Protection device and method of frequency converter and frequency converter

Abstract

The invention discloses a protection device and method for a frequency converter and the frequency converter. The inverter end of the frequency converter is provided with an IGBT module, and a driving board is provided with a driving chip; the device comprises a first detection unit which is arranged at an emitting electrode of an IGBT module, detects whether the IGBT module has a type of short-circuit fault, and outputs a signal of the type of short-circuit fault to an input end of a driving chip when the IGBT module is detected to have the type of short-circuit fault so as to enable the driving chip to perform driving and wave turning-off, and a second detection unit which is arranged at an emitting electrode of the IGBT module and is used for detecting whether the IGBT module has the type of short-circuit fault. And the second detection unit is arranged at the collector of the IGBT module, detects whether the IGBT module has a second-class short circuit fault or not, and outputs a signal of the second-class short circuit fault to the input end of the driving chip when detecting that the IGBT module has the second-class short circuit fault, so that the driving chip drives to turn off waves. According to the scheme, the IGBT short-circuit fault detection circuit is arranged on the driving board of the frequency converter, so that rapid protection of first-class short circuit and second-class short circuit is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of frequency converters, and specifically relates to a protection device, method and frequency converter for a frequency converter, and more particularly to an IGBT short-circuit detection and protection device, method and frequency converter for a high-power frequency converter. Background Art

[0002] The main function of the inverter part of the frequency converter is to convert direct current into three-phase alternating current of the required frequency and voltage. The inverter module (i.e., the inverter part) commonly used in high-power frequency converters is the insulated gate bipolar transistor (IGBT) module. The IGBT module is usually used with a driver board. The main control of the frequency converter (such as the main control chip on the main control board) outputs a pulse width modulation (PWM) drive signal. After processing by the drive circuit on the driver board, the output is a PWM wave that meets the requirements of driving the IGBT. The driver board synchronously monitors the fault condition of the inverter end and transmits the fault signal to the main control to achieve fault protection.

[0003] The most important fault protection for the inverter side is IGBT short-circuit protection. However, in related solutions, the accuracy of detection and timely protection of IGBT short-circuit faults cannot be guaranteed.

[0004] The above content is only used to assist in understanding the technical solution of the present invention and does not mean that the above content is recognized as a related solution. Summary of the Invention

[0005] The object of the present invention is to provide a protection device, method and inverter for a frequency converter, so as to solve the problem in related schemes that the detection accuracy and protection timeliness of IGBT short-circuit faults at the inverter end of the frequency converter cannot be guaranteed, and to achieve the effect of rapid protection against Class I and Class II short circuits by setting an IGBT short-circuit fault detection circuit on the drive board of the frequency converter.

[0006] The present invention provides a protection device for a frequency converter, wherein the frequency converter has an inverter end and a drive board, the inverter end has an IGBT module, and the drive board has a drive chip; the output end of the drive chip is used to provide a drive signal to the gate of the IGBT module; the protection device for the frequency converter comprises: a first detection unit and a second detection unit; wherein the first detection unit is arranged at the emitter of the IGBT module, and is used to detect whether a type I short-circuit fault occurs in the IGBT module, and when the type I short-circuit fault is detected in the IGBT module, the first detection unit outputs a type I short-circuit fault signal to the input end of the drive chip, so that the drive chip performs drive shutdown; the second detection unit is arranged at the collector of the IGBT module, and is used to detect whether a type II short-circuit fault occurs in the IGBT module, and when the type II short-circuit fault is detected in the IGBT module, the second detection unit outputs a type II short-circuit fault signal to the input end of the drive chip, so that the drive chip performs drive shutdown.

[0007] In some embodiments, the inverter also has a main control board; wherein the first detection unit is further used to output the signal of the first type of short-circuit fault to the first input end of the main control board, so that the main control board determines that the type of short-circuit fault of the IGBT module is a first type of short-circuit fault based on the signal of the first type of short-circuit fault; the second detection unit is further used to output the signal of the second type of short-circuit fault to the second input end of the main control board, so that the main control board determines that the type of short-circuit fault of the IGBT module is a second type of short-circuit fault based on the signal of the second type of short-circuit fault.

[0008] In some embodiments, the emitter of the IGBT module includes: a first emitter and a second emitter, and a parasitic inductance module is provided between the first emitter of the IGBT module and the second emitter of the IGBT module; the first detection unit includes: a negative reference voltage module, a first comparison module, and a first logic processing module; wherein the first emitter of the IGBT module is grounded; the second emitter of the IGBT module is used to provide the voltage of the second emitter of the IGBT module to the inverting input terminal of the first comparison module; the negative reference voltage module is used to provide a preset negative reference voltage to the inverting input terminal of the first comparison module; the first comparison module is used to compare the voltage of the second emitter of the IGBT module based on the preset negative reference voltage to obtain a first comparison result; the first logic processing module is used to perform logic processing based on the first comparison result and the driving signal of the gate of the IGBT module to obtain a first logic processing result; the first logic processing result includes: a judgment result of whether a type of short circuit fault occurs in the IGBT module.

[0009] In some embodiments, the first logic processing module includes: a non-logic module and a first AND logic module; wherein, the first logic processing module performs logic processing based on the first comparison result and the driving signal of the gate of the IGBT module to obtain a first logic processing result, including: the non-logic module, which is used to perform non-logic processing based on the first comparison result to obtain a non-logic processing result; the first AND logic module, which is used to perform AND logic processing based on the first comparison result and the driving signal of the gate of the IGBT module to obtain the first logic processing result.

[0010] In some embodiments, the second detection unit includes: a voltage-dividing sampling module, a first reference voltage module, a second reference voltage module, a second comparison module, a third comparison module, and a second logic processing module; wherein the voltage-dividing sampling module is used to collect voltage from the collector of the IGBT module to obtain the voltage of the collector of the IGBT module; and input the voltage of the collector of the IGBT module to the inverting input terminal of the second comparison module and the non-inverting input terminal of the third comparison module respectively; the first reference voltage module is used to provide a preset first reference voltage to the non-inverting input terminal of the second comparison module; the second comparison module is used to compare the voltage based on the preset first reference voltage and the third comparison module. and the collector voltage of the IGBT module to obtain a second comparison result; a preset second reference voltage module is used to provide a preset second reference voltage to the non-inverting input terminal of the third comparison module; the third comparison module is used to process based on the preset second reference voltage and the collector voltage of the IGBT module to obtain a third comparison result; the second logic processing module is used to perform logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result; the second logic processing result includes: a judgment result of whether a type II short-circuit fault occurs in the IGBT module.

