Fault detection circuit, system and method for buses and switching tubes between buses

Abstract

The invention provides a fault detection circuit, system and method for buses and switch tubes between the buses, multiple groups of switch tubes are connected between positive and negative buses, the detection circuit comprises a switch module and a voltage-dividing sampling detection module, and the voltage-dividing sampling detection module comprises a power supply and a voltage-dividing resistance network. The divider resistance network comprises a detection resistor with a voltage dividing function, and the switch module is arranged to connect the two ends of the detection resistor to a positive bus and a negative bus respectively when the switch module is closed, so that the detection resistor is short-circuited when the positive bus and the negative bus are short-circuited. And the sampling voltage output by the voltage division sampling detection module is different from the sampling voltage output when the positive and negative buses are not short-circuited. The bus voltage short-circuit detection function and the switch tube short-circuit and open-circuit detection function between buses are achieved.

Description

Technical Field

[0001] The present invention relates to circuit fault detection technology, and in particular to a busbar and switch tube fault detection circuit, system and method therebetween. Background Art

[0002] The busbar circuit is mainly composed of a rectifier circuit at the front end and an inverter circuit at the back end. Figure 1 As shown, the rectifier circuit includes switch tubes Q1, Q2, Q5, and Q6, wherein the switch tubes Q1 and Q5 are connected in series between the positive bus and the negative bus, and the switch tubes Q2 and Q6 are connected in series between the positive bus and the negative bus. The inverter circuit includes switch tubes Q3, Q4, Q7, and Q8, wherein the switch tubes Q3 and Q7 are connected in series between the positive bus and the negative bus, and the switch tubes Q4 and Q8 are connected in series between the positive bus and the negative bus. The prior art lacks a circuit capable of detecting bus short circuits and switch tube short circuits, which will result in the inability to detect faults when bus and switch tube faults occur. At this time, starting the AC output will cause the circuit to suffer secondary faults and even damage more components, increasing maintenance time and cost, and causing safety hazards.

[0003] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0004] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and to provide a busbar and its switch tube fault detection circuit, system and method.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A busbar and switch tube fault detection circuit therebetween, with multiple groups of switch tubes between the positive and negative busbars, including a switch module and a voltage-dividing sampling detection module, the voltage-dividing sampling detection module including a power supply and a voltage-dividing resistor network, the voltage-dividing resistor network including a detection resistor with a voltage-dividing function, the switch module being configured to connect the two ends of the detection resistor to the positive busbar and the negative busbar, respectively, so that when the positive and negative busbars are short-circuited, the detection resistor is short-circuited, so that the sampling voltage output by the voltage-dividing sampling detection module is different from the sampling voltage output when the positive and negative busbars are not short-circuited.

[0007] Furthermore, the switch module is a relay.

[0008] Furthermore, the voltage-dividing sampling detection module includes a voltage-dividing sampling circuit and a differential operational amplifier circuit. The voltage-dividing sampling circuit generates a voltage signal affected by whether the detection resistor is short-circuited through the voltage-dividing resistor network. The differential operational amplifier circuit is used to receive the voltage signal generated by the voltage-dividing sampling circuit and finally output a differential signal reflecting whether the bus is short-circuited.

[0009] Furthermore, the voltage-dividing sampling circuit includes a voltage follower, a first voltage-dividing resistor, a second voltage-dividing resistor and a diode; the anode of the diode is connected to the power supply, the cathode of the diode is connected to the first contact of the relay and the non-phase input terminal of the voltage follower through the first voltage-dividing resistor, the first contact of the relay is connected to the positive bus when the relay is closed, the non-phase input terminal of the voltage follower is also connected to the ground, the inverting input terminal of the voltage follower and the second contact of the relay through the second voltage-dividing resistor serving as the detection resistor, and is connected to the negative bus when the relay is closed, and the output terminal of the voltage follower is connected to the input terminal of the differential operational amplifier circuit.

[0010] Furthermore, the differential operational amplifier circuit includes an operational amplifier, two gain setting first resistors and two gain setting second resistors, the output end of the voltage follower is connected to the non-inverting input end of the operational amplifier through a gain setting first resistor and is grounded through a gain setting second resistor, the anti-inverting input end of the operational amplifier is grounded through another gain setting first resistor and is connected to the output end of the operational amplifier through another gain setting second resistor, and the output end of the operational amplifier outputs the sampling voltage.

[0011] A busbar and switch tube fault detection system comprises the busbar and switch tube fault detection circuit and a control unit connected thereto.

