Short-circuit protection system and method applied to power electronic converter

Abstract

The invention discloses a short-circuit protection system and method applied to a power electronic converter, and the system comprises a conversion device which is used for collecting SGT MOSFET, VD MOSFET source drain voltage and system action signals, generating SGT loop current according to the SGT MOSFET source drain voltage, and generating drive control voltage according to the VD MOSFET source drain voltage; the logic control chip is used for judging whether the SGT loop current exceeds a short-circuit current threshold value or not, if yes, continuing to judge whether system current increase caused by the power electronic converter itself occurs or not according to the system action signal, if yes, generating a first VD drive control signal according to the drive control voltage, and outputting the first VD drive control signal; and if yes, adjusting the VD MOSFET from a current limiting working area to a variable resistance area according to the first VD driving control signal, if not, judging that a short circuit condition occurs, generating a second VD driving control signal, and adjusting the VD MOSFET to be closed according to the second VD driving control signal.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor power devices, and particularly relates to a short-circuit protection system and method applied to a power electronic converter. BACKGROUND

[0002] With the rapid development of the domestic power supply industry, power electronic converters gradually evolve towards high power and high density, which puts higher requirements on the reliability and safety of the system. Short circuit, as a severe working condition in the circuit, may lead to circuit overload due to the action of continuous high current, and puts higher requirements on the bearing capacity of components. If the short-circuit state cannot be controlled in time, it may cause serious accidents, even damage the components and shorten their service life. Under this background, how to effectively detect and suppress short-circuit current has become a key technical problem in the design of power electronic converters.

[0003] At present, the commonly used short-circuit protection methods mainly include sampling resistance detection and magnetic detection means. However, these methods have many shortcomings in practical application. For example, the sampling resistance has poor detection accuracy when short circuit occurs, because the system current increases significantly, which is difficult to meet the high-precision requirement. Although the magnetic detection means can realize non-contact detection, its anti-interference ability is weak, and the cost is high, which is difficult to be widely applied in various scenes. In addition, the existing protection system usually has slow response speed, and cannot quickly cut off the circuit after short circuit occurs, which may cause the equipment to be subjected to a large current impact, affecting the stability of the system.

[0004] In recent years, domestic discrete devices have been continuously updated with the development of the power supply industry, and have been optimized for different application scenarios to meet the diversified use requirements. In particular, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) plays an important role in surge current suppression due to its excellent output characteristics. However, the existing short-circuit protection schemes mostly rely on single devices or simple control logic, lack accurate judgment and fast response ability to short-circuit state, and have high probability of false triggering. Therefore, there is an urgent need for a protection method and system that can accurately detect short-circuit current, quickly respond and effectively suppress the impact of short circuit, in order to improve the overall reliability and safety of the power electronic converter. SUMMARY

[0005] In order to solve the above problems in the prior art, the present application provides a short-circuit protection system and method applied to a power electronic converter. The technical problem to be solved by the present application is solved by the following technical scheme: In a first aspect, an embodiment of the present application provides a short-circuit protection system applied to a power electronic converter, the short-circuit protection system comprising an SGT MOSFET, a VD MOSFET, a logic control chip and a conversion device, wherein The source end and the drain end of the SGT (Split Gate Trench) MOSFET and the VD (Vertical Double-diffused) MOSFET are connected with the conversion device, and the source end and the gate end of the SGT MOSFET and the VD MOSFET are connected with the logic control chip. The conversion device is used for collecting the source-drain voltage of the SGT MOSFET, the source-drain voltage of the VD MOSFET and a system action signal, and generating an SGT loop current according to the source-drain voltage of the SGT MOSFET and generating a drive control voltage according to the source-drain voltage of the VD MOSFET, wherein the system action signal is generated by the power electronic converter. The logic control chip is used for judging whether the SGT loop current exceeds a short-circuit current threshold value, if yes, judging whether the system current caused by the power electronic converter itself increases to a preset threshold value according to the system action signal, if yes, generating a first VD drive control signal according to the drive control voltage and adjusting the VD MOSFET from a current-limiting working area to a variable resistance area according to the first VD drive control signal, if no, judging that a short-circuit condition occurs and generating a second VD drive control signal, and adjusting the VD MOSFET to a closed state according to the second VD drive control signal, wherein when the system current caused by the power electronic converter itself increases to the preset threshold value, the VD MOSFET is adjusted to work in the current-limiting working area.

