Silicon carbide power device short circuit failure online early warning device, system and method

Abstract

The embodiment of the invention relates to a silicon carbide power device short circuit failure online early warning device, system and method. The silicon carbide power device short circuit failure online early warning device comprises a power module, a signal sampling and calculating module and a short circuit judging module. The power module comprises a driving unit, and the driving unit is connected with a to-be-tested power device. The signal sampling and calculating module is connected with the power module and a to-be-measured power device, and is used for respectively acquiring the driving signal and the on-state grid voltage of the to-be-measured power device, and calculating the grid resistance of the to-be-measured power device according to the driving signal and the on-state grid voltage; the short circuit judgment module is connected with the signal sampling and calculating module and used for judging whether short circuit occurs according to the grid resistance of the power device to be tested and a grid resistance threshold value. According to the technical scheme provided by the embodiment of the invention, the early warning signal is sent out when the gate resistance of the to-be-tested power device has the abnormal fluctuation conforming to the characteristic of the endangered short-circuit failure, so that early warning before the short-circuit failure is realized.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of power electronics technology, and in particular to an online early warning device, system and method for short-circuit failure of a silicon carbide power device. Background Art

[0002] With the continuous development of power electronics technology, silicon carbide metal oxide semiconductor field effect transistor (SiCMOSFET) has been increasingly widely used in new energy vehicles, rail transit, smart grid and other fields due to its excellent performance, such as high switching speed, low on-resistance, high temperature resistance and other characteristics.

[0003] However, SiC MOSFET may have two types of faults during operation: short-circuit faults and open-circuit faults. In fact, short-circuit faults account for a higher proportion and have a more severe impact on the system. Short-circuit faults not only cause serious damage to the equipment itself, but may also affect the normal operation of the entire system and even cause safety accidents. At present, the detection of SiC MOSFET short-circuit faults is mainly carried out after the fault occurs, and there are relatively few methods for early warning before short-circuit failure. Summary of the invention

[0004] Based on the above situation of the prior art, the purpose of the embodiments of the present invention is to provide an online early warning device, system and method for short-circuit failure of a silicon carbide power device, which sends a warning signal when the gate resistance of the power device to be tested shows abnormal fluctuations that meet the characteristics of an impending short-circuit failure, thereby realizing early warning before short-circuit failure.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an online early warning device for short-circuit failure of a silicon carbide power device, comprising a power module, a signal sampling and calculation module and a short-circuit judgment module;

[0006] The power module comprises a driving unit, wherein the driving unit is connected to the power device to be tested and is used to output a driving signal to the gate of the power device to be tested;

[0007] The signal sampling and calculation module is connected to the power module and the power device to be tested, and is used to respectively collect the driving signal and the on-state gate voltage of the power device to be tested, and calculate the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage;

[0008] The short circuit judgment module is connected to the signal sampling and calculation module, and is used to judge whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested.

[0009] Furthermore, the power module further includes a driving resistor, and the driving unit is connected to the gate of the power device to be tested via the driving resistor.

[0010] Further, the gate resistance of the power device to be measured is calculated according to the driving signal and the on-state gate voltage, including using the following formula to calculate the gate resistance of the power device to be measured:

[0011]

[0012] Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

[0013] Further, judging whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested includes:

[0014] If R ge ≥R t h1, the result is normal;

[0015] If R t h2≤R ge <R t h1, it is judged that slight gate aging occurs;

[0016] If R ge <R t h2, it is judged that serious gate aging has occurred and an early warning signal is output;

[0017] Among them, R t h1 represents the first gate resistance threshold, R t h2 represents a second gate resistance threshold. Further, the power device to be tested is a SiC power device; the power device to be tested includes a plurality of power devices connected in series, or the power device to be tested includes a plurality of power devices connected in parallel.

[0018] According to a second aspect of the present invention, there is provided an online early warning system for short-circuit failure of a silicon carbide power device, wherein the power circuit comprises a DC power supply, a first controllable switch and a second controllable switch;

[0019] The first controllable switch and the second controllable switch are connected in series and connected to the DC power supply;

[0020] The first controllable switch and the second controllable switch are both power devices, the two ends of the first controllable switch are connected to the load inductor, and the gate of the second controllable switch is connected to the power device short-circuit failure online early warning device as described in the first aspect of the present invention.

