Method and device for identifying short circuit of insulated gate bipolar transistor in converter

Abstract

The invention provides a short circuit identification method and device for an insulated gate bipolar transistor in a converter, and belongs to the technical field of short circuit detection. The method comprises the following steps: acquiring circuit parameter information of the insulated gate bipolar transistor; and determining the type of the short circuit of the insulated gate bipolar transistor based on the circuit parameter information. According to the embodiment of the invention, whether the first-class short circuit or the second-class short circuit occurs or not is judged by acquiring the circuit parameter information, and the method has certain guiding significance for state detection of the insulated gate bipolar transistor.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of short-circuit detection, and particularly relates to a method, device, electronic device, computer-readable storage medium and computer program product for identifying short circuits of insulated gate bipolar transistors inside a converter. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) devices have the advantages of fast switching speed of MOSFET (Metal Oxide Semiconductor Field Effect Transistor) devices and low on-state loss of bipolar devices, making IGBTs widely used in new energy converters, flexible DC transmission equipment, dynamic reactive power compensation equipment and other occasions. However, during the turn-on transient process of the IGBT, the collector current i C and the collector-emitter voltage u CE change sharply. Mastering the states of i C and u CE is very important for conducting power loss analysis and transient electrical stress analysis. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a method, device, computer-readable storage medium and computer program product for detecting short circuits of IGBTs inside a converter. The solution provided by the present disclosure can detect short circuits of IGBTs inside the converter in a timely and accurate manner.

[0004] To achieve the above object, in a first aspect, an embodiment of the present disclosure provides a method for detecting short circuits of IGBTs inside a converter, the method comprising:

[0005] Obtaining circuit parameter information of the insulated gate bipolar transistor;

[0006] Determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information.

[0007] In some embodiments, the circuit parameter information includes first gate current information during the actual turn-on process of the insulated gate bipolar transistor and second gate current information during the normal turn-on process of the insulated gate bipolar transistor. Determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information includes:

[0008] Calculating the reduction value of the gate charge during the actual turn-on process of the insulated gate bipolar transistor compared to the normal turn-on process of the insulated gate bipolar transistor based on the first gate current information and the second gate current information;

[0009] Comparing the reduction value of the gate charge with a preset value to obtain a first comparison result;

[0010] Determine the type of short circuit of the insulated gate bipolar transistor based on the first comparison result.

[0011] In some embodiments, the preset value is the integral value of the gate charge during the Miller plateau stage in the normal turn-on process of the insulated gate bipolar transistor.

[0012] In some embodiments, the method further includes:

[0013] According to the second gate current information in the normal turn-on process of the insulated gate bipolar transistor, calculate the product of the collector-emitter voltage and the gate-to-collector capacitance at the start moment of the Miller plateau stage in the normal turn-on process of the insulated gate bipolar transistor to obtain the preset value.

[0014] In some embodiments, the determining the type of short circuit of the insulated gate bipolar transistor based on the first comparison result includes:

[0015] If the first comparison result is that the reduction value of the gate charge is the same as the preset value, determine that the type of short circuit of the insulated gate bipolar transistor is a type I short circuit.

[0016] In some embodiments, the circuit parameter information further includes the collector current information and the collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor. The determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information includes:

[0017] According to the collector current information and the collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor, determine the change trend of the collector current and the change trend of the collector-emitter voltage;

[0018] If the collector current and the collector-emitter voltage both show an upward trend, determine that the type of short circuit of the insulated gate bipolar transistor is a type II short circuit.

[0019] In a second aspect, the present disclosure further provides a device for detecting short circuits of IGBTs inside a converter, including:

[0020] An acquisition module for acquiring the circuit parameter information of the insulated gate bipolar transistor;

[0021] A detection module for determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information.

[0022] In some embodiments, the circuit parameter information includes the first gate current information during the actual turn-on process of the insulated gate bipolar transistor and the second gate current information during the normal turn-on process of the insulated gate bipolar transistor. The detection module includes:

[0023] A calculation module, configured to calculate a reduction value of the gate charge during the actual turn-on process of an insulated gate bipolar transistor compared to the normal turn-on process of the insulated gate bipolar transistor based on the first gate current information and the second gate current information;

[0024] A comparison module, configured to compare the reduction value of the gate charge with a preset value to obtain a first comparison result;

[0025] A determination module, configured to determine the type of short circuit of the insulated gate bipolar transistor based on the first comparison result.

[0026] In some embodiments, the determination module is specifically configured to, if the first comparison result is that the reduction value of the gate charge is the same as the preset value, determine that the type of short circuit of the insulated gate bipolar transistor is a type-I short circuit.