[0012] Furthermore, the control unit is an MCU.

[0013] A method for detecting faults using the busbar and the switch tube fault detection circuit therebetween, comprising:

[0014] Control the switch tubes between the positive and negative busbars to be disconnected;

[0015] Controlling the switch module to close;

[0016] When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, it is determined that the positive and negative busbars are not short-circuited;

[0017] When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that the positive and negative busbars are short-circuited;

[0018] The first voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is not short-circuited, and the second voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is short-circuited.

[0019] Furthermore, it also includes:

[0020] Controlling the switching tubes except the switching tube to be tested in a group of switching tubes connected in series between the positive and negative busbars to be turned on, and controlling the other switching tubes between the busbars to be turned off;

[0021] When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, it is determined that the switch tube to be tested is not short-circuited;

[0022] When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that the switch tube to be tested is short-circuited.

[0023] Furthermore, it also includes:

[0024] Control a group of switch tubes connected in series between the positive and negative busbars to be turned on, and control the other switch tubes between the busbars to be turned off;

[0025] When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, determining that at least one switch tube in the group of switch tubes is open circuit;

[0026] When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that all the switch tubes in the group of switch tubes are not open-circuited.

[0027] The present invention has the following beneficial effects:

[0028] The present invention can effectively detect the short circuit and open circuit faults of the busbar and the switch tube therebetween, thereby significantly improving the safety and reliability of the circuit. By adding a switch module and a voltage-dividing sampling detection module between the positive and negative busbars, the present invention realizes accurate detection of busbar voltage short circuit. When the busbar is short-circuited, the switch module is closed to cause the voltage-dividing resistor to be short-circuited, and the voltage-dividing sampling detection module then outputs a sampling voltage different from that when it is not short-circuited. This change is captured by the detection module and used to determine whether the busbar is short-circuited. In addition, the present invention also provides a detection function for short circuit and open circuit of the switch tube. By controlling the conduction and disconnection of the switch tube, the same voltage-dividing sampling detection module is used to detect whether the switch tube to be tested is short-circuited or open-circuited. This design not only avoids the risk of short-circuiting the high-voltage ground and the low-voltage ground during the detection process, but also reduces the possibility of the circuit being subjected to secondary faults, effectively avoiding component damage caused by faults, increased maintenance time and cost, and potential safety hazards. By realizing these detection functions, the present invention not only improves the self-diagnosis capability of the circuit, but also enhances the stability of the system and the convenience of maintenance.

[0029] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the circuit structure diagram of the busbar part.

[0031] Figure 2 It is a structural diagram of a busbar and switch tube fault detection circuit according to an embodiment of the present invention.

[0032] Figure 3 A schematic diagram of detecting whether a switch tube is short-circuited according to an embodiment of the present invention.

[0033] Figure 4 The present invention is a flowchart of a method for detecting short circuit and open circuit of a busbar and the switch tubes therebetween according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0036] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] See also Figure 2An embodiment of the present invention provides a busbar and switch tube fault detection circuit therebetween. There are multiple groups of switch tubes between the positive and negative busbars, including a switch module and a voltage-dividing sampling detection module. The voltage-dividing sampling detection module includes a power supply and a voltage-dividing resistor network. The voltage-dividing resistor network includes a detection resistor with a voltage-dividing function. The switch module is configured to connect the two ends of the detection resistor to the positive busbar and the negative busbar respectively when closed, so that the detection resistor is short-circuited when the positive and negative busbars are short-circuited, so that the sampling voltage output by the voltage-dividing sampling detection module is different from the sampling voltage output when the positive and negative busbars are not short-circuited.

[0039] like Figure 2 As shown, in some embodiments, the switch module is a relay, and the voltage-dividing sampling detection module includes a voltage-dividing sampling circuit and a differential operational amplifier circuit. The voltage-dividing sampling circuit generates a voltage signal affected by whether the detection resistor is short-circuited through the voltage-dividing resistor network, and the differential operational amplifier circuit is used to receive the voltage signal generated by the voltage-dividing sampling circuit, and finally output a differential signal reflecting whether the positive and negative busbars are short-circuited.

[0040] An embodiment of the present invention also provides a method for detecting a bus short circuit fault using the bus and switch tube fault detection circuit therebetween, including bus short circuit detection: controlling the switch tubes between the positive and negative bus bars to be disconnected; controlling the switch module to be closed; when the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, judging that the positive and negative bus bars are not short-circuited; when the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, judging that the positive and negative bus bars are short-circuited; wherein the first voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is not short-circuited, and the second voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is short-circuited.

