Three-terminal device drive circuit fault detection method and system for electronic engineering

Abstract

The present application relates to the technical field of IGBT drive circuit fault detection, and specifically to a method and system for fault detection of a three-terminal device drive circuit for electronic engineering, the method comprising: obtaining the gate turn-on voltage of the IGBT to be detected, collecting the collector-emitter voltage and gate voltage during the operation of the IGBT drive circuit to be detected in real time, and the temperature data of the IGBT to be detected; determining the abnormality, variation index and abnormal factor of the collector-emitter voltage; obtaining each conduction voltage, and determining the gate voltage abnormality of the IGBT drive circuit to be detected by analyzing the difference between each conduction voltage and the gate turn-on voltage, and the number of conduction voltages, and combining the decrease of the gate voltage; obtaining the abnormal value of the IGBT drive circuit to be detected; and detecting the fault condition of the drive circuit to be detected. The present application aims to improve the accuracy of fault detection of the IGBT drive circuit.

Description

Technical Field

[0001] The present application relates to the technical field of IGBT drive circuit fault detection, and in particular to a method and system for detecting faults in a three-terminal device drive circuit for electronic engineering. Background Art

[0002] Three-terminal devices, also known as three-terminal components, refer to electronic components with three ports. With the increasing demand for power electronic devices in fields such as industrial automation, energy transmission and consumer electronic devices, IGBT (Insulate-Gate Bipolar Transistor) is widely used. Fault detection of IGBT drive circuits is a necessary step to ensure reliable and stable operation of IGBTs.

[0003] When a short-circuit condition exists during the operation of the IGBT, if the on-state voltage drop of the IGBT does not reach the high-voltage specified voltage, the desaturation process will not occur, resulting in the inability to detect the short-circuit fault state according to the IGBT desaturation mechanism. The unstable gate voltage of the drive circuit, external electromagnetic interference and heat dissipation problems will cause the on-state voltage drop to fail to reach the high-voltage specified voltage when the IGBT drive circuit is short-circuited, affecting the accuracy of the IGBT drive circuit fault detection. Summary of the invention

[0004] In view of the above, it is necessary to provide a three-terminal device drive circuit fault detection method and system for electronic engineering, which improves the accuracy of fault detection of IGBT drive circuit compared with the traditional three-terminal device drive circuit fault detection method for electronic engineering:

[0005] In a first aspect, an embodiment of the present application provides a method for detecting a fault in a three-terminal device driving circuit for electronic engineering, the method comprising the following steps:

[0006] Obtain the gate turn-on voltage of the IGBT to be tested, and collect the collector-emitter voltage, gate voltage, and temperature data of the IGBT to be tested in real time during the operation of the IGBT drive circuit to be tested;

[0007] By analyzing the time distribution of the overshoot phenomenon of the collector-emitter voltage at all acquisition moments, as well as the change of the collector-emitter voltage at all acquisition moments, and combining the degree to which each collector-emitter voltage deviates from the preset gate threshold voltage, the abnormality of the collector-emitter voltage is determined;

[0008] Based on the collector-emitter voltage and gate voltage at each acquisition moment, the actual gate threshold voltage at each acquisition moment is calculated; the moment of temperature increase is obtained as the temperature increase moment, and the change index of the collector-emitter voltage is determined by the decrease of the actual gate threshold voltage at all temperature increase moments and the frequency distribution of all collector-emitter voltages in the preset time period before each temperature increase moment in the frequency domain;

[0009] Determining an abnormal factor of the collector-emitter voltage by using the abnormal degree and the variation index;

[0010] By comparing the gate turn-on voltage with the gate voltage at each acquisition moment, each conduction voltage is obtained, and by analyzing the difference between each conduction voltage and the gate turn-on voltage, as well as the number of conduction voltages, and combining the decrease of the gate voltage, the gate voltage abnormality of the IGBT drive circuit to be detected is determined;

[0011] The abnormal factor is combined with the gate voltage abnormality to obtain an abnormal value of the IGBT drive circuit to be detected;

[0012] The fault condition of the IGBT driving circuit to be detected is detected by using the abnormal value.

[0013] In one embodiment, the abnormality degree is determined as follows:

[0014] Obtain each peak value of the collector-emitter voltage at all acquisition moments, and record the moment of the peak value as the peak moment;

[0015] Determine the degree of instability of the collector-emitter high voltage through the discreteness of the time intervals between any two adjacent peak moments and the difference between the maximum value of the collector-emitter voltages at all acquisition moments and the preset gate threshold voltage;

[0016] The expression of the abnormality is:

[0017] ; In the formula, A is the abnormality of the collector-emitter voltage; b is the instability of the high voltage of the collector-emitter; T is the total number of acquisition moments of the collector-emitter voltage; , They represent the collector-emitter voltages at the t+1th and tth acquisition moments respectively; exp( ) represents an exponential function with a natural constant as the base.

[0018] In one embodiment, the high voltage instability degree is the product of the dispersion and the difference.

