A power circuit, a fault diagnosis method and a power electronic device

Abstract

The application provides a power circuit, a fault diagnosis method and a power electronic device, and relates to the technical field of power electronics. The technical scheme provided by the application can analyze the fault type based on the diagnosis data of the diagnosis voltage within the preset time before and after the moment when the IGBT fails, so that the fault type of the power circuit can be quickly and accurately located, and the fault maintenance cost of the power electronic device is effectively reduced. Moreover, the power circuit provided by the embodiment of the application has a simple structure and no use limit, and is suitable for different types of power scenarios.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more specifically, to a power circuit, a fault diagnosis method, and a power electronic device. Background Technology

[0002] With the development of new energy and electrification, various types of power electronic equipment are being used more and more widely. Compared with traditional power transmission equipment, the core of power electronic equipment is the use of power circuits. Due to the relatively high failure rate and fault rate of power circuits, how to diagnose faults in power circuits of power electronic equipment has become an increasingly urgent problem for the industry, especially in high-power, high-reliability scenarios such as rail transit, power grid equipment, ship propulsion, and high-voltage high-power frequency converters. Summary of the Invention

[0003] In view of this, this application provides a power circuit, a fault diagnosis method, and a power electronic device, which effectively solves the technical problems existing in the prior art, realizes fault detection and type analysis of the power circuit, effectively reduces the fault maintenance cost of power electronic devices, and is applicable to different types of power scenarios.

[0004] To achieve the above objectives, the technical solution provided in this application is as follows:

[0005] A power circuit includes a main controller and at least one power unit, the power unit comprising:

[0006] The collector of the IGBT is electrically connected to the positive terminal of the DC bus, and the emitter of the IGBT is electrically connected to the negative terminal of the DC bus.

[0007] A drive protection board is electrically connected to the main controller and to the IGBT via an electrical wiring harness. The drive protection board is used to send a fault signal when the IGBT malfunctions, and simultaneously control the IGBT to turn off.

[0008] A fault diagnosis device includes a diode detection circuit, which comprises a constant current source, a storage capacitor, and a diode unit. The diode unit includes at least one detection diode. The input terminal of the constant current source is electrically connected to a power supply voltage terminal, and the output terminal of the constant current source is electrically connected to both the first plate of the storage capacitor and the positive terminal of the diode unit. The second plate of the storage capacitor is electrically connected to a ground terminal, and the negative terminal of the diode unit is electrically connected to the collector of the IGBT through an electrical wiring harness. The fault diagnosis device is used to collect the diagnostic voltage at the first plate of the storage capacitor, and when a fault signal is received from the drive protection board, it stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data.

[0009] Optionally, the fault types include: SC fault, OC fault, wiring harness fault, and EMC interference fault;

[0010] When the SC fault occurs, the diagnostic voltage rises from 0V to the power supply voltage value at the power supply voltage terminal within a time not greater than a first threshold value, and the duration of the diagnostic voltage at the power supply voltage value is within a first set duration range.

[0011] During the OC fault, the diagnostic voltage rises from a set voltage value to the fault voltage value within a time not greater than the first threshold value, and the duration of the diagnostic voltage at the fault voltage value is not less than the second threshold value. The set voltage value is the saturation voltage drop of the IGBT, the fault voltage value is less than the power supply voltage value, and the upper limit of the first set duration range is less than the second threshold value.

[0012] When the wiring harness fails, the diagnostic voltage rises from 0V to the power supply voltage value within a time not less than a third threshold time, and the duration of the diagnostic voltage at the power supply voltage value is within the first set time range, and the third threshold time is greater than the first threshold time.

[0013] During the EMC interference fault, the diagnostic voltage exhibits a disordered fluctuation curve within the preset time period.

[0014] Optionally, the fault diagnosis device includes:

[0015] A voltage sampling circuit is electrically connected to the first plate of the storage capacitor, and the voltage sampling circuit is used to acquire the diagnostic voltage at the first plate of the storage capacitor;

[0016] The processor is electrically connected to both the drive protection board and the voltage sampling circuit. When the processor acquires a fault signal sent by the drive protection board, it stores diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data.

[0017] Optionally, the fault diagnosis device further includes:

[0018] The memory is electrically connected to the processor and is used to store diagnostic data of the diagnostic voltage within a preset time period before and after the IGBT malfunctions, according to the control of the processor.

