Power tube fault detection circuit and device

Abstract

The utility model relates to the field of power tube detection, in particular to a power tube fault detection circuit and device. The fault detection circuit comprises a fault detection unit and a signal transmission unit which are sequentially connected with a power tube, wherein the signal transmission unit is used for outputting a detection result of the fault detection unit; the fault detection unit comprises an open circuit detection circuit and a short circuit detection circuit, and the open circuit detection circuit is connected with the power tube and used for detecting whether the power tube is in an open circuit or not; the short circuit detection circuit is connected with the power tube and is used for detecting whether the power tube is short-circuited or not. The fault detection circuit provided by the utility model can detect whether the power tube breaks down on line in real time, thereby avoiding loss caused by accidents due to the fault of the power tube.

Description

TECHNICAL FIELD

[0001] The utility model relates to power tube detection field generally. More specifically, the utility model relates to a kind of power tube fault detection circuit and device. BACKGROUND

[0002] Power tube is generally applied to high-power electronic equipment, such as charging pile, inverter, high-speed rail, electric vehicle and the like, and the stable, reliable and safe operation of these devices becomes very important, because these devices are applied to high-voltage and high-current occasions, and damage may cause fire or other safety accidents.

[0003] In the prior art, voltage sampling or current sampling is generally performed on the power tube, and then compared with the set threshold to determine whether the power tube fails, or the device is stopped for manual detection. However, the response time of voltage sampling or current sampling is relatively slow, and the real-time performance is low; manual detection after stopping the device is time-consuming and laborious, and will interrupt the work of the device, and the feasibility is low. Therefore, how to detect whether the power tube fails in real time online (when the device is in working state) is a problem to be solved urgently. UTILITY MODEL CONTENT

[0004] To solve one or more of the above technical problems, the utility model provides a scheme in the following aspects.

[0005] In the first aspect, the utility model provides a power tube fault detection circuit, comprising a fault detection unit and a signal transmission unit connected in sequence with a power tube, the signal transmission unit is used for outputting the detection result of the fault detection unit; the fault detection unit comprises an open circuit detection circuit and a short circuit detection circuit, the open circuit detection circuit is connected with the power tube, and is used for detecting whether the power tube is open; the short circuit detection circuit is connected with the power tube, and is used for detecting whether the power tube is short-circuited.

[0006] Further, the open circuit detection circuit comprises a first diode, a second diode, a first voltage stabilizer, a second voltage stabilizer, a first resistor, a second resistor, a fourth resistor, a sixth resistor, a seventh resistor, a first triode and a second triode; wherein the first diode, the second diode, the first voltage stabilizer, the second resistor and the sixth resistor are connected in series on the drain of the power tube, the second voltage stabilizer is connected with the gate of the power tube; the second voltage stabilizer and the fourth resistor are connected in series on the gate of the power tube; one end of the first resistor is connected between the second diode and the first voltage stabilizer, and the other end is connected with a direct current power supply; the base of the first triode is connected between the second resistor and the sixth resistor, the emitter of the first triode is connected with the collector of the second triode, and the base of the second triode is connected between the fourth resistor and the seventh resistor.

[0007] Further, the short circuit detection circuit comprises a first diode, a second diode, a first voltage stabilizer, a second voltage stabilizer, a first resistor, a third resistor, a fifth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a third triode, a fourth triode, a fifth triode and a sixth triode; wherein the first diode, the second diode, the first voltage stabilizer, the third resistor and the ninth resistor are connected in series on the drain of the power tube, the second voltage stabilizer, the fifth resistor and the eighth resistor are connected in series on the gate of the power tube; the seventh resistor is connected on the source of the power tube; the first resistor and the tenth resistor are connected in series on the third triode; one end of the eleventh resistor is connected between the fourth triode and the fifth triode, and the other end is connected on a direct current power supply; the fifth triode is connected with the sixth triode.

[0008] Further, the third triode is NPN type.

[0009] Further, the signal transmission unit comprises an optical coupling and a current limiting resistor, one end of the current limiting resistor is connected with the source of the power tube, and the other end is connected with the optical coupling.

[0010] Further, the power tube is NMOS tube.