[0011] In some embodiments, the second logic processing module includes: an SR trigger module and a second AND logic module; wherein the second logic processing module performs logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result, including: the SR trigger module, which is used to perform SR trigger processing based on the second comparison module and the inverted signal of the gate drive signal of the IGBT module to obtain the trigger processing result; the second AND logic module, which is used to perform AND logic processing based on the trigger processing result and the third comparison result to obtain the second logic processing result.

[0012] In some embodiments, the voltage divider sampling module includes: a first resistor module, a second resistor module and a diode module; wherein the collector of the IGBT module is grounded after passing through the first resistor module and the second resistor module; a preset positive DC power supply is connected to the cathode of the diode module; the common end of the first resistor module and the second resistor module is connected to the anode of the diode module; the common end of the first resistor module and the second resistor module serves as the output end of the voltage divider sampling module, and is used to output the voltage of the collector of the IGBT module.

[0013] In some embodiments, it also includes: an OR logic module; wherein the output end of the first detection unit is connected to the first input end of the OR logic module; the output end of the second detection unit is connected to the second input end of the OR logic module; the output end of the OR logic module is connected to the input end of the driver chip.

[0014] Matching the above device, the present invention further provides a frequency converter, including: the protection device for the frequency converter described above.

[0015] Matching the above-mentioned frequency converter, the present invention provides a frequency converter protection method on another aspect, including: detecting whether a type I short-circuit fault occurs in the IGBT module through the first detection unit, and outputting a type I short-circuit fault signal when the type I short-circuit fault is detected in the IGBT module; and detecting whether a type II short-circuit fault occurs in the IGBT module through the second detection unit, and outputting a type II short-circuit fault signal when the type II short-circuit fault is detected in the IGBT module; driving the shut-off wave based on the type I short-circuit fault signal through the driving chip; and driving the shut-off wave based on the type II short-circuit fault signal through the driving chip.

[0016] In some embodiments, it also includes: transmitting the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault to the main control board of the inverter respectively; determining, through the main control board, based on the signal of the first type of short-circuit fault, that the type of short-circuit fault of the IGBT module is a first type of short-circuit fault; and determining, through the main control board, based on the signal of the second type of short-circuit fault, that the type of short-circuit fault of the IGBT module is a second type of short-circuit fault.

[0017] Therefore, the solution of the present invention is to provide an IGBT short-circuit fault detection circuit on the drive board of the inverter for Class I and Class II short-circuit faults of the IGBT in the inverter. The IGBT short-circuit fault detection circuit can detect Class I and Class II short-circuit faults of the IGBT, and drive shutdown wave is realized through the drive board when Class I or Class II short-circuit faults of the IGBT are detected; thus, by providing the IGBT short-circuit fault detection circuit on the drive board of the inverter, rapid protection against Class I and Class II short-circuit faults is achieved.

[0018] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of an embodiment of a protection device for a frequency converter of the present invention;

[0021] Figure 2 Schematic diagram of two types of short circuits for IGBT;

[0022] Figure 3 A schematic diagram of a Vce desaturation detection circuit for a short circuit is provided in a related solution;

[0023] Figure 4 Schematic diagram of the structure of the IGBT short-circuit detection and protection circuit of the present invention;

[0024] Figure 5 1 is a flow chart of an embodiment of a method for protecting a frequency converter according to the present invention;

[0025] Figure 6 The figure is a flow chart of an embodiment of determining the type of short-circuit fault based on the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault in the method of the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Considering that the relevant solutions cannot guarantee the accuracy of detection and timely protection of IGBT short-circuit faults, there are two types of IGBT short circuits: Type I and Type II. Type I short circuits are intra-phase short circuits, which refer to a shoot-through phenomenon in any arm of a half-bridge. Type II short circuits are inter-phase short circuits, which refer to a short circuit between any two phases within the three phases, or a short circuit between any phase and ground.

[0028] In IGBT short-circuit protection, for Type I short-circuits, a Vce desaturation circuit is typically designed into the driver board for detection and protection. For Type II protection, current sensors are typically used to detect current at the three-phase output terminals. When the current exceeds a set threshold, the main control board initiates protection. However, current sensors are susceptible to external interference, are relatively expensive, and are bulky. Furthermore, using a Vce desaturation circuit for detection has a blind spot in short-circuit protection, making false alarms a common occurrence.

[0029] Figure 2 Schematic diagram of two types of IGBT short circuits. Figure 2 ① represents a type of short circuit. The first type of short circuit is an intra-phase short circuit, which means that any bridge arm in the half-bridge has a shoot-through phenomenon. Figure 2 ② represents a Class II short circuit, which is a phase-to-phase short circuit, manifested as a short circuit between any two phases in the three phases, or a short circuit between any one phase and the ground. Figure 2As shown, the DC bus voltage Vdc powers motor M through bus capacitor C1 and the inverter terminal. The positive DC+ output terminal of the DC bus voltage Vdc is connected to the positive terminal of bus capacitor C1; the negative DC- output terminal of the DC bus voltage Vdc is connected to the negative terminal of bus capacitor C1. The inverter terminal includes IGBT transistors Q1, Q2, Q3, Q4, Q5, and Q6. IGBT transistors Q1 and Q4 are the upper and lower transistors of the U-phase bridge arm, respectively. IGBT transistors Q2 and Q5 are the upper and lower transistors of the U-phase bridge arm, respectively. IGBT transistors Q3 and Q6 are the upper and lower transistors of the U-phase bridge arm, respectively. The collectors of IGBT Q1, IGBT Q2, and IGBT Q3 are all connected to the positive DC+ output terminal of the DC bus voltage Vdc. The emitters of IGBT Q4, IGBT Q5, and IGBT Q6 are all connected to the negative DC- output terminal of the DC bus voltage Vdc. The emitter of IGBT Q1 is connected to the collector of IGBT Q4, and the common terminal of the emitter of IGBT Q1 and the collector of IGBT Q4 is connected to the U-phase winding of the three-phase winding of motor M. The emitter of IGBT Q2 is connected to the collector of IGBT Q5, and the common terminal of the emitter of IGBT Q2 and the collector of IGBT Q5 is connected to the V-phase winding of the three-phase winding of motor M. The emitter of the IGBT tube Q3 is connected to the collector of the IGBT tube Q6 , and a common end of the emitter of the IGBT tube Q3 and the collector of the IGBT tube Q6 is connected to the W-phase winding of the three-phase winding of the motor M.

