Resistance welding fault detection method, system, power module and electronic device

Abstract

The application provides a resistance welding fault detection method, system, power module and electronic equipment. The method can be applied to a power module, the power module includes at least one switching tube circuit, the switching tube circuit includes a switching tube and at least one welding resistor, and the method includes: in response to a detection instruction, controlling the switching tube circuit to be turned on and outputting a test current to the switching tube circuit; collecting an actual voltage value of the switching tube circuit; in the case that a deviation value between the actual voltage value of the switching tube circuit and a theoretical voltage value is greater than a preset deviation threshold value, determining that the switching tube circuit has a resistance welding fault; and the theoretical voltage value is calculated according to the test current, an output characteristic curve of the switching tube and the resistance value of each welding resistor. The resistance welding fault in the power module can be quickly and accurately detected. The welding resistor detection efficiency in the power module can be effectively improved, and the poor welding resistor in the switching tube circuit can be more accurately measured.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a method, system, power module, and electronic equipment for detecting resistance welding faults. Background Technology

[0002] With the development of science and technology, various power modules have been widely used. Power modules typically have resistors soldered on them according to actual needs. During the soldering process, poor soldering quality can cause the resistor value to fail to meet application requirements, easily leading to power module failure. Therefore, it is necessary to test the soldering resistance of power modules.

[0003] In existing technologies, resistance measurement is usually used to test each welding resistor individually. However, the resistance value of welding resistors is usually small, and using existing resistance measurement equipment will result in large measurement errors, and it is difficult to set up test points, resulting in low detection efficiency. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method, system, power module, and electronic device for detecting resistance welding faults, which can quickly and accurately detect whether the resistors in the power module have welding faults. The specific solution is as follows:

[0005] A method for detecting resistance welding faults, applied to a power module, the power module including at least one switching transistor circuit, the switching transistor circuit including a switching transistor and at least one welding resistor, the method comprising:

[0006] In response to a detection command, the switching transistor circuit is turned on, and a test current is output to the switching transistor circuit.

[0007] Collect the actual voltage value of the switching transistor circuit;

[0008] If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is greater than a preset deviation threshold, a resistance welding fault is determined in the switching transistor circuit; the theoretical voltage value is calculated based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each welding resistor.

[0009] Optionally, the process of setting the deviation threshold in the above method includes:

[0010] Obtain the discrete deviation voltage of the switching transistor and the preset deviation voltage;

[0011] The deviation threshold is obtained by summing the discrete deviation voltage and the deviation voltage.

[0012] Optionally, in the above method, the step of calculating the theoretical voltage value based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each of the welding resistors includes:

[0013] The voltage drop of the switching transistor is determined based on the test current and the output characteristic curve.

[0014] The resistance voltage of the switching transistor circuit is calculated based on the test current and each of the welding resistors.

[0015] The theoretical voltage value of the switching transistor circuit is calculated based on the voltage drop of the switching transistor and the voltage of the resistor.

[0016] Optionally, in the above method, the test current is the maximum rated current of the switching transistor in the switching transistor circuit.

[0017] The above methods may also include:

[0018] If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is not greater than a preset deviation threshold, the resistor welding of the switching transistor circuit is determined to be normal.

[0019] Optionally, in the above method, acquiring the actual voltage value of the switching transistor circuit includes:

[0020] After outputting a test current to the switching transistor circuit, a preset timer is started;

[0021] When the timer reaches the preset first duration, the actual voltage value of the switching transistor circuit is collected.

[0022] The above methods may also include:

[0023] When the timer reaches a preset second duration, the output of test current to the switching transistor circuit stops; the second duration is longer than the first duration and is also greater than the time constant of the power module.

[0024] A resistance welding fault detection system is applied to a power module, the power module including at least one switching transistor circuit, the switching transistor circuit including a switching transistor and at least one welding resistor; the system includes:

[0025] Current output module, voltage acquisition module, gate drive module, and control equipment;

[0026] The output terminal of the current output module is connected to the base of the switching transistor through at least one welding resistor, and the input terminal of the current output module is connected to the emitter of the switching transistor through at least one welding resistor. The current output module is used to output current to the switching transistor circuit.

[0027] The gate drive module is connected to the gate of the switching transistor and is used to control the switching transistor to be turned on or off.