[0019] In one embodiment, the method for obtaining the temperature raising time is:

[0020] The average value of the temperature data of all the collection moments before each collection moment is calculated and recorded as the average value of each collection moment, and the collection moment when the temperature data is greater than the average value is taken as the temperature increase moment.

[0021] In one embodiment, the process of determining the variation index is as follows:

[0022] Each acquisition moment and a preset number of adjacent acquisition moments before it form a time window of each acquisition moment, and all collector-emitter voltages in each time window are processed using fast Fourier transform technology to obtain frequency components of all collector-emitter voltages in each time window in the frequency domain;

[0023] ; In the formula, B is the variation index of the collector-emitter voltage; a is the degree of decrease of the actual gate threshold voltage, which is obtained by the overall decrease of the actual gate threshold voltage at all temperature increase moments; J is the total number of temperature increase moments; the frequency components of all collector-emitter voltages in each time window in the frequency domain are arranged from large to small according to the amplitude, It represents the sum of the amplitudes of the first preset number of frequency components of all collector-emitter voltages in the time window at the jth temperature increase moment in the frequency domain; norm() is a normalization operation.

[0024] In one embodiment, the abnormal factor is the ratio of the abnormal degree to the variation index.

[0025] In one embodiment, the process of determining the abnormality of the gate voltage is as follows:

[0026] The gate voltage greater than the gate turn-on voltage is recorded as the on-voltage, and the gate voltage less than the gate turn-on voltage is recorded as the off-voltage, and each off-voltage and its time are combined into each data point; and a fitting curve of all data points is obtained;

[0027] By analyzing the difference between each on-state voltage and the gate turn-on voltage and combining the number of on-state voltages, the degree of gate voltage on-state abnormality is obtained;

[0028] Obtain the gate turn-off voltage of the IGBT to be detected; the expression of the gate voltage abnormality is:

[0029] ; In the formula, D is the gate voltage abnormality of the IGBT drive circuit to be detected; g is the conduction abnormality degree of the gate voltage; The fitting curve and the straight line y=Vgoff, x=0, y= The integral area of ​​the area enclosed by is, where Vgoff is the gate turn-off voltage of the IGBT to be tested, is the gate voltage at the current moment.

[0030] In one embodiment, the method for calculating the abnormal conduction degree is:

[0031] Calculating the average of all the on-state voltages, and calculating the difference between the average and the gate turn-on voltage;

[0032] The conduction abnormality degree is the product of the difference value and the number.

[0033] In one embodiment, the process of detecting the fault condition of the IGBT drive circuit to be detected is:

[0034] The same calculation method as that for the abnormal value of the IGBT drive circuit to be detected is used to calculate the abnormal values ​​of a preset number of IGBT drive circuits, and the abnormal values ​​are used as the input of the regression classification algorithm, and the abnormal values ​​of the IGBT drive circuit corresponding to the optimal hyperplane are output as the fault threshold;

[0035] If the abnormal value of the IGBT drive circuit to be detected is greater than or equal to the fault threshold, it is determined that a short circuit fault occurs in the IGBT drive circuit to be detected; otherwise, it is determined that no short circuit fault occurs in the IGBT drive circuit.

[0036] In a second aspect, an embodiment of the present application also provides a three-terminal device driving circuit fault detection system for electronic engineering, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements any of the steps of the above-mentioned three-terminal device driving circuit fault detection method for electronic engineering when executing the computer program.

[0037] This application has at least the following beneficial effects:

[0038] The present application determines the abnormality of the collector-emitter voltage by analyzing the time distribution of the overshoot phenomenon of the collector-emitter voltage and the degree to which the collector-emitter voltage is in an unstable high-voltage state, and characterizes the abnormal condition of the collector-emitter voltage caused by the tendency of short-circuit faults during the operation of the IGBT; and then combines the external high temperature influence and the strong electromagnetic interference condition to obtain the abnormal factor of the collector-emitter voltage, and performs compensation analysis on the abnormal condition of the collector-emitter voltage, effectively reducing the risk of misjudging the abnormal change of the collector-emitter voltage caused by external environmental interference as a short-circuit fault;

[0039] Furthermore, when a short-circuit fault occurs, the change in the collector-emitter voltage will cause the change in the gate voltage. The abnormality of the gate voltage is determined by analyzing the abnormal rise degree and the drop speed of the gate voltage. In combination with the abnormal factor, the abnormal value of the IGBT drive circuit to be detected is determined, and the tendency of the desaturation process to occur when the on-state voltage drop of the IGBT drive circuit does not reach the high-voltage specified voltage is characterized. The fault condition of the IGBT drive circuit to be detected is detected through the abnormal value, which avoids the disadvantage that the desaturation process will not occur when the on-state voltage drop does not reach the high-voltage requirement, thereby making it impossible to detect the short-circuit fault state according to the IGBT desaturation mechanism, thereby improving the accuracy of fault detection for the IGBT drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A flowchart of a method for detecting a fault in a three-terminal device driving circuit for electronic engineering provided by an embodiment of the present application;

[0042] Figure 2 It is a collector-emitter voltage detection circuit;

[0043] Figure 3 It is a gate voltage detection circuit;

[0044] Figure 4 is a gate threshold voltage measurement circuit;

[0045] Figure 5 Schematic diagram of the process of determining outliers. DETAILED DESCRIPTION

[0046] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example" and the like are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "or", "for example" and the like is intended to present related concepts in a concrete manner.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the present application. The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It should be understood that, unless otherwise specified, " / " means or.