[0030] There are two types of short circuits in IGBTs: Figure 2 As shown, Figure 2 The first type of short circuit is represented by a straight-through phenomenon in any bridge arm. After the short circuit, the inductance in the loop is small, mainly due to the busbar stray inductance, which is basically at the nH (nanohenry) level. The first type of short circuit is a short circuit fault that occurs before the IGBT is turned on. Figure 2 For example, if IGBT Q4 is directly connected, a short-circuit fault has already occurred before IGBT Q1 is turned on. The voltage Vce across CE of IGBT Q1 is the bus voltage. When IGBT Q1 receives the turn-on signal, the collector current ic will increase rapidly in a type of short-circuit fault. Because of the stray inductance in the loop, Vce will drop slightly and then rise back to the bus voltage Vdc.

[0031] Figure 2 ② represents a Class II short circuit, which is manifested as a short circuit between any two phases in the three phases, or a short circuit between any phase and the ground. After the short circuit, the inductance in the loop is large, mainly the load inductance, which is basically at the mH (millihenry) level. Class II short circuit is a short circuit fault that occurs after the IGBT is turned on. Figure 2 For example, when a short circuit occurs between the V and W phases, the IGBT enters the short circuit state from the normal working state. In the second type of short circuit fault, the collector current ic will increase rapidly, and Vce will increase from the conduction voltage drop Vcesat in the normal working state to the bus voltage Vdc.

[0032] Figure 3 This is a schematic diagram of a Vce desaturation detection circuit for a short circuit. Figure 3 Able to demonstrate the Vce desaturation detection method for a type of short circuit. Figure 3 As shown, a VCE desaturation detection circuit for a short circuit includes: an IGBT Q1, a transistor Q0, a capacitor Ca, a resistor Rm, a diode D1, a diode D2, a 1.4mA (milliampere) current source, a 150µA (microampere) current source, and a comparator A1. The gate G of IGBT Q1 receives a drive signal. The collector C of IGBT Q1 is connected to the cathode of diode D2, and the emitter E of IGBT Q1 is grounded. The 1.4mA current source is connected to the non-inverting input V+ of comparator A1, and the 150µA current source is connected to the inverting input V- of comparator A1. The 1.4mA current source is connected to the collector of transistor Q0, and the emitter of transistor Q0 is grounded. The 1.4mA current source is connected to ground via capacitor Ca and, after passing through resistor Rm, to the anode of diode D1. The cathode of diode D1 is connected to the anode of diode D2. The 150uA current source is also grounded after passing through the resistor Rthx.

[0033] Related solutions for a type of short circuit Vce desaturation detection method such as Figure 3As shown, the voltage at the inverting input terminal V- of comparator A1 serves as the reference voltage for comparator A1. The specific voltage value is the current of the constant current source 150uA multiplied by the resistor Rthx. When the voltage at the non-inverting input terminal V+ of comparator A1 is greater than the voltage at the inverting input terminal V- of comparator A1, comparator A1 outputs a high level, triggering the first type of short-circuit protection. Transistor Q0 is an NPN transistor. When the drive signal of IGBT Q1 is low, IGBT Q1 is not conducting and transistor Q0 is conducting. At this time, the non-inverting input terminal V+ of comparator A1 is grounded. The voltage at the non-inverting input terminal V+ of comparator A1 is less than the voltage at the inverting input terminal V- of comparator A1. Comparator A1 outputs a low level, ensuring that the first type of short-circuit protection is not triggered when IGBT Q1 is not conducting. If IGBT Q1 is conducting normally, its collector voltage equals its forward voltage drop, typically around 2V. The voltage at comparator A1's non-inverting input, V+, equals the forward voltage drop of IGBT Q1 plus the voltage drop of two high-voltage diodes, such as diodes D1 and D2, and the voltage drop of the 1.4mA constant current source across resistor Rm. This voltage is lower than comparator A1's reference voltage, or the voltage at its inverting input, V-, causing comparator A1 to output a low level. If a short circuit occurs while IGBT Q1 is conducting, its collector voltage equals the bus voltage. High-voltage diodes, such as diodes D1 and D2, are reverse-biased and cut off, allowing the 1.4mA constant current source to charge capacitor Ca. After a certain period of time, the voltage at comparator A1's non-inverting input, V+, exceeds the voltage at its inverting input, V-, causing comparator A1 to flip to a low output, triggering short-circuit protection. However, when the IGBT (such as IGBT tube Q1) is normally turned on, it takes time for the collector-emitter Vce of the IGBT to drop from the bus voltage to the conduction voltage drop from the time the IGBT gate receives a high-level signal to the time the IGBT is turned on. This time can be regarded as a detection blind spot, and fault false triggering is prone to occur within the detection blind spot.

[0034] Therefore, the solution of the present invention proposes a protection device for an inverter, specifically an inverter IGBT short-circuit protection device, which directly completes the fault detection and protection of IGBT short circuit through the driver board, realizes fault detection and timely protection of Class I short circuit and Class II short circuit on the driver board, and will not cause false alarms.

[0035] According to an embodiment of the present invention, a protection device for a frequency converter is provided. Figure 1The schematic diagram of the structure of an embodiment of the device of the present invention is shown. The inverter comprises an inverter terminal and a driver board. The inverter terminal comprises an IGBT module, and the driver board comprises a driver chip. The output terminal of the driver chip is used to provide a drive signal to the gate of the IGBT module, specifically to control the switching of the IGBT module. A short-circuit fault of the IGBT module includes a Class I short-circuit fault or a Class II short-circuit fault. Figure 4 The schematic diagram of the structure of the IGBT short circuit detection and protection circuit of the present invention is as follows: Figure 4 The IGBT tube Q1 shown in FIG. In the solution of the present invention, as Figure 1 As shown, the protection device of the frequency converter includes: a first detection unit and a second detection unit.

[0036] Among them, the first detection unit is arranged between the emitter of the IGBT module and the input end of the driver chip, and is used to detect whether a type of short-circuit fault occurs in the IGBT module. When a type of short-circuit fault is detected in the IGBT module, the first detection unit outputs a type of short-circuit fault signal to the input end of the driver chip, so that the driver chip drives the shutdown wave, specifically, the driver chip turns off the drive signal output to the gate of the IGBT module.

