Quasi-current source inverter short circuit fault diagnosis system and method

Abstract

The invention relates to a quasi-current source inverter short-circuit fault diagnosis system and method, and the system comprises the steps: obtaining a three-phase electric signal of a three-phase voltage inverter in real time through a signal collection device; in combination with an arranged diagnosis device, whether the three-phase voltage type inverter is short-circuited or not is determined according to the difference between the obtained combination of the signal extreme value starting point vector and the signal extreme value end point vector and the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the normal signal waveform in the same interval; and obtaining the short circuit condition of each switching device of the three-phase voltage type inverter according to the difference between the obtained combination of the signal extreme value starting point vector and the signal extreme value end point vector and all the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the contrast signal waveform in the same interval, thereby realizing fault diagnosis and avoiding potential safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of electric digital data processing, and more particularly, to a quasi-current source inverter short-circuit fault diagnosis system and method. Background Art

[0002] The rotor spinning technology belongs to the typical open-end spinning technology. This technology separates the two important processes of twisting and winding in the rotor spinning process and they do not restrict each other. The rotor spinning technology not only has the advantages of high speed and large package, but also can simplify the process, reduce the labor intensity of workers and improve the working environment, significantly improving the production efficiency of spinning. The technical core of the rotor spinning technology is the improvement of the rotor spinning machine, which requires the rotor spinning machine to meet the requirements of automation and intelligence.

[0003] Regarding the improvement of the rotor spinning machine, a permanent magnet motor driver for a rotor spinning machine is disclosed in the prior art to drive the operation of the rotor spinning machine. Its drive circuit is called a quasi-current source inverter (Quasi Current Source Inverter, abbreviated as QCSI). The quasi-current source inverter can drive the permanent magnet motor of the rotor spinning machine to a speed of 150,000 revolutions per minute.

[0004] However, during the driving process, the quasi-current source inverter is prone to short-circuit and open-circuit faults of switching devices, especially short-circuit faults. If not properly handled, it may cause dangerous accidents such as fires, and the prior art does not propose a relatively systematic and efficient diagnostic technology for the short-circuit faults of the quasi-current source inverter. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to overcome the technical defect of the lack of diagnosis and prevention of short-circuit faults of the quasi-current source inverter in the prior art. To overcome the above defects of the prior art, the present invention provides a quasi-current source inverter short-circuit fault diagnosis system and method, specifically including a quasi-current source inverter short-circuit fault diagnosis system and a quasi-current source inverter short-circuit fault diagnosis method.

[0006] A quasi-current source inverter short-circuit fault diagnosis system provided by the present invention includes: A quasi-current source inverter, including a buck chopper circuit and a three-phase voltage source inverter electrically connected to each other; A signal acquisition device, electrically connected to the three-phase voltage source inverter, for real-time acquisition of three-phase electrical signals of the three-phase voltage source inverter; A diagnostic device, electrically connected to the signal acquisition device, is configured to divide a period into at least four intervals, and obtain a signal waveform of at least one period by means of signal simulation using the signal distribution of the three-phase electrical signals. Then, it acquires the combination of the signal extreme value start vector and the signal extreme value end vector of each interval signal waveform in at least four consecutive intervals, and determines whether the three-phase voltage source inverter is short-circuited according to the difference between the obtained combination of the signal extreme value start vector and the signal extreme value end vector and the combination of the signal extreme value start vector and the signal extreme value end vector of the normal signal waveform in the same interval. And when there is a short circuit, it obtains the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the obtained combination of the signal extreme value start vector and the signal extreme value end vector and all the combinations of the signal extreme value start vector and the signal extreme value end vector of the reference signal waveform in the same interval.

[0007] The quasi-current source inverter short-circuit fault diagnosis system disclosed by the present invention obtains the three-phase electrical signals of the three-phase voltage source inverter in real time by setting a signal acquisition device, and combines the set diagnostic device to determine whether the three-phase voltage source inverter is short-circuited according to the difference between the obtained combination of the signal extreme value start vector and the signal extreme value end vector and the combination of the signal extreme value start vector and the signal extreme value end vector of the normal signal waveform in the same interval. And when there is a short circuit, it obtains the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the obtained combination of the signal extreme value start vector and the signal extreme value end vector and all the combinations of the signal extreme value start vector and the signal extreme value end vector of the reference signal waveform in the same interval, so as to realize fault diagnosis and avoid potential safety hazards. At the same time, since the present invention only needs to acquire three-phase electrical signals, only three current sensors are required to detect the three-phase currents, and the change of the three-phase current values is judged to obtain the fault diagnosis result. Furthermore, complex hardware circuits and complex algorithm support are not required, and the diagnosis efficiency is relatively high.