[0021] According to a third aspect of the present invention, a method for online early warning of short-circuit failure of a power device is provided, wherein the online early warning device for short-circuit failure of a power device according to the first aspect of the present invention is used to perform online early warning of short-circuit failure, and the method for online early warning of short-circuit failure comprises the following steps:

[0022] Collecting the driving signal output by the driving unit and the on-state gate voltage of the power device to be tested;

[0023] Calculating the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage;

[0024] Whether a short circuit occurs is determined according to the gate resistance and the gate resistance threshold of the power device to be tested.

[0025] Further, the gate resistance of the power device to be measured is calculated according to the driving signal and the on-state gate voltage, including using the following formula to calculate the gate resistance of the power device to be measured:

[0026]

[0027] Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

[0028] Further, judging whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested includes:

[0029] If R ge ≥R t h1, the result is normal;

[0030] If R t h2≤R ge <R t h1, it is judged that slight gate aging occurs;

[0031] If R ge <R t h2, it is judged that serious gate aging has occurred and an early warning signal is output;

[0032] Among them, R t h1 represents the first gate resistance threshold, R t h2 represents a second gate resistance threshold. Further, the power device to be tested is a SiC power device; the power device to be tested includes a plurality of power devices connected in series, or the power device to be tested includes a plurality of power devices connected in parallel.

[0033] In summary, the embodiments of the present invention provide an online early warning device, system and method for short-circuit failure of silicon carbide power devices, the device comprising a power module, a signal sampling and calculation module and a short-circuit judgment module; the power module comprises a driving unit, the driving unit is connected to the power device to be tested, and is used to output a driving signal to the gate of the power device to be tested; the signal sampling and calculation module is connected to the power module and the power device to be tested, and is used to respectively collect the driving signal and the on-state gate voltage of the power device to be tested, and calculate the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage; the short-circuit judgment module is connected to the signal sampling and calculation module, and is used to judge whether a short circuit occurs according to the gate resistance of the power device to be tested and the gate resistance threshold. The technical solution provided by the embodiments of the present invention can achieve the following beneficial effects:

[0034] First, avoid equipment damage. The technical solution of the embodiment of the present invention can accurately predict the short circuit situation, so that the SiC power device can be shut down in time before the short circuit fault develops to a catastrophic level, avoiding the device from being damaged by excessive current and heat. The cost of equipment maintenance and replacement is reduced, and the availability of the system is improved. Early shutdown can also prevent the fault from causing chain damage to other equipment and system components, reducing overall losses.

[0035] Secondly, improve system reliability. Accurate prediction and timely shutdown can effectively prevent short-circuit faults from causing serious impact on the normal operation of the system and improve the reliability and stability of the power electronic system. This is especially important for some application fields with high reliability requirements, such as aerospace, medical equipment, etc.

[0036] Finally, the system is safe. In some cases, a short circuit fault may cause a fire, explosion or other safety incident, posing a serious threat to personnel and equipment. By accurately predicting and shutting down components, the embodiments of the present invention can take measures before a fault occurs to ensure the safe operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a gate equivalent circuit diagram of a SiC power device after being turned on provided by an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of the gate voltage waveform when the Sic power device is healthy;

[0039] Figure 3 This is a schematic diagram of the gate voltage waveform when the Sic power device is on the verge of short circuit failure;

[0040] Figure 4 Schematic diagram of the circuit structure of the short-circuit failure online early warning system provided by an embodiment of the present invention;

[0041] Figure 5 Schematic diagram of the circuit structure of the signal sampling and calculation module provided by an embodiment of the present invention;

[0042] Figure 6 It is a flow chart of an online early warning method for short-circuit failure of a power device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0044] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in one or more embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0045] In the prior art, the solution to the short-circuit fault of SiC power devices is mainly to cut off the faulty bridge arm. However, this requires the addition of additional components such as fuses in the branch where the SiC power device is located. On the one hand, this increases the complexity of the system and stray parameters such as loop inductance. On the other hand, due to the characteristics of SiC power devices themselves, SiC power devices are difficult to cut off after a short circuit occurs, which poses a great challenge to power electronic systems. As a result, most converters containing SiC power devices can only shut down the system after a short circuit occurs in the device. Specifically,

[0046] First, SiC power devices have the characteristics of high switching speed, which makes the current rise very quickly when a short circuit occurs. Since the short-circuit current is usually very large, it may exceed the response capability of the protection device, making it difficult to quickly cut off the fault. In addition, the rapidly rising large current may cause serious thermal damage and mechanical stress to the device and system in a short period of time, further increasing the difficulty of cutting off the fault.

[0047] Secondly, SiC power devices generate a lot of heat in the case of a short circuit. Due to their good high temperature resistance, they may remain in working condition for a certain period of time, but this also means that the fault may continue to develop and it is difficult to remove it in time through traditional protection methods. High temperature may cause the performance and reliability of the device to decline, and even cause secondary faults, making the short circuit situation more complicated.