[0027] In some embodiments, the detection module includes:

[0028] A judgment module, configured to determine the change trend of the collector current and the change trend of the collector-emitter voltage according to the collector current information and the collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor;

[0029] A determination module, configured to, if the collector current and the collector-emitter voltage both show an upward trend, determine that the type of short circuit of the insulated gate bipolar transistor is a type-II short circuit.

[0030] In a third aspect, the present disclosure further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the calculation method in the first aspect is implemented.

[0031] In a fourth aspect, the present disclosure further provides a computer-readable storage medium storing a computer program for executing the calculation method in the first aspect.

[0032] In a fifth aspect, the present disclosure further provides a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, the steps of the calculation method in the first aspect are implemented.

[0033] The embodiments of the present disclosure determine whether a type-I short circuit or a type-II short circuit occurs by obtaining circuit parameter information, which has certain guiding significance for IGBT state detection. Description of the Drawings

[0034] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0035] Figure 1a Schematic diagram of a half-bridge circuit model in a commutation loop provided by an embodiment of the present disclosure;

[0036] Figure 1b Schematic diagram of the structure of an IGBT provided by an embodiment of the present disclosure;

[0037] Figure 2 Flowchart of a method for short-circuit detection of IGBTs inside a converter provided by an embodiment of the present disclosure;

[0038] Figures 3a - 3b Waveform diagrams of a first type of short circuit and a second type of short circuit process respectively;

[0039] Figure 4 Flowchart of executing step S2 provided by an embodiment of the present disclosure;

[0040] Figures 5a - 5b Waveform diagrams of gate charging charge characteristics under different working conditions respectively;

[0041] Figure 6 Structural diagram of a device for short-circuit detection of IGBTs inside a converter provided by an embodiment of the present disclosure;

[0042] Figure 7 Schematic diagram of the structure of an electronic device provided by an embodiment of the present disclosure. Detailed implementation manners

[0043] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail and completely below in conjunction with the accompanying drawings and specific implementation manners. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present disclosure.

[0044] Figure 1a Schematic diagram of a half-bridge circuit model in a commutation loop provided by an embodiment of the present disclosure. Figure 1b Schematic diagram of the structure of an IGBT provided by an embodiment of the present disclosure. As Figure 1a shown, U DC is the DC bus voltage, u GE is the gate voltage, u CEis the collector-emitter voltage (u CE,chip is the collector-emitter voltage of the IGBT chip, L s,CE is the parasitic inductance of the IGBT device package), i C is the collector current, u F is the FWD voltage (u F,chip is the collector-emitter voltage of the chip, L s,F is the parasitic inductance of the FWD device package), i F is the FWD current, I L is the load inductor current, L s,1 is the value of the parasitic inductance of the IGBT loop, L s,2 is the value of the parasitic inductance of the FWD freewheeling loop. Among them, Figure 1a the outermost dotted line m in is the reference direction of voltage and current.

[0045] As Figure 1b shown, the IGBT includes a gate G, a collector C, and an emitter E. The three main capacitors inside the IGBT include an input capacitor (Cies), an output capacitor (Coss), and a reverse transfer capacitor (Cres), which have an important impact on the switching performance of the IGBT.

[0046] Among them, the input capacitor Cies refers to the capacitor between the gate G and the emitter E and between the gate G and the collector C of the IGBT, which includes the gate-emitter capacitor (C GE ) and the gate-collector capacitor (C Gc ). The input capacitor plays an important role in the IGBT turn-on process. When the input capacitor is charged to the threshold voltage, the device can turn on; when it is discharged to a certain value, the device can turn off. Therefore, the input capacitor mainly affects the switching speed and switching loss of the device.

[0047] The output capacitor Coss refers to the capacitor between the collector C and the emitter E and between the gate G and the emitter E of the IGBT, which includes the gate-collector capacitor (C Gc ) and the collector-emitter capacitor (C CE ). The output capacitor mainly affects the change of the device VCE and limits dv / dt during the switching transition. Since the capacitance of the output capacitor is very small, its influence can be ignored under large current conditions, but when the load current is small, it may cause a significant change in the IGBT collector voltage.

[0048] The reverse transfer capacitor Cres is also called the Miller capacitor and refers to the capacitor between the gate G and the collector C of the IGBT, that is, C Gc . It mainly affects the coupling relationship between the gate voltage VGE and VCE of the device. During the IGBT turn-on process, the Miller capacitor will cause the gate voltage to remain at a relatively high plateau for a period of time, and this stage is called the Miller plateau.

[0049] In addition, the working principle of the IGBT is as follows: when a positive voltage is applied to the gate G, a channel is formed in the MOSFET, allowing current to flow from the emitter to the base region. At this time, the base current of the BJT also increases, causing the BJT to conduct and allowing a large current to flow from the collector to the emitter, and the IGBT enters the on state. When the gate voltage is zero or reverse, the channel of the MOSFET disappears, the base current of the BJT is cut off, and the IGBT enters the off state.