[0019] Optionally, the diode detection circuit further includes:

[0020] A resistor, wherein the first end of the resistor is electrically connected to the first plate of the storage capacitor, and the second end of the resistor is electrically connected to the second plate of the storage capacitor.

[0021] Optionally, the drive protection board detects a fault in the IGBT based on the IGBT's Vce voltage and sends a fault signal.

[0022] Optionally, the drive protection board is electrically connected to the first plate of the storage capacitor, and the drive protection board sends the fault signal when the IGBT fails based on the diagnostic voltage; wherein, when the diode unit is turned on, the diagnostic voltage is the same as the Vce voltage of the IGBT.

[0023] Optionally, the power circuit includes: a single-transistor circuit, a half-bridge circuit, or a full-bridge circuit.

[0024] Based on the same inventive concept, this application also provides a fault diagnosis method, which is applied to the aforementioned power circuit, wherein the fault diagnosis method includes:

[0025] Obtain the fault signal sent by the drive protection board;

[0026] The diagnostic data of the diagnostic voltage is stored within a preset time period before and after the IGBT malfunctions, so as to analyze the fault type through the diagnostic data.

[0027] Based on the same inventive concept, this application also provides a power electronic device, which includes the power circuit described above.

[0028] Compared with existing technologies, the technical solution provided in this application has at least the following advantages:

[0029] This application provides a power circuit, a fault diagnosis method, and a power electronic device. The power circuit includes a main controller and at least one power unit. The power unit includes: an IGBT, the collector of which is electrically connected to the positive terminal of a DC bus, and the emitter of which is electrically connected to the negative terminal of the DC bus; a drive protection board, which is electrically connected to the main controller and to the IGBT via an electrical harness; the drive protection board is used to send a fault signal when a fault occurs in the IGBT and simultaneously control the IGBT to turn off; and a fault diagnosis device, which includes a diode detection circuit, and the diode detection circuit includes a constant current source. The system comprises a storage capacitor and a diode unit, wherein the diode unit includes at least one detection diode; the input terminal of the constant current source is electrically connected to the power supply voltage terminal, the output terminal of the constant current source is electrically connected to both the first plate of the storage capacitor and the positive terminal of the diode unit, the second plate of the storage capacitor is electrically connected to the ground terminal, and the negative terminal of the diode unit is electrically connected to the collector of the IGBT through the electrical wiring harness; the fault diagnosis device is used to collect the diagnostic voltage at the first plate of the storage capacitor, and when acquiring the fault signal sent by the drive protection board, it stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data.

[0030] As can be seen from the above, the technical solution provided in this application can analyze the fault type based on diagnostic voltage data within a preset time before and after the IGBT fault occurs. This allows for rapid and accurate identification of the fault type in the power circuit, effectively reducing the maintenance cost of power electronic equipment. Furthermore, the power circuit provided in this application has a simple structure and no usage limitations, making it suitable for different types of power scenarios. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 A circuit diagram of a power circuit provided in an embodiment of this application;

[0033] Figure 2 A graph showing the diagnostic voltage during an SC fault;

[0034] Figure 3 A graph showing the diagnostic voltage during an overload (OC) fault.

[0035] Figure 4 A graph showing the diagnostic voltage during a wiring harness fault;

[0036] Figure 5 A graph showing the diagnostic voltage during EMC interference faults;

[0037] Figure 6 A circuit diagram of another power circuit provided in an embodiment of this application;

[0038] Figure 7 A circuit diagram of yet another power circuit provided in an embodiment of this application;

[0039] Figure 8 A circuit diagram of a three-phase half-bridge circuit provided for an embodiment of this application;

[0040] Figure 9 This is a flowchart of a fault diagnosis method provided in an embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 100 Main controller; 210 Drive protection board; 220 Electrical wiring harness; 230 Fault diagnosis device; 231 Diode detection circuit; 2311 Constant current source; 2312 Diode unit; 232 Voltage sampling circuit; 233 Processor; 234 Memory; Cj Collector; Gj Gate; Ej Emitter; Dd Detection diode; Cd Storage capacitor; GND Ground terminal; Vcc Power supply voltage terminal; R Resistor; S1 First power unit; S2 Second power unit; S3 Third power unit; S4 Fourth power unit; S5 Fifth power unit; S6 Sixth power unit; Cdc Bus capacitor; M Motor. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] As described in the background section, with the development of new energy and electrification, various types of power electronic equipment are being used more and more widely. Compared with traditional power transmission equipment, the core of power electronic equipment is the use of power circuits. Due to the relatively high failure rate and fault rate of power circuits, how to diagnose faults in power circuits of power electronic equipment has become an increasingly urgent problem for the industry, especially in high-power, high-reliability scenarios such as rail transit, power grid equipment, ship propulsion, and high-voltage high-power frequency converters.