[0028] One end of the voltage acquisition module is connected to the input terminal of the switching transistor circuit, and the other end of the voltage acquisition module is connected to the output terminal of the switching transistor circuit. The voltage acquisition module is used to acquire the voltage of the switching transistor circuit.

[0029] The control device is connected to the current output module, the voltage acquisition module, and the gate drive module, respectively.

[0030] The control device is used to perform the resistance welding fault detection method as described above.

[0031] A power module, comprising:

[0032] Control device, capacitor, multiple parallel switching transistor circuits; each of the switching transistor circuits includes a switching transistor and multiple solder resistors;

[0033] The base of each of the switching transistors is connected to the capacitor via at least one of the welding resistors; the emitter of each of the switching transistors is connected via at least one of the welding resistors.

[0034] The control device is used to perform the resistance welding fault detection method described above.

[0035] An electronic device includes a memory and one or more instructions, wherein one or more instructions are stored in the memory and configured to be executed by one or more processors of the above-described resistance welding fault detection method.

[0036] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0037] This invention provides a method, system, power module, and electronic device for detecting resistance welding faults. The method can be applied to a power module, which includes at least one switching transistor circuit. Each switching transistor circuit includes a switching transistor and at least one welding resistor. The method includes: responding to a detection command, controlling the switching transistor circuit to conduct and outputting a test current to the switching transistor circuit; acquiring the actual voltage value of the switching transistor circuit; and determining a resistance welding fault in the switching transistor circuit if the deviation between the actual voltage value and the theoretical voltage value exceeds a preset deviation threshold. The theoretical voltage value is calculated based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each welding resistor. This method can quickly and accurately detect whether the resistors in the power module have welding faults, avoiding the measurement errors and low detection efficiency problems associated with prior art methods that rely on resistance measuring equipment. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figure 1 This is a structural example diagram of a power module provided in an embodiment of the present invention;

[0040] Figure 2 This is a structural example diagram of a switching transistor circuit provided in an embodiment of the present invention;

[0041] Figure 3 A flowchart of a resistance welding fault detection method provided in an embodiment of the present invention;

[0042] Figure 4 A flowchart illustrating the process of calculating a theoretical voltage value is provided in an embodiment of the present invention.

[0043] Figure 5 An example diagram of an output characteristic curve provided in an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the structure of a resistance welding fault detection system provided in an embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of the structure of an inverter power module provided in an embodiment of the present invention;

[0046] Figure 8 An equivalent circuit diagram of an inverter power module provided in an embodiment of the present invention;

[0047] Figure 9 An example diagram illustrating an implementation scenario for resistance welding fault detection provided in an embodiment of the present invention;

[0048] Figure 10 This is a schematic diagram of the structure of a multi-tube parallel power module provided in an embodiment of the present invention;

[0049] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

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

[0051] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0052] Currently, in the process of testing the welding resistance of power modules, resistance measurement is usually used to test each welding resistor individually. However, the resistance value of welding resistors is usually small, and the measurement using existing resistance measurement equipment will result in large measurement errors, and it is difficult to set up test points, resulting in low testing efficiency.

[0053] Based on this, embodiments of the present invention provide a method for detecting resistance welding faults, applied to power modules, see [link to relevant documentation]. Figure 1 The above is a structural example diagram of a power module provided in an embodiment of the present invention. The power module includes at least one switching transistor circuit, and the structural example diagram of the switching transistor circuit is shown below. Figure 2 As shown, the switching circuit includes a switching transistor and at least one welding resistor. After a drive signal is input to the gate of the switching circuit, the switching transistor is turned on, and then current is output to the input terminal of the switching circuit, causing the current to flow out of the output terminal of the switching circuit. The flowchart of the resistance welding fault detection method is shown below. Figure 3 As shown, it specifically includes:

[0054] S301: In response to a detection command, control the switching transistor circuit to turn on and output a test current to the switching transistor circuit.

[0055] In this embodiment, the detection command can be a command triggered by the user clicking a preset button or virtual control, or a command triggered by some applications during automatic operation. The detection command can be used to instruct the welding resistance of the switching transistor circuit of the power module to be fault-detected.

[0056] Optionally, the gate driver can be controlled to output a drive signal to the gate of the switching transistor to turn on the switching transistor circuit; the current output device can be controlled to output a test current to the input terminal of the switching transistor circuit, and the current output device can be a constant current source.

[0057] S302: Collect the actual voltage value of the switching transistor circuit.