[0048] It should also be noted that the terms "first" and "second" in the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0049] The specific scheme of the three-terminal device driving circuit fault detection method and system for electronic engineering provided by the present application is described in detail below with reference to the accompanying drawings.

[0050] See also Figure 1 , which shows a flowchart of a method for detecting a fault in a three-terminal device driving circuit for electronic engineering provided by an embodiment of the present application, the method comprising the following steps:

[0051] Step 1: Real-time acquisition of collector-emitter voltage, gate voltage, and temperature data of the IGBT during the operation of the IGBT drive circuit to be tested.

[0052] The collector-emitter voltage detection circuit in the short-circuit fault detection process of the IGBT drive circuit to be detected is as follows: Figure 2 As shown in FIG. 1 , the gate voltage detection circuit in the short-circuit fault detection process of the IGBT drive circuit to be detected is as follows: Figure 3 As shown, Figure 2 and Figure 3 The PWM in the text refers to the pulse width modulation circuit.

[0053] The collector-emitter voltage and gate voltage of the IGBT drive circuit to be detected are collected in real time through the voltage sensor, and the temperature data of the IGBT to be detected is collected in real time through the temperature sensor.

[0054] In this embodiment, the collection frequency of the collector-emitter voltage and the gate voltage is 100Khz, and the collection frequency of the temperature data is 1Khz. The collection frequencies of the collector-emitter voltage, the gate voltage and the temperature data are all preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0055] In order to avoid data loss due to network fluctuations or external environmental interference during data transmission, a data filling method is used to fill in missing values. In order to avoid the impact of different data dimensions on subsequent analysis, the collector-emitter voltage, gate voltage and temperature data are normalized. In this embodiment, the Z-Score normalization method is used to normalize the collector-emitter voltage, gate voltage and temperature data. The Z-Score normalization method is a well-known technology and will not be described in detail in this application.

[0056] In this embodiment, the missing values ​​are filled by the median filling method. The median filling method is a well-known technology and will not be described in detail in this application. As other implementation methods, on the basis of being able to fill the missing values, the implementer may adopt other existing technologies, such as the mean filling method, the interpolation method, etc., and this application does not make any special restrictions.

[0057] Step 2, by analyzing the time distribution of the overshoot phenomenon of the collector-emitter voltage at all acquisition moments, and the change of the collector-emitter voltage at all acquisition moments, and combining the degree to which each collector-emitter voltage deviates from the preset gate threshold voltage, the abnormality of the collector-emitter voltage is determined.

[0058] The gate threshold voltage of IGBT is the minimum voltage required for IGBT to switch from off state to on state. During the operation of IGBT, when a positive voltage greater than the gate threshold voltage is applied to the gate, a strong inversion layer will appear under the gate oxide layer to form a conductive channel. When a positive voltage is applied to the collector, the electrons in the emitter will flow from the emitter to the collector continuously under the action of the electric field, and the holes in the collector will flow from the collector to the emitter to form a current. When the IGBT enters the short-circuit state from normal working conditions, such as a phase-to-phase short-circuit fault, the voltage between the collector and the emitter rises linearly with the increase of the collector current. After reaching a certain critical point, the collector-emitter voltage increases rapidly, but the collector current does not increase accordingly, and the IGBT exits the saturation region. At this time, the IGBT loss increases and the heat is serious.

[0059] Specifically, when the IGBT has a tendency to short-circuit failure or is subjected to excessive voltage during the shutdown process, the stray inductance in the IGBT will generate an induced voltage during the IGBT shutdown process, which is further superimposed on the bus voltage, causing the collector-emitter voltage to rise rapidly and voltage spikes and overshoots to occur, and maintain an unstable higher voltage state.