[0050] When Figure 1a the upper half-bridge arm in the commutation loop in

[0051] is short-circuited (i.e., point A and point K are short-circuited), the IGBT may experience a type-I short circuit or a type-II short circuit.

[0052] In view of the above problems in the prior art, an embodiment of the present disclosure provides a method for detecting a short circuit of an IGBT inside a converter.

[0053] Figure 2 The following is a flowchart of a method for detecting a short circuit of an IGBT inside a converter provided by an embodiment of the present disclosure. As Figure 2 shown, the detection method includes:

[0054] S1. Obtain the circuit parameter information of the IGBT.

[0055] S2. Determine the type of IGBT short circuit based on the circuit parameter information.

[0056] Specifically, when Figure 1a the upper half-bridge arm in the commutation loop in

[0057] is short-circuited (i.e., point A and point K are short-circuited), the IGBT may experience a type-I short circuit or a type-II short circuit.

[0058] Among them, when the short circuit of the upper half-bridge arm in the commutation loop (i.e., short circuit between point A and point K) occurs when the IGBT has not yet been turned on, a type-I short circuit will occur when the IGBT is turned on.

[0059] Figures 3a - 3b are respectively waveform diagrams of the type-I short circuit and type-II short circuit processes.

[0060] As Figures 3a - 3b shown, tSC When a short circuit occurs at points A and K in the half-bridge circuit, in different short-circuit types, the circuit parameters of the IGBT in the half-bridge circuit change differently. According to the circuit parameters of the IGBT, the directions of voltage and current in the half-bridge circuit can be determined, and then the type of short circuit can be determined.

[0061] The embodiments of the present disclosure have certain guiding significance for IGBT state detection by obtaining circuit parameter information to determine whether a type-I short circuit or a type-II short circuit occurs.

[0062] Figure 4 This is a flowchart of an execution step S2 provided by the embodiments of the present disclosure.

[0063] As Figure 4 shown, in some embodiments, the circuit parameter information includes first gate current information during the actual turn-on process of the IGBT and second gate current information during the normal turn-on process of the IGBT. Step S2, determining the type of short circuit based on the circuit parameter information, includes:

[0064] S21. Based on the first gate current information and the second gate current information, calculate the reduction value of the gate charge amount during the actual turn-on process of the IGBT compared to the normal turn-on process of the IGBT.

[0065] S22. Compare the reduction value of the gate charge amount with a preset value to obtain a first comparison result.

[0066] S23. Determine the type of IGBT short circuit based on the first comparison result.

[0067] Specifically, during the normal turn-on process of the IGBT, the Miller capacitance increases as the device voltage decreases. At this time, most of the gate current (i G ) charges the gate-emitter capacitance (C GE ), and the gate voltage (u GE ) slowly rises into the Miller plateau period. When a type-I short-circuit fault occurs, the current linear region is exited, and the IGBT collector-emitter voltage (u CE ) rises to the DC bus voltage U DC . At this time, the Miller capacitance is small and basically unchanged, and only a very small part of the gate current (i G ) charges the Miller capacitance, and the Miller plateau period disappears, resulting in a smaller gate charging charge QG under the type-I short-circuit fault compared to the normal turn-on process. The detection of the type-I short-circuit fault can be realized by identifying the QG difference.

[0068] Optionally, the first gate current information may be the waveform information of the gate current during the actual turn-on process of the IGBT, and the second gate current information is the theoretical waveform information of the gate current during the normal turn-on process of the IGBT. The reduction value of the gate charge during the actual turn-on process of the IGBT compared to the normal turn-on process of the IGBT can be determined by the waveform of the gate current during the actual turn-on process of the IGBT and the theoretical waveform of the gate current during the normal turn-on process of the IGBT, and then the reduction value of the gate charge can be obtained based on this difference.

[0069] Optionally, the first gate current information is the real-time gate current during the actual turn-on process of the IGBT, and the second gate current information is the theoretical gate current at each moment during the normal turn-on process of the IGBT. Optionally, the reduction value of the gate charge during the actual turn-on process of the IGBT compared to the normal turn-on process of the IGBT can also calculate the first gate charge during the actual turn-on process of the IGBT according to the first gate current information, calculate the theoretical gate charge during the normal turn-on process of the IGBT according to the second gate current information, calculate the difference between the first gate charge and the theoretical gate charge, and obtain the reduction value of the gate charge.

[0070] Of course, the reduction value of the gate charge during the actual turn-on process of the IGBT compared to the normal turn-on process of the IGBT can also be obtained by other means, and the present disclosure does not limit this.