[0037] The second detection unit is arranged between the collector of the IGBT module and the input end of the driver chip, and is used to detect whether a Class II short-circuit fault occurs in the IGBT module. When a Class II short-circuit fault is detected in the IGBT module, the second detection unit outputs a Class II short-circuit fault signal to the input end of the driver chip to enable the driver chip to perform drive shutdown, specifically, to enable the driver chip to shut down the drive signal output to the gate of the IGBT module.

[0038] The solution of the present invention is applicable to the field of inverter control. The solution of the present invention proposes an inverter IGBT short-circuit protection solution, specifically a high-power inverter IGBT short-circuit detection and protection solution. This solution directly detects and protects against IGBT short-circuits through the driver board, achieving fault detection and timely protection for both Class I and Class II short-circuits on the driver board without false alarms.

[0039] In some embodiments, the inverter further includes a main control board; wherein the protection device of the inverter is further configured to determine the type of short-circuit fault based on the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault, as follows:

[0040] The first detection unit is also arranged between the emitter of the IGBT module and the first input terminal of the main control board, and is also used to output the signal of the type of short-circuit fault to the first input terminal of the main control board, so that the main control board determines that the type of short-circuit fault of the IGBT module is a type of short-circuit fault based on the signal of the type of short-circuit fault.

[0041] The second detection unit is also arranged between the collector of the IGBT module and the second input terminal of the main control board, and is also used to output the signal of the second type short-circuit fault to the second input terminal of the main control board, so that the main control board determines that the type of the short-circuit fault of the IGBT module is a second type short-circuit fault based on the signal of the second type short-circuit fault.

[0042] In the solution of the present invention, the driver fault signal is sent directly to the driver chip to achieve driver shutdown, without the need for feedback to the main control board, which then shuts down the system. This allows for rapid shutdown after short circuit detection, improving product reliability. In the solution of the present invention, both Class I and Class II short circuits can be detected, and each type of short circuit can be detected separately and fault signals can be sent to the main control board, facilitating fault location and cause analysis after a shutdown.

[0043] In some embodiments, the emitter of the IGBT module includes: a first emitter and a second emitter, and a parasitic inductance module is provided between the first emitter of the IGBT module and the second emitter of the IGBT module. Figure 4 The auxiliary emitter E shown, the second emitter of the IGBT module is as shown Figure 4 The power emitter PE shown in FIG. Figure 4 The parasitic inductance L shown; the first detection unit includes: a negative reference voltage module, a first comparison module, a first logic processing module, the negative reference voltage module as shown Figure 4 The voltage Vref3 shown in FIG. Figure 4 The comparator U3 and the first logic processing module shown are as follows Figure 4 Shown are the NOT gate U4 and the AND gate AND2.

[0044] The first emitter of the IGBT module is grounded; the second emitter of the IGBT module is connected to the non-inverting input terminal of the first comparison module, for providing the voltage of the second emitter of the IGBT module to the inverting input terminal of the first comparison module.

[0045] The negative reference voltage module is connected to the inverting input terminal of the first comparison module and is used to provide a preset negative reference voltage to the inverting input terminal of the first comparison module; wherein the negative reference voltage module is composed of Figure 4 The -15V power supply shown is composed of resistors R7 and R8, and the -15V power supply is grounded (i.e., 0V potential) after passing through resistors R7 and R8.

[0046] The first comparison module is used to compare the voltage of the second emitter of the IGBT module with the preset negative reference voltage to obtain a first comparison result, such as Figure 4 The signal U3-out shown is the output end of the first comparison module, connected to the input end of the first logic processing module.

[0047] The first logic processing module is used to perform logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain a first logic processing result; the first logic processing result includes: a judgment result of whether a type of short circuit fault occurs in the IGBT module.

[0048] The present invention implements a type of short-circuit protection by detecting and processing the voltage of the IGBT's emitter parasitic inductance using a circuit. Compared to related solutions, the present invention avoids the short-circuit protection blind spot that can easily lead to false alarms, making short-circuit detection and protection more accurate and timely.

[0049] In some embodiments, the first logic processing module includes: a non-logic module, a first AND logic module, a negative reference voltage module such as Figure 4 The voltage Vref3 shown in FIG. Figure 4 The comparator U3 and the non-logic module are shown as Figure 4 The NOT gate U4 and the first AND logic module are shown as follows Figure 4 AND gate AND2 is shown.

[0050] The first logic processing module performs logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain a first logic processing result, including:

[0051] The non-logical module is used to perform non-logical processing based on the first comparison result to obtain a non-logical processing result.

[0052] The first AND logic module is used to perform AND logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain the first logic processing result, such as Figure 4 The signal SO_2 is shown.

[0053] like Figure 4As shown, if a short circuit occurs before IGBT Q1 turns on, the voltage across IGBT Q1 is the bus voltage, i.e., Vce = Vdc. When IGBT Q1 turns on, its collector voltage (Vce) drops slightly before returning to the bus voltage (Vdc). Collector current (ic) of IGBT Q1 increases rapidly, generating a voltage (Vpe) across the parasitic inductance (L) between the power emitter (PE) and auxiliary emitter (E) of IGBT Q1. The magnitude of Vpe is related to the rate of increase of current (ic), i.e., Vpe = -L*dic / dt. This voltage is negative, where L is the inductance of parasitic inductance (L). When voltage Vpe is less than voltage Vref3, comparator U3's output signal (U3-out) is low, NOT gate U4's output signal (U4-out) is high, AND gate AND2 outputs a high level, and OR gate OR1 outputs a high level to the driver chip, triggering short-circuit protection and driving the OFF wave. The main control board receives the high level output by AND gate AND2 and determines that a type 1 short circuit occurs.

[0054] In this solution, the driver board quickly implements a type of short-circuit detection and protection. Compared with related solutions, this solution avoids the drawback of short-circuit protection blind spots that can easily cause false alarms. This makes short-circuit detection and protection more accurate and timely, accurately pinpoints the short-circuit type, and facilitates fault location and maintenance.

[0055] In some embodiments, the second detection unit includes: a voltage division sampling module, a first reference voltage module, a second reference voltage module, a second comparison module, a third comparison module, and a second logic processing module. The voltage division sampling module is composed of Figure 4 The resistor R1, the resistor R2 and the diode D0 are shown in FIG. 1 , and the first reference voltage module is composed of Figure 4 The power supply 15V, resistor R3 and resistor R4 are shown, and the second reference voltage module is composed of Figure 4 The power supply 15V, resistor R5 and resistor R6 are shown, and the second comparison module is as shown in FIG. Figure 4 The comparator U1 and the third comparison module shown are as follows Figure 4 The comparator U2 shown in FIG. Figure 4 SR processor S1 and AND gate AND1 are shown.