[0041] In some embodiments, after eliminating the bus fault, the method further includes switch tube short circuit detection: controlling the switch tubes except the switch tube to be tested in a group of switch tubes connected in series between the positive and negative bus bars to be turned on, and controlling the other switch tubes between the bus bars to be disconnected; when the sampling voltage output by the voltage divider sampling detection module is a preset first voltage, it is judged that the switch tube to be tested is not short-circuited; when the sampling voltage output by the voltage divider sampling detection module is a preset second voltage, it is judged that the switch tube to be tested is short-circuited.

[0042] In some embodiments, after eliminating the bus fault, the method further includes switch tube open circuit detection: controlling a group of switch tubes connected in series between the positive and negative bus bars to be turned on, and controlling other switch tubes between the bus bars to be turned off; when the sampling voltage output by the voltage divider sampling detection module is a preset first voltage, determining that at least one switch tube in the group of switch tubes is open circuit; when the sampling voltage output by the voltage divider sampling detection module is a preset second voltage, determining that all switch tubes in the group of switch tubes are not open circuit.

[0043] The specific embodiments of the present invention are further described below.

[0044] A busbar and switch tube fault detection circuit therebetween includes a switch module and a voltage-dividing sampling detection module added between a positive busbar and a negative busbar. When the switch module is closed, a voltage-dividing resistor (i.e., a detection resistor) of the voltage-dividing sampling detection module is connected between the positive and negative busbars. If the positive and negative busbars are not short-circuited, the voltage-dividing sampling detection module outputs a first voltage when the voltage-dividing resistor is not short-circuited. If the positive and negative busbars are short-circuited, the voltage-dividing sampling detection module outputs a second voltage different from the first voltage when the voltage-dividing resistor is short-circuited by the positive and negative busbars. Thus, by detecting whether the sampling voltage output by the voltage-dividing sampling detection module is the first voltage or the second voltage, it can be determined whether the busbar is short-circuited (including short-circuited due to a busbar fault or short-circuited due to a switch tube fault).

[0045] like Figure 2 As shown, in a specific embodiment, the circuit composition and working mode of the switch module and the voltage-dividing sampling detection module are as follows:

[0046] The switch module includes a relay RLY1, and the voltage-dividing sampling detection module includes a voltage-dividing sampling circuit and a differential operational amplifier circuit. The voltage-dividing sampling circuit includes a voltage follower U1, voltage-dividing resistors R1 and R4 (wherein the voltage-dividing resistor R4 acts as the detection resistor), and a diode D1; the differential operational amplifier circuit includes an operational amplifier U2, two resistors R2 (gain setting second resistors) and two resistors R3 (gain setting first resistors). In the voltage-dividing sampling circuit, the anode of the diode D1 is connected to the power supply VCC, and the cathode of the diode D1 is connected to the first contact of the relay RLY1 through the voltage-dividing resistor R1 ( Figure 2 The first contact of the relay RLY1 is connected to the positive bus BUS+ when the relay RLY1 is closed. The non-inverting input terminal of the voltage follower U1 is also connected to the ground GND through the voltage divider resistor R4, and is connected to the inverting input terminal of the voltage follower U1 and the second contact of the relay RLY1 ( Figure 2The contact 3 of the relay RLY1 in the circuit is connected, and is connected to the negative bus GND_BUS when the relay RLY1 is closed. The output end of the voltage follower U1 (i.e., point A) is connected to the non-inverting input end of the operational amplifier U2 of the differential operational amplifier circuit through the resistor R3. The non-inverting input end of the operational amplifier U2 is also connected to the ground GND through the resistor R2. The anti-inverting input end of the operational amplifier U2 is grounded through another resistor R3, and is connected to the output end of the operational amplifier U2 through another resistor R2. The output end of the operational amplifier U2 (i.e., point B) outputs the sampling voltage Vref.

[0047] When the relay of the switch module is closed, the short-circuit detection circuit is connected to control all switch tubes to be disconnected. At this time, the voltage at the output end of the voltage follower U1, that is, the voltage at point A, is:

[0048] The voltage dividing resistor R4 is not short-circuited;

[0049] V A =(V CC -V D1 )---The bus is short-circuited. When the relay is closed, the voltage-dividing resistor R4 connected between the positive bus BUS+ and the negative bus GND_BUS is short-circuited;

[0050] After passing through the differential op amp circuit, the voltage at the output of op amp U2, i.e., the voltage at point B, is: Right now:

[0051]

[0052]

[0053] By collecting the voltage at point B, that is, the output sampling voltage Vref, it is possible to determine whether there is a short circuit between the positive bus BUS+ and the negative bus GND_BUS.