[0071] In some embodiments, S23, determining the type of IGBT short circuit based on the first comparison result, includes: if the first comparison result is that the reduction value of the gate charge is the same as the preset value, then determine that the type of IGBT short circuit is a type-I short circuit; if the first comparison result is that the reduction value of the gate charge is different from the preset value, then determine that the type of IGBT short circuit is not a type-I short circuit.

[0072] In some embodiments, the preset value is the integral value of the gate charge during the Miller plateau stage during the normal turn-on process of the IGBT.

[0073] Specifically, Figures 5a - 5b are the waveform diagrams of the gate charging charge characteristics under different working conditions. As Figures 5a - 5b shown, among them, Figure 5a is the waveform diagram of each circuit parameter during the type-I short circuit process of the IGBT, Figure 5b is the waveform diagram of each circuit parameter during the normal turn-on process of the IGBT.

[0074] From Figures 5a - 5b it can be seen that the gate charging process during the type-I short circuit process includes one stage:

[0075] ① The gate voltage rises from Figure 5a at time t0 to Figure 5a at time t3 from U G,off to U G,on .

[0076] Comparing with the gate charging process during the normal turn-on of IGBT, the gate charging process includes the following three stages:

[0077] ① The gate voltage rises from Figure 5b at time t0 to Figure 5b at time t2 from U G,off to the Miller plateau voltage U G,miller .

[0078] ② Miller plateau stage: From Figure 5b at time t2 to Figure 5b at time t3, the gate voltage remains unchanged.

[0079] ③ From Figure 5b at time t3 to Figure 5b at time t4, the gate voltage rises from the Miller plateau voltage U G,miller to U G,on .

[0080] Comparing Figure 5a with Figure 5b , compared with the normal turn-on process of IGBT, the value of the reduction in gate charge during a type of short-circuit process is approximately the integral of the gate charge during the Miller plateau stage ( Figure 5b from t2 to t3) of the normal turn-on process.

[0081] In some embodiments, the detection method not only includes S1 to S2, but also includes:

[0082] S3. According to the second gate current information during the normal turn-on of IGBT, calculate the product of the collector-emitter voltage and the capacitance from the gate to the collector at the start time of the Miller plateau stage during the normal turn-on of IGBT to obtain the preset value.

[0083] Specifically, the relationship between the capacitance charge Q, the capacitance value c, and the voltage u is:

[0084] Q = cu (1);

[0085] Based on the analysis of Figure 5a and Figure 5b , compared with the normal turn-on process of IGBT, the value of the reduction in gate charge during a type of short-circuit process is approximately the integral of the gate charge during the Miller plateau stage ( Figure 5b from t2 to t3, where t2 is the start time of the Miller plateau and t3 is the end time of the Miller plateau) of the normal turn-on process. The change in gate charge during the Miller plateau process is:

[0086] Q G,miller = Q G,t2 -Q G,t3 = C GC,t2 ×u GC,t2 -C GC,t3 ×u GC,t3 (2);

[0087] Considering u GC ≈ u CE and at time t3, u CE ≈ 0, then Equation (2) can be written as:

[0088] Q G,miller = C GC,t2 ×u CE,t2 ;

[0089] That is, during a type-I short-circuit process of the IGBT, compared with the normal turn-on process of the IGBT, the theoretical value of the reduction in gate charge is the product of the collector-emitter voltage and the capacitance from the gate to the collector at the start of the Miller plateau stage during the normal turn-on process of the IGBT.

[0090] Since the IGBT is already fully conducting when a type-II short-circuit process occurs, the type-II short-circuit process cannot be identified by the above method.

[0091] In some embodiments, the circuit parameter information further includes collector current information and collector-emitter voltage information. Step S2, determining the type of IGBT short-circuit based on the circuit parameter information, includes:

[0092] According to the collector current information and collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor, determine the change trend of the collector current and the change trend of the collector-emitter voltage; if both the collector current and the collector-emitter voltage show an upward trend, determine that the type of short-circuit is a type-II short-circuit.

[0093] Specifically, referring to Figure 1a , when the IGBT is already fully conducting, the current path is: the current flows through the load L load into the IGBT, and the DC bus voltage U DC is shared by both the load L load and the IGBT. If the upper half-bridge arm of the commutation loop is short-circuited at this time (i.e., points A and K are short-circuited), then the DC bus voltage U DC is completely shared by the IGBT, resulting in a sudden increase in the collector-emitter voltage u CE . Therefore, after a type-II short-circuit occurs, there is a process in which both the collector current i C and the collector-emitter voltage u CE rise simultaneously. "i C and u CE"Simultaneous rise" can be used as a feature for the second type of short - circuit detection.

[0094] See Figure 3b , a second - type short - circuit occurs during the tsc~t2 period of Figure 3b , where tsc is the start time of the second - type short - circuit, and t2 is the start time of the Miller plateau during the normal turn - on process of the IGBT.