[0058] In this embodiment, the actual voltage value of the switching transistor can be acquired using a voltage measuring device.

[0059] Optionally, one end of the voltage measuring device can be connected to the input terminal of the switching transistor circuit, and the other end of the voltage measuring device can be connected to the output terminal of the switching transistor circuit. After the switching transistor circuit has stabilized, the actual voltage value of the switching transistor circuit can be collected through the voltage measuring device.

[0060] In some embodiments, the test current may be less than or equal to the maximum rated current of the switching transistor in the switching transistor circuit.

[0061] S303: If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is greater than a preset deviation threshold, a resistance welding fault is determined in the switching transistor circuit; the theoretical voltage value is calculated based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each welding resistor.

[0062] In this embodiment, the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit can be calculated. This deviation value can be the difference between the actual voltage value and the theoretical voltage value, or it can be the absolute value of the difference.

[0063] S304: If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is not greater than a preset deviation threshold, the resistor welding of the switching transistor circuit is determined to be normal.

[0064] By applying the method provided in this embodiment of the invention, the actual voltage value of the switching transistor circuit is measured, and then the actual voltage value is compared with the theoretical voltage value, thereby determining whether the resistance welding of the switching transistor circuit is faulty. This can effectively improve the welding resistance detection efficiency in the power module and more accurately measure the resistance of poorly welded components in the switching transistor circuit.

[0065] In one embodiment of the present invention, the process of setting the deviation threshold includes:

[0066] Obtain the discrete deviation voltage of the switching transistor and the preset deviation voltage;

[0067] The deviation threshold is obtained by summing the discrete deviation voltage and the deviation voltage.

[0068] Optionally, the deviation voltage of the switching transistor circuit can be calculated based on the deviation current, the output characteristic curve of the switching transistor, and the resistance value of each of the welding resistors. This deviation current can be the minimum current among the currents passing through each switching transistor circuit of the power module under the maximum current deviation.

[0069] In one embodiment of the present invention, based on the above implementation process, optionally, the theoretical voltage value is calculated according to the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each of the welding resistors, such as... Figure 4 As shown, it includes:

[0070] S401: Determine the voltage drop of the switching transistor based on the test current and the output characteristic curve.

[0071] In this embodiment, the voltage drop of the switching transistor can be obtained by querying the output characteristic curve through testing the current.

[0072] See Figure 5 This is an example diagram of an output characteristic curve provided in an embodiment of the present invention. The output characteristic curve may include the correspondence between the current Ic of the switching transistor and the voltage drop Vce. For example, if the test voltage is Imax, then the voltage drop of the switching transistor may be Vcep.

[0073] S402: Calculate the resistance voltage of the switching transistor circuit based on the test current and each of the welding resistors.

[0074] In this embodiment, when the welding resistors are connected in series, the test current can be multiplied by the sum of the resistance values ​​of the individual welding resistors to obtain the resistance voltage.

[0075] S403: The theoretical voltage value of the switching transistor circuit is calculated based on the voltage drop of the switching transistor and the voltage of the resistor.

[0076] In this embodiment, the voltage drop of the switching transistor and the voltage across the resistor can be summed to obtain the theoretical voltage value of the switching transistor circuit.

[0077] In one embodiment of the present invention, the step of acquiring the actual voltage value of the switching transistor circuit includes:

[0078] After outputting a test current to the switching transistor circuit, a preset timer is started;

[0079] When the timer reaches the preset first duration, the actual voltage value of the switching transistor circuit is collected.

[0080] In this embodiment, the first duration can be the duration required for the current of the switching transistor circuit to stabilize after the current is output to the switching transistor circuit. When the timer reaches the preset first duration, the actual voltage value of the switching transistor circuit is collected, which can accurately obtain the actual voltage value of the switching transistor circuit under the test current.

[0081] In one embodiment of the present invention, based on the above implementation process, optionally, the method further includes:

[0082] When the timer reaches a preset second duration, the output of test current to the switching transistor circuit stops; the second duration is longer than the first duration and is also greater than the time constant of the power module.

[0083] In this embodiment, the power module contains multiple parallel switching transistor circuits.

[0084] See Figure 6 This is a schematic diagram of a resistance welding fault detection system provided in an embodiment of the present invention. The system can be applied to a power module, which includes at least one switching transistor circuit. The switching transistor circuit includes a switching transistor and at least one welding resistor. The system includes:

[0085] The current output module 601, the voltage acquisition module 602, the gate drive module 603, and the control device 604 are included.