[0045] Based on this, the embodiments of this application provide a power circuit, a fault diagnosis method, and a power electronic device, which effectively solves the technical problems existing in the prior art, realizes fault detection and type analysis of the power circuit, effectively reduces the fault maintenance cost of the power electronic device, and is applicable to different types of power scenarios.

[0046] To achieve the above objectives, the technical solutions provided in this application are as follows, in specific combination with... Figures 1 to 9 The technical solutions provided in the embodiments of this application will be described in detail.

[0047] refer to Figure 1 The diagram shown is a circuit diagram of a power circuit provided in an embodiment of this application. The power circuit includes a main controller 100 and at least one power unit. The power unit includes an IGBT (Insulated Gate Bipolar Transistor), the collector Cj of which is electrically connected to the positive terminal of a DC bus (not shown), and the emitter Ej of which is electrically connected to the negative terminal of the DC bus. A drive protection board 210 is electrically connected to the main controller 100, and the drive protection board 210 is electrically connected to the collector Cj, gate Gj, and emitter Ej of the IGBT via an electrical harness 220. The drive protection board 210 is used to send a fault signal when a fault occurs in the IGBT, and simultaneously control the IGBT to turn off. When the power circuit includes more power units, when the main controller 100 obtains the fault signal, it sends a turn-off signal to the drive protection boards 210 of the remaining power units to control the remaining IGBTs to turn off. The main controller 100 at least interacts with the drive protection board 210, and the main controller 100 provides the drive protection board 210 with pulse signals (PWM) for controlling the operation of the IGBT.

[0048] The power circuit also includes a fault diagnosis device 230, which includes a diode detection circuit 231. The diode detection circuit 231 includes a constant current source 2311, a storage capacitor Cd, and a diode unit 2312. The diode unit 2312 includes at least one detection diode Dd. The input terminal of the constant current source 2311 is electrically connected to the power supply voltage terminal Vcc. The output terminal of the constant current source 2311 is electrically connected to the first plate of the storage capacitor Cd and the positive terminal of the diode unit 2312. The second plate of the storage capacitor Cd is electrically connected to the ground terminal GND. The negative terminal of the diode unit 2312 is electrically connected to the collector Cj of the IGBT through the electrical wiring harness 220. The fault diagnosis device 230 is used to collect the diagnostic voltage at the first plate of the storage capacitor Cd. When the fault signal sent by the drive protection board 210 is obtained, the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs is stored, so as to analyze the fault type through the diagnostic data. Optionally, the diode unit 2312 provided in this application embodiment includes a detection diode Dd. The anode of the detection diode Dd is electrically connected to the output terminal of the constant current source 2311 and the first plate of the storage capacitor Cd. The cathode of the detection diode Dd is electrically connected to the collector Cj of the IGBT through the electrical wiring harness 220.

[0049] It is understood that the technical solution provided in this application can analyze the fault type based on diagnostic voltage data within a preset time before and after the IGBT fault occurs, thereby quickly and accurately locating the fault type of the power circuit and effectively reducing the fault maintenance cost of power electronic equipment. The power circuit provided in this application has a simple structure and no usage limitations, and is suitable for different types of power scenarios.