[0095] In some embodiments, according to the second gate - current information during the normal turn - on process of the IGBT, the collector - current information and the collector - emitter voltage information during the actual turn - on process of the IGBT, determine the change trends of the collector current and the collector - emitter voltage at the moment corresponding to the moment before the start stage of the Miller plateau during the normal turn - on process of the IGBT during the actual turn - on process of the IGBT. Among them, according to the second gate - current information during the normal turn - on process of the IGBT, the start time of the Miller plateau during the normal turn - on process of the IGBT can be determined. Furthermore, during the actual turn - on process of the IGBT, determine whether there is a simultaneous rise in the collector current and the collector - emitter voltage at the moment corresponding to the moment before the start stage of the Miller plateau during the normal turn - on process of the IGBT. If so, determine that the type of short - circuit is the second - type short - circuit.

[0096] See Figure 3b , when a second - type short - circuit occurs, during the tsc~t1 period of Figure 3b , the change rate of i C is in the following relationship:

[0097]

[0098] In formula (4), Ls is Figure 1a the sum of Ls,1, Ls,2 and Ls, CE .

[0099] i C can be calculated by formula (5):

[0100]

[0101] In formula (5), t starts from the tsc moment.

[0102] During the tsc~t1 period of Figure 3b , u CE is calculated by formula (6):

[0103]

[0104] Considering that the IGBT chip voltage u CE,chip remains at the saturation level during this process, and its value is u CE,sat (generally about 3V). Combining formula (4), formula (6) can be written as:

[0105]

[0106] Combining the above formulas (5) and (7), it can be seen that in the case of a type-II short circuit, i C and u CE rise simultaneously.

[0107] According to the above embodiments, combining the variation rules of various parameters in the processes of type-I and type-II short circuits, the differential detection methods for type-I and type-II short circuit processes are obtained as shown in Table 1:

[0108] Table 1 Differential Detection Methods for Type-I and Type-II Short Circuit Processes

[0109]

[0110] In the embodiments of the present disclosure, only based on the circuit parameter information of the IGBT, it can be determined whether a type-I short circuit and a type-II short circuit occur. Specifically, according to the circuit parameter information of the IGBT, the reduction amount of the gate charge during the actual turn-on process of the IGBT is judged to determine whether a type-I short circuit occurs, and according to the circuit parameter information of the IGBT, it is judged whether the collector current and the collector-emitter voltage rise simultaneously during the actual turn-on process of the IGBT to determine whether a type-II short circuit occurs. The embodiments of the present disclosure can perform differential detection on type-I and type-II short circuits, which has certain guiding significance for the IGBT status detection, can quickly and accurately detect the type of short circuit, and then timely protect against the short circuit.

[0111] In a second aspect, based on the same inventive concept, the embodiments of the present disclosure further provide a device for identifying short circuits of IGBTs inside a converter.

[0112] Figure 6 FIG. 600 is a structural diagram of a device 600 for identifying short circuits of IGBTs inside a converter provided by the embodiments of the present disclosure. The device 600 can be used to identify the short circuit type of a half-bridge circuit as shown in Figure 1a . As shown in Figure 6 , the device 600 includes an acquisition module 601 and a detection module 602.

[0113] Among them, the acquisition module 601 is used to acquire the circuit parameter information of the IGBT.

[0114] The detection module 602 is used to determine the type of IGBT short circuit based on the circuit parameter information.

[0115] Specifically, when Figure 1a in the commutation loop of the upper half-bridge arm is short-circuited (i.e., the A point and the K point are short-circuited), the IGBT may have a type-I short circuit or a two-way short circuit.

[0116] Among them, when a short circuit occurs in the upper half-bridge arm of the commutation loop (i.e., the short circuit between point A and point K) in a state where the IGBT has not yet been turned on, when the IGBT is turned on, a type of short circuit will occur.

[0117] When a short circuit occurs in the upper half-bridge arm of the commutation loop (i.e., the short circuit between point A and point K) in a state where the IGBT has already been turned on, then a type II short circuit will occur to the IGBT.

[0118] See Figures 3a - 3b As shown, t SC is the moment when a short circuit occurs between point A and point K in the half-bridge circuit. In different short circuit types, the circuit parameters of the IGBT in the half-bridge circuit change differently. According to the circuit parameters of the IGBT, the directions of voltage and current in the half-bridge circuit can be determined, and then the type of short circuit can be determined.

[0119] The device provided by the embodiments of the present disclosure determines whether a type I short circuit or a type II short circuit occurs by obtaining circuit parameter information, which has certain guiding significance for the IGBT state detection.

[0120] In some embodiments, the circuit parameter information includes first gate current information during the actual turn-on process of the IGBT and second gate current information during the normal turn-on process of the IGBT. The detection module 602 includes a calculation module 612, a comparison module 622, and a determination module 632.