[0060] Based on the above analysis, the abnormality of the collector-emitter voltage is determined to characterize the abnormal condition of the collector-emitter voltage caused by the short-circuit fault tendency during the operation of the IGBT. The specific process is as follows:

[0061] The collector-emitter voltages at all acquisition moments are arranged in time sequence to form a collector-emitter voltage sequence, and the peak value detection algorithm is used to obtain each peak value in the collector-emitter voltage sequence, and the time at which the peak value is located is recorded as the peak time;

[0062] In this embodiment, an automatic multi-scale peak search algorithm is used to obtain the peak value in the collector-emitter voltage sequence. The automatic multi-scale peak search algorithm is a well-known technology and will not be described in detail in this application. As other implementation methods, on the basis of being able to obtain the peak value in the collector-emitter voltage sequence, the implementer may use other existing technologies, such as an extreme point detection algorithm, and this application does not make any special restrictions;

[0063] By analyzing the discreteness of the time intervals between all two adjacent peak moments and the changes in the collector-emitter voltage at all acquisition moments, and combining the difference between each collector-emitter voltage and the preset gate threshold voltage, the abnormality of the collector-emitter voltage is determined. The expression is:

[0064] ; In the formula, A is the abnormality of the collector-emitter voltage; b is the instability of the high voltage of the collector-emitter; T is the total number of acquisition moments of the collector-emitter voltage; , denote the collector-emitter voltage at the t+1th and tth acquisition moments, respectively; exp( ) denotes an exponential function with a natural constant as the base, the purpose of which is to convert is mapped to a positive number; the calculation formula for the instability of the collector-emitter high voltage is: , where c is the discreteness of the time interval between any two adjacent peak moments, is the difference between the maximum value of the collector-emitter voltages at all acquisition moments and the preset gate threshold voltage. In this embodiment, the preset gate threshold voltage is 15V, and the preset gate threshold voltage is determined by the specific model and specification of the IGBT.

[0065] In this embodiment, the dispersion of the time interval is the standard deviation. As other implementation methods, on the basis of being able to measure the uneven distribution of the time interval, the implementer may adopt other existing technologies, such as variance, coefficient of variation, etc., and this application does not impose any special restrictions.

[0066] It should be noted that when the voltage between the collector and the emitter increases rapidly over time, The larger the value, the greater the instability of the high voltage. In this process, since the induced voltage generated by the stray inductance in the IGBT is constantly superimposed on the bus voltage, the overshoot phenomenon of the collector-emitter voltage is more obvious, the more unstable the higher voltage state is, the more irregular the peak moment is, the larger the maximum value of the collector-emitter voltage at all acquisition moments is, and the greater the degree of high voltage instability is. Then, when the tendency of the IGBT to enter the short-circuit fault state from the normal operating condition during operation is more significant, the abnormality of the collector-emitter voltage is more obvious, and the calculated abnormality of the collector-emitter voltage is greater.

[0067] Step 3, based on the collector-emitter voltage and gate voltage at each acquisition moment, calculate the actual gate threshold voltage at each acquisition moment; obtain the moment of temperature increase as the temperature increase moment, and determine the collector-emitter voltage change index through the decrease of the actual gate threshold voltage at all temperature increase moments and the frequency distribution of all collector-emitter voltages in the preset time period before each temperature increase moment in the frequency domain.

[0068] During the IGBT fault test, the current when the IGBT is turned on is mainly carried by the bipolar transistor. When the IGBT is subjected to large current or is affected by external high temperature, the carrier concentration in the bipolar transistor will increase, but the carrier mobility will decrease. At the same time, the IGBT saturation voltage drop will increase with the increase of junction temperature, resulting in a higher electric field required to maintain the drift speed of the carriers under the same current conditions. Specifically, under external high temperature environment, the gate threshold voltage of the IGBT will decrease, and as the temperature increases, the gate threshold voltage will decrease more obviously. At this time, IGBT short-circuit fault detection based only on the abnormality of the collector-emitter voltage will result in misjudgment.

[0069] In addition, IGBTs are mostly used in large and medium-sized power electronic conversion devices. In circuits with multiple IGBTs in parallel or closely arranged, the transient current magnetic field generated when the adjacent IGBT drive signals switch from high level to low level may cause drive crosstalk, resulting in strong electromagnetic interference to the collector-emitter voltage, generating high-frequency components. The high-frequency components cause oscillations in the voltage waveform, which may be misjudged as short-circuit faults. The more serious the drive crosstalk caused by strong external electromagnetic interference to the IGBT, the more prominent the high-frequency components of the collector-emitter voltage of the IGBT.

[0070] Based on the above analysis, the variation index of the collector-emitter voltage is determined to characterize the degree of abnormal variation of the collector-emitter voltage caused by external environmental interference during the operation of the IGBT. The specific process is as follows:

[0071] Calculate the average value of the temperature data of all the collection moments before each collection moment, record it as the average value of each collection moment, and take the collection moment when the temperature data is greater than the average value as the temperature increase moment;

[0072] The specific method of obtaining the actual gate threshold voltage is as follows:

[0073] Figure 4 It is a gate threshold voltage measurement circuit. When measuring the actual gate threshold voltage, the gate voltage is only slightly higher than the actual gate threshold voltage, resulting in extremely high resistance in the channel region. The conduction voltage drop in the channel region plays a dominant role. At this time, the calculation formula for the actual gate threshold voltage is obtained by inversely deducing the calculation formula for the collector-emitter voltage. The calculation formula for the collector-emitter voltage is:

[0074]

[0075] The actual gate threshold voltage is calculated as:

[0076]

[0077] In the formula, is the collector-emitter voltage; is the cell pitch; is the channel length; To measure current; is the electron mobility within the inversion layer; is the gate oxide layer capacitance; is the gate voltage, i.e. the gate voltage, is the actual gate threshold voltage.