[0006] In an embodiment of the present application, in the logic control chip, if the SGT loop current does not exceed the short-circuit current threshold value, it is judged whether the system current caused by the power electronic converter itself increases to the preset threshold value according to the system action signal, if yes, a first VD drive control signal is generated according to the drive control voltage, and the VD MOSFET is adjusted from the current-limiting working area to the variable resistance area according to the first VD drive control signal.

[0007] In an embodiment of the present application, the source electrode of the SGT MOSFET and the drain electrode of the VD MOSFET are further connected with the power electronic converter, so that the power electronic converter is in a non-working state when a short circuit occurs.

[0008] In an embodiment of the present application, the conversion device comprises a resistor R1, a resistor R2, a resistor R3 and an operational amplifier A, wherein One end of the resistor R1 is connected to the positive input terminal of the operational amplifier A, the other end of the resistor R1 is grounded, one end of the resistor R2 is connected to the input terminal of the conversion device, the other end of the resistor R2 is connected to one end of the resistor R3 and the inverting input terminal of the operational amplifier A, the other end of the resistor R3 is connected to the output terminal of the operational amplifier A, and the output terminal of the operational amplifier A is connected to the output terminal of the conversion device.

[0009] In one embodiment of the present application, the logic control chip comprises a logic control unit and a resistor R, a transistor Q1 and a transistor Q2; wherein, The input terminal of the logic control unit is connected to the conversion device, one end of the resistor R is connected to the output terminal of the logic control unit, the other end of the resistor R is connected to the base of the transistor Q1 and the base of the transistor Q2, the collector of the transistor Q1 is connected to the power supply VDD, the emitter of the transistor Q1 is connected to the emitter of the transistor Q2, the collector of the transistor Q2 is grounded, and the emitter of the transistor Q1 is connected to the output terminal of the logic control chip.

[0010] In one embodiment of the present application, the SGT MOSFET is in an open state and works in a variable resistance region under the control of the logic control chip, and the drain-source voltage of the SGT MOSFET has a linear relationship with the SGT loop current.

[0011] In the second aspect, the embodiments of the present application provide a short-circuit protection method applied to a power electronic converter, and the short-circuit protection method corresponds to the short-circuit protection system of any one of the first aspect, and the short-circuit protection method comprises the following steps: The conversion device collects the source-drain voltage of the SGT MOSFET and the source-drain voltage of the VD MOSFET, and a system action signal, generates the SGT loop current according to the source-drain voltage of the SGT MOSFET, and generates the drive control voltage according to the source-drain voltage of the VD MOSFET; wherein, the system action signal is generated by the power electronic converter; The logic control chip is used to judge whether the SGT loop current exceeds the short-circuit current threshold value, if yes, continue to judge whether the system current caused by the power electronic converter itself increases to a preset threshold value according to the system action signal, if yes, generate the first VD drive control signal according to the drive control voltage, and adjust the VD MOSFET from the current limiting working region to the variable resistance region according to the first VD drive control signal, if no, judge that a short-circuit condition occurs, generate the second VD drive control signal, and adjust the VD MOSFET to the closed state according to the second VD drive control signal; wherein, when the system current caused by the power electronic converter itself increases to the preset threshold value, the VD MOSFET is automatically adjusted to work in the current limiting working region.

[0012] In one embodiment of the present application, the logic control chip determines whether the system action signal is generated if the SGT loop current does not exceed the short-circuit current threshold value, and if so, generates a first VD drive control signal according to the drive control voltage, and adjusts the VD MOSFET from the current-limiting operating zone to the variable resistance zone according to the first VD drive control signal.

[0013] In one embodiment of the present application, the SGT MOSFET is in an open state and works in the variable resistance zone under the control of the logic control chip, and the drain-source voltage thereof is linearly related to the SGT loop current.