[0008] In a possible implementation manner, the signal acquisition device is a three-phase current sensor, so that the three-phase level change situation can be obtained when a circuit fault occurs, ensuring that the short-circuit fault of a single switching device can be detected and the specific switching device can be located.

[0009] In a possible implementation manner, the combination of the signal extreme value start vector and the signal extreme value end vector of the signal waveform in any interval is a Cartesian product in the following form: , wherein, represents the signal extreme value start vector of the signal waveform in this interval; represents the signal extreme value end vector of the signal waveform in this interval; represent the extreme value that the phase current reaches first in this interval in the said signal waveform; represent the extreme value that the phase current reaches first in this interval in the said signal waveform; represent the extreme value that the phase current reaches first in this interval in the said signal waveform; represent the extreme value that the phase current reaches last in this interval in the said signal waveform; represent the extreme value that the phase current reaches last in this interval in the said signal waveform; represent the extreme value that the phase current reaches last in this interval in the said signal waveform;

[0010] In a possible implementation manner, the combination of all signal extreme value start vectors and signal extreme value end vectors of the reference signal waveform in any interval is a Cartesian product set with the following form: , , wherein, represents the combination of the signal extreme value start vector and the signal extreme value end vector corresponding to the short circuit of the th switching device with the phase type in the said three-phase voltage source inverter; represents the signal extreme value start vector when the th switching device with the phase type in the said three-phase voltage source inverter has a short circuit; represents the th switching device with the phase type in the said three-phase voltage source inverter when it has a short circuit the extreme value that the phase current reaches first in this interval; represents the th switching device with the phase type in the said three-phase voltage source inverter when it has a short circuit the extreme value that the phase current reaches first in this interval; represents the th switching device with the ​​​​​​When a switching device has a short circuit The extreme value that the phase current reaches first in this interval; Represents the phase type in the three-phase voltage source inverter as The Signal extreme value end vector when the Represents the phase type in the three-phase voltage source inverter as The When the The extreme value that the phase current reaches last in this interval; Represents the phase type in the three-phase voltage source inverter as The When the The extreme value that the phase current reaches last in this interval; Represents the phase type in the three-phase voltage source inverter as The When the The extreme value that the phase current reaches last in this interval; The above solution provides a clear definition for the signal extreme value start vector and the signal extreme value end vector, which not only conforms to the circuit state facts of the three-phase voltage source inverter, but also facilitates the efficient formation of a data set and provides a judgment basis for short-circuit fault diagnosis.

[0011] In a possible implementation manner, the diagnostic device includes: A simulation module, electrically connected to the signal acquisition device, and configured to obtain at least one cycle of signal waveforms in real time by using signal simulation to simulate the signal distribution of the three-phase electrical signals; A memory, configured to store the signal extreme value start vectors and signal extreme value end vectors of several cycles of normal signal waveforms, and store the signal extreme value start vectors and signal extreme value end vectors of several cycles of comparison signal waveforms; An alarm module, configured to send an alarm signal when a short circuit occurs in the three-phase voltage source inverter, and cut off the power supply of the quasi-current source inverter after the alarm signal is sent; A display device, configured to display the short-circuit conditions of each switching device of the three-phase voltage source inverter in real time; A central processing unit, electrically connected to the simulation module, the memory, the alarm module, and the display device at the same time, and configured to determine whether the three-phase voltage source inverter is short-circuited, call the display device to display the short-circuit conditions, and call the alarm module to operate when a short circuit occurs; This solution can ensure the integration of the changes in the three-phase current values, obtain the fault diagnosis results through the central processing unit, without the support of complex hardware circuits and complex algorithms.

[0012] In a possible implementation manner, the method for the simulation module to obtain the signal waveforms of several cycles includes the following steps: A1: Retrieve the signal distribution of the three-phase electrical signals acquired by the signal acquisition device within at least one cycle; A2: Obtain the signal waveforms by using the signal distribution of the three-phase electrical signals obtained in step A1 through linear interpolation; This solution can ensure the accurate construction of the current change waveform, guarantee the improvement of the diagnosis efficiency, and save the operation cost.

