current magnitude; The three-phase currents are normalized, and the normalized phase currents are then processed. Its absolute value Perform calculations separately to obtain intermediate variables , ; Adopting about Position angle The integral is averaged, i.e. = and a fixed length of The window is divided into a fixed number of X parts. Perform discretization calculations; Using data collected at times k and k-1 and Reconstruct the lost Discrete points; Reconstruction The discrete points are summed using a sliding window to obtain the real-time diagnostic variables after each sampling. Similarly, numerical values ​​are calculated using the same process to obtain real-time diagnostic variables. Numerical value; The obtained and The data is processed by fault identification coding to quickly obtain fault information of the three-phase bridge arm power transistors; Phase current Its absolute value Perform a summation operation to obtain intermediate variables Specifically: = + ； Phase current Its absolute value Perform the difference operation to obtain the intermediate variable. Specifically: = - ； Using data collected at times k and k-1 and Reconstruct the lost Discrete points, specifically: when[ ]-[ If ]=Y, then in to Within the closed interval, there exist Y numbers Discrete points, where, [ For the purpose of Round down; Let be the position angle at time k. Use the following formula to calculate the value of the missing discrete point: in, For the first jz indivual The position angle of a discrete point; jz= [ -z]; z= 0,1,....,Y-1; X represents the number of equal parts into which the electrical angle window of fixed length 2π is divided; The obtained and The data undergoes fault identification coding processing, as detailed below: by and For example: Similarly, the other two phases can be obtained. and Set fault identification codes: 。 2. The method for locating open-circuit faults in a three-phase inverter power transistor according to claim 1, characterized in that: The phase current magnitude can be specifically expressed as: In the formula, i d and i q for dq Axis current.

3. The method for locating open-circuit faults in a three-phase inverter power transistor according to claim 2, characterized in that: The normalized phase current Specifically, it can be expressed as: In the formula, Let n be the stator phase current, n = a, b, c.

4. The method for locating open-circuit faults in a three-phase inverter power transistor according to claim 3, characterized in that, right Discretization calculation is performed, specifically as follows: = = in, As an intermediate variable, = + ; For normalized stator phase current, n =a, b, c; diagnostic variables for The average value, N =A, B, C; j =0,1,...,X-1, where X is a value divisible by 360.

5. A three-phase inverter power transistor open-circuit fault location device, used to implement the three-phase inverter power transistor open-circuit fault location method according to any one of claims 1 to 4, characterized in that, include: The conversion module is used to convert the three-phase current values ​​into synchronous rotation values ​​via Park transformation. dq The current value in the coordinate system is used to obtain the phase current magnitude; The processing module is used to normalize the three-phase currents and process the normalized phase currents. Its absolute value Perform calculations separately to obtain intermediate variables , ; The first calculation module is used to adopt information about Position angle The integral is averaged, i.e. = and a fixed length of The window is divided into a fixed number of X parts. Perform discretization calculations; The discrete point reconstruction module is used to utilize the data acquired at times k and k-1. and Reconstruct the lost Discrete points; The second calculation module is used to reconstruct the... The discrete points are summed using a sliding window to obtain the real-time diagnostic variables after each sampling. Similarly, numerical values ​​are calculated using the same process to obtain real-time diagnostic variables. Numerical value; The fault identification module is used to identify the fault. and The data is processed by fault identification coding to quickly obtain fault information of the three-phase bridge arm power transistors.

6. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that, The memory stores a computer program that can run on a processor. When the processor loads and executes the computer program, it employs the three-phase inverter power tube open-circuit fault location method as described in any one of claims 1 to 4.

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