[0048] Finally, in modern power electronic systems, SiC power devices are often integrated with other devices and complex control circuits. This increases the complexity of the system, making it more difficult to locate and remove the fault when a short circuit occurs. The interaction and influence between different devices may mask the characteristics of the short circuit fault, resulting in the inability of the protection device to accurately judge the fault condition and take timely measures.

[0049] The embodiments of the present invention provide an online warning device, system and method for short-circuit failure of a power device, which can accurately predict and shut down the SiC power device before a catastrophic short-circuit failure occurs. The technical scheme of the present invention is described in detail below in conjunction with the accompanying drawings. The embodiments of the present invention provide an online warning device for short-circuit failure of a power device, which includes a power module, a signal sampling and calculation module and a short-circuit judgment module.

[0050] The power module includes a driving unit, which is connected to the power device to be tested and is used to output a driving signal to the gate of the power device to be tested. The power module also includes a driving resistor, through which the driving unit is connected to the gate of the power device to be tested. In this embodiment of the present invention, the power device to be tested is a SiC power device. The online early warning device for short-circuit failure of a power device provided in an embodiment of the present invention can realize online early warning of short-circuit failure of a power device without the need to specially build a detection device. Among them, the power module is a power circuit for power conversion, and the driving unit is a driving circuit in the power circuit that provides a driving signal to the power device.

[0051] The signal sampling and calculation module is connected to the power module and the power device to be tested, and is used to respectively collect the driving signal and the on-state gate voltage of the power device to be tested, and calculate the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage. In this embodiment of the present invention, the gate resistance of the power device to be tested is calculated using the following formula:

[0052]

[0053] Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

[0054] SiC power devices are voltage-type fully controlled devices. The gate equivalent circuit of SiC power devices after they are turned on is as follows: Figure 1 When the device is turned on, the gate source of the SiC power device can be equivalent to a relatively large resistor R ge , resistor R ge and the driving resistor R g Therefore, the relationship between the on-state gate voltage V1 of the power device to be tested and the driving signal voltage V3 issued by the driving unit can be expressed as:

[0055]

[0056] Based on this relationship, the above formula for calculating the gate resistance of the power device to be tested can be obtained.

[0057] A short circuit judgment module is connected to the signal sampling and calculation module and is used to judge whether a short circuit occurs according to the gate resistance and gate resistance threshold of the power device to be tested. Whether a short circuit occurs can be judged according to the comparison of the gate resistance of the power device to be tested and the gate resistance threshold:

[0058] If R ge ≥R t h, the result is normal;

[0059] If R ge <R t h, it is judged that a short circuit occurs and an early warning signal is output;

[0060] Among them, R t h represents the gate resistance threshold.

[0061] When the SiC power device is healthy, the gate resistance R ge Usually it is several k to several hundred k ohms. The driving resistor R g Usually it is several ohms to tens of ohms. In this embodiment of the present invention, the driving resistor R g is 50 ohms. Therefore:

[0062]

[0063] That is:

[0064] V1≈V3

[0065] According to the data measured in the embodiment of the present invention, when the driving signal voltage V3 is 15V, the magnitude of the on-state gate voltage V1 of the power device to be tested is about 14.6V, and the voltage waveform is as follows: Figure 2 shown.

[0066] Therefore, the on-state equivalent gate resistance R of a healthy SiC power device can be obtained. ge The value of is:

[0067]

[0068] When the SiC power device is on the verge of short circuit failure, the gate resistance R ge It will be significantly reduced, generally from several thousand ohms to several hundred ohms, or even smaller. Therefore, it meets the following requirements:

[0069]

[0070] That is to satisfy:

[0071] V1 <V3

[0072] According to the data measured in the embodiment of the present invention, when the driving signal voltage V3 is 15V, the on-state gate voltage V1 of the power device to be tested is less than about 8.5V, and the voltage waveform is as follows: Figure 3 shown.

[0073] Therefore, the on-state equivalent gate resistance R of the SiC power device can be obtained. ge for:

[0074]

[0075] Therefore, the gate resistance R can be calculated by monitoring the gate voltage after the device is turned on (in the on state). ge To judge the health of SiC power devices. In the embodiment of the present invention, the gate resistance threshold R t h is 100 ohms, when the device gate resistance R ge When the gate resistance R is greater than 100 ohms, the device is considered to be still operational. ge When it is less than 100 ohms, an early warning is required and the device needs to be replaced through inspection. t The value of h can be set according to the actual situation of the power system and the devices used.