[0013] In a possible implementation manner, the central processing unit is set to execute the following steps: B1: Divide one cycle into at least four intervals, and then collect the combination of the signal extreme value starting vector and the signal extreme value ending vector of each interval in at least four consecutive intervals; B2: Calculate the difference between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and the combination of the signal extreme value starting vector and the signal extreme value ending vector of the normal signal waveform in the same interval; B3: Determine whether the difference obtained in step B2 is less than the first threshold; If so, it is determined that the three-phase voltage source inverter has not short-circuited, and the display device is called to display this judgment result, and then return to execute step B1; If not, it is determined that the three-phase voltage source inverter has short-circuited, and the alarm module is called to operate, and then proceed to the next step; B4: Calculate the differences between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and all the combinations of the signal extreme value starting vector and the signal extreme value ending vector of the reference signal waveform in the same interval respectively; B5: Determine whether there is a difference between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and a certain combination of the signal extreme value starting vector and the signal extreme value ending vector of the reference signal waveform that is less than the second threshold according to the calculation result of step B4; If so, it is determined that the switching device corresponding to this combination of the signal extreme value starting vector and the signal extreme value ending vector has short-circuited, and the display device is called to display this judgment result; If not, the display device is called to display the information that further judgment of the short-circuit fault is required; The above judgment algorithm has a simple logic and a small amount of computation, and has the advantage of fast diagnosis speed. It only takes a short time to obtain a fault diagnosis result from the appearance of a fault feature, and can detect the short-circuit fault of a single switching device and locate it to a specific switching device.

[0014] Another technical solution of the present invention is to provide a short-circuit fault diagnosis method for a quasi-current source inverter, including the following steps: S1: Divide a period into at least four intervals, and obtain the signal extreme value starting point vector and signal extreme value ending point vector combination of the normal signal waveform of the three-phase voltage source inverter for experiment, as well as all signal extreme value starting point vectors and signal extreme value ending point vector combinations of the reference signal waveform in each interval; S2: Store the result obtained in step S1 in a diagnostic device; S3: Obtain the three-phase electrical signals of the three-phase voltage source inverter of the quasi-current source inverter in real time through a signal acquisition device; S4: Use the diagnostic device to obtain the signal waveform of at least one period by signal simulation using the signal distribution of the three-phase electrical signals, and then collect the signal extreme value starting point vector and signal extreme value ending point vector combination of the signal waveform in each of at least four consecutive intervals; S5: Determine whether the three-phase voltage source inverter is short-circuited by the diagnostic device according to the difference between the signal extreme value starting point vector and signal extreme value ending point vector combination obtained in step S4 and the signal extreme value starting point vector and signal extreme value ending point vector combination of the normal signal waveform in the same interval. When short-circuited, obtain the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the obtained signal extreme value starting point vector and signal extreme value ending point vector combination and all signal extreme value starting point vectors and signal extreme value ending point vector combinations of the reference signal waveform in the same interval.

[0015] The method disclosed in this application first stores in the diagnostic device the combination of the signal extreme value start vector and the signal extreme value end vector of the normal signal waveform of the three-phase voltage source inverter for experiments, as well as all the signal extreme value start vector and signal extreme value end vector combinations of the reference signal waveform in each interval. Subsequently, the signal acquisition device is used to obtain the three-phase electrical signals of the three-phase voltage source inverter in real time, and in combination with the set diagnostic device, it is determined whether the three-phase voltage source inverter is short-circuited according to the difference between the obtained signal extreme value start vector and signal extreme value end vector combination and the signal extreme value start vector and signal extreme value end vector combination of the normal signal waveform in the same interval. And when there is a short circuit, the short-circuit situation of each switching device of the three-phase voltage source inverter is obtained according to the difference between the obtained signal extreme value start vector and signal extreme value end vector combination and all the signal extreme value start vector and signal extreme value end vector combinations of the reference signal waveform in the same interval, so as to realize fault diagnosis and avoid potential safety hazards. At the same time, since this method only needs to collect three-phase electrical signals, only three current sensors are required to detect the three-phase current, and by judging the change situation of the three-phase current values, the fault diagnosis result can be obtained without complex hardware circuits and complex algorithm support, and the diagnosis efficiency is relatively high.

[0016] In a possible implementation manner, step S1 includes the following steps: S11: Divide a cycle into at least four intervals, and use the signal acquisition device to obtain the three-phase electrical signals of the three-phase voltage source inverter for experiments during normal operation for at least one cycle, and then collect the signal extreme value start vector and signal extreme value end vector of this three-phase electrical signal in each interval to obtain the combination of the signal extreme value start vector and signal extreme value end vector of the normal signal waveform; S12: Apply a safe current to the three-phase voltage source inverter for experiments, and separately short-circuit each switching device of the three-phase voltage source inverter for experiments, and use the signal acquisition device to separately obtain the three-phase electrical signals of the three-phase voltage source inverter for at least one cycle when each switching device is separately short-circuited; S13: Respectively collect the signal extreme value start vector and signal extreme value end vector of the at least one cycle of three-phase electrical signals obtained in step S12 in each interval to obtain all the signal extreme value start vector and signal extreme value end vector combinations of the reference signal waveform in each interval; This solution obtains the combination of the signal extreme value start vector and signal extreme value end vector of the normal signal waveform and the reference signal waveform of the three-phase voltage source inverter for experiments during normal operation through the signal acquisition device, and further provides a reference basis for later diagnosis.