[0054] If the output sampling voltage Vref is measured as:

[0055] This means that there is no short circuit between the positive bus BUS+ and the negative bus GND-_BUS;

[0056] If the output sampling voltage Vref is measured as:

[0057] This indicates that a short circuit occurs between the positive bus BUS+ and the negative bus GND_BUS.

[0058] It can further determine whether the switch tubes Q1-Q8 in the rectifier circuit and inverter circuit between the positive and negative busbars are short-circuited. Figure 3 , take the detection of switch tube Q5 as an example:

[0059] The control circuit controls Q1 to be turned on and Q5 to be turned off in the switch tube of the group to be tested, and controls the switch tubes of other groups to be turned off at the same time. ref You can know whether the switch tube Q5 is short-circuited: If V ref = V1, then the switch tube Q5 is not short-circuited. If V ref =V2, the switch tube Q5 is short-circuited, and the other switch tubes are tested in the same way.

[0060] Similarly, it is possible to further determine whether the switch tubes Q1-Q8 are open circuited. Take the open circuit detection of the switch tubes Q1 and Q5 as an example:

[0061] Control the Q1 and Q5 of the switch tubes in the group to be tested to be turned on, and control the switch tubes in other groups to be turned off. If the sample V ref = V1, then at least one of the switch tubes Q1 and Q5 is open circuit. If V ref =V2, then the switch tubes Q1 and Q5 are not open.

[0062] The truth table of the short-circuit and open-circuit test of the switch tube is shown in Table 1 (the "1" of the switch tube means it is turned on, "0" means it is turned off, and a blank space means "0" or no fault):

[0063] Table 1

[0064]

[0065]

[0066] Test method: By turning on one switch tube and measuring the bus short-circuit state, the short-circuit state of another switch tube on the same bridge arm can be determined; by turning on two switch tubes and measuring the bus short-circuit state, the open-circuit state of the two switch tubes on the same bridge arm can be determined.

[0067] The above truth table gives the process and results of the short-circuit and open-circuit tests of the switch tube.

[0068] Test process: first test the short circuit fault, if there is no short circuit fault, then test the open circuit fault.

[0069] Test results: The last three columns of the truth table give the feedback signal value received by the MCU when a switch failure occurs and the inference of a short-circuited or open-circuited switch.

[0070] The overall flow chart of the busbar and the switch tube short circuit and open circuit detection method according to the embodiment of the present invention is as follows: Figure 4 shown.

[0071] After power-on, first confirm whether there is a busbar fault short circuit. If a short circuit is detected, directly protect it. If the busbar is not short-circuited, to ensure normal operation, further confirm whether the switch tube between the busbars is short-circuited or open-circuited; first check whether there is a switch tube short-circuited, and then check whether there is a switch tube open-circuited.

[0072] The specific process is as follows:

[0073] After power-on, the MCU controls the switch module to close and the detection circuit is connected (the switch tubes are all in the disconnected state at this time);

[0074] Sampled V ref And compare with the preset values ​​V1 and V2:

[0075] If V ref =V2; the bus is short-circuited, the MCU controls the switch module to disconnect, and the detection module is disconnected from the main circuit; at the same time, a short-circuit fault is reported and the power is cut off in time to protect the equipment.

[0076] If V ref =V1, the busbar is not short-circuited, and further fault detection is performed;

[0077] Control the rectifier module and the inverter module to turn on the light tubes Q1~Q8 in sequence, and sample the corresponding V in the on state ref ; After this

[0078] The four pairs of switch tubes Q1 and Q5, Q2 and Q6, Q3 and Q7, Q4 and Q8 are controlled to conduct in sequence, and the V ref .

[0079] The above V ref Compare with the preset truth table, and at the same time, the MCU controls the switch module to disconnect, disconnecting the detection module from the main circuit.

[0080] If there is a fault point after comparison, the fault switch tube information can be derived according to the truth table comparison, and the power can be cut off in time so that the staff can deal with the fault point in time and protect the equipment; if there is no fault after comparison, normal rectification and inversion work will start.