[0011] In the second aspect, the utility model provides a power tube fault detection device, including the power tube fault detection circuit according to any one of the first aspect.

[0012] The utility model discloses beneficial effect lies in: the utility model discloses can detect whether the power tube has taken place the breakdown when the equipment is in the working condition, and real -time is high, when detecting that the power tube has taken place the breakdown, can in time the failure signal is delivered, thereby can in time the equipment is closed down, avoided the expansion and the serious loss of the breakdown, thereby make the equipment can be more safe, reliable, steady operation. In addition, the utility model discloses can also determine the breakdown type of power tube according to the failure signal, thereby takes the corresponding maintenance measure, improves maintenance efficiency and accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0013] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which several embodiments of the application will be shown by way of illustration. In the drawings, the same or corresponding reference numerals indicate the same or corresponding parts, wherein:

[0014] Figure 1 is the structural block diagram of the power tube fault detection circuit according to the embodiment of the utility model.

[0015] Figure 2 is the circuit diagram of the power tube fault detection circuit according to the embodiment of the utility model. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the utility model will be apparently and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0017] The specific embodiments of the utility model will be described in detail below with reference to the drawings.

[0018] Figure 1 is the structural block diagram of the power tube fault detection circuit according to the embodiment of the utility model.

[0019] Since the power tube is generally open circuit or short circuit when damaged, whether the power tube is damaged can be judged by detecting whether the power tube is open circuit or short circuit. In the first aspect, the utility model provides a power tube fault detection circuit, which can detect whether the power tube is open circuit or short circuit, so as to judge whether the power tube is damaged, that is, the fault detection of the power tube is realized. Specifically, the structural block diagram of the power tube fault detection circuit is as shown in Figure 1

[0020] As​Figure 1 As shown, the power transistor fault detection circuit of this utility model includes a fault detection unit and a signal transmission unit. The fault detection unit includes an open-circuit detection circuit and a short-circuit detection circuit. Specifically, the open-circuit detection circuit detects whether the power transistor is open-circuited, and the short-circuit detection circuit detects whether the power transistor is short-circuited; the signal transmission unit outputs the detection results from the open-circuit and short-circuit detection circuits.

[0021] In one embodiment, a fault detection unit is disposed between the power transistor under test and the signal transmission unit. Specifically, an open-circuit detection circuit is connected to the power transistor, and a short-circuit detection circuit is also connected to the power transistor.

[0022] Specifically, when the power transistor is open-circuited or short-circuited, the fault detection unit in the power transistor fault detection circuit will detect that the power transistor has failed, and then transmit the detected fault information to the signal transmission unit, so that the signal transmission unit can transmit the fault information.

[0023] Figure 2 This is a schematic diagram illustrating a power transistor fault detection circuit according to an embodiment of the present invention.

[0024] In one embodiment, the specific circuit diagram of the power transistor fault detection circuit of this utility model is as follows: Figure 2 As shown. By Figure 2 It can be seen that the signal transmission unit includes an optocoupler U1 and a current-limiting resistor R12, wherein one end of the current-limiting resistor R12 is connected to the power transistor (i.e., Figure 2 The source terminal of the power device is connected to the power transistor, and the other end is connected to the optocoupler U1. When a fault signal is received from the power transistor, the signal transmission unit will transmit the isolated fault signal to the control system so that the control system can perform corresponding operations, such as shutting down the equipment in time, thereby avoiding the expansion of the fault and serious losses.

[0025] Furthermore, in this embodiment, the fault detection unit includes an open-circuit detection circuit and a short-circuit detection circuit, wherein the open-circuit detection circuit is used to detect whether the power transistor is open-circuited, and the short-circuit detection circuit is used to detect whether the power transistor is short-circuited.