[0078] Based on the collector-emitter voltage and gate voltage at each acquisition moment, the actual gate threshold voltage at each acquisition moment is calculated using the calculation formula of the actual gate threshold voltage. The actual gate threshold voltages at all temperature increase moments are arranged in time sequence to form an actual threshold voltage sequence. Each acquisition moment and its adjacent previous W acquisition moments form a time window for each acquisition moment, and all collector-emitter voltages in each time window are processed using fast Fourier transform technology to obtain the frequency components of all collector-emitter voltages in each time window in the frequency domain. Among them, fast Fourier transform is a well-known technology and will not be repeated in this application.

[0079] In this embodiment, the value of W is 3000. The value of W is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0080] The variation index of the collector-emitter voltage is determined by the decrease of the actual gate threshold voltage at all temperature increase moments and the frequency distribution of all collector-emitter voltages in the time window of each temperature increase moment in the frequency domain. The expression is:

[0081] ; In the formula, B is the variation index of the collector-emitter voltage; a is the degree of decrease of the actual gate threshold voltage, which is obtained by the overall decrease of the actual gate threshold voltage at all temperature increase moments; J is the total number of temperature increase moments; the frequency components of all collector-emitter voltages in each time window in the frequency domain are arranged from large to small according to the amplitude, represents the sum of the amplitudes of the first preset number of frequency components of all collector-emitter voltages in the time window at the jth temperature increase moment in the frequency domain; norm() is a normalization operation. In this embodiment, the decimal calibration normalization method is used to normalize Perform normalization.

[0082] In this embodiment, the inverse of the sum of all elements in the first-order differential sequence of the actual threshold voltage sequence is used as the decrease degree of the actual gate threshold voltage.

[0083] In another embodiment, the actual threshold voltage sequence is used as the input of the STL (Seasonal and Trend decomposition using Loess) algorithm, and the trend sequence is output. The inverse of the sum of the differences between all elements in the trend sequence and their adjacent previous elements is used as the degree of decrease of the actual gate threshold voltage.

[0084] In this embodiment, the value of the preset number is 10. The value of the preset number is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0085] It should be noted that: the more significant the gate threshold voltage drop caused by the high temperature of the external environment, the greater the degree to which the actual gate threshold voltage gradually decreases over time, and the greater the calculated decrease in the actual gate threshold voltage; the greater the accumulation result of the high-frequency frequency component amplitude of the IGBT collector-emitter voltage due to strong external electromagnetic interference, that is, The larger the value is, the greater the change index of the calculated collector-emitter voltage will be when the IGBT drive circuit is subjected to higher temperature and stronger electromagnetic interference in the external environment during the fault test.

[0086] Step 4: Determine the abnormal factor of the collector-emitter voltage according to the abnormal degree and the variation index.

[0087] Further, the abnormal factor of the collector-emitter voltage is determined by the variation index of the collector-emitter voltage and the abnormality of the collector-emitter voltage. Specifically, the ratio of the abnormality of the collector-emitter voltage to the variation index of the collector-emitter voltage is used as the abnormal factor of the collector-emitter voltage.

[0088] It should be noted that: during the fault test of the IGBT drive circuit, the smaller the influence of external high temperature and strong electromagnetic interference, the more obvious the rapid increase of the collector-emitter voltage over time, and the more significant the superposition of the induced voltage generated by the stray inductance in the IGBT on the bus voltage, the more obvious the tendency of the IGBT to change from normal operating conditions to short-circuit fault conditions, and the larger the calculated abnormal factor of the collector-emitter voltage.

[0089] Step 5, obtain the gate turn-on voltage of the IGBT to be tested, obtain each on-voltage by comparing the gate turn-on voltage with the gate voltage at each acquisition moment, and determine the gate voltage abnormality of the IGBT drive circuit to be tested by analyzing the difference between each on-voltage and the gate turn-on voltage, as well as the number of on-voltages, and combining the drop of the gate voltage.

[0090] When the IGBT has a tendency to short-circuit failure, the collector-emitter voltage will not only change accordingly, but will also be fed back to the gate through the Miller capacitor, causing the gate voltage, that is, the gate voltage, to change accordingly, affecting the conduction state of the IGBT. When the short-circuit failure tendency during the normal operation of the IGBT, that is, the desaturation process is more obvious, due to the Miller effect, the Miller capacitor will generate an instantaneous current between the collector and the gate, causing the gate voltage to increase abnormally for a long time, which may cause the IGBT to be triggered to turn on by mistake, exacerbating the short-circuit failure; at the same time, when the IGBT has a soft fault, that is, the IGBT has a non-physical damage fault during operation, rapid shutdown may cause the IGBT to explode under high current.