[0050] In some embodiments, the fault type analysis provided in this application can be performed automatically by the fault diagnosis device 230, or by the main controller 100, or the user can download the diagnostic data for analysis. This application does not impose specific limitations on these methods. (Specifically combined with...) Figures 2 to 5 Table 1 illustrates the fault types provided in the embodiments of this application. Figure 2 This is a graph showing the diagnostic voltage during an SC (Short Circuit) fault. Figure 3 This is a graph showing the diagnostic voltage during an OC (Overcurrent) fault. Figure 4 This is a graph showing the diagnostic voltage during a wiring harness fault. Figure 5 A graph showing the diagnostic voltage during EMC (Electromagnetic Compatibility) interference faults, where... Figures 2 to 5In the schematic coordinate system, the horizontal axis represents time, and the vertical axis represents diagnostic voltage. Table 1 is a comparison table of fault types and diagnostic voltages, where Vx is the rise parameter of the diagnostic voltage, Tf is the time required for the diagnostic voltage to rise, and Ts is the duration after the diagnostic voltage reaches its maximum value. The fault types provided in this application embodiment include: SC fault, OC fault, wiring harness fault (i.e., fault of electrical wiring harness 220), and EMC interference fault, wherein:

[0051]

[0052] Table 1

[0053] Combination Figure 2 As shown in Table 1, during the SC fault, the diagnostic voltage rises from 0V to the power supply voltage value at the power supply voltage terminal within a time not exceeding a first threshold, and the duration of the diagnostic voltage at the power supply voltage value is within a first set time range. Taking a three-phase half-bridge power circuit as an example, when an SC fault occurs, such as a shoot-through fault in the upper and lower bridge arms, the IGBT current will increase sharply, the IGBT will quickly desaturate, and the Vce voltage of the IGBT will approach the bus voltage. At this time, the diode unit 2312 in the diode detection circuit 231 will be turned off, and the voltage of the power supply voltage terminal Vcc will charge the storage capacitor Cd through the constant current source 2311, causing the diagnostic voltage to rise rapidly from 0V to the power supply voltage value. In some embodiments, the first threshold time provided in this application embodiment can be 500ns, the power supply voltage value can be 15V, and the first set time range can be 8-10us; that is, when the diagnostic voltage rises from 0V to 15V within no more than 500ns, and the duration of the diagnostic voltage at 15V is within 8-10us, the fault type is determined to be an SC fault.

[0054] Combination Figure 3As shown in Table 1, during an OC fault, the diagnostic voltage rises from a set voltage value to a fault voltage value within a time not exceeding the first threshold value, and the duration of the diagnostic voltage at the fault voltage value is not less than a second threshold time. The set voltage value is the saturation voltage drop of the IGBT, the fault voltage value is less than the power supply voltage value, and the upper limit of the first set time range is less than the second threshold time. Taking a three-phase half-bridge power circuit as an example, when an OC fault occurs, if a load short-circuit fault occurs, it will cause an overcurrent problem in the IGBT. Due to the presence of the short-circuit load, the IGBT will slowly desaturate, and the Vce voltage of the IGBT will gradually rise from the saturation voltage drop to the fault voltage. Since the diode unit 2312 is conducting during an OC fault, the voltage at the first plate of the storage capacitor Cd is equal to the Vce voltage of the IGBT; that is, the diagnostic voltage is equal to the Vce voltage of the IGBT. In some embodiments, the saturation voltage drop of the IGBT provided in this application can be 3V, the second threshold time can be 20us, and the fault voltage can be 10V; that is, when the diagnostic voltage rises from 3V to 10V within no more than 500ns, and the duration of the diagnostic voltage at 10V is no less than 20us, the fault type is determined to be an OC fault.

[0055] Combination Figure 4 As shown in Table 1, when the wiring harness fails, the diagnostic voltage rises from 0V to the power supply voltage value within a time not less than a third threshold time, and the duration of the diagnostic voltage at the power supply voltage value is within the first set time range, while the third threshold time is greater than the first threshold time. Taking a three-phase half-bridge power circuit as an example, when a wiring harness failure occurs, such as an installation-related failure, specifically, during the IGBT turn-on process, if the wire connecting the collector Cj suddenly loosens due to vibration or other issues, the diode unit 2312 will be cut off, and the voltage at the power supply voltage terminal Vcc will charge the storage capacitor Cd through the constant current source 2311, causing the diagnostic voltage to rise rapidly from 0V to the power supply voltage value. Since this is a physical loosening process, the voltage rise time will be greater than the first threshold time for a fault like SC. In some embodiments, the third threshold time provided in this application can be 1µs, and the first set time range can be 8-10µs; that is, when the diagnostic voltage rises from 0V to 15V within a time not less than 1µs, and the duration of the diagnostic voltage at 15V is within 8-10µs, the fault type is determined to be a wiring harness failure.