[0056] Among them, the voltage divider sampling module is used to collect voltage from the collector of the IGBT module to obtain the voltage of the collector of the IGBT module; and input the voltage of the collector of the IGBT module to the inverting input terminal of the second comparison module and the non-inverting input terminal of the third comparison module respectively; the input terminal of the voltage divider sampling module is connected to the collector of the IGBT module; the output terminal of the voltage divider sampling module is connected to the inverting input terminal of the second comparison module and the non-inverting input terminal of the third comparison module respectively.

[0057] The first reference voltage module is connected to the non-inverting input terminal of the second comparison module and is used to provide a preset first reference voltage to the non-inverting input terminal of the second comparison module; the first reference voltage is Figure 4 The second comparison module is configured to perform processing based on a preset first reference voltage and a voltage of the collector of the IGBT module to obtain a second comparison result.

[0058] The preset second reference voltage module is connected to the inverting input terminal of the third comparison module and is used to provide a preset second reference voltage to the non-inverting input terminal of the third comparison module; the second reference voltage is as follows Figure 4 The third comparison module is configured to perform processing based on a preset second reference voltage and the voltage of the collector of the IGBT module to obtain a third comparison result.

[0059] The second logic processing module is used to perform logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result; the second logic processing result includes: a judgment result of whether a Class II short-circuit fault occurs in the IGBT module.

[0060] The solution of the present invention processes the detection of the Vce of the IGBT through a circuit, and realizes that reducing the Vce to the conduction voltage drop is used as the enabling condition of the Vce detection. After the enabling is completed, as long as the Vce rises to a certain threshold due to a short circuit, the second type of short circuit protection is triggered.

[0061] In the solution of the present invention, the circuit detects Vce and processes it to achieve Class II short-circuit protection. Compared with related solutions that use current sensors to detect current and determine whether the current exceeds a threshold, the detection is more timely and can directly determine whether a Class II short circuit has occurred and provide feedback, facilitating fault location and maintenance.

[0062] In some embodiments, the second logic processing module includes: an SR trigger module, a second AND logic module, and the SR trigger module is as follows: Figure 4The SR processor S1 shown in FIG. 1 and the second logic module are as follows: Figure 4 AND gate AND1 is shown.

[0063] The second logic processing module performs logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result, including:

[0064] The SR trigger module is configured to perform SR trigger processing based on the second comparison module and the inverted signal of the gate drive signal of the IGBT module to obtain a trigger processing result.

[0065] The second AND logic module is used to perform AND logic processing based on the trigger processing result and the third comparison result to obtain the second logic processing result, such as Figure 4 The signal SO_1 is shown.

[0066] like Figure 4 As shown in the figure, before IGBT Q1 turns on, the voltage across the IGBT is the bus voltage, i.e., Vce = Vdc. After IGBT Q1 turns on, the CE voltage Vce of IGBT Q1 is the IGBT's conduction voltage drop. This voltage is divided by resistors R1 and R2 to obtain voltage V0. If voltage V0 is less than voltage Vref1, comparator U1's output signal U1-out is high. The S input of SR flip-flop S1 is high, while its R input is low. The Q output of SR flip-flop S1 is high, and Type II short-circuit detection is enabled. If a Type II short-circuit occurs, IGBT Q1 exits the saturation region, and its CE voltage Vce begins to rise. When voltage V0 exceeds voltage Vref2, comparator U2's output signal U2-out is high. The output of SR flip-flop S1 remains unchanged, and AND gate AND1 outputs a high level. OR gate OR1 also outputs a high level to the driver chip, triggering short-circuit protection and driving the OFF wave. The main control board receives the high level output by AND gate AND1 and determines that a type II short circuit occurs.

[0067] The solution of the present invention quickly detects Class II short circuits and implements protection through circuits. Compared with related solutions that use current sensors to detect current and determine whether the current exceeds a threshold, the detection is more timely and can directly determine whether a Class II short circuit has occurred and provide feedback, facilitating fault location and maintenance.

[0068] In some embodiments, the voltage-dividing sampling module includes: a first resistor module, a second resistor module and a diode module, wherein the first resistor module is as follows: Figure 4 The resistor R1 shown, the second resistor module is as follows Figure 4 The resistor R2 and diode modules are shown as Figure 4Diode D0 is shown.

[0069] The collector of the IGBT module is grounded after passing through the first and second resistor modules; a preset positive DC power supply is connected to the cathode of the diode module; the common terminal of the first and second resistor modules is connected to the anode of the diode module. The common terminal of the first and second resistor modules serves as the output terminal of the voltage divider sampling module, which is used to output the voltage of the collector of the IGBT module.

[0070] Related solutions design a Vce desaturation circuit for Class I short circuit detection, and use a current sensor to determine whether the current exceeds the threshold for Class II short circuit detection. The solution of the present invention can achieve rapid detection and protection of Class I and Class II short circuits through the IGBT short circuit detection and protection circuit, and avoid the disadvantage of the short circuit protection blind spot in related solutions that easily causes false alarms. Figure 4 As shown, the IGBT short-circuit detection and protection circuit proposed in the present invention includes: an IGBT Q1, resistors R1, R2, R3, R4, R5, R6, R7, and R8, a diode D0, comparators U1, U2, and U3, an SR trigger S1, AND gates AND1 and AND2, a NOT gate U4 (i.e., a NOT gate logic chip), an OR gate OR1, a main control board, and a driver chip. There are two emitters inside the IGBT Q1: a power emitter PE, which is generally used to connect to the main circuit; and an auxiliary emitter E, which is used to connect to the driver board. L is the parasitic inductance between the power emitter PE and the auxiliary emitter E of the IGBT Q1.

[0071] The gate G of IGBT Q1 receives the drive signal from the driver chip. The collector C of IGBT Q1 is connected to the cathode of its body diode. The auxiliary emitter E of IGBT Q1 is connected to the anode of its body diode and is grounded (i.e., at 0V). The auxiliary emitter E of IGBT Q1 is connected to the power emitter PE of IGBT Q1 via parasitic inductor L. The collector C of IGBT Q1 is connected to ground (i.e., at 0V) via resistors R1 and R2. The common terminal of resistors R1 and R2 is connected to the anode of diode D0. The 15V power supply is connected to the cathode of diode D0.