[0076] The embodiment of the present invention also provides an online early warning system for short-circuit failure of a silicon carbide power device. Figure 4 The schematic diagram of the circuit structure of the short-circuit failure online warning system is shown in FIG. The power circuit includes, for example, a DC power supply V, a first controllable switch M1, and a second controllable switch M2. According to some optional embodiments, the power circuit may also be a topology including more controllable switches (SiC power devices), such as a full-bridge topology, a half-bridge topology, a push-pull topology, a forward topology, and a flyback topology.

[0077] The first controllable switch M1 and the second controllable switch M2 are connected in series and connected to a DC power supply V;

[0078] The first controllable switch M1 and the second controllable switch M2 are both SiC power devices. Both ends of the first controllable switch M1 are connected to the load inductor L, and the gate of the second controllable switch M2 is connected to the power device short-circuit failure online early warning device provided in the above embodiment, which is used to perform short-circuit failure online early warning on the controllable switch SiC power device M2.

[0079] According to some optional embodiments, the signal sampling and calculation module includes a DSP and a conditioning circuit. Figure 5 The circuit structure diagram of the signal sampling and calculation module is shown in FIG. Figure 5 As shown, in the conditioning circuit, the first resistor R1, the second resistor R2 and the first operational amplifier U1 form a first in-phase amplifier for conditioning the gate voltage V1. The third resistor R3, the fourth resistor R4 and the second operational amplifier U2 form a second in-phase amplifier for conditioning the drive signal voltage V3. The DSP circuit (digital signal processing circuit) is used to receive the output voltage from the first operational amplifier U1 and the second operational amplifier U2. The DSP is used to perform short-circuit failure early warning judgment through the judgment logic described above in the present invention.

[0080] According to certain optional embodiments, one or more of the above-mentioned power device short-circuit failure online warning devices may also be provided in any type of power system to provide online short-circuit failure online warning for one or more SiC power devices in the power system.

[0081] According to some optional embodiments, the power device to be tested is a power device connected in series, or the power device to be tested is a power device connected in parallel. For power devices connected in series, each power device has a separate drive circuit; for power devices connected in parallel, each power device has a separate drive circuit, or all power devices connected in parallel share a drive circuit. For power devices connected in parallel, if all power devices connected in parallel share a drive circuit, if any power device has a reduced gate-source resistance, it is considered that the bridge arm in which it is located is on the verge of short circuit failure.

[0082] The embodiment of the present invention also provides an online early warning method for short-circuit failure of a silicon carbide power device. Figure 6 , a flowchart of the short-circuit failure online early warning method is shown in FIG. The short-circuit failure online early warning method uses the short-circuit failure online early warning device for silicon carbide power device provided by the above embodiment of the present invention to perform short-circuit detection. The short-circuit failure online early warning method includes the following steps:

[0083] S202, collecting the driving signal output by the driving unit and the on-state gate voltage of the power device to be tested. A high-precision voltage sensor can be used to collect the driving signal output by the driving unit and the on-state gate voltage of the power device to be tested to improve the accuracy of the early warning result. The on-state moment of the power device can be determined by gate driving signal detection.

[0084] S204, calculating the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage. In this step, the gate resistance of the power device to be tested is calculated using the following formula:

[0085]

[0086] Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

[0087] S206, judging whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested, including:

[0088] If R ge ≥R t h1, the result is normal;

[0089] If R t h2≤R ge <R t h1, it is judged that slight gate aging has occurred. In this case, the driving signal dead zone of the power device to be tested can be appropriately increased, and the load current can be appropriately reduced;

[0090] If R ge <R t h2, it is judged that serious gate aging has occurred, that is, the power device under test is on the verge of short-circuit failure, and an early warning signal is output at this time.

[0091] Among them, R t h1 represents the first gate resistance threshold, R t h2 represents the second gate resistance threshold. The first gate resistance threshold and the second gate resistance threshold can be obtained by a cyclic short circuit test.

[0092] According to some optional embodiments, if the calculated gate resistance R of the power device to be tested is ge With the gate resistance threshold R t If the resistance values ​​of h are close, the voltage can be collected multiple times and the average value of the multiple collection results can be calculated to improve the accuracy of the short circuit judgment result.