[0014] Advantages of the present application: The short-circuit protection system for power electronic converters provided by the present application includes a SGT MOSFET for detecting loop current, a VD MOSFET for suppressing system short-circuit, a logic control chip, and a conversion device. The VD MOSFET and the SGT MOSFET are respectively connected to the logic control chip through the source and the gate, and the drain and the source are connected to the protected circuit (power electronic converter), and the collected signals are fed back to the logic control chip through the conversion device. This structure design enables the system to monitor the loop current in real time and adjust the working state according to the feedback signal. The SGT MOSFET detects the loop current and combines the output characteristic change of the VD MOSFET to accurately determine the short-circuit state. The logic control chip can complete the short-circuit protection action within several microseconds through the built-in control algorithm, significantly improves the response speed of the system, and eliminates the impact of short-circuit on the equipment in the first time. The real-time monitoring of the SGT MOSFET and the VD MOSFET reduces the probability of false triggering and enhances the reliability of the system. The conversion device amplifies the signal to improve the resistance of the system to environmental noise and electromagnetic interference. The logic control chip dynamically adjusts the working characteristics of the VD MOSFET to achieve adaptive adaptation to different application scenarios. The system provided by the present application has the characteristics of simple structure and easy integration, the connection relationship between the components is clear and explicit, the control logic is simple and efficient, and it can be applied as an independent module in existing devices, or it can work with other protection mechanisms to further improve the overall performance of the system.

[0015] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of a short-circuit protection system for power electronic converters provided by an embodiment of the present application; Figure 2This is a schematic diagram of the control principle of a short-circuit protection system for power electronic converters provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the conversion device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the logic control chip provided in an embodiment of the present invention; Figure 5 This is a flowchart illustrating a short-circuit protection method for power electronic converters provided in an embodiment of the present invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0018] Firstly, please see Figure 1 and Figure 2 This invention provides a short-circuit protection system for a power electronic converter, comprising an SGT MOSFET, a VD MOSFET, a logic control chip, and a conversion device; wherein, Both the source and drain terminals of the SGT MOSFET and VD MOSFET are connected to the conversion device, while their source and gate terminals are also connected to the logic control chip. The source of the SGT MOSFET and the drain of the VD MOSFET are also connected to the power electronic converter to disable it in the event of a short circuit. The VD MOSFET has strong surge capability and fast switching characteristics, which can suppress short-circuit current and ensure rapid system response in the event of a short circuit. The SGT MOSFET has strong conduction characteristics and can detect current; its high-precision conduction characteristics make the current detection results more accurate. Both the SGT MOSFET and VD MOSFET are controlled by the logic control chip, which sends drive control signals to them via their source and gate to control their on / off states. The SGT MOSFET and VD MOSFET work together to achieve rapid detection and accurate protection against short circuits.

[0019] In this embodiment of the invention, the SGT MOSFET is normally on and operates in the variable resistance region under the control of the logic control chip. Its drain-source voltage is linearly related to the SGT loop current. Figure 2 As shown, under normal operating conditions, the drain-source voltage of the SGT MOSFET is linearly related to the SGT loop current, which allows changes in the SGT loop current to be accurately detected.

[0020] The conversion device is used for collecting the source-drain voltage of the SGT MOSFET, the source-drain voltage of the VD MOSFET, and the system action signal, and generating the SGT loop current according to the source-drain voltage of the SGT MOSFET and generating the drive control voltage according to the source-drain voltage of the VD MOSFET; wherein the system action signal is generated by the power electronic converter and is used for representing that the power electronic converter itself causes the system current to increase. It can be seen that the conversion device converts the collected data into the data required by the logic control chip and provides the basis for judgment.

[0021] The logic control chip is used for judging whether the SGT loop current exceeds the short-circuit current threshold value, if yes, then judging whether the power electronic converter itself causes the system current to increase to the preset threshold value according to the system action signal, if yes, then generating the first VD drive control signal according to the drive control voltage and adjusting the VDMOSFET from the current-limiting working area to the variable resistance area according to the first VD drive control signal, if no, then judging that the short-circuit condition occurs and generating the second VD drive control signal, and adjusting the VD MOSFET to the closed state according to the second VD drive control signal; wherein when the power electronic converter itself causes the system current to increase to the preset threshold value, the VD MOSFET is spontaneously adjusted to work in the current-limiting working area. It can be seen that the logic control chip receives the feedback of the conversion device in real time, controls the working state of the VD MOSFET and the SGT MOSFET by judging the data fed back by the conversion device, and realizes the comprehensive control of the short-circuit protection process. When the short-circuit occurs, the system current will increase and the current continues to increase is inhibited, and the VD MOSFET is timely closed to cut off the system loop and protect the system. When the power electronic converter itself causes the system current to increase, the VD MOSFET is spontaneously adjusted to work in the current-limiting working area, but the current-limiting working area may not meet the demand of the increased current, so it is needed to adjust the VD MOSFET from the current-limiting working area to the variable resistance area, realize the adaptive adjustment of the applied current range, and make the maximum limit current greater than and close to the system current, so that even if the system is short-circuited, the current will not rapidly increase, and the system is protected.