[0091] Specifically, when the desaturation tendency or short-circuit fault tendency of the IGBT during operation is more obvious, the gate voltage will continue to be pulled up due to the Miller effect because the IGBT cannot normally exit the on state. Therefore, when the drive circuit has a soft fault, the gate voltage will drop more unstably and rapidly.

[0092] Based on the above analysis, the gate voltage abnormality of the IGBT drive circuit to be tested is determined to characterize the abnormal conditions of gate voltage conduction and shutdown caused by short-circuit fault tendency. The specific process is as follows:

[0093] The gate turn-on voltage and gate turn-off voltage of the IGBT in this application are obtained by using a circuit detection method. The gate turn-on voltage refers to the minimum gate voltage required to turn on the IGBT, that is, to enter the on state, and the gate turn-off voltage is the gate voltage required to ensure that the IGBT is completely turned off;

[0094] The gate voltage greater than the gate turn-on voltage is recorded as the on-voltage, the gate voltage less than the gate turn-on voltage is recorded as the off-voltage, the moment when the off-voltage is recorded as the off-time, each off-time and its off-voltage form each data point, and the fitting curve of all data points is obtained;

[0095] In this embodiment, the least square method is used to obtain the fitting curve of all data points. The least square method is a well-known technology and will not be described in detail in this application. As other implementation methods, on the basis of being able to obtain the fitting curve of all data points, the implementer may use other existing technologies, such as local weighted regression, K-nearest neighbor regression, etc., and this application does not make any special restrictions;

[0096] Furthermore, by analyzing the difference between each on-state voltage and the gate turn-on voltage, as well as the number of on-state voltages, and combining the drop in gate voltage, the gate voltage abnormality of the IGBT drive circuit to be tested is determined, and the expression is:

[0097] ; In the formula, D is the gate voltage abnormality of the IGBT drive circuit to be detected; g is the conduction abnormality degree of the gate voltage, ,in, is the average value of all on-state voltages, is the gate turn-on voltage of the IGBT to be tested, and n is the number of conduction voltages; The fitting curve and the straight line y=Vgoff, x=0, y= The integral area of ​​the area enclosed; wherein the x-axis of the coordinate axis is time, the y-axis is the voltage value, Vgoff is the gate turn-off voltage of the IGBT to be tested, is the gate voltage at the current moment.

[0098] It should be noted that: when the IGBT has a more significant tendency to desaturate or short-circuit during operation, the gate voltage data will be more abnormal, and the calculated gate voltage abnormality of the IGBT drive circuit to be tested will be greater; due to the Miller effect, the abnormal rise of the gate voltage increases, the duration becomes longer, and the conduction abnormality of the gate voltage becomes greater; in this process, the self-adjustment mechanism of the IGBT will perform shutdown processing when a soft fault occurs, and the faster the gate voltage drops, the easier it is to cause the IGBT to explode under high current, and the calculated gate voltage abnormality will be greater. The smaller.

[0099] Step 6: Merge the abnormal factor with the gate voltage abnormality to obtain an abnormal value of the IGBT drive circuit to be detected.

[0100] During the operation of the IGBT, when the on-state voltage drop of the IGBT does not reach the high voltage specified voltage, although a short-circuit soft fault has occurred, the desaturation mechanism will not be executed. At this time, if the abnormal condition of the collector-emitter voltage in the IGBT drive circuit is more significant without external environmental interference, and the abnormality of the IGBT gate voltage due to the Miller effect is more obvious, it means that the IGBT has a higher tendency to convert from normal operating conditions to a short-circuit fault state.

[0101] Based on the above analysis, the abnormal value of the IGBT drive circuit to be detected is determined through the abnormal factor of the collector-emitter voltage and the abnormality of the gate voltage of the IGBT drive circuit to be detected, which is used to characterize the tendency of the desaturation process when the on-state voltage drop of the IGBT drive circuit does not reach the high voltage specified voltage. Specifically, it is:

[0102] The result of fusing the abnormal factor of the collector-emitter voltage and the abnormality of the gate voltage of the IGBT drive circuit to be detected is taken as the abnormal value of the IGBT drive circuit to be detected.

[0103] It should be understood that fusion refers to combining multiple independent variables in a way that enhances the overall effect, such as multiplication relationship, addition relationship, etc., and implementers can limit it according to actual conditions.

[0104] In this embodiment, the product of the abnormal factor of the collector-emitter voltage and the abnormality of the gate voltage of the IGBT driving circuit to be detected is taken as the abnormal value of the IGBT driving circuit to be detected.

[0105] In another embodiment, the sum of the abnormal factor of the collector-emitter voltage and the abnormality of the gate voltage of the IGBT driving circuit to be detected is used as the abnormal value of the IGBT driving circuit to be detected.