[0017] In a possible implementation, the safety current introduced in step S12 is a current not exceeding 30 mA to ensure experimental safety and can also determine the first threshold and the second threshold according to the difference between the magnitude of the introduced safety current and the operating current of the quasi-current source inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a schematic structural diagram of a quasi-current source inverter short-circuit fault diagnosis system disclosed in an embodiment of the present application; Figure 2 FIG. is a schematic circuit diagram of a quasi-current source inverter disclosed in an embodiment of the present application; Figure 3 FIG. is a flowchart of the operation of a central processing unit disclosed in an embodiment of the present application; Figure 4 FIG. is a flowchart of a method disclosed in an embodiment of the present application; Figure 5 FIG. is a schematic diagram of switch drive waveforms and three-phase output currents when a three-phase voltage source inverter for experiments operates normally in an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] First of all, those skilled in the art should understand that these embodiments are only used to explain the technical principles of the embodiments of the present application and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments according to needs to adapt to specific application scenarios.

[0020] In the embodiments of the present application, unless otherwise clearly specified and limited, the electrical connection between the first feature and the second feature means that there is an electrical signal transmission between the first feature and the second feature, that is, there is an electrical relationship, and the way to realize the electrical signal transmission can be wire electrical connection, radio connection, electrical connection of an electromagnetic medium (such as a semiconductor), communication realized by a channel, etc.

[0021] In the embodiments of the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower horizontal height than the second feature.

[0022] The present application will be further described in detail below with reference to the drawings and specific embodiments.

[0023] See Figures 1 to 5, an embodiment of the present application discloses a short - circuit fault diagnosis system for a quasi - current - source inverter. The structural schematic diagram of the short - circuit fault diagnosis system is as Figure 1 shown. The short - circuit fault diagnosis system includes a quasi - current - source inverter, a signal acquisition device, and a diagnosis device. Among them, the quasi - current - source inverter includes a buck - chopper circuit and a three - phase voltage - source inverter that are electrically connected to each other; the signal acquisition device is electrically connected to the three - phase voltage - source inverter, and the diagnosis device is electrically connected to the signal acquisition device.

[0024] See Figure 1 and Figure 2 , in this short - circuit fault diagnosis system, the quasi - current - source inverter (abbreviated as QCSI inverter) includes a buck - chopper circuit and a three - phase voltage - source inverter (Voltage Source Inverter, abbreviated as VSI). Figure 2 In , , and the inductor L form a buck - chopper circuit with synchronous rectifier current control; the switches ~ form a three - phase voltage - source inverter. The buck - chopper circuit outputs a DC current, and the three - phase voltage - source inverter converts the output DC current of the chopper circuit into three - phase currents for output. In order to prevent over - voltage in the six switches ( ~ ) of the quasi - current - source inverter, a diode D is added. Figure 2 In and the switch are two switching devices of the phase circuit, the switch and the switch are two switching devices of the phase circuit, the switch and the switch are two switching devices of the phase circuit.

[0025] For the convenience of statistics and calculation, in this embodiment, the switch is regarded as the first switching device of the phase type in the three - phase voltage - source inverter, and the switch is regarded as the second switching device of the phase type in the three - phase voltage - source inverter; the switch is regarded as the first switching device of the phase type in the three - phase voltage - source inverter, and the switch is regarded as the second switching device of the The second switching device; the switch is regarded as the first switching device in the phase type of a three-phase voltage source inverter, and the switch is regarded as the second switching device in the phase type of a three-phase voltage source inverter.

[0026] In this short-circuit fault diagnosis system, the signal acquisition device is used to obtain the three-phase electrical signals of the three-phase voltage source inverter in real time. The signal acquisition device in this embodiment is a three-phase current sensor, so that current signals or level signals can be obtained, which is convenient for signal analysis.

[0027] See Figure 1 and Figure 3 , in this short-circuit fault diagnosis system, the diagnosis device is configured to divide a period into at least four intervals, and obtain the signal waveforms of at least one period through signal simulation using the signal distribution of the three-phase electrical signals, and then collect the signal extreme value starting vector and the signal extreme value ending vector combinations of each interval signal waveform in at least four consecutive intervals, and determine whether the three-phase voltage source inverter is short-circuited according to the difference between the obtained signal extreme value starting vector and signal extreme value ending vector combinations and the signal extreme value starting vector and signal extreme value ending vector combinations of the normal signal waveform in the same interval. And when short-circuited, obtain the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the obtained signal extreme value starting vector and signal extreme value ending vector combinations and all the signal extreme value starting vector and signal extreme value ending vector combinations of the reference signal waveform in the same interval.