[0022] In the logical control chip of the embodiment of the present application, if the SGT loop current does not exceed the short-circuit current threshold value, the system action signal is used to continue to determine whether the system current is increased to the preset threshold value caused by the power electronic converter itself, if yes, the first VD drive control signal is generated according to the drive control voltage, and the VD MOSFET is adjusted from the current limiting working area to the variable resistance area according to the first VD drive control signal. As described above, when the system current is increased caused by the power electronic converter itself, the VD MOSFET is automatically adjusted to work in the current limiting working area, but the current limiting working area may not meet the requirement of the increased current, and therefore, it is necessary to adjust the VD MOSFET from the current limiting working area to the variable resistance area, so as to realize the adaptive adjustment of the applied current range.

[0023] Further, as shown in the conversion device in the embodiment of the present application, Figure 3 The one end of the resistor R1 is connected with the positive input end of the operational amplifier A, the other end of the resistor R1 is grounded, the one end of the resistor R2 is used as the input end of the conversion device, the other end of the resistor R2 is connected with the one end of the resistor R3 and the inverting input end of the operational amplifier A, the other end of the resistor R3 is connected with the output end of the operational amplifier A, and the output end of the operational amplifier A is used as the output end of the conversion device. It can be seen that the conversion device is used for amplifying and processing the collected signals. The operational amplifier A amplifies the drain-source voltage from the SGT MOSFET and the VD MOSFET, and after the signal is preliminarily processed through the voltage division network composed of the resistor R1 and the resistor R2, the signal is transmitted to the logic control chip through the data interface, so as to provide the judgment basis for the logic control chip. In addition, the resistor R3 is used for current limiting protection of the signal output by the operational amplifier A, so as to avoid damaging the logic control chip due to the too large signal. The design of the conversion device is easy to accept the source-drain voltage signal, and the requirement for the conversion device is not high. Compared with other magnetic detection current means, the anti-interference ability to environmental noise and electromagnetic interference is stronger, and the cost and precision have great advantages, so that the conversion device can work stably in a complex electromagnetic environment.

[0024] The logic control chip in the embodiment of the present application is as shown in Figure 4As shown, the logic control chip includes a logic control unit and resistors R, a transistor Q1 and a transistor Q2; wherein the input end of the logic control unit is connected with the conversion device, one end of the resistor R is connected with the output end of the logic control unit, the other end of the resistor R is connected with the base of the transistor Q1 and the base of the transistor Q2, the collector of the transistor Q1 is connected with the power supply VDD, the emitter of the transistor Q1 is connected with the emitter of the transistor Q2, the collector of the transistor Q2 is grounded, and the emitter of the transistor Q1 serves as the output end of the logic control chip. Among them, the transistor Q1 is NPN type, and the transistor Q2 is PNP type. It can be seen that the logic control chip generates a corresponding VD drive control signal to control the working characteristics by monitoring the working state of the SGT MOSFET and the VD MOSFET in real time. For example, when the SGT MOSFET detects that the power electronic converter itself causes the system current to increase, the VD MOSFET spontaneously adjusts to the current limiting working area to limit the growth of short-circuit current, but the current limiting working area may not meet the demand of increasing current, so the logic control chip needs to generate a VD drive control signal to adjust the VD MOSFET from the current limiting working area to the variable resistance area. This driving mechanism ensures that the system can complete the protection action within a few microseconds after the short circuit occurs, significantly improving the response speed and reliability of the system. The control logic of this logic control chip design is simple, the structure is simple, and it can be compatible with the device and can also act independently.