[0106] It should be noted that: when the IGBT drive circuit is converted from normal working condition to soft fault state, the more obvious the abnormal condition of the collector-emitter voltage in the IGBT drive circuit is, the less the interference from the external environment is, the more obvious the gate voltage abnormality caused by the Miller effect is, the stronger the tendency of the IGBT drive circuit to desaturate, and the larger the calculated abnormal value of the IGBT drive circuit to be detected. The flow chart of determining the abnormal value is as follows: Figure 5 shown.

[0107] Step 7: Detect the fault condition of the IGBT drive circuit to be detected by using the abnormal value.

[0108] In this embodiment, N IGBT drive circuits are randomly selected for fault testing, wherein there are IGBT drive circuits with short-circuit faults and IGBT drive circuits without short-circuit faults in the N IGBT drive circuits. According to the historical data of the N IGBT drive circuits, the same calculation method as the abnormal value of the IGBT drive circuit to be detected is used to calculate the abnormal values ​​of the N IGBT drive circuits, and the abnormal values ​​of the N IGBT drive circuits are used as the input of the support vector machine (SVM), wherein the abnormal value label of the IGBT drive circuit with short-circuit fault is set to the first preset value, and the abnormal value label of the IGBT drive circuit without fault is set to the second preset value, and the abnormal value of the IGBT drive circuit corresponding to the optimal hyperplane is output as the fault threshold. Among them, the support vector machine is a well-known technology, and this application will not repeat it, and the implementer can choose other existing feasible regression classification algorithms.

[0109] In this embodiment, the value of N is 50. The value of N is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0110] In this embodiment, the first preset value and the second preset value are 1 and 0 respectively. On the basis that the first preset value and the second preset value are not equal, the implementer can set the values ​​of the first preset value and the second preset value by himself.

[0111] If the abnormal value of the IGBT drive circuit to be detected is greater than or equal to the fault threshold, it is determined that a short circuit fault occurs in the IGBT drive circuit, and timely measures must be taken to avoid causing power accidents; otherwise, it is determined that no short circuit fault occurs in the IGBT drive circuit.

[0112] Based on the same inventive concept as the above method, an embodiment of the present application also provides a three-terminal device driving circuit fault detection system for electronic engineering, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above-mentioned three-terminal device driving circuit fault detection methods for electronic engineering are implemented.

[0113] In summary, the present application determines the abnormality of the collector-emitter voltage by analyzing the time distribution of the overshoot phenomenon of the collector-emitter voltage and the degree to which the collector-emitter voltage is in an unstable high-voltage state, and characterizes the abnormal condition of the collector-emitter voltage caused by the tendency of short-circuit faults during the operation of the IGBT; and then combines the external high temperature influence and the strong electromagnetic interference condition to obtain the abnormal factor of the collector-emitter voltage, and performs compensation analysis on the abnormal condition of the collector-emitter voltage, effectively reducing the risk of misjudging the abnormal change of the collector-emitter voltage caused by external environmental interference as a short-circuit fault;

[0114] Furthermore, when a short-circuit fault occurs, the change in the collector-emitter voltage will cause the change in the gate voltage. The abnormality of the gate voltage is determined by analyzing the abnormal rise degree and the drop speed of the gate voltage. In combination with the abnormal factor, the abnormal value of the IGBT drive circuit to be detected is determined, and the tendency of the desaturation process to occur when the on-state voltage drop of the IGBT drive circuit does not reach the high-voltage specified voltage is characterized. The fault condition of the IGBT drive circuit to be detected is detected through the abnormal value, which avoids the disadvantage that the desaturation process will not occur when the on-state voltage drop does not reach the high-voltage requirement, thereby making it impossible to detect the short-circuit fault state according to the IGBT desaturation mechanism, thereby improving the accuracy of fault detection for the IGBT drive circuit.

[0115] The flowchart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to the embodiment of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. In the description corresponding to the flowchart and the block diagram in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in a different order from the order disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0116] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic features of the present application. Therefore, no matter from which point of view, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A method for detecting a fault in a three-terminal device driving circuit for electronic engineering, characterized in that: The method comprises the following steps: Obtain the gate turn-on voltage of the IGBT to be tested, and collect the collector-emitter voltage, gate voltage, and temperature data of the IGBT to be tested in real time during the operation of the IGBT drive circuit to be tested; By analyzing the time distribution of the overshoot phenomenon of the collector-emitter voltage at all acquisition moments, as well as the change of the collector-emitter voltage at all acquisition moments, and combining the degree to which each collector-emitter voltage deviates from the preset gate threshold voltage, the abnormality of the collector-emitter voltage is determined; Based on the collector-emitter voltage and gate voltage at each acquisition moment, the actual gate threshold voltage at each acquisition moment is calculated; the moment of temperature increase is obtained as the temperature increase moment, and the change index of the collector-emitter voltage is determined by the decrease of the actual gate threshold voltage at all temperature increase moments and the frequency distribution of all collector-emitter voltages in the preset time period before each temperature increase moment in the frequency domain; Determining an abnormal factor of the collector-emitter voltage by using the abnormal degree and the variation index; By comparing the gate turn-on voltage with the gate voltage at each acquisition moment, each conduction voltage is obtained, and by analyzing the difference between each conduction voltage and the gate turn-on voltage, as well as the number of conduction voltages, and combining the decrease of the gate voltage, the gate voltage abnormality of the IGBT drive circuit to be detected is determined; The abnormal factor is combined with the gate voltage abnormality to obtain an abnormal value of the IGBT drive circuit to be detected; The fault condition of the IGBT driving circuit to be detected is detected by using the abnormal value.