[0093] In summary, the embodiment of the present invention relates to an online early warning device, system and method for short-circuit failure of a silicon carbide power device, the device comprising a power module, a signal sampling and calculation module and a short-circuit judgment module; the power module comprises a driving unit, the driving unit is connected to the power device to be tested, and is used to output a driving signal to the gate of the power device to be tested; the signal sampling and calculation module is connected to the power module and the power device to be tested, and is used to respectively collect the driving signal and the on-state gate voltage of the power device to be tested, and calculate the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage; the short-circuit judgment module is connected to the signal sampling and calculation module, and is used to judge whether a short circuit occurs according to the gate resistance and gate resistance threshold of the power device to be tested. The technical solution provided by the embodiment of the present invention calculates the gate resistance of the power device to be tested by detecting various parameters of the power module, and when the gate resistance of the power device to be tested has abnormal fluctuations that meet the characteristics of imminent short-circuit failure, a warning signal can be issued in time, so as to take effective protection measures before the short-circuit fault actually occurs, so as to avoid damage to the SiC power device due to short circuit, thereby ensuring the reliable operation of the power electronic system.

[0094] It should be understood that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present invention (including claims) is limited to these examples; under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of one or more embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. The above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the scope of protection of the present invention. In addition, the claims attached to the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims, or the equivalent forms of such scope and boundaries.

Claims

1. An online early warning device for short-circuit failure of a silicon carbide power device, characterized in that: It includes a power module, a signal sampling and calculation module and a short circuit judgment module; The power module comprises a driving unit, wherein the driving unit is connected to the power device to be tested and is used to output a driving signal to the gate of the power device to be tested; The signal sampling and calculation module is connected to the power module and the power device to be tested, and is used to respectively collect the driving signal and the on-state gate voltage of the power device to be tested, and calculate the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage; The short circuit judgment module is connected to the signal sampling and calculation module, and is used to judge whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested.

2. The device according to claim 1, characterized in that The power module further includes a driving resistor, and the driving unit is connected to the gate of the power device to be tested through the driving resistor.

3. The device according to claim 2, characterized in that Calculating the gate resistance of the power device to be measured according to the driving signal and the on-state gate voltage includes calculating the gate resistance of the power device to be measured using the following formula: Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

4. The device according to claim 3, characterized in that Determining whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested includes: If R ge ≥R t h1, the result is normal; If R t h2≤R ge <R t h1, it is judged that slight gate aging occurs; If R ge <R t h2, it is judged that serious gate aging has occurred and an early warning signal is output; Among them, R t h1 represents the first gate resistance threshold, R t h2 represents the second gate resistance threshold.

5. The device according to any one of claims 1 to 4, characterized in that: The power device to be tested is a SiC power device; the power device to be tested includes a plurality of power devices connected in series, or the power device to be tested includes a plurality of power devices connected in parallel.

6. An online early warning system for short-circuit failure of silicon carbide power devices in power circuits, characterized in that: The power circuit includes a DC power supply, a first controllable switch and a second controllable switch; The first controllable switch and the second controllable switch are connected in series and connected to the DC power supply; The first controllable switch and the second controllable switch are both power devices, the two ends of the first controllable switch are connected to the load inductor, and the gate of the second controllable switch is connected to the power device short-circuit failure online early warning device as described in any one of claims 1-5.

7. An online early warning method for short-circuit failure of a silicon carbide power device, characterized in that: An online warning method for short-circuit failure of a silicon carbide power device is used to perform online warning for short-circuit failure. The online warning method for short-circuit failure comprises the following steps: Collecting the driving signal output by the driving unit and the on-state gate voltage of the power device to be tested; Calculating the gate resistance of the power device to be tested according to the driving signal and the on-state gate voltage; Whether a short circuit occurs is determined according to the gate resistance and the gate resistance threshold of the power device to be tested.

8. The method according to claim 7, characterized in that Calculating the gate resistance of the power device to be measured according to the driving signal and the on-state gate voltage includes calculating the gate resistance of the power device to be measured using the following formula: Among them, R ge represents the gate resistance of the power device to be tested, V1 represents the on-state gate voltage of the power device to be tested, V3 represents the drive signal voltage, R g Represents the driving resistance.

9. The method according to claim 8, characterized in that Determining whether a short circuit occurs according to the gate resistance and the gate resistance threshold of the power device to be tested includes: If R ge ≥R t h1, the result is normal; If R t h2≤R ge <R t h1, it is judged that slight gate aging occurs; If R ge <R t h2, it is judged that serious gate aging has occurred and an early warning signal is output; Among them, R t h1 represents the first gate resistance threshold, R t h2 represents the second gate resistance threshold.

10. The method according to any one of claims 7 to 9, characterized in that: The power device to be tested is a SiC power device; the power device to be tested includes a plurality of power devices connected in series, or the power device to be tested includes a plurality of power devices connected in parallel.

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