[0028] In this embodiment, the signal extreme value starting vector and signal extreme value ending vector combination of the signal waveform of any interval is a Cartesian product with the following form: , wherein, represents the signal extreme value starting vector of the signal waveform in this interval; represents the signal extreme value ending vector of the signal waveform in this interval; represents the extreme value that the phase current in the signal waveform reaches first in this interval; represents the extreme value that the phase current in the signal waveform reaches first in this interval; represents the extreme value that the phase current in the signal waveform reaches first in this interval; represents the extreme value that the The extreme value that the phase current finally reaches in this interval; Represents in the signal waveform The extreme value that the phase current finally reaches in this interval; Represents in the signal waveform The extreme value that the phase current finally reaches in this interval.

[0029] At the same time, in this embodiment, the combination of all signal extreme value start vectors and signal extreme value end vectors of the reference signal waveform in any interval is a Cartesian product set with the following form: , , In the formula, Represents the phase type in the three-phase voltage source inverter as Of the Signal extreme value start vector and signal extreme value end vector combination corresponding to the short circuit of the Represents the phase type in the three-phase voltage source inverter as Of the Signal extreme value start vector when the Represents the phase type in the three-phase voltage source inverter as Of the When the The extreme value that the phase current reaches first in this interval; Represents the phase type in the three-phase voltage source inverter as Of the When the The extreme value that the phase current reaches first in this interval; Represents the phase type in the three-phase voltage source inverter as Of the When the The extreme value that the phase current reaches first in this interval; Represents the phase type in the three-phase voltage source inverter as Of the Signal extreme value end vector when the Represents the phase type in the three-phase voltage source inverter as Of the When the The extreme value that the phase current finally reaches in this interval; Represents the th switching device in the phase current when a short circuit occurs, which is the extreme value finally reached by the phase current in this interval; Represents the th switching device in the phase current when a short circuit occurs, which is the extreme value finally reached by the phase current in this interval.

[0030] See Figure 1 , in this embodiment, the diagnostic device includes a simulation module, a memory, an alarm module, a display device, and a central processor. Among them, the simulation module is electrically connected to the signal acquisition device, and the central processor is simultaneously electrically connected to the simulation module, the memory, the alarm module, and the display device.

[0031] In the diagnostic device, the simulation module is configured to obtain the signal waveforms of at least one cycle in real time by means of signal simulation and analog using the signal distribution of three-phase electrical signals. In this embodiment, the method for the simulation module to obtain the signal waveforms of several cycles includes the following steps: A1: Retrieve the signal distribution of the three-phase electrical signals obtained by the signal acquisition device within at least one cycle; A2: Obtain the signal waveforms by using the signal distribution of the three-phase electrical signals obtained in step A1 through linear interpolation. The method for determining the length of the cycle is: Retrieve any phase current signal of the three-phase electrical signals within the specified time, determine the time interval between two adjacent moments with the same signal value in this phase current signal, and take twice this time interval as the time length of one cycle.

[0032] In the diagnostic device, the memory is used to store the signal extreme value start vectors and signal extreme value end vectors of the normal signal waveforms of several cycles, as well as the signal extreme value start vectors and signal extreme value end vectors of the reference signal waveforms of several cycles. The alarm module is configured to send an alarm signal when a short circuit occurs in the three-phase voltage source inverter, and cut off the power supply of the quasi-current source inverter after the alarm signal is sent. The display device is configured to display the short circuit conditions of each switching device of the three-phase voltage source inverter in real time.

[0033] See Figure 3 , in the diagnostic device, the central processor is configured to determine whether the three-phase voltage source inverter is short-circuited, call the display device to display the short circuit conditions, and call the alarm module to operate when a short circuit occurs. Specifically, in this embodiment, the central processor is configured to execute the following steps: B1: Divide one cycle into at least four intervals, and then collect the combinations of the signal extreme value start vectors and signal extreme value end vectors of the signal waveforms in each of at least four consecutive intervals.

[0034] B2: Calculate the difference between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and the combination of the signal extreme value starting vector and the signal extreme value ending vector of the normal signal waveform in the same interval; the calculation method of the difference can adopt the Euclidean distance algorithm or the norm-induced distance algorithm, such as the 1-norm-induced distance algorithm.

[0035] B3: Determine whether the difference obtained in step B2 is less than the first threshold; If so, it is determined that the three-phase voltage source inverter has not short-circuited, and the display device is called to display this judgment result, and then step B1 is executed again; If not, it is determined that the three-phase voltage source inverter has short-circuited, and the alarm module is called to operate, and then the next step is executed.

[0036] B4: Calculate the differences between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and all the combinations of the signal extreme value starting vector and the signal extreme value ending vector of the reference signal waveform in the same interval respectively.

