A protection device, method and frequency converter

Abstract

The application discloses a kind of protection device, method and frequency converter of frequency converter, and the inverter end of frequency converter has IGBT module, and drive board has drive chip;The device comprises: first detection unit, be set in the emitter of IGBT module, detect whether the short-circuit fault of type one occurs in IGBT module, and in the case where the short-circuit fault of type one is detected to occur in IGBT module, the signal of short-circuit fault of type one is output to the input end of drive chip, to make drive chip drive off wave;Second detection unit, be set in the collector of IGBT module, detect whether the short-circuit fault of type two occurs in IGBT module, and in the case where the short-circuit fault of type two is detected to occur in IGBT module, the signal of short-circuit fault of type two is output to the input end of drive chip, to make drive chip drive off wave.The scheme, by setting IGBT short-circuit fault detection circuit on the drive board of frequency converter, the fast protection of short-circuit of type one and short-circuit of type two is realized.

Description

Technical Field

[0001] This invention belongs to the field of frequency converter technology, specifically relating to a protection device, method, and frequency converter for frequency converters, and particularly to a short-circuit detection and protection device, method, and frequency converter for high-power frequency converters IGBTs. Background Technology

[0002] The main function of the inverter section of a frequency converter is to convert direct current into three-phase alternating current with the required frequency and voltage. The inverter module (i.e., the inverter section) commonly used in high-power frequency converters is the Insulated Gate Bipolar Transistor (IGBT) module. The IGBT module is usually used in conjunction with a driver board. The main controller of the frequency converter (such as the main control chip on the main control board) outputs a pulse width modulation (PWM) drive signal. After being processed by the drive circuit on the driver board, the PWM wave that meets the requirements for driving the IGBT is output. The driver board synchronously monitors the fault condition of the inverter end and transmits the fault signal to the main controller to realize fault protection.

[0003] The most critical fault protection for the inverter is the short-circuit protection of the IGBTs. However, in existing solutions, the accuracy of IGBT short-circuit fault detection and the timeliness of protection cannot be guaranteed.

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

[0005] The purpose of this invention is to provide a protection device, method, and inverter for frequency converters, so as to solve the problem that the detection accuracy and protection timeliness of IGBT short-circuit faults at the inverter end of the frequency converter cannot be guaranteed in related solutions. The invention achieves 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] This invention provides a protection device for a frequency converter. The frequency converter has an inverter terminal and a drive board. The inverter terminal has an IGBT module, and the drive board has a drive chip. The output terminal 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 includes: a first detection unit and a second detection unit. The first detection unit is disposed at the emitter of the IGBT module and is used to detect whether a Class I short-circuit fault has occurred in the IGBT module. If a Class I short-circuit fault is detected, the first detection unit outputs a Class I short-circuit fault signal to the input terminal of the drive chip to cause the drive chip to shut down. The second detection unit is disposed at the collector of the IGBT module and is used to detect whether a Class II short-circuit fault has occurred in the IGBT module. If a Class II short-circuit fault is detected, the second detection unit outputs a Class II short-circuit fault signal to the input terminal of the drive chip to cause the drive chip to shut down.

[0007] In some embodiments, the frequency converter further includes a main control board; wherein the first detection unit is further configured to output a signal of the first type of short circuit fault to a first input terminal of the main control board, so that the main control board determines the type of short circuit fault of the IGBT module as 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 configured to output a signal of the second type of short circuit fault to a second input terminal of the main control board, so that the main control board determines the type of short circuit fault of the IGBT module as 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 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 a voltage of the second emitter of the IGBT module to the non-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 with 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 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 the IGBT module has experienced a type I short-circuit fault.

[0009] In some embodiments, the first logic processing module includes: a NOT 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 NOT logic module is used to perform NOT logic processing based on the first comparison result to obtain a NOT logic processing result; the first AND logic module is used to perform AND logic processing based on the NOT logic processing result and the gate drive signal of the IGBT module to obtain the first logic processing result.

[0010] In some embodiments, the second detection unit includes: a voltage divider 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 divider sampling module is used to sample voltage from the collector of the IGBT module to obtain the collector voltage of the IGBT module; and input the collector voltage 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, based on the preset first reference voltage,... The voltage of the collector of the IGBT module is processed 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 the voltage of the collector of the IGBT module 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 a second logic processing result; the second logic processing result includes: a judgment result on whether the IGBT module has experienced a type II short circuit fault.

[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 is used to perform SR trigger processing based on the second comparison result 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.

[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 terminal of the first resistor module and the second resistor module is connected to the anode of the diode module; the common terminal of the first resistor module and the second resistor module serves as the output terminal of the voltage divider sampling module, used to output the voltage of the collector of the IGBT module.

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

[0014] In conjunction with the above-described device, the present invention further provides a frequency converter, comprising: the protection device for the frequency converter described above.

[0015] In conjunction with the aforementioned frequency converter, this invention further provides a protection method for the frequency converter, comprising: detecting, via a first detection unit, whether a Type I short-circuit fault has occurred in the IGBT module, and outputting a Type I short-circuit fault signal if a Type I short-circuit fault is detected in the IGBT module; detecting, via a second detection unit, whether a Type II short-circuit fault has occurred in the IGBT module, and outputting a Type II short-circuit fault signal if a Type II short-circuit fault is detected in the IGBT module; performing drive shutdown based on the Type I short-circuit fault signal via the drive chip; and performing drive shutdown based on the Type II short-circuit fault signal via the drive chip.