[0026] Specifically, such as Figure 2As shown, the open circuit detection circuit includes: a first diode D1, a second diode D2, a first voltage stabilizing tube DW1, a second voltage stabilizing tube DW2, a first resistor R1, a second resistor R2, a fourth resistor R4, a sixth resistor R6, a seventh resistor R7, a first triode Q1 and a second triode Q2; wherein the first diode D1, the second diode D2, the first voltage stabilizing tube DW1, the second resistor R2 and the sixth resistor R6 are connected in series on the drain of the power tube; the second voltage stabilizing tube DW2 and the fourth resistor R4 are connected in series on the gate of the power tube; one end of the first resistor R1 is connected between the second diode D2 and the first voltage stabilizing tube DW1 (i.e. at point A in Figure 2 ), and the other end is connected with a direct current power supply VCC; one end of the seventh resistor R7 is connected on the source of the power tube, and the other end is connected between the fourth resistor R4 and the second triode Q2; the base of the first triode Q1 is connected between the second resistor R2 and the sixth resistor R6, the emitter of the first triode Q1 is connected with the collector of the second triode Q2, and the collector of the first triode Q1 is connected with the direct current power supply VCC; the base of the second triode Q2 is connected between the fourth resistor R4 and the seventh resistor R7, and the collector of the second triode Q2 is connected with the optocoupler U1.

[0027] In the open circuit detection circuit, the first diode D1, the second diode D2 and the first resistor R1 provide the required bias for the detection of the power tube, when the power tube is open, the potential between the second diode D2 and the first voltage stabilizing tube DW1 (i.e. at point A in Figure 2 ) is close to the direct current power supply VCC, at this time the first voltage stabilizing tube DW1 is turned on, and the voltage signal makes the first triode Q1 conduct, but when the power tube is in the off state without the driving signal, a high level signal is also presented, at this time the driving signal for driving the power tube needs to be introduced to determine whether the power tube has failed. If the introduced driving signal has reached point B in Figure 2 , but the potential of the drain of the power tube does not become low, then the potential of point A will not become low, and the high level of point A makes the first triode Q1 conduct, and the introduced driving signal makes the second triode Q2 conduct, so that the optocoupler U1 is turned on, that is, the open circuit detection of the power tube is realized, and the failure signal of the power tube is transmitted out through the signal unit.

[0028] Further, the failure signal (open circuit damage) can be transmitted to the control system to take corresponding actions, so as to avoid the expansion of the failure and loss.

[0029] In one embodiment, the short circuit detection circuit comprises: a first diode D1, a second diode D2, a first voltage stabilizing tube DW1, a second voltage stabilizing tube DW2, a first resistor R1, a third resistor R3, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third triode Q3, a fourth triode Q4, a fifth triode Q5, and a sixth triode Q6; wherein the first diode D1, the second diode D2, the first voltage stabilizing tube DW1, the third resistor R3, and the ninth resistor R9 are connected in series on the drain of the power tube, the second voltage stabilizing tube DW2, the fifth resistor R5, and the eighth resistor R8 are connected in series on the gate of the power tube; the seventh resistor R7 is connected on the source of the power tube; the first resistor R1 and the tenth resistor R10 are connected in series on the collector of the third triode Q3, the base of the third triode Q3 is connected between the fifth resistor R5 and the eighth resistor R8, the emitter of the third triode Q3 is connected on the source of the power tube; one end of the eleventh resistor R11 is connected between the collector of the fourth triode Q4 and the base of the fifth triode Q5, and the other end is connected on the DC power supply VCC; the collector of the fifth triode Q5 is connected on the DC power supply VCC, the emitter of the fifth triode Q5 is connected with the collector of the sixth triode Q6; the base of the sixth triode Q6 is connected between the collector of the third triode Q3 and the tenth resistor R10, and the emitter of the sixth triode Q6 is connected with the optocoupler U1.

[0030] In the short circuit detection circuit, when the power tube is short-circuited, the potential of point A is about 1.2V, and due to the presence of the first voltage stabilizing tube DW1, this voltage cannot make the first triode Q1 and the fourth triode Q4 conduct, but the fifth triode Q5 can conduct. At this time, if the low level of the driving signal B end (i.e. point B in the figure) of the device cannot make the power device turn off, the voltage of the D pole will not return to high level, so that the short-circuit damage state of the power device can be detected. At this time, the low level of the B end makes the third triode Q3 cut off, and the sixth triode Q6 will conduct, so that the optocoupler U1 is turned on, that is, the short circuit detection of the power tube is realized, and the fault signal of the power tube is transmitted out through the signal transmission unit.