[0086] The output terminal of the current output module is connected to the base of the switching transistor through at least one welding resistor, and the input terminal of the current output module is connected to the emitter of the switching transistor through at least one welding resistor. The current output module is used to output current to the switching transistor circuit.

[0087] The gate drive module is connected to the gate of the switching transistor and is used to control the switching transistor to be turned on or off.

[0088] One end of the voltage acquisition module is connected to the input terminal of the switching transistor circuit, and the other end of the voltage acquisition module is connected to the output terminal of the switching transistor circuit. The voltage acquisition module is used to acquire the voltage of the switching transistor circuit.

[0089] The control device is connected to the current output module, the voltage acquisition module, and the gate drive module, respectively.

[0090] The control device is used to perform the resistance welding fault detection method described above.

[0091] In this embodiment, the power module can be an inverter power module, such as... Figure 7As shown, the power module includes capacitor C1 and a three-phase inverter bridge arm (U / V / W). Each switch in the three-phase inverter bridge arm is composed of multiple devices connected in parallel. The connection points N1, N2… between the upper switch and the capacitor in each bridge arm, N4 between the upper bridge arm and the bridge arm devices, and N5 between the AC output copper busbar and the devices are all laser-welded, and each weld point has a welding resistor. Figure 7 One phase of the power module shown can be equivalent to Figure 8 The electrical network shown, Figure 8 In the diagram, Q1 and Q2 are parallel upper bridge arm devices of a certain phase of the power module, and Q3 and Q4 are parallel lower bridge arm devices of a certain phase of the power module. R1 and R2 are the welding resistances between the upper bridge arm devices and the positive busbar of the bus capacitor, R3 and R4 are the welding resistances between the upper and lower bridge arm devices, R5 and R6 are the welding resistances between the output copper busbar and the bridge arm, and R7 and R8 are the welding resistances between the lower bridge arm devices and the negative busbar of the bus capacitor.

[0092] Optionally, the voltage acquisition module can be a voltage measurement device.

[0093] In the specific testing process, such as Figure 9 As shown, a gate driver can be connected to the gates of parallel devices Q1 and Q2 to output a drive signal, turning on the parallel devices Q1 and Q2. A constant current source is connected to the positive busbar and the AC output terminal of the busbar. When the parallel devices Q1 and Q2 are turned on, the constant current source provides a set constant current. The constant current is given according to the number of parallel devices, and the recommended current magnitude is N*Imax, where N is the number of parallel devices, Imax is the maximum allowable current of a single tube, and the duration of this current is T. Since the power module carries a capacitor, the duration T must be greater than the system time constant τ.

[0094] After the current of the parallel devices stabilizes, a high-precision voltage measurement device is used to measure the positive busbar and AC output terminal of the busbar to obtain the actual voltage value V.

[0095] Optionally, the voltage drop of the device can be determined as VceP based on the output characteristic curve of the power device. Then the theoretical voltage of the parallel branch is VceT = VceP + Imax * (R1 + R3 + R5).

[0096] Based on the parameter dispersion of Vce of the power device, the maximum median deviation of the parameter dispersion is set to ΔVce. If V-VceT > ΔVce + Vlmt, then a welding problem is identified in the resistor, where Vlmt is the set allowable deviation value. If V-VceT ≤ ΔVce + Vlmt, then the resistor welding is considered normal. After measuring the upper bridge arm, the lower bridge arm can be measured in the same way, which will not be elaborated further here.

[0097] This invention also provides a power module with multiple transistors connected in parallel, the schematic diagram of which is shown below. Figure 10 As shown, it includes:

[0098] The control device 1001, capacitor 1002, and multiple parallel-connected switching transistor circuits 1003; each of the switching transistor circuits includes a switching transistor and multiple welding resistors;

[0099] The base of each of the switching transistors is connected to the capacitor via at least one of the welding resistors; the emitter of each of the switching transistors is connected via at least one of the welding resistors.

[0100] The control device is used to perform the resistance welding fault detection method described above.

[0101] This invention also provides a storage medium that includes stored instructions, wherein the execution of the instructions controls the device containing the storage medium to perform the resistance welding fault detection method described above.