2. The method for detecting faults in a three-terminal device driving circuit for electronic engineering as claimed in claim 1, characterized in that: The process of determining the abnormality is as follows: Obtain each peak value of the collector-emitter voltage at all acquisition moments, and record the moment of the peak value as the peak moment; Determine the degree of instability of the collector-emitter high voltage by the discreteness of the time intervals between any two adjacent peak moments and the difference between the maximum value of the collector-emitter voltages at all acquisition moments and the preset gate threshold voltage; the degree of instability of the high voltage is the product of the discreteness and the difference; The expression of the abnormality is: ; In the formula, A is the abnormality of the collector-emitter voltage; b is the instability of the high voltage of the collector-emitter; T is the total number of acquisition moments of the collector-emitter voltage; , They represent the collector-emitter voltages at the t+1th and tth acquisition moments respectively; exp( ) represents an exponential function with a natural constant as the base.

3. The method for detecting faults in a three-terminal device driving circuit for electronic engineering as claimed in claim 1, characterized in that: The method for obtaining the temperature raising moment is: The average value of the temperature data of all the collection moments before each collection moment is calculated and recorded as the average value of each collection moment, and the collection moment when the temperature data is greater than the average value is taken as the temperature increase moment.

4. The method for detecting faults in a three-terminal device driving circuit for electronic engineering as claimed in claim 1, characterized in that: The determination process of the change index is: Each acquisition moment and a preset number of adjacent acquisition moments before it form a time window of each acquisition moment, and all collector-emitter voltages in each time window are processed using fast Fourier transform technology to obtain frequency components of all collector-emitter voltages in each time window in the frequency domain; ; In the formula, B is the variation index of the collector-emitter voltage; a is the degree of decrease of the actual gate threshold voltage, which is obtained by the overall decrease of the actual gate threshold voltage at all temperature increase moments; J is the total number of temperature increase moments; the frequency components of all collector-emitter voltages in each time window in the frequency domain are arranged from large to small according to the amplitude, It represents the sum of the amplitudes of the first preset number of frequency components of all collector-emitter voltages in the time window at the jth temperature increase moment in the frequency domain; norm() is a normalization operation.

5. The method for detecting faults in a three-terminal device driving circuit for electronic engineering according to claim 1, characterized in that: The abnormal factor is the ratio of the abnormal degree to the variation index.

6. The method for detecting faults in a three-terminal device driving circuit for electronic engineering as claimed in claim 1, characterized in that: The process of determining the gate voltage abnormality is as follows: The gate voltage greater than the gate turn-on voltage is recorded as the on-voltage, and the gate voltage less than the gate turn-on voltage is recorded as the off-voltage, and each off-voltage and its time are combined into each data point; and a fitting curve of all data points is obtained; By analyzing the difference between each on-state voltage and the gate opening voltage, combined with the number of on-state voltages, the degree of on-state abnormality of the gate voltage is obtained; the mean of all on-state voltages is calculated, and the difference between the mean and the gate opening voltage is calculated; the degree of on-state abnormality is the product of the difference and the number; Obtain the gate turn-off voltage of the IGBT to be detected; the expression of the gate voltage abnormality is: ; In the formula, D is the gate voltage abnormality of the IGBT drive circuit to be detected; g is the conduction abnormality degree of the gate voltage; The fitting curve and the straight line y=Vgoff, x=0, y= The integral area of ​​the area enclosed by is, where Vgoff is the gate turn-off voltage of the IGBT to be tested, is the gate voltage at the current moment.

7. The method for detecting faults in a three-terminal device driving circuit for electronic engineering as claimed in claim 1, characterized in that: The process of detecting the fault condition of the IGBT drive circuit to be detected is as follows: The same calculation method as that for the abnormal value of the IGBT drive circuit to be detected is used to calculate the abnormal values ​​of a preset number of IGBT drive circuits, and the abnormal values ​​are used as the input of the regression classification algorithm, and the abnormal values ​​of the IGBT drive circuit corresponding to the optimal hyperplane are output as the fault threshold; If the abnormal value of the IGBT drive circuit to be detected is greater than or equal to the fault threshold, it is determined that a short circuit fault occurs in the IGBT drive circuit to be detected; Otherwise, it is determined that there is no short circuit fault in the IGBT drive circuit.

8. A three-terminal device driving circuit fault detection system for electronic engineering, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method for detecting faults in a three-terminal device driving circuit for electronic engineering as described in any one of claims 1 to 7 are implemented.

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