[0031] Further, the fault signal (short circuit damage) can be transmitted to the control system to take corresponding actions, so as to avoid the expansion of the fault and loss.

[0032] By detecting in a targeted manner according to the form of damage (short circuit or open circuit) of the power tube, the state of the power tube can be more accurately judged, the efficiency of power tube fault positioning is improved, and thus the efficiency and accuracy of maintenance are improved. In addition, potential faults of the power tube can also be found in time, so that measures can be taken at the initial stage of the fault or when the device has not yet caused serious damage, thereby improving the reliability and safety of the device.

[0033] It can be understood that in the embodiment, the first diode D1, the second diode D2, the first voltage stabilizing tube DW1, the second voltage stabilizing tube DW2 and the first resistor R1 are included in both the open circuit detection circuit and the short circuit detection circuit. By using common elements, the hardware cost can be reduced, the circuit board space can be saved, and the circuit structure can be simplified. In alternative embodiments, the open circuit detection circuit and the short circuit detection circuit can also be set as two independent circuits, i.e., the open circuit detection circuit and the short circuit detection circuit do not share common elements. By not sharing elements, the reliability and stability of the fault detection unit can be improved, and debugging and optimization can also be facilitated. These can be selected by those skilled in the art according to actual needs.

[0034] Although the open circuit detection circuit and the short circuit detection circuit have common elements, the open circuit detection circuit and the short circuit detection circuit are independent when detecting the fault of the power tube and do not affect each other, i.e., it can be determined whether the power tube has an open circuit or a short circuit.

[0035] In an embodiment, the signal transmission unit can output the detection results of the open circuit detection circuit and the short circuit detection circuit to the control system. The fault signal is transmitted to the control system after being isolated by the optocoupler U1, thereby improving the accuracy and safety of the output fault signal, i.e., improving the anti-interference ability and accuracy of the detection circuit.

[0036] Further, since the open circuit detection circuit and the short circuit detection circuit can independently detect whether the power tube is open or short, the fault type of the power tube (damage in the form of open circuit and damage in the form of short circuit) can be distinguished according to the fault signals output by the open circuit detection circuit and the short circuit detection circuit, and recorded on the control system, so that the control system can perform corresponding operations, such as allowing the device to shut down in time or checking the fault type of the power tube during maintenance, thereby quickly and accurately maintaining the device, shortening the maintenance time, and avoiding serious accidents and losses caused by the expansion of power tube faults.

[0037] In an alternative embodiment, the signal transmission unit can also be implemented by other circuits, and those skilled in the art can set the signal transmission unit according to actual needs.

[0038] In an alternative embodiment, a corresponding display unit can also be added, for example, a light emitting diode is added, wherein different light emitting diodes emit different colors to represent different fault types, etc., so that the fault type of the power tube can be displayed more intuitively. By quickly determining the fault type of the power tube, the maintenance personnel can quickly take corresponding maintenance measures, thereby reducing the downtime of the equipment and ensuring the continuous operation of the equipment and the efficiency of production.

[0039] It can be understood that, since the power tube fault detection circuit can feed back the power tube fault information to the control system in time, the real-time performance of detection is high.

[0040] In the embodiment, the detected power tube is an NMOS tube. In addition, in the power tube fault detection circuit, the first transistor Q1, the second transistor Q2, the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5 and the sixth transistor Q6 are all NPN type. It can be understood that the power tube fault detection circuit of the utility model can also be used for detecting a PMOS tube.

[0041] In the second aspect, the utility model provides a kind of power tube fault detection device, including the power tube fault detection circuit described in the first aspect.The detailed structure of the power tube fault detection circuit can refer to the above embodiment, and it is not repeated here;It can be understood that, since the above power tube fault detection circuit is used in the power tube fault detection device of the utility model, therefore, the embodiment of the power tube fault detection device of the utility model includes all the technical solutions of all the above power tube fault detection circuit embodiments, and the technical effects achieved are also exactly the same, and it is not repeated here.

[0042] Therefore, the power tube fault detection device can also detect when the equipment is in working state, thereby avoiding the time-consuming and laborious situation of shutdown manual detection, ensuring the continuous operation of the equipment, and being more feasible.