[0102] This invention also provides an electronic device, the structural schematic of which is shown below. Figure 11 As shown, it specifically includes a memory 1101 and one or more instructions 1102, wherein one or more instructions 1102 are stored in the memory 1001 and configured to be executed by one or more processors 1103 to perform the following operations:

[0103] In response to a detection command, the switching transistor circuit is turned on, and a test current is output to the switching transistor circuit.

[0104] Collect the actual voltage value of the switching transistor circuit;

[0105] If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is greater than a preset deviation threshold, a resistance welding fault is determined in the switching transistor circuit; the theoretical voltage value is calculated based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each welding resistor.

[0106] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0107] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0108] For ease of description, the above apparatus is described by dividing it into various functional units. Of course, in implementing this invention, the functions of each unit can be implemented in one or more software and / or hardware components.

[0109] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0110] The above provides a detailed description of the resistance welding fault detection method provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for detecting resistance welding faults, characterized in that, Applied to a power module, the power module including at least one switching transistor circuit, the switching transistor circuit including a switching transistor and at least one soldering resistor, the method includes: In response to a detection command, the switching transistor circuit is turned on, and a test current is output to the switching transistor circuit. Collect the actual voltage value of the switching transistor circuit; If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is greater than a preset deviation threshold, a resistance welding fault is determined in the switching transistor circuit; the theoretical voltage value is calculated based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each welding resistor.

2. The method according to claim 1, characterized in that, The process of setting the deviation threshold includes: Obtain the discrete deviation voltage of the switching transistor and the preset deviation voltage; The deviation threshold is obtained by summing the discrete deviation voltage and the deviation voltage.

3. The method according to claim 1, characterized in that, The calculation of the theoretical voltage value based on the test current, the output characteristic curve of the switching transistor, and the resistance values ​​of each of the welding resistors includes: The voltage drop of the switching transistor is determined based on the test current and the output characteristic curve. The resistance voltage of the switching transistor circuit is calculated based on the test current and each of the welding resistors. The theoretical voltage value of the switching transistor circuit is calculated based on the voltage drop of the switching transistor and the voltage of the resistor.

4. The method according to claim 3, characterized in that, The test current is the maximum rated current of the switching transistor in the switching transistor circuit.

5. The method according to claim 1, characterized in that, Also includes: If the deviation between the actual voltage value and the theoretical voltage value of the switching transistor circuit is not greater than a preset deviation threshold, the resistor welding of the switching transistor circuit is determined to be normal.

6. The method according to claim 1, characterized in that, The acquisition of the actual voltage value of the switching transistor circuit includes: After outputting a test current to the switching transistor circuit, a preset timer is started; When the timer reaches the preset first duration, the actual voltage value of the switching transistor circuit is collected.

7. The method according to claim 6, characterized in that, Also includes: When the timer reaches the preset second duration, the output of test current to the switching transistor circuit stops. The second duration is greater than the first duration and is also greater than the time constant of the power module.

8. A resistance welding fault detection system, characterized in that, The system is applied to a power module, the power module including at least one switching transistor circuit, the switching transistor circuit including a switching transistor and at least one soldering resistor; the system includes: Current output module, voltage acquisition module, gate drive module, and control equipment; The output terminal of the current output module is connected to the base of the switching transistor through at least one welding resistor, and the input terminal of the current output module is connected to the emitter of the switching transistor through at least one welding resistor. The current output module is used to output current to the switching transistor circuit. The gate drive module is connected to the gate of the switching transistor and is used to control the switching transistor to be turned on or off. One end of the voltage acquisition module is connected to the input terminal of the switching transistor circuit, and the other end of the voltage acquisition module is connected to the output terminal of the switching transistor circuit. The voltage acquisition module is used to acquire the voltage of the switching transistor circuit. The control device is connected to the current output module, the voltage acquisition module, and the gate drive module, respectively. The control device is used to perform the resistance welding fault detection method as described in any one of claims 1 to 7.

9. A power module, characterized in that, include: Control device, capacitor, multiple parallel switching transistor circuits; each of the switching transistor circuits includes a switching transistor and multiple solder resistors; The base of each of the switching transistors is connected to the capacitor via at least one of the welding resistors; the emitter of each of the switching transistors is connected via at least one of the welding resistors. The control device is used to perform the resistance welding fault detection method as described in any one of claims 1 to 7.

10. An electronic device, characterized in that, It includes a memory and one or more instructions, wherein one or more instructions are stored in the memory and configured to be executed by one or more processors as described in any one of claims 1 to 7.

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