[0037] B5: Judge whether there is a difference between the combination of the signal extreme value starting vector and the signal extreme value ending vector obtained in step B1 and a certain combination of the signal extreme value starting vector and the signal extreme value ending vector of the reference signal waveform that is less than the second threshold according to the calculation result of step B4; If so, it is determined that the switching device corresponding to this combination of the signal extreme value starting vector and the signal extreme value ending vector has short-circuited, and the display device is called to display this judgment result; If not, the display device is called to display the information that further judgment of the short-circuit fault is required.

[0038] Next, the usage method of the quasi-current source inverter short-circuit fault diagnosis system in this embodiment is further disclosed. Figure 4 As shown in the flowchart of this method, this method includes the following steps: S1; Divide a cycle into at least four intervals, and obtain the combination of the signal extreme value starting vector and the signal extreme value ending vector of the normal signal waveform of the three-phase voltage source inverter for experiment, and all the combinations of the signal extreme value starting vector and the signal extreme value ending vector of the reference signal waveform in each interval.

[0039] In this embodiment, step S1 includes the following steps: S11: Divide a cycle into at least four intervals, obtain at least one cycle of three-phase electrical signals when the three-phase voltage source inverter for experiment is working normally through the signal acquisition device, and then collect the signal extreme value starting vector and the signal extreme value ending vector of this three-phase electrical signal in each interval to obtain the combination of the signal extreme value starting vector and the signal extreme value ending vector of the normal signal waveform; S12: Apply a safe current to the three-phase voltage source inverter for experiments. I d , separately short-circuit each switching device of the three-phase voltage source inverter for experiments, and respectively obtain at least one cycle of three-phase electrical signals of the three-phase voltage source inverter when each switching device is separately short-circuited through a signal acquisition device; the applied safe current is a current with a magnitude not exceeding 30 mA. S13: Respectively collect the signal extreme value start vectors and signal extreme value end vectors of the at least one cycle of three-phase electrical signals obtained in step S12 in each interval, so as to obtain all combinations of signal extreme value start vectors and signal extreme value end vectors of the control signal waveform in each interval.

[0040] Figure 5 is a schematic diagram of the switching drive waveform and three-phase output current when the three-phase voltage source inverter for experiments operates normally. The output current of the buck chopper circuit is a constant value. I d , in Figure 5 , ~ are respectively the drive waveforms of switches ~ , where the high level indicates that the switch is in the on state and the low level indicates that the switch is in the off state; , and are respectively the three-phase output currents of the three-phase voltage source inverter. In the figure, a cycle is divided into four large intervals A, B, C, and D, where the widths of intervals A and C are 60°, and the widths of intervals B and D are 120°. Interval B includes two parts, interval B1 and interval B2, and interval D includes two parts, interval D1 and interval D2, that is, this embodiment divides a cycle into 6 intervals.

[0041] By executing step S1, the information acquisition results of the three-phase voltage source inverter for experiments are as follows in the table:

[0042] The numbers in the table are the last reached extreme values of the corresponding intervals.

[0043] This embodiment also organizes the change situations of the corresponding three-phase currents when two switches a of a phase bridge arm have short-circuit faults into a table, which is specifically as follows in the table: and

[0044] In the table, "X" represents any current value, which may be 0 under normal circumstances or may not be 0. Among the data in the table, the data at the starting point of the arrow is the earliest extreme value reached in the corresponding interval, and the data at the end point of the arrow is the latest extreme value reached in the corresponding interval. Based on the above results, a combination of the starting point vector and the signal extreme value end point vector can be obtained.

[0045] S2: Store the result obtained in step S1 in the diagnostic device.

[0046] S3: Obtain the three-phase electrical signals of the three-phase voltage source inverter in real time through the signal acquisition device.

[0047] S4: Use the diagnostic device to obtain the signal waveforms of at least one cycle by signal simulation using the signal distribution of the three-phase electrical signals, and then collect the combination of the signal extreme value starting point vector and the signal extreme value end point vector of each interval signal waveform in at least four consecutive intervals.

[0048] S5: Use the diagnostic device to determine whether the three-phase voltage source inverter is short-circuited according to the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained in step S4 and the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the normal signal waveform in the same interval. When it is short-circuited, obtain the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained and all the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the reference signal waveform in the same interval.

[0049] In the quasi-current source inverter short-circuit fault diagnosis system disclosed in this embodiment, by setting a signal acquisition device to obtain the three-phase electrical signals of the three-phase voltage source inverter in real time, and combining the set diagnostic device to determine whether the three-phase voltage source inverter is short-circuited according to the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained and the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the normal signal waveform in the same interval. When it is short-circuited, obtain the short-circuit conditions of each switching device of the three-phase voltage source inverter according to the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained and all the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the reference signal waveform in the same interval, so as to realize fault diagnosis and avoid potential safety hazards. At the same time, since the technical solution of this embodiment only needs to collect three-phase electrical signals, only three current sensors are required to detect the three-phase current, and by judging the change of the three-phase current values, the fault diagnosis result can be obtained, without complex hardware circuits and complex algorithm support, and the diagnosis efficiency is relatively high.