[0043] In conclusion, the utility model can detect whether power tube fails when equipment is in working state, and the real-time performance is high, when detecting that power tube fails, fault signal is transmitted to control system, to make control system can shut down equipment in time, to avoid the expansion of accident and avoid producing serious loss.In addition, the utility model can also judge the fault type of power tube according to fault signal, to carry out corresponding maintenance, improve the efficiency and accuracy of maintenance.

[0044] While the present application has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application. It is therefore intended that the application not be limited to the exact form and details herein shown and described, except as defined in the appended claims.

Claims

1. A power tube fault detection circuit, characterized by, The power tube is connected with a fault detection unit and a signal transmission unit in sequence, and the signal transmission unit is used for outputting the detection result of the fault detection unit; The fault detection unit comprises an open circuit detection circuit and a short circuit detection circuit, the open circuit detection circuit is connected with the power tube and used for detecting whether the power tube is open circuit, and the short circuit detection circuit is connected with the power tube and used for detecting whether the power tube is short circuit; The open circuit detection circuit comprises a first diode D1, a second diode D2, a first voltage stabilizing tube DW1, a second voltage stabilizing tube DW2, a first resistor R1, a second resistor R2, a fourth resistor R4, a sixth resistor R6, a seventh resistor R7, a first triode Q1 and a second triode Q2, wherein the first diode D1, the second diode D2, the first voltage stabilizing tube DW1, the second resistor R2 and the sixth resistor R6 are connected in sequence on the drain of the power tube, the second voltage stabilizing tube DW2 and the fourth resistor R4 are connected in sequence on the gate of the power tube, one end of the first resistor R1 is connected between the second diode D2 and the first voltage stabilizing tube DW1, and the other end is connected with a direct current power supply VCC, one end of the seventh resistor R7 is connected on the source of the power tube, and the other end is connected between the fourth resistor R4 and the second triode Q2, the base of the first triode Q1 is connected between the second resistor R2 and the sixth resistor R6, the emitter of the first triode Q1 is connected with the collector of the second triode Q2, and the collector of the first triode Q1 is connected with the direct current power supply VCC, and the base of the second triode Q2 is connected between the fourth resistor R4 and the seventh resistor R7. The short circuit detection circuit comprises a first diode D1, a second diode D2, a first voltage stabilizing tube DW1, a second voltage stabilizing tube DW2, a first resistor R1, a third resistor R3, a fifth resistor R5, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a third triode Q3, a fourth triode Q4, a fifth triode Q5 and a sixth triode Q6; wherein the first diode D1, the second diode D2, the first voltage stabilizing tube DW1, the third resistor R3 and the ninth resistor R9 are connected in series on the drain of the power tube, the second voltage stabilizing tube DW2, the fifth resistor R5 and the eighth resistor R8 are connected in series on the gate of the power tube; the seventh resistor R7 is connected on the source of the power tube; the first resistor R1 and the tenth resistor R10 are connected in series on the collector of the third triode Q3, the base of the third triode Q3 is connected between the fifth resistor R5 and the eighth resistor R8, the emitter of the third triode Q3 is connected on the source of the power tube; one end of the eleventh resistor R11 is connected between the collector of the fourth triode Q4 and the base of the fifth triode Q5, and the other end is connected on the direct current power supply VCC; the collector of the fifth triode Q5 is connected on the direct current power supply VCC, the emitter of the fifth triode Q5 is connected with the collector of the sixth triode Q6; the base of the sixth triode Q6 is connected between the collector of the third triode Q3 and the tenth resistor R10.

2. The power tube fault detection circuit of claim 1, wherein, The third triode Q3 is NPN type.

3. The power tube fault detection circuit of claim 1, wherein, The signal transmission unit comprises an optical coupling U1 and a current limiting resistor R12, one end of the current limiting resistor R12 is connected with the source of the power tube, and the other end is connected with the optical coupling U1.

4. The power tube fault detection circuit of claim 1, wherein, The power tube is NMOS tube.

5. A power tube failure detection apparatus characterized by comprising: The power tube fault detection circuit comprises the power tube fault detection circuit according to any one of claims 1-4.

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