[0025] More specifically: (1), the present application detects the loop current by SGT MOSFET, and realizes high-precision current detection by using the conduction characteristics of SGT MOSFET. SGT MOSFET works in the variable resistance area in the normal working state, and the drain-source voltage of SGT MOSFET is linearly related to the SGT loop current, so as to realize accurate monitoring of the loop current. The conversion device amplifies the SGT loop current generated by the drain-source voltage of the SGT MOSFET and feeds it back to the logic control chip, so as to provide accurate current data for the logic control chip.

[0026] (2), the present application realizes short-circuit current suppression by the surge capacity of VD MOSFET. VD MOSFET works in the variable resistance area in the normal working state, and when a short circuit occurs, the source-drain voltage of VD MOSFET rapidly rises and switches to the current limiting working area, thereby limiting the growth of short-circuit current. The logic control chip generates a VD drive control signal to control the turn-off of the VD MOSFET according to the change of the source-drain voltage of the VD MOSFET, and cuts off the loop.

[0027] (3), the logic control chip realizes the fast response to the short circuit state. The logic control chip receives the data feedback from the conversion device, analyzes the data in real time through the control algorithm built in the logic control unit, judges whether the short circuit occurs. If it is determined that the short circuit occurs, the VD drive control signal is generated to control the VD MOSFET to be turned off; if it is determined that the current change is caused by the system self-regulation, the working area of the VD MOSFET is adjusted again according to the SGT loop current.

[0028] (4), the control algorithm built in the logic control unit is optimized to reduce the false triggering probability. When judging the short circuit state, the logic control unit not only considers the change of the VD MOSFET source-drain voltage, but also comprehensively analyzes the SGT MOSFET loop current. The logic control chip determines the short circuit and executes the protection action, thereby effectively reducing the false triggering probability.

[0029] Particularly, the present application significantly improves the sensitivity of short circuit protection through the double MOSFET cooperative working mechanism. The SGT MOSFET and the VD MOSFET respectively undertake the functions of current detection and short circuit current suppression, and cooperate with each other to realize the fast response and accurate protection to the short circuit state. In addition, the logic control chip realizes the comprehensive control of the short circuit protection process through the real-time monitoring of the SGT MOSFET and the VD MOSFET.

[0030] In summary, the short-circuit protection system applied to the power electronic converter provided by the embodiment of the application comprises an SGT MOSFET for detecting loop current, a VD MOSFET for inhibiting system short circuit, a logic control chip and a conversion device, the VD MOSFET and the SGT MOSFET are connected with the logic control chip through the source and the gate respectively, the drain and the source are connected with the protected circuit, and the collected signals are fed back to the logic control chip through the conversion device. The structure design enables the system to monitor the loop current in real time and adjust the working state according to the feedback signal. The SGT MOSFET detects the loop current and combines the output characteristic change of the VD MOSFET, so that the short-circuit state can be accurately judged. The control algorithm built in the logic control chip can complete the short-circuit protection action within several microseconds, significantly improves the response speed of the system, and eliminates the influence of short circuit on the equipment in the first time. The real-time monitoring of the SGT MOSFET and the VD MOSFET reduces the probability of false triggering and enhances the reliability of the system. The amplification processing of the conversion device on the signal improves the resistance of the system to environmental noise and electromagnetic interference. The dynamic adjustment of the logic control chip on the working characteristic of the VD MOSFET realizes the adaptive adaptation to different application scenarios. The system has the characteristics of simple structure and easy integration, the connection relationship between the components is clear and definite, the control logic is simple and efficient, and the system can be applied to existing devices as an independent module or work cooperatively with other protection mechanisms, so as to further improve the overall performance of the system.