[0121] Among them, the calculation module 612 is used to calculate the reduction value of the gate charge amount during the actual turn-on process of the IGBT compared with the normal turn-on process of the IGBT based on the first gate current information and the second gate current information. The comparison module 622 is used to compare the reduction value of the gate charge amount with a preset value to obtain a first comparison result. The determination module 632 is used to determine the type of IGBT short circuit based on the first comparison result.

[0122] In some embodiments, the determination module 632 is specifically configured to determine that the type of IGBT short circuit is a type I short circuit if the first comparison result is that the reduction value of the gate charge amount is the same as the preset value.

[0123] Specifically, during the normal turn-on process of the IGBT, the Miller capacitance increases as the device voltage decreases. At this time, most of the gate current (i G ) charges the gate-emitter capacitance (C GE ), and the gate voltage (u GE ) slowly rises into the Miller plateau period. When a type I short circuit fault occurs, the current linear region is exited, and the IGBT collector-emitter voltage (u CE ) rises to the DC bus voltage U DC . At this time, the Miller capacitance is small and basically unchanged, and the gate current (i G)Only a very small part charges the Miller capacitor, and the Miller plateau disappears, resulting in a smaller gate charging charge QG during a type of short - circuit fault compared to the normal turn - on process. The detection module 602 can detect the type of short - circuit fault by identifying the difference in QG.

[0124] Optionally, the first gate current information can be the waveform information of the gate current during the actual turn - on process of the IGBT, and the second gate current information is the theoretical waveform information of the gate current during the normal turn - on process of the IGBT. During the actual turn - on process of the IGBT compared to the normal turn - on process of the IGBT, for the reduction value of the gate charge quantity, the calculation module 612 can determine the difference between the gate current during the actual turn - on process of the IGBT and the theoretical gate current during the normal turn - on process of the IGBT through the waveform of the gate current during the actual turn - on process of the IGBT and the theoretical waveform of the gate current during the normal turn - on process of the IGBT, and then obtain the reduction value of the gate charge quantity based on the difference in gate current. Further, the comparison module 622 compares the reduction value with a preset value, and finally the determination module 632 determines the type of IGBT short - circuit according to the comparison result.

[0125] Optionally, the first gate current information is the real - time gate current during the actual turn - on process of the IGBT, and the second gate current information is the theoretical gate current at each moment during the normal turn - on process of the IGBT. Optionally, during the actual turn - on process of the IGBT compared to the normal turn - on process of the IGBT, the reduction value of the gate charge quantity can also be calculated by the calculation module 612. The calculation module 612 calculates the first gate charge quantity during the actual turn - on process of the IGBT according to the first gate current information, calculates the theoretical gate charge quantity during the normal turn - on process of the IGBT according to the second gate current information, calculates the difference between the first gate charge quantity and the theoretical gate charge quantity, and obtains the reduction value of the gate charge quantity. Further, the comparison module 622 compares the reduction value with a preset value, and finally the determination module 632 determines the type of IGBT short - circuit according to the comparison result.

[0126] Of course, during the actual turn - on process of the IGBT compared to the normal turn - on process of the IGBT, the reduction value calculation module 612 of the gate charge quantity can also be calculated by other methods, and the present disclosure does not limit this.

[0127] In some embodiments, the preset value is the integral value of the gate charge quantity during the Miller plateau stage in the normal turn - on process of the IGBT. In some embodiments, the calculation module 612 is further configured to calculate the integral value of the gate charge quantity during the Miller plateau stage in the normal turn - on process of the IGBT.

[0128] Specifically, referring to Figures 5a - 5b it can be seen that the gate charging process during a type of short - circuit process includes a stage: the gate voltage changes from Figure 5a at time t0 to Figure 5a at time t3 from UG,off Rise to U G,on .

[0129] For the comparison, the gate charging process during the normal turn-on process of the IGBT includes the following three stages:

[0130] 1. From the moment t0 of Figure 5b to the moment t2 of Figure 5b , the gate voltage rises from U G,off to the Miller plateau voltage U G,miller .

[0131] 2. Miller plateau stage: From the moment t2 of Figure 5b to the moment t3 of Figure 5b , the gate voltage remains unchanged.

[0132] 3. From the moment t3 of Figure 5b to the moment t4 of Figure 5b , the gate voltage rises from the Miller plateau voltage U G,miller to U G,on .

[0133] Comparing Figure 5a with Figure 5b , compared with the normal turn-on process of the IGBT, the value of the reduction in the gate charge amount during a type of short-circuit process is approximately the integral of the gate charge amount during the Miller plateau stage ( Figure 5b from t2 to t3 of

[0134] In some embodiments, the calculation module 612 is further configured to calculate the product of the collector-emitter voltage and the capacitance from the gate to the collector at the start moment of the Miller plateau stage during the normal turn-on process of the IGBT according to the second gate current information during the normal turn-on process of the IGBT, to obtain the preset value.