[0056] Combination Figure 5As shown in Table 1, during the EMC interference fault, the diagnostic voltage exhibits a disordered fluctuation curve within the preset time. During an EMC interference fault, such as during IGBT turn-on, the wiring harness connecting the collector Cj may introduce interference voltage into the diode unit 2312 due to structural installation and wiring. The amplitude of this interference voltage will randomly change under different operating conditions, resulting in a random fluctuation curve.

[0057] refer to Figure 6 The diagram shown is a circuit diagram of another power circuit provided in an embodiment of this application. The fault diagnosis device 230 provided in this embodiment includes: a voltage sampling circuit 232, electrically connected to the first plate of the storage capacitor Cd, used to collect the diagnostic voltage at the first plate of the storage capacitor Cd; and a processor 233, electrically connected to both the drive protection board 210 and the voltage sampling circuit 232, used to store diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs when the drive protection board 210 sends a fault signal, so as to analyze the fault type through the diagnostic data. Optionally, the processor 233 provided in this embodiment can be an MCU (Micro Controller Unit) processor.

[0058] In some embodiments, the diagnostic data provided in this application can be stored by the processor 233 itself. Alternatively, the diagnostic data provided in this application can also be stored by a separately configured memory 234. Figure 7 The diagram shown is a circuit diagram of another power circuit provided in an embodiment of this application. The fault diagnosis device 230 provided in this embodiment of the application further includes: a memory 234, which is electrically connected to the processor 233. The memory 234 is used to store diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, according to the control of the processor 233.

[0059] Continue as Figure 7 As shown in the embodiment of this application, the diode detection circuit 231 further includes a resistor R, the first end of which is electrically connected to the first plate of the storage capacitor Cd, and the second end of which is electrically connected to the second plate of the storage capacitor Cd. By setting the resistor R, the voltage at the first plate of the storage capacitor Cd can be filtered and stabilized, improving the diagnostic voltage acquired by the voltage sampling circuit 232.

[0060] In some embodiments, the drive protection board 210 provided in this application can detect and send a fault signal when the IGBT malfunctions based on the IGBT's Vce voltage. Optionally, the drive protection board 210 provided in this application is electrically connected to the first plate of the storage capacitor Cd. The drive protection board 210 detects and sends a fault signal when the IGBT malfunctions based on the diagnostic voltage. When the diode unit 2312 is turned on, the diagnostic voltage is the same as the IGBT's Vce voltage. Therefore, the drive protection board 210 can reuse the diode detection circuit 231 to obtain the IGBT's Vce voltage, simplifying the circuit structure in the drive protection board 210 and reducing the cost of the power circuit. It should be noted that the drive protection board 210 provided in this application can also obtain the IGBT's Vce voltage by setting its own related detection circuit; this application does not impose specific limitations on this.

[0061] In some embodiments, the power circuit provided in this application may include a single-transistor circuit, a half-bridge circuit, or a full-bridge circuit. The half-bridge circuit may be a single-phase half-bridge circuit or a three-phase half-bridge circuit, etc., and the full-bridge circuit may be a single-phase full-bridge circuit or a three-phase full-bridge circuit, etc., and this application does not impose specific limitations in this regard. Taking a three-phase half-bridge circuit as an example, refer to... Figure 8 As shown, the power circuit provided in this embodiment is a three-phase half-bridge circuit. The power circuit includes a main controller 100 and six power units, namely the first power unit S1, the second power unit S2, the third power unit S3, the fourth power unit S4, the fifth power unit S5, and the sixth power unit S6. Each power unit includes an IGBT, a drive protection board 210, an electrical wiring harness 220, and a fault diagnosis device 230 (the drive protection board 210, the electrical wiring harness 220, and the fault diagnosis device 230 are not included in the diagram). Figure 8 (Drawn in the middle). The first power unit S1 and the fourth power unit S4 form a phase bridge arm, the third power unit S3 and the sixth power unit S6 form a phase bridge arm, and the fifth power unit S5 and the second power unit S2 form a phase bridge arm. Each phase bridge arm is connected in parallel with the bus capacitor Cdc, and the three phase bridge arms are electrically connected to the motor M.