[0050] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms indicating directions or positional relationships such as "inner" and "outer" are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present application.

[0051] In the description of the present application, the description with reference to terms such as "one embodiment", "some embodiments", "in this embodiment", "specific examples", or "some examples" means that the specific features, mechanisms, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0052] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A quasi-current source inverter short-circuit fault diagnosis system, characterized in that: include: A quasi-current source inverter comprises a step-down chopper circuit and a three-phase voltage source inverter electrically connected to each other; A signal acquisition device, electrically connected to the three-phase voltage type inverter, for acquiring the three-phase electrical signals of the three-phase voltage type inverter in real time; A diagnostic device is electrically connected to the signal acquisition device, and is configured to divide a cycle into at least four intervals, and obtain a signal waveform of at least one cycle using the signal distribution of the three-phase electrical signal through a signal simulation method, and then collect the signal extreme value starting point vector and the signal extreme value end point vector combination of the signal waveform in each interval of at least four consecutive intervals, and determine whether the three-phase voltage-type inverter is short-circuited based on the difference between the obtained signal extreme value starting point vector and the signal extreme value end point vector combination and the signal extreme value starting point vector and the signal extreme value end point vector combination of the normal signal waveform in the same interval, and when short-circuited, the short-circuit condition of each switching device of the three-phase voltage-type inverter is obtained based on the difference between the obtained signal extreme value starting point vector and the signal extreme value end point vector combination and all signal extreme value starting point vectors and signal extreme value end point vector combinations of the control signal waveform in the same interval.

2. The quasi-current source inverter short-circuit fault diagnosis system according to claim 1, characterized in that: The signal acquisition device is a three-phase current sensor.

3. The quasi-current source inverter short-circuit fault diagnosis system according to claim 1 or 2, characterized in that: The combination of the signal extreme value starting point vector and the signal extreme value ending point vector of the signal waveform in any interval is a Cartesian product having the following form: ， In the formula, A signal extreme value starting point vector representing the signal waveform in the interval; A signal extreme value endpoint vector representing the signal waveform in the interval; Represents the signal waveform The phase current reaches the extreme value first in this interval; Represents the signal waveform The phase current reaches the extreme value first in this interval; Represents the signal waveform The phase current reaches the extreme value first in this interval; Represents the signal waveform The phase current finally reaches the extreme value in this interval; Represents the signal waveform The phase current finally reaches the extreme value in this interval; Represents the signal waveform The phase current finally reaches the extreme value in this interval.

4. The quasi-current source inverter short-circuit fault diagnosis system according to claim 3, characterized in that: The combination of all signal extreme value starting point vectors and signal extreme value ending point vectors of the reference signal waveform in any interval is a Cartesian product set having the following form: ， , In the formula, Represents the phase type of the three-phase voltage source inverter No. The combination of the signal extreme value starting point vector and the signal extreme value end point vector corresponding to the short circuit of each switching device; Represents the phase type of the three-phase voltage source inverter No. The starting point vector of the signal extreme value when a switching device is short-circuited; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current reaches the extreme value first in this interval; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current reaches the extreme value first in this interval; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current reaches the extreme value first in this interval; Represents the phase type of the three-phase voltage source inverter No. The signal extreme value endpoint vector when a switching device is short-circuited; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current finally reaches the extreme value in this interval; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current finally reaches the extreme value in this interval; Represents the phase type of the three-phase voltage source inverter No. When a switching device is short-circuited The phase current finally reaches the extreme value in this interval.

5. The quasi-current source inverter short-circuit fault diagnosis system according to claim 4, characterized in that: The diagnostic device comprises: A simulation module, electrically connected to the signal acquisition device, and configured to obtain at least one period of signal waveform by using the signal distribution of the three-phase electrical signal in real time through a signal simulation method; A memory, used to store a signal extreme value starting point vector and a signal extreme value end point vector of a normal signal waveform of several cycles, and to store a signal extreme value starting point vector and a signal extreme value end point vector of a control signal waveform of several cycles; an alarm module, configured to send out an alarm signal when a short circuit occurs in the three-phase voltage-source inverter, and to cut off the power supply of the quasi-current source inverter after the alarm signal is sent; A display device, configured to display in real time the short circuit conditions of each switch device of the three-phase voltage-type inverter; The central processing unit is electrically connected to the simulation module, the memory, the alarm module and the display device, and is configured to determine whether the three-phase voltage-type inverter is short-circuited, call the display device to display the short-circuit condition, and call the alarm module to run when a short circuit occurs.