[0072] The 15V power supply is connected to ground (i.e., 0V potential) after passing through resistors R4 and R3. The common terminal of resistors R4 and R3 can output voltage Vref1 to the non-inverting input of comparator U1; the common terminal of resistors R1 and R2 can output voltage V0 to the inverting input of comparator U1. The output of comparator U1 can output signal U1-out to the S input of SR flip-flop S1. The R input of SR flip-flop S1 is used to receive a trigger signal, and the Q terminal of SR flip-flop S1 is used to output signal S1-out to the first input of AND gate AND1. The common terminal of resistors R1 and R2 can also output voltage V0 to the non-inverting input of comparator U2. The 15V power supply is connected to ground (i.e., 0V potential) after passing through resistors R5 and R6. The common terminal of resistors R5 and R6 can output voltage Vref2 to the inverting input of comparator U2; the output of comparator U2 can output signal U2-out to the second input of AND gate AND1. The output terminal of AND gate AND1 can output signal SO_1. The output signal SO_1 of the output terminal of AND gate AND1 can be transmitted to the first input terminal of the main control board; the output signal SO_1 of the output terminal of AND gate AND1 can also be input to the first input terminal of OR gate OR1.

[0073] The -15V power supply is grounded (i.e., 0V potential) after passing through resistors R7 and R8. The common terminal of resistors R7 and R8 can output voltage Vref3 to the inverting input terminal of comparator U3. The power emitter PE of IGBT tube Q1 can output voltage Vpe to the non-inverting input terminal of comparator U3. The output terminal of comparator U3 can output signal U3-out to the input terminal of NOT gate U4; the output terminal of NOT gate U4 can output signal U4-out to the second input terminal of AND gate AND2. The first input terminal of AND gate AND2 is used to receive a pulse signal. The output terminal of AND gate AND2 can output signal SO_2. The output signal SO_2 of the output terminal of AND gate AND2 can be transmitted to the second input terminal of the main control board; the output signal SO_2 of the output terminal of AND gate AND2 can also be input to the second input terminal of OR gate OR1. The output terminal of OR gate OR1 can output a control signal to the driver chip.

[0074] A Type I short circuit occurs before IGBT Q1 turns on, while a Type II short circuit occurs after IGBT Q1 turns on. The difference is that during a Type I short circuit, the CE voltage Vce of IGBT Q1 does not drop to its conduction voltage drop. However, before a Type II short circuit occurs, the CE voltage Vce of IGBT Q1 remains at its conduction voltage drop. When a Type II short circuit occurs, the CE voltage Vce of IGBT Q1 rises from its conduction voltage drop to the bus voltage Vdc. Therefore, during a Type I short circuit, the voltage V0 obtained by dividing the CE voltage Vce of IGBT Q1 by resistors R1 and R2 exceeds the voltage Vref1. The output signal U1-out of comparator U1 is low, the output signal S1-out of SR flip-flop S1 remains low, and the output signal SO_1 of AND gate AND1 remains low, preventing the Type II short circuit detection function from being triggered. The rising rate of the collector current ic of the IGBT tube Q1 in the second type short circuit is much smaller than the rising rate of the collector current ic of the IGBT tube Q1 in the first type short circuit fault. Therefore, the voltage Vpe in the second type short circuit is larger, the output signal U3-out of the comparator U3 is high, the output signal U4-out of the NOT gate U4 is low, and the AND gate AND1 outputs a low level, which will not trigger the first type short circuit protection.

[0075] In the solution of the present invention, the two detection schemes are combined through circuit construction, and the two detections do not affect each other, thereby achieving fast and accurate short-circuit protection.

[0076] The solution of the present invention proposes a high-power inverter IGBT short-circuit detection and protection solution, which directly completes IGBT short-circuit fault detection and protection through the driver board, without the need to achieve shutdown through the current sensor and the judgment of the main control board. The driver board can detect two types of short circuits and implement drive protection.

[0077] Among them, the main control board is the upper computer, which is responsible for sending the driving signal to the driver board and receiving the fault signal of the driver board. The driver board is the lower computer, which is responsible for receiving the driver board signal from the main control board, driving the IGBT after processing, completing the inversion, and at the same time being responsible for transmitting the driving fault signal to the upper computer main control board. If two types of short circuits are detected by the main control board and drive protection is implemented, it is necessary for the main control board to detect that the current exceeds the threshold or the driver board feeds back the fault signal to the main control board, and the main control board stops the output of the driving signal, and the driver board stops working after receiving the off-wave signal to achieve shutdown. In the solution of the present invention, if two types of short circuits are detected by the driver board and drive protection is implemented, the driver board directly implements the off-wave after detecting the fault, the IGBT stops working, and at the same time feeds back the fault signal to the main control board. The solution of the present invention completes fault detection and protection through the driver board, the short-circuit protection is more timely, and the frequency converter is safer.

[0078] In the solution of the present invention, the fault detection and protection of IGBT short circuit is completed by the driver board, and there is no need to realize the shutdown through the judgment of the current sensor and the main control board. The driver board can detect two types of short circuits and directly complete the shutdown, realizing timely and effective short circuit protection, protecting the safety of the components in the cabinet of the inverter, solving the problem of related solutions relying on current sensors to realize the second type of short circuit protection, and also solving the problem of related solutions that the IGBT short circuit protection is prone to false triggering of fault protection.

[0079] In some embodiments, the protection device of the frequency converter further includes: or a logic module, or a logic module such as Figure 4 The OR gate OR1 is shown.

[0080] Among them, the output end of the first detection unit is connected to the first input end of the OR logic module; the output end of the second detection unit is connected to the second input end of the OR logic module; the output end of the OR logic module is connected to the input end of the driver chip.

[0081] like Figure 4 As shown, when the output signal SO_1 at the output of AND gate AND1 or the output signal SO_2 at the output of AND gate AND2 is high, OR gate OR1 outputs a high level to the driver chip, triggering short-circuit protection and turning off the drive of IGBT Q1. A drive signal that is consistent with the gate of IGBT Q1 (i.e., gate G of IGBT Q1) is connected to the input of AND gate AND2, and a drive signal that is opposite in phase to the gate of IGBT Q1 (i.e., gate G of IGBT Q1) is connected to the R input of SR trigger S1. This ensures that fault detection only works when the drive signal to the gate of IGBT Q1 (i.e., gate G of IGBT Q1) is high. The CE voltage Vce of the IGBT tube Q1 is divided by resistors R1 and R2 to obtain voltage V0. The 15V voltage provided by the 15V power supply is divided by resistors R3 and R4 to obtain voltage Vref1. The 15V voltage provided by the 15V power supply is divided by resistors R5 and R6 to obtain voltage Vref2. The -15V voltage provided by the -15V power supply is divided by resistors R7 and R8 to obtain voltage Vref3.