[0081] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A busbar and switch tube fault detection circuit, wherein there are multiple sets of switch tubes between the positive and negative busbars, characterized in that: The invention comprises a switch module and a voltage-dividing sampling detection module, wherein the voltage-dividing sampling detection module comprises a power supply and a voltage-dividing resistor network, wherein the voltage-dividing resistor network comprises a detection resistor having a voltage-dividing function, and wherein the switch module is configured to connect the two ends of the detection resistor to a positive bus and a negative bus respectively when closed, so that when the positive and negative bus are short-circuited, the detection resistor is short-circuited, so that the sampling voltage output by the voltage-dividing sampling detection module is different from the sampling voltage output when the positive and negative bus are not short-circuited.

2. The busbar and switch tube fault detection circuit according to claim 1, characterized in that: The switch module is a relay.

3. The busbar and switch tube fault detection circuit as described in claim 2, wherein the voltage-dividing sampling detection module includes a voltage-dividing sampling circuit and a differential operational amplifier circuit, the voltage-dividing sampling circuit generates a voltage signal affected by whether the detection resistor is short-circuited through the voltage-dividing resistor network, and the differential operational amplifier circuit is used to receive the voltage signal generated by the voltage-dividing sampling circuit and finally output a differential signal reflecting whether the busbar is short-circuited.

4. The busbar and switch tube fault detection circuit according to claim 3, characterized in that: The voltage-dividing sampling circuit comprises a voltage follower (U1), a first voltage-dividing resistor (R1), a second voltage-dividing resistor (R2) and a diode (D1); the anode of the diode is connected to the power supply, the cathode of the diode is connected to the first contact of the relay and the in-phase input terminal of the voltage follower through the first voltage-dividing resistor, the first contact of the relay is connected to the positive bus when the relay is closed, the in-phase input terminal of the voltage follower is also connected to the ground, the inverting input terminal of the voltage follower and the second contact of the relay through the second voltage-dividing resistor serving as the detection resistor, and is connected to the negative bus when the relay is closed, and the output terminal of the voltage follower is connected to the input terminal of the differential operational amplifier circuit.

5. The busbar and switch tube fault detection circuit according to claim 4, characterized in that: The differential operational amplifier circuit comprises an operational amplifier (U2), two gain setting first resistors (R3) and two gain setting second resistors (R2), the output end of the voltage follower is connected to the in-phase input end of the operational amplifier through a gain setting first resistor and is grounded through a gain setting second resistor, the inverting input end of the operational amplifier is grounded through another gain setting first resistor and is connected to the output end of the operational amplifier through another gain setting second resistor, and the output end of the operational amplifier outputs the sampling voltage.

6. A busbar and switch tube fault detection system, characterized in that: It comprises a busbar and switch tube fault detection circuit as claimed in any one of claims 1 to 5 and a control unit connected to the busbar and switch tube fault detection circuit.

7. The busbar and switch tube fault detection circuit according to claim 6, characterized in that: The control unit is MCU.

8. A method for detecting faults using the busbar and switch tube fault detection circuit according to any one of claims 1 to 5, characterized in that: include: Control the switch tubes between the positive and negative busbars to be disconnected; Controlling the switch module to close; When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, it is determined that the positive and negative busbars are not short-circuited; When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that the positive and negative busbars are short-circuited; The first voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is not short-circuited, and the second voltage is the voltage output by the voltage-dividing sampling detection module when the detection resistor is short-circuited.

9. The method for detecting a short circuit fault of a switch tube by a busbar and a switch tube fault detection circuit therebetween as claimed in claim 8, characterized in that: Also includes: Controlling the switch tubes except the switch tube to be tested in a group of switch tubes connected in series between the positive and negative busbars to be turned on, and controlling the other switch tubes between the busbars to be turned off; When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, it is determined that the switch tube to be tested is not short-circuited; When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that the switch tube to be tested is short-circuited.

10. The method for detecting a short circuit fault of a switch tube by a busbar and a switch tube fault detection circuit therebetween according to claim 8 or 9, characterized in that: Also includes: Control a group of switch tubes connected in series between the positive and negative busbars to be turned on, and control the other switch tubes between the busbars to be turned off; When the sampling voltage output by the voltage-dividing sampling detection module is a preset first voltage, determining that at least one switch tube in the group of switch tubes is open circuit; When the sampling voltage output by the voltage-dividing sampling detection module is a preset second voltage, it is determined that all the switch tubes in the group of switch tubes are not open-circuited.

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