6. The quasi-current source inverter short-circuit fault diagnosis system according to claim 5, characterized in that: The method in which the simulation module obtains at least one cycle of the signal waveform comprises the following steps: A1: Retrieving the signal distribution of the three-phase electrical signal acquired by the signal acquisition device in at least one cycle; A2: Obtain the signal waveform by linear interpolation using the signal distribution of the three-phase electrical signal obtained in step A1.

7. The quasi-current source inverter short-circuit fault diagnosis system according to claim 5 or 6, characterized in that: The central processing unit is configured to perform the following steps: B1: Divide a cycle into at least four intervals, and then collect a combination of a signal extreme value starting point vector and a signal extreme value ending point vector of the signal waveform in each interval of at least four consecutive intervals; B2: Calculate the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained in step B1 and the combination of the signal extreme value starting point vector and the signal extreme value end point vector of the normal signal waveform in the same interval; B3: Determine whether the difference obtained in step B2 is less than a first threshold; If yes, it is determined that the three-phase voltage source inverter is not short-circuited, and the display device is called to display the judgment result, and then the step B1 is executed again; If not, it is determined that the three-phase voltage type inverter is short-circuited, and the alarm module is called to run, and then the next step is executed; B4: respectively calculating the difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained in step B1 and all combinations of the signal extreme value starting point vector and the signal extreme value end point vector of the control signal waveform in the same interval; B5: judging, based on the calculation result of step B4, whether there is a difference between the combination of the signal extreme value starting point vector and the signal extreme value end point vector obtained in step B1 and a combination of the signal extreme value starting point vector and the signal extreme value end point vector of the reference signal waveform that is smaller than a second threshold; If so, it is determined that the switch device corresponding to the combination of the signal extreme value starting point vector and the signal extreme value end point vector is short-circuited, and the display device is called to display the judgment result; If not, the display device is called to display information that requires further determination of the short-circuit fault.

8. A method for diagnosing short-circuit faults of a quasi-current source inverter, characterized in that: A quasi-current source inverter short-circuit fault diagnosis system applicable to any one of claims 1 to 7, comprising the following steps: S1: Divide a cycle into at least four intervals, obtain a signal extreme value starting point vector and a signal extreme value end point vector combination of a normal signal waveform of a three-phase voltage-source inverter used for the experiment, and all signal extreme value starting point vectors and signal extreme value end point vector combinations of a control signal waveform in each interval; S2: storing the result obtained in step S1 in a diagnostic device; S3: acquiring three-phase electrical signals of a three-phase voltage-type inverter of a quasi-current source inverter in real time through a signal acquisition device; S4: obtaining at least one cycle of a signal waveform by using the signal distribution of the three-phase electrical signal in a signal simulation manner through the diagnostic device, and then collecting a combination of a signal extreme value starting point vector and a signal extreme value ending point vector of the signal waveform in each interval of at least four consecutive intervals; S5: Determine whether the three-phase voltage inverter is short-circuited by the diagnostic device based on the difference between the signal extreme value starting point vector and the signal extreme value end point vector combination obtained in step S4 and the signal extreme value starting point vector and the signal extreme value end point vector combination of the normal signal waveform in the same interval, and when short-circuited, obtain the short-circuit condition of each switching device of the three-phase voltage inverter based on the difference between the obtained signal extreme value starting point vector and the signal extreme value end point vector combination and all signal extreme value starting point vectors and signal extreme value end point vector combinations of the control signal waveform in the same interval.

9. The short-circuit fault diagnosis method of a quasi-current source inverter according to claim 8, characterized in that: The step S1 comprises the following steps: S11: Divide a cycle into at least four intervals, obtain a three-phase electrical signal of at least one cycle when the three-phase voltage-type inverter used for the experiment works normally through a signal acquisition device, and then collect the signal extreme value starting point vector and the signal extreme value end point vector of the three-phase electrical signal in each interval to obtain a combination of the signal extreme value starting point vector and the signal extreme value end point vector of a normal signal waveform; S12: Passing a safety current into the three-phase voltage-type inverter used for the experiment, short-circuiting each switch device of the three-phase voltage-type inverter used for the experiment, and acquiring at least one cycle of three-phase electrical signals of the three-phase voltage-type inverter when each switch device is short-circuited by a signal acquisition device; S13: respectively collecting the signal extreme value starting point vector and the signal extreme value ending point vector of each interval of at least one cycle of the three-phase electrical signal obtained in step S12 to obtain all signal extreme value starting point vectors and signal extreme value ending point vector combinations of the control signal waveform in each interval.

10. The short-circuit fault diagnosis method of a quasi-current source inverter according to claim 9, characterized in that: The safety current introduced in step S12 is a current whose magnitude does not exceed 30 mA.

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