[0062] Continue to combine Figure 8As shown, in the three-phase half-bridge circuit provided in this application embodiment, during operation, the fault diagnosis device 230 acquires the diagnostic voltage collected by the diode detection circuit 231 in real time according to a certain time window (such as 20ms). Optionally, the fault diagnosis device 230 is triggered by two signals to store the collected diagnostic data. One is a fault signal. After acquiring the fault signal sent by the drive protection board 210, the fault diagnosis device 230 stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs. The other is a shutdown signal. After acquiring the shutdown signal sent by the main controller 100, the fault diagnosis device 230 stores the diagnostic data of the diagnostic voltage within a preset time before and after the corresponding shutdown signal. The fault signal is stored at a higher level than the shutdown signal.

[0063] In a three-phase half-bridge circuit, after the drive protection board 210 in a certain power unit detects an IGBT fault, it sends a fault signal and immediately shuts down the IGBT in that power unit. After receiving the fault signal, the main controller 100 sends a shutdown signal to the remaining power units to control the drive protection boards 210 of the other power units to shut down the IGBTs electrically connected to their respective phases. The fault diagnosis devices 230 of these power units store diagnostic data of the diagnostic voltage within a preset time before and after the shutdown signal. Simultaneously, after receiving the fault signal, the fault diagnosis device 230 stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault. In other words, after the drive protection board 210 in a certain power unit detects an IGBT fault, the fault diagnosis device 230 of that power unit stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault, while the fault diagnosis devices 230 of the other five power units store the diagnostic data of the diagnostic voltage within a preset time before and after the shutdown signal.

[0064] After a fault shutdown, the fault diagnosis device 230 can analyze the fault type based on the diagnostic data; or, the main controller 100 can retrieve the diagnostic data stored in the fault diagnosis device 230 to analyze the fault type; or, the user can read and download the diagnostic data stored in the fault diagnosis device 230, and then use relevant methods to analyze the fault type to determine whether the fault type is SC fault, OC fault, wiring harness fault, or EMC interference fault based on the diagnostic data.

[0065] Based on the same inventive concept, embodiments of this application also provide a fault diagnosis method. (Reference) Figure 9The diagram shows a flowchart of a fault diagnosis method provided in an embodiment of this application. The fault diagnosis method provided in this application is applied to the power circuit provided in any of the above embodiments. The fault diagnosis method includes: acquiring a fault signal sent by the drive protection board 210; storing diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data.

[0066] Based on the same inventive concept, embodiments of this application also provide a power electronic device, which includes the power circuit provided in any of the above embodiments. Optionally, the power electronic device provided in embodiments of this application may include an inverter, rectifier, frequency converter, switching power supply, etc., and this application does not impose specific limitations on this. Furthermore, the power electronic device provided in embodiments of this application can be applied to equipment such as new energy vehicles.

[0067] In summary, this application provides a power circuit, a fault diagnosis method, and a power electronic device. The power circuit includes a main controller and at least one power unit. The power unit includes: an IGBT, the collector of which is electrically connected to the positive terminal of a DC bus, and the emitter of which is electrically connected to the negative terminal of the DC bus; a drive protection board, which is electrically connected to the main controller and to the IGBT via an electrical harness; the drive protection board is used to send a fault signal when a fault occurs in the IGBT and simultaneously control the IGBT to turn off; and a fault diagnosis device, which includes a diode detection circuit. The system comprises a constant current source, a storage capacitor, and a diode unit, wherein the diode unit includes at least one detection diode. The input terminal of the constant current source is electrically connected to the power supply voltage terminal, and the output terminal of the constant current source is electrically connected to both the first plate of the storage capacitor and the positive terminal of the diode unit. The second plate of the storage capacitor is electrically connected to the ground terminal, and the negative terminal of the diode unit is electrically connected to the collector of the IGBT through the electrical wiring harness. The fault diagnosis device is used to collect the diagnostic voltage at the first plate of the storage capacitor, and when acquiring the fault signal sent by the drive protection board, it stores the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data. As can be seen from the above, the technical solution provided by this application embodiment can analyze the fault type based on the diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, thereby quickly and accurately locating the fault type of the power circuit and effectively reducing the fault maintenance cost of power electronic equipment. Furthermore, the power circuit provided by this application embodiment has a simple structure and no usage restrictions, and is suitable for different types of power scenarios.