[0082] In the solution of the present invention, the combination of two detection solutions is utilized to avoid the fault false alarm problem caused by the short-circuit protection blind area in related solutions through circuit processing, and rapid protection of Class I and Class II short circuits is achieved.

[0083] The present invention is not limited to the parameter voltages designed in the above examples, and the parameters can be adjusted and designed according to the actual application. For example, in the present invention, the driver board voltage is 15V and -15V, and the voltage is divided by a voltage divider resistor. The reference voltage Vref after the voltage division is compared with V0 and Vpe to determine whether a short circuit has occurred. If the actual application circuit involves other common driver board reference voltages such as 15V and -10V, 12V and -8V, the voltage divider resistor can be adjusted and matched according to the actual application voltage to achieve short circuit detection and protection.

[0084] In the solution of the present invention, the short circuit types are Class I and Class II. The short circuit detection method is as follows: if a Class I short circuit occurs, the IGBT tube Q1 is turned on, the collector current ic of the IGBT tube Q1 rises rapidly, and a negative voltage Vpe is generated on the parasitic inductance L between the auxiliary emitter E and the power emitter PE of the IGBT tube Q1. When the voltage Vpe is less than the set value, the short circuit protection is triggered. If no short circuit occurs before the IGBT tube Q1 is turned on, the CE voltage Vce of the IGBT tube Q1 when the IGBT tube Q1 is turned on is the IGBT tube Q1 conduction voltage drop, and Class II short circuit detection is enabled. If a Class II short circuit occurs, the CE voltage Vce of the IGBT tube Q1 rises, and when it exceeds the set value, the short circuit protection is triggered. The short circuit protection method is to directly provide the fault signal to the driver chip to achieve drive shutdown.

[0085] In the solution of the present invention, both Class I and Class II short circuits can be detected. The two types of short circuits can be detected separately and fault signals can be sent to the main control board separately, making it easier to locate the fault location and analyze the cause of the fault after the fault shutdown. After a short circuit fault is detected, the fault signal is sent to the driver chip. By enabling the controller driver chip, the output of the drive signal is directly controlled, eliminating the need to process the fault signal and then execute the shutdown wave, resulting in faster short circuit protection. The solution of the present invention includes two detection schemes for Class I and Class II short circuits. Both schemes are effective when the IGBT drive signal is at a high level. If a Class I short circuit has occurred at the time of opening, short circuit protection is immediately activated. If no fault has occurred at the time of opening, when the CE voltage Vce of the IGBT tube Q1 reaches the conduction voltage drop after the IGBT tube Q1 is turned on, Class II short circuit protection detection is enabled. Once Class II protection occurs, short circuit detection and protection are executed.

[0086] By adopting the technical solution of the present invention, an IGBT short-circuit fault detection circuit is provided on the drive board of the frequency converter for Class I and Class II short-circuit faults of the IGBT in the frequency converter. The IGBT short-circuit fault detection circuit can detect Class I and Class II short-circuit faults of the IGBT, and when a Class I or Class II short-circuit fault of the IGBT is detected, a drive shutdown wave is realized through the drive board; thus, by providing the IGBT short-circuit fault detection circuit on the drive board of the frequency converter, rapid protection against Class I and Class II short circuits is achieved.

[0087] According to an embodiment of the present invention, a frequency converter corresponding to the protection device of the frequency converter is also provided. The frequency converter may include: the protection device of the frequency converter described above.

[0088] Since the processing and functions implemented by the frequency converter of this embodiment basically correspond to the embodiments, principles and examples of the device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0089] According to an embodiment of the present invention, a protection method for a frequency converter is also provided, such as Figure 5 FIG. 1 is a flow chart of an embodiment of the method of the present invention. The inverter protection method may include steps S110 to S120.

[0090] At step S110, the first detection unit is used to detect whether a type I short-circuit fault occurs in the IGBT module, and when it is detected that the type I short-circuit fault occurs in the IGBT module, a type I short-circuit fault signal is output; and the second detection unit is used to detect whether a type II short-circuit fault occurs in the IGBT module, and when it is detected that the type II short-circuit fault occurs in the IGBT module, a type II short-circuit fault signal is output.

[0091] At step S120, the driver chip performs a drive shutoff based on the signal of the first type of short-circuit fault, specifically, the driver chip shuts off the drive signal output to the gate of the IGBT module; and the driver chip performs a drive shutoff based on the signal of the second type of short-circuit fault, specifically, the driver chip shuts off the drive signal output to the gate of the IGBT module.

[0092] The solution of the present invention directly completes the fault detection and protection of IGBT short circuit through the driver board, realizes the fault detection and timely protection of Class I short circuit and Class II short circuit on the driver board, and does not cause false alarms.

[0093] In some embodiments, the inverter protection method according to the solution of the present invention further includes: a process of determining the type of short-circuit fault based on the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault.

[0094] The following combination Figure 6 The flowchart of an embodiment of determining the type of short-circuit fault based on the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault in the method of the present invention is shown, further illustrating the process of determining the type of short-circuit fault based on the signal of the first type of short-circuit fault and the signal of the second type of short-circuit fault, including: steps S210 to S230.

[0095] In step S210 , the signal of the first type of short circuit fault and the signal of the second type of short circuit fault are transmitted to the main control board of the inverter respectively.

[0096] Step S220 : determining, by the main control board, based on the signal of the first type of short-circuit fault, that the type of the short-circuit fault of the IGBT module is a first type of short-circuit fault.

[0097] Step S230 : determining, by the main control board, based on the signal of the second-type short-circuit fault, that the type of the short-circuit fault of the IGBT module is a second-type short-circuit fault.

[0098] In the solution of the present invention, the driver fault signal is sent directly to the driver chip to achieve driver shutdown, without the need for feedback to the main control board, which then shuts down the system. This allows for rapid shutdown after short circuit detection, improving product reliability. In the solution of the present invention, both Class I and Class II short circuits can be detected, and each type of short circuit can be detected separately and fault signals can be sent to the main control board, facilitating fault location and cause analysis after a shutdown.

[0099] Since the processing and functions implemented by the method of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned frequency converter, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0100] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0101] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims.