[0031] In the second aspect, referring to Figure 5 The embodiment of the application provides a short-circuit protection method applied to a power electronic converter, and the short-circuit protection method corresponds to the short-circuit protection system applied to the power electronic converter. S10, the conversion device collects the source-drain voltage of the SGT MOSFET and the source-drain voltage of the VD MOSFET, and a system action signal, generates the SGT loop current according to the source-drain voltage of the SGT MOSFET, and generates the drive control voltage according to the source-drain voltage of the VD MOSFET; wherein the system action signal is generated by the power electronic converter. S20, a logic control chip is used for judging whether the SGT loop current exceeds a short-circuit current threshold value, if yes, a first VD drive control signal is generated according to a drive control voltage and the VDMOSFET is adjusted from a current-limiting working zone to a variable resistance zone according to the first VD drive control signal, if no, a second VD drive control signal is generated according to a system action signal, and the VDMOSFET is adjusted to a closed state; wherein when the power electronic converter itself causes the system current to increase to a preset threshold value, the VDMOSFET is spontaneously adjusted to work in the current-limiting working zone.

[0032] In S20, the logic control chip judges whether the SGT loop current exceeds a short-circuit current threshold value, if no, a first VD drive control signal is generated according to a drive control voltage and the VDMOSFET is adjusted from a current-limiting working zone to a variable resistance zone according to the first VD drive control signal; wherein when the power electronic converter itself causes the system current to increase to a preset threshold value, the VDMOSFET is spontaneously adjusted to work in the current-limiting working zone.

[0033] In the embodiment of the present application, the SGT MOSFET is in a normally open state and works in a variable resistance zone under the control of the logic control chip, and the drain-source voltage thereof has a linear relationship with the SGT loop current.

[0034] In the embodiment of the present application, when the system works normally, the SGT MOSFET is opened to detect the current of the main loop, and the current detection data is fed back to the logic control chip to adjust the working characteristics of the VDMOSFET, when a short circuit occurs or the system changes, the working characteristics of the VDMOSFET change, the conversion device detects the source-drain voltage of the VDMOSFET and the source-drain voltage of the SGT MOSFET, converts them into a drive control voltage and an SGT loop current, and feeds them back to the logic control chip to judge and control the VDMOSFET to be turned off, so as to prevent the damage of the large current of the loop to the power electronic converter in the main loop. The method can accurately judge the short-circuit current, provide a protection action, and ensure the stability of the whole system. In addition, the logic control chip is used for real-time monitoring of the conduction characteristics of the VDMOSFET, and the conversion device is used for processing the signals, so as to realize the rapid response to the short-circuit state. In the method, the double MOSFETs work cooperatively, which not only improves the sensitivity of the short-circuit protection, but also reduces the probability of false triggering, and through the optimization of the control process, the protection action can be completed within several microseconds after the short circuit occurs, so as to significantly improve the reliability and safety of the power electronic converter.

[0035] For the method embodiments of the second aspect, since they are basically similar to the system embodiments of the first aspect, the description is relatively simple, and the relevant parts are referred to the part of the description of the system embodiments of the first aspect.

[0036] In the description of the present application, it should be understood that the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0037] Although the present application is described herein in conjunction with various embodiments, other variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from a study of the drawings, the disclosure and the appended claims. In the description, the word "comprising" does not exclude other components or steps, and "a" or "one" does not exclude a plurality. Certain measures recited in mutually different embodiments can be combined to produce a better result.

[0038] The above is a further detailed description of the present application in conjunction with specific preferred embodiments, and cannot be considered as limiting the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, which should be considered as falling within the protection scope of the present application.

Claims

1. A short-circuit protection system for power electronic converters, characterized in that, The short-circuit protection system includes an SGT MOSFET, a VD MOSFET, a logic control chip, and a conversion device; wherein, The source and drain terminals of the SGT MOSFET and VD MOSFET are both connected to the switching device, and the source and gate terminals of the SGT MOSFET and VD MOSFET are both connected to the logic control chip. The conversion device is used to acquire the source-drain voltage of the SGT MOSFET and the source-drain voltage of the VD MOSFET, as well as the system operation signal, and to generate the SGT loop current based on the source-drain voltage of the SGT MOSFET and the drive control voltage based on the source-drain voltage of the VD MOSFET; wherein, the system operation signal is generated by the power electronic converter. The logic control chip is used to determine whether the SGT loop current exceeds the short-circuit current threshold. If it does, it further determines whether the power electronic converter itself has caused the system current to increase to a preset threshold based on the system action signal. If so, it generates a first VD drive control signal based on the drive control voltage and adjusts the VD MOSFET from the current-limiting operating region to the variable resistance region based on the first VD drive control signal. If not, it determines that a short circuit has occurred, generates a second VD drive control signal, and adjusts the VD MOSFET to the off state based on the second VD drive control signal. Among them, when the power electronic converter itself causes the system current to increase to the preset threshold, the VD MOSFET automatically adjusts to operate in the current-limiting operating region.