[0135] Specifically, the relationship between the capacitance charge amount Q, the capacitance value c, and the voltage u is:

[0136] Q = cu (1);

[0137] According to the analysis of Figure 5a and Figure 5b , compared with the normal turn-on process of the IGBT, the value of the reduction in the gate charge amount during a type of short-circuit process is approximately the integral of the gate charge amount during the Miller plateau stage ( Figure 5b from t2 to t3, where t2 is the start time of the Miller plateau and t3 is the end time of the Miller plateau) of the normal turn-on process. The change in the gate charge amount during the Miller plateau process is:

[0138] Q G,miller = Q G,t2 - Q G,t3 = C GC,t2 × u GC,t2-C GC,t3 ×u GC,t3 (2);

[0139] Considering u GC ≈u CE and at time t3, u CE ≈0, then Equation (2) can be written as:

[0140] Q G,miller = C GC,t2 ×u CE,t2 ;

[0141] That is, during the first type of short - circuit process of the IGBT compared to the normal turn - on process of the IGBT, the theoretical decrease value of the gate charge is the product of the collector - emitter voltage and the gate - to - collector capacitance at the start time of the Miller plateau stage during the normal turn - on process of the IGBT.

[0142] Since the IGBT is already fully conducting when the second type of short - circuit process occurs, the device 600 cannot identify the second type of short - circuit process through the above - mentioned method. Refer to Figure 1a , when the IGBT is already fully conducting, the current path is: the current flows through the load L load into the IGBT, and the DC bus voltage U DC is shared by both the load L load and the IGBT. If the upper half - bridge arm of the commutation loop is short - circuited at this time (i.e., the A point and the K point are short - circuited), then the DC bus voltage U DC is completely borne by the IGBT, resulting in a sudden increase in the collector - emitter voltage u CE . Therefore, after the second type of short - circuit occurs, there is a process in which the collector current i C and the collector - emitter voltage u CE rise simultaneously ( Figure 3b during the tsc - t2 time period, where tsc is the start time of the second type of short - circuit and t2 is the start time of the Miller plateau during the normal turn - on process of the IGBT), and "i C and u CE rising simultaneously" can be used as a feature for detecting the second type of short - circuit.

[0143] For the case of the second type of short - circuit, in some embodiments, the detection module 602 includes a judgment module 642 and a determination module 632.

[0144] Among them, the judgment module 642 is used to determine the change trend of the collector current and the change trend of the collector - emitter voltage according to the collector current information and the collector - emitter voltage information during the actual turn - on process of the insulated gate bipolar transistor.

[0145] Specifically, the determination module 642 is configured to determine the change trends of the collector current and the collector-emitter voltage within a preset time period before the start stage of the Miller plateau during the normal turn-on process of the IGBT according to the second gate current information, the collector current information, and the collector-emitter voltage information during the normal turn-on process of the IGBT.

[0146] The determination module 632 is configured to determine that the type of IGBT short circuit is a type-II short circuit if both the collector current and the collector-emitter voltage show an upward trend.

[0147] The device 600 provided in the embodiments of the present disclosure only obtains the circuit parameter information of the IGBT through the obtaining module 601, and the detection module 602 can determine whether a type-I short circuit and a type-II short circuit occur based on the circuit parameters obtained by the obtaining module 601. Specifically, the detection module 602 determines whether a type-I short circuit occurs according to the reduction amount of the gate charge during the actual turn-on process of the IGBT based on the circuit parameter information of the IGBT, and determines whether a type-II short circuit occurs according to whether the collector current and the collector-emitter voltage rise simultaneously during the actual turn-on process of the IGBT. The device 600 provided in the embodiments of the present disclosure can perform differential detection on type-I short circuits and type-II short circuits, which has certain guiding significance for the IGBT state detection, can quickly and accurately detect the type of short circuit, and then protect against the short circuit in a timely manner.

[0148] It can be understood that for the specific details of the computing device provided in the embodiments of the present disclosure, reference may be made to the specific details of the first aspect of the method embodiments described above, and details will not be repeated here.

[0149] In a third aspect, the embodiments of the present disclosure further provide an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method described in any one of the embodiments in the first aspect is implemented.

[0150] Specifically, Figure 7 is a schematic structural diagram of an electronic device provided in the embodiments of the present disclosure. As Figure 7 shown, the electronic device 003 includes a memory 302, a processor 301, a bus 303, and a computer program stored on the memory 302 and executable on the processor. Among them, the processor 301 and the memory 302 communicate with each other through the bus 303, and the processor 301 calls the computer program in the memory 302 to implement the method described in any one of the embodiments in the first aspect.