Claims

1. A protection device for a frequency converter, characterized in that: The inverter has an inverter end and a drive board, the inverter end has an IGBT module, and the drive board has a drive chip; the output end of the drive chip is used to provide a drive signal to the gate of the IGBT module; The protection device of the frequency converter includes: a first detection unit and a second detection unit; wherein, The first detection unit is provided at the emitter of the IGBT module, and is used to detect whether a type of short circuit fault occurs in the IGBT module. When a type of short circuit fault is detected in the IGBT module, the first detection unit outputs a type of short circuit fault signal to the input terminal of the driver chip, so that the driver chip performs driving shutdown. The second detection unit is arranged at the collector of the IGBT module, and is used to detect whether a Class II short-circuit fault occurs in the IGBT module. When a Class II short-circuit fault is detected in the IGBT module, the second detection unit outputs a Class II short-circuit fault signal to the input end of the driver chip to enable the driver chip to drive the shutdown wave.

2. The protection device for the frequency converter according to claim 1, characterized in that: The frequency converter also has a main control board; wherein, The first detection unit is further configured to output the signal of the first type of short-circuit fault to the first input terminal of the main control board, so that the main control board determines that the type of the short-circuit fault of the IGBT module is a first type of short-circuit fault according to the signal of the first type of short-circuit fault; The second detection unit is further configured to output the signal of the second type short circuit fault to the second input terminal of the main control board, so that the main control board determines that the type of the short circuit fault of the IGBT module is a second type short circuit fault based on the signal of the second type short circuit fault.

3. The protection device for the frequency converter according to claim 1 or 2, characterized in that: The emitter of the IGBT module includes: a first emitter and a second emitter, and a parasitic inductance module is provided between the first emitter of the IGBT module and the second emitter of the IGBT module; the first detection unit includes: a negative reference voltage module, a first comparison module, and a first logic processing module; wherein, The first emitter of the IGBT module is grounded; the second emitter of the IGBT module is used to provide the voltage of the second emitter of the IGBT module to the inverting input terminal of the first comparison module; The negative reference voltage module is used to provide a preset negative reference voltage to the inverting input terminal of the first comparison module; The first comparison module is configured to compare a preset negative reference voltage with the voltage of the second emitter of the IGBT module to obtain a first comparison result; The first logic processing module is used to perform logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain a first logic processing result; the first logic processing result includes: a judgment result of whether a type of short circuit fault occurs in the IGBT module.

4. The protection device for the frequency converter according to claim 3, characterized in that: The first logic processing module includes: a non-logic module and a first AND logic module; wherein, The first logic processing module performs logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain a first logic processing result, including: The non-logical module is configured to perform non-logical processing based on the first comparison result to obtain a non-logical processing result; The first AND logic module is configured to perform AND logic processing based on the first comparison result and the gate drive signal of the IGBT module to obtain the first logic processing result.

5. The protection device for a frequency converter according to any one of claims 1 to 4, characterized in that: The second detection unit includes: a voltage division sampling module, a first reference voltage module, a second reference voltage module, a second comparison module, a third comparison module, and a second logic processing module; wherein, The voltage-dividing sampling module is configured to collect voltage from the collector of the IGBT module to obtain the voltage of the collector of the IGBT module; and input the voltage of the collector of the IGBT module to the inverting input terminal of the second comparison module and the non-inverting input terminal of the third comparison module respectively; The first reference voltage module is configured to provide a preset first reference voltage to the non-inverting input terminal of the second comparison module; the second comparison module is configured to perform processing based on the preset first reference voltage and the voltage of the collector of the IGBT module to obtain a second comparison result; a preset second reference voltage module, configured to provide a preset second reference voltage to the non-inverting input terminal of the third comparison module; the third comparison module is configured to perform processing based on the preset second reference voltage and the voltage of the collector of the IGBT module to obtain a third comparison result; The second logic processing module is used to perform logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result; the second logic processing result includes: a judgment result of whether a Class II short-circuit fault occurs in the IGBT module.

6. The protection device for the frequency converter according to claim 5, characterized in that: The second logic processing module includes: an SR trigger module and a second AND logic module; wherein, The second logic processing module performs logic processing based on the second comparison result, the third comparison result, and the inverted signal of the gate drive signal of the IGBT module to obtain the second logic processing result, including: The SR trigger module is configured to perform SR trigger processing based on the second comparison module and the inverted signal of the gate drive signal of the IGBT module to obtain a trigger processing result; The second AND logic module is used to perform AND logic processing based on the trigger processing result and the third comparison result to obtain the second logic processing result.

7. The protection device for the frequency converter according to claim 5, characterized in that: The voltage division sampling module includes: a first resistance module, a second resistance module and a diode module; wherein, The collector of the IGBT module is grounded after passing through the first resistor module and the second resistor module; a preset positive DC power supply is connected to the cathode of the diode module; and the common end of the first resistor module and the second resistor module is connected to the anode of the diode module; The common end of the first resistance module and the second resistance module serves as the output end of the voltage division sampling module, and is used to output the voltage of the collector of the IGBT module.

8. The protection device for a frequency converter according to any one of claims 1 to 7, characterized in that: Also includes: or logic module; wherein, The output end of the first detection unit is connected to the first input end of the OR logic module; The output end of the second detection unit is connected to the second input end of the OR logic module; The output end of the OR logic module is connected to the input end of the driver chip.

9. A frequency converter, characterized in that: include: The protection device for a frequency converter according to any one of claims 1 to 8.

10. A method for protecting a frequency converter corresponding to the protection device for the frequency converter according to any one of claims 1 to 8, characterized in that: include: detecting, by the first detection unit, whether a type I short-circuit fault occurs in the IGBT module, and outputting a type I short-circuit fault signal when the type I short-circuit fault is detected in the IGBT module; and detecting, by the second detection unit, whether a type II short-circuit fault occurs in the IGBT module, and outputting a type II short-circuit fault signal when the type II short-circuit fault is detected in the IGBT module; The driving chip is used to drive the OFF wave based on the signal of the first type of short circuit fault; and the driving chip is used to drive the OFF wave based on the signal of the second type of short circuit fault.

11. The inverter protection method according to claim 10, characterized in that: Also includes: transmitting the signal of the first type of short circuit fault and the signal of the second type of short circuit fault to the main control board of the frequency converter respectively; Determining, by the main control board, based on the signal of the type of short-circuit fault, that the type of the short-circuit fault of the IGBT module is a type of short-circuit fault; The main control board determines, based on the signal of the second-type short-circuit fault, that the type of the short-circuit fault of the IGBT module is a second-type short-circuit fault.

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