2. The short-circuit protection system for power electronic converters according to claim 1, characterized in that, In the logic control chip, if the SGT loop current does not exceed the short-circuit current threshold, then based on the system action signal, it is further determined whether the power electronic converter itself has caused the system current to increase to the preset threshold. If so, a first VD drive control signal is generated based on the drive control voltage, and the VD MOSFET is adjusted from the current-limiting operating region to the variable resistance region based on the first VD drive control signal.

3. The short-circuit protection system for power electronic converters according to claim 1, characterized in that, The source of the SGTMOSFET and the drain of the VD MOSFET are also connected to the power electronic converter so that the power electronic converter is inactive in the event of a short circuit.

4. The short-circuit protection system for power electronic converters according to claim 1, characterized in that, The conversion device includes resistors R1, R2, and R3, and operational amplifier A; wherein, One end of resistor R1 is connected to the non-inverting input of operational amplifier A, and the other end of resistor R1 is grounded. One end of resistor R2 serves as the input of the conversion device, and the other end of resistor R2 is connected to one end of resistor R3 and the inverting input of operational amplifier A. The other end of resistor R3 is connected to the output of operational amplifier A, and the output of operational amplifier A serves as the output of the conversion device.

5. The short-circuit protection system for power electronic converters according to claim 1, characterized in that, The logic control chip includes a logic control unit, a resistor R, and transistors Q1 and Q2. The input terminal of the logic control unit is connected to the conversion device. One end of the resistor R is connected to the output terminal of the logic control unit, and the other end of the resistor R is connected to the base of transistors Q1 and Q2. The collector of transistor Q1 is connected to the power supply VDD, the emitter of transistor Q1 is connected to the emitter of transistor Q2, the collector of transistor Q2 is grounded, and the emitter of transistor Q1 serves as the output terminal of the logic control chip.

6. The short-circuit protection system for power electronic converters according to claim 1, characterized in that, The SGTMOSFET is normally open and operates in the variable resistance region under the control of the logic control chip. Its drain-source voltage is linearly related to the SGT loop current.

7. A short-circuit protection method for power electronic converters, characterized in that, Based on the short-circuit protection system applied to a power electronic converter according to any one of claims 1 to 6, the corresponding short-circuit protection method includes: The conversion device acquires the source-drain voltage of the SGT MOSFET and the source-drain voltage of the VD MOSFET, as well as the system action signal, and generates the SGT loop current based on the source-drain voltage of the SGT MOSFET and the drive control voltage based on the source-drain voltage of the VD MOSFET; wherein, the system action signal is generated by the power electronic converter. The logic control chip is used to determine whether the SGT loop current exceeds the short-circuit current threshold. If it does, it further determines whether the power electronic converter itself has caused the system current to increase to a preset threshold based on the system action signal. If so, it generates a first VD drive control signal based on the drive control voltage and adjusts the VD MOSFET from the current-limiting operating region to the variable resistance region based on the first VD drive control signal. If not, it determines that a short circuit has occurred, generates a second VD drive control signal, and adjusts the VD MOSFET to the off state based on the second VD drive control signal. Among them, when the power electronic converter itself causes the system current to increase to the preset threshold, the VD MOSFET automatically adjusts to operate in the current-limiting operating region.

8. The short-circuit protection method for power electronic converters according to claim 7, characterized in that, If the logic control chip determines that the SGT loop current does not exceed the short-circuit current threshold, it will continue to determine whether the power electronic converter itself has caused the system current to increase to the preset threshold. If so, it will generate a first VD drive control signal according to the drive control voltage, and adjust the VD MOSFET from the current-limiting operating region to the variable resistance region according to the first VD drive control signal.

9. The short-circuit protection method for power electronic converters according to claim 7, characterized in that, The SGTMOSFET is normally open and operates in the variable resistance region under the control of the logic control chip. Its drain-source voltage is linearly related to the SGT loop current.

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