[0151] In a fourth aspect, the embodiments of the present disclosure further provide a computer-readable storage medium storing a computer program of the method described in any one of the embodiments in the first aspect.

[0152] In a fifth aspect, embodiments of the present disclosure further provide a computer program product, including a computer program / instructions, which when executed by a processor, implement the steps of the method described in any one of the embodiments in the first aspect above.

[0153] Those skilled in the art should understand that the embodiments of the present disclosure may be provided as a method, a system, or a computer program product. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present disclosure may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0154] The present disclosure is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices produce a device for implementing the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram.

[0155] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device that implements the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram.

[0156] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flows in the flowchart and / or one or more blocks in the block diagram.

[0157] Specific embodiments are applied in the present disclosure to elaborate on the principles and implementation manners of the present disclosure. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present disclosure; at the same time, for those of ordinary skill in the art, according to the idea of the present disclosure, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present disclosure.

Claims

1. A short - circuit identification method for an insulated - gate bipolar transistor inside a converter, characterized in that The method includes: Obtaining circuit parameter information of the insulated gate bipolar transistor; Determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information.

2. The method according to claim 1, wherein The circuit parameter information includes first gate current information during the actual turn-on process of the insulated gate bipolar transistor and second gate current information during the normal turn-on process of the insulated gate bipolar transistor. Determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information includes: Calculating the reduction value of the gate charge during the actual turn-on process of the insulated gate bipolar transistor compared to the normal turn-on process of the insulated gate bipolar transistor based on the first gate current information and the second gate current information; Comparing the reduction value of the gate charge with a preset value to obtain a first comparison result; Determining the type of short circuit of the insulated gate bipolar transistor based on the first comparison result.

3. The method according to claim 2, wherein The preset value is the integral value of the gate charge during the Miller plateau stage in the normal turn-on process of the insulated gate bipolar transistor.

4. The method according to claim 2, characterized in that, The method further includes: Calculating the product of the collector-emitter voltage and the capacitance from the gate to the collector at the start time of the Miller plateau stage during the normal turn-on process of the insulated gate bipolar transistor according to the second gate current information during the normal turn-on process of the insulated gate bipolar transistor to obtain the preset value.

5. The method according to claim 2, wherein Determining the type of short circuit of the insulated gate bipolar transistor based on the first comparison result includes: If the first comparison result is that the reduction value of the gate charge is the same as the preset value, determining that the type of short circuit of the insulated gate bipolar transistor is a type-I short circuit.

6. The method according to claim 2, characterized in that, The circuit parameter information further includes collector current information and collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor. Determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information includes: Determining the change trend of the collector current and the change trend of the collector-emitter voltage according to the collector current information and the collector-emitter voltage information during the actual turn-on process of the insulated gate bipolar transistor; If the collector current and the collector-emitter voltage both show an upward trend, determining that the type of short circuit of the insulated gate bipolar transistor is a type-II short circuit.

7. A device for short - circuit identification of an insulated gate bipolar transistor inside a converter, characterized in that, The device includes: An acquisition module for acquiring circuit parameter information of the insulated gate bipolar transistor; A detection module for determining the type of short circuit of the insulated gate bipolar transistor based on the circuit parameter information.

8. The device according to claim 7, characterized in that, The circuit parameter information includes first gate current information during the actual turn-on process of the insulated gate bipolar transistor and second gate current information during the normal turn-on process of the insulated gate bipolar transistor. The detection module includes: A calculation module for calculating the reduction value of the gate charge during the actual turn-on process of the insulated gate bipolar transistor compared to the normal turn-on process of the insulated gate bipolar transistor based on the first gate current information and the second gate current information; A comparison module for comparing the reduction value of the gate charge with a preset value to obtain a first comparison result; A determination module for determining the type of short circuit of the insulated gate bipolar transistor based on the first comparison result.

9. The device according to claim 8, wherein, The determining module is specifically configured to determine that the short - circuit type of the insulated - gate bipolar transistor is a type - I short - circuit if the first comparison result shows that the decrease value of the gate charge quantity is the same as the preset value.

10. The device according to claim 7, characterized in that, The detection module includes: A judgment module, configured to determine the change trend of the collector current and the change trend of the collector - emitter voltage according to the collector - current information and the collector - emitter - voltage information during the actual turn - on process of the insulated - gate bipolar transistor; A determining module, configured to determine that the short - circuit type of the insulated - gate bipolar transistor is a type - II short - circuit if both the collector current and the collector - emitter voltage show an upward trend.

11. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

12. A computer-readable storage medium, characterized in that, The computer - readable storage medium stores a computer program for executing the method according to any one of claims 1 to 6.

13. A computer program product comprising a computer program / instruction, characterized in that, When the computer program / instructions are executed by the processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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