[0068] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and other terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0070] In the embodiments of this application, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0071] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0072] In the embodiments of this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A power circuit, characterized in that, The power circuit includes a main controller and at least one power unit, the power unit comprising: The collector of the IGBT is electrically connected to the positive terminal of the DC bus, and the emitter of the IGBT is electrically connected to the negative terminal of the DC bus. A drive protection board is electrically connected to the main controller and to the IGBT via an electrical wiring harness. The drive protection board is used to send a fault signal when the IGBT malfunctions, and simultaneously control the IGBT to turn off. A fault diagnosis device includes a diode detection circuit, which comprises a constant current source, a storage capacitor, and a diode unit. The diode unit includes at least one detection diode. The input terminal of the constant current source is electrically connected to a power supply voltage terminal. The output terminal of the constant current source is electrically connected to both the first plate of the storage capacitor and the positive terminal of the diode unit. The second plate of the storage capacitor is electrically connected to a ground terminal. The negative terminal of the diode unit is electrically connected to the collector of the IGBT via an electrical wiring harness. The fault diagnosis device is used to acquire the diagnostic voltage at the first plate of the storage capacitor and, when acquiring a fault signal sent by the drive protection board, stores diagnostic data of the diagnostic voltage within a preset time period before and after the IGBT fault occurs, so as to analyze the fault type of the IGBT through the diagnostic data. The fault types include one of the following: SC fault, OC fault, wiring harness fault, and EMC interference fault; When the SC fault occurs, the diagnostic voltage rises from 0V to the power supply voltage value at the power supply voltage terminal within a time not greater than a first threshold value, and the duration of the diagnostic voltage at the power supply voltage value is within a first set duration range. During the OC fault, the diagnostic voltage rises from a set voltage value to the fault voltage value within a time not greater than the first threshold value, and the duration of the diagnostic voltage at the fault voltage value is not less than the second threshold value. The set voltage value is the saturation voltage drop of the IGBT, the fault voltage value is less than the power supply voltage value, and the upper limit of the first set duration range is less than the second threshold value. When the wiring harness fails, the diagnostic voltage rises from 0V to the power supply voltage value within a time not less than a third threshold time, and the duration of the diagnostic voltage at the power supply voltage value is within the first set time range, and the third threshold time is greater than the first threshold time. During the EMC interference fault, the diagnostic voltage exhibits a disordered fluctuation curve within the preset time period.

2. The power circuit according to claim 1, characterized in that, The fault diagnosis device includes: A voltage sampling circuit is electrically connected to the first plate of the storage capacitor, and the voltage sampling circuit is used to acquire the diagnostic voltage at the first plate of the storage capacitor; The processor is electrically connected to both the drive protection board and the voltage sampling circuit. When the processor acquires a fault signal sent by the drive protection board, it stores diagnostic data of the diagnostic voltage within a preset time before and after the IGBT fault occurs, so as to analyze the fault type through the diagnostic data.

3. The power circuit according to claim 2, characterized in that, The fault diagnosis device also includes: The memory is electrically connected to the processor and is used to store diagnostic data of the diagnostic voltage within a preset time period before and after the IGBT malfunctions, according to the control of the processor.

4. The power circuit according to claim 1, characterized in that, The diode detection circuit further includes: A resistor, wherein the first end of the resistor is electrically connected to the first plate of the storage capacitor, and the second end of the resistor is electrically connected to the second plate of the storage capacitor.

5. The power circuit according to claim 1, characterized in that, The drive protection board detects when an IGBT malfunctions based on the IGBT's Vce voltage and sends a fault signal.

6. The power circuit according to claim 5, characterized in that, The drive protection board is electrically connected to the first plate of the storage capacitor. The drive protection board sends the fault signal when the IGBT fails, based on the diagnostic voltage. When the diode unit is turned on, the diagnostic voltage is the same as the Vce voltage of the IGBT.

7. The power circuit according to claim 1, characterized in that, The power circuit includes: a single-transistor circuit, a half-bridge circuit, or a full-bridge circuit.

8. A fault diagnosis method, characterized in that, The fault diagnosis method is applied to the power circuit according to any one of claims 1-7, wherein the fault diagnosis method includes: Obtain the fault signal sent by the drive protection board; The diagnostic data of the diagnostic voltage is stored within a preset time period before and after the IGBT malfunctions, so as to analyze the fault type through the diagnostic data.

9. A power electronic device, characterized in that, The power electronic device includes the power circuit according to any one of claims 1-7.

Images