[0016] In some implementations, the method further includes: transmitting the signals of the first type of short circuit fault and the signals of the second type of short circuit fault to the main control board of the frequency converter; determining, based on the signals of the first type of short circuit fault, that the short circuit fault of the IGBT module is a first type of short circuit fault using the main control board; and determining, based on the signals of the second type of short circuit fault, that the short circuit fault of the IGBT module is a second type of short circuit fault using the main control board.

[0017] Therefore, the solution of this invention addresses both Class I and Class II short-circuit faults in IGBTs within a frequency converter by installing an IGBT short-circuit fault detection circuit on the frequency converter's drive board. This circuit can detect both Class I and Class II short-circuit faults in the IGBT and, upon detecting either a Class I or Class II short-circuit fault, enables drive shutdown via the drive board. Thus, by installing the IGBT short-circuit fault detection circuit on the frequency converter's drive board, rapid protection against both Class I and Class II short circuits is achieved.

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

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

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

[0021] Figure 2 This is a schematic diagram of two types of short circuits in IGBTs;

[0022] Figure 3 This is a schematic diagram of the Vce desaturation detection circuit for a type of short circuit in the relevant scheme;

[0023] Figure 4 This is a schematic diagram of the IGBT short-circuit detection and protection circuit of the present invention;

[0024] Figure 5 This is a flowchart illustrating an embodiment of the inverter protection method of the present invention;

[0025] Figure 6 This is a flowchart illustrating an embodiment of the method of the present invention for determining the short-circuit fault type based on the signals of the first type of short-circuit fault and the signals of the second type of short-circuit fault. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0027] Considering that the accuracy of IGBT short-circuit fault detection and the timeliness of protection cannot be guaranteed in the relevant solutions, IGBT short circuits are divided into two types: Class I short circuits and Class II short circuits. Class I short circuits are intra-phase short circuits, which refer to a shoot-through phenomenon in any arm of the bridge within a half-bridge; Class 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 one phase and ground.

[0028] In IGBT short-circuit protection, for Class I short circuits, detection and protection are typically achieved by designing a Vce desaturation circuit on the driver board. For Class II protection, current sensors are generally used to detect the current at the three-phase output terminals, and the main control board initiates protection when the detected current exceeds a set threshold. However, current sensors are susceptible to external interference, are relatively expensive, and are bulky; furthermore, the use of a Vce desaturation circuit for detection has a short-circuit protection blind zone, which can easily lead to false alarms.

[0029] Figure 2 This is a schematic diagram of two types of short circuits in IGBTs. Figure 2 ① represents a type of short circuit, which is an intra-phase short circuit, referring to a shoot-through phenomenon in any arm of the bridge within a half-bridge. Figure 2 ② represents a Class II short circuit, which is a phase-to-phase short circuit, characterized by a short circuit between any two phases within the three-phase system, or a short circuit between any one phase and ground. For example... Figure 2As shown, the DC bus voltage Vdc supplies power to motor M after passing through bus capacitor C1 and the inverter terminal. The positive terminal (DC+) of the DC bus voltage Vdc output is connected to the positive terminal of bus capacitor C1; the negative terminal (DC-) of the DC bus voltage Vdc output is connected to the negative terminal of bus capacitor C1. The inverter terminal includes IGBTs Q1, Q2, Q3, Q4, Q5, and Q6. IGBTs Q1 and Q4 are the upper and lower transistors of the U-phase bridge arm, respectively; IGBTs Q2 and Q5 are the upper and lower transistors of the U-phase bridge arm, respectively; and IGBTs Q3 and Q6 are the upper and lower transistors of the U-phase bridge arm, respectively. The collectors of IGBT Q1, Q2, and Q3 are all connected to the positive terminal (DC+) of the DC bus voltage Vdc output. The emitters of IGBT Q4, Q5, and Q6 are all connected to the negative terminal (DC-) of the DC bus voltage Vdc output. The emitter of IGBT Q1 is connected to the collector of IGBT Q4, and the common terminal of the emitters of IGBT Q1 and 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 emitters of IGBT Q2 and Q5 is connected to the V-phase winding of the three-phase winding of motor M. The emitter of IGBT Q3 is connected to the collector of IGBT Q6, and the common terminal of the emitter of IGBT Q3 and the collector of IGBT Q6 is connected to the W phase winding of the three-phase winding of motor M.

[0030] IGBT has two types of short circuits, such as Figure 2 As shown, Figure 2 ① represents a Class I short circuit, characterized by a shoot-through in any bridge arm. After the short circuit, the inductance within the circuit is relatively small, primarily consisting of stray inductance from the busbar, typically in the nH (nanohenry) range. Class I short circuits are short-circuit faults that occur before the IGBT is turned on. Figure 2 For example, if IGBT Q4 is shot-through, a short circuit fault has already occurred in IGBT Q1 before it is turned on. The voltage Vce across the collector and collector of IGBT Q1 is the bus voltage. When IGBT Q1 receives the turn-on signal, the collector current ic in a type I short circuit fault will rise rapidly. Because there is stray inductance in the circuit, Vce will drop slightly and then rise back to the bus voltage Vdc.

[0031] Figure 2 ② represents a Class II short circuit, characterized by a short circuit between any two phases of the three-phase circuit, or a short circuit between any one phase and ground. After the short circuit, the inductance within the circuit is relatively large, primarily due to the load inductance, typically in the mH (millihenry) range. A 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 phases V and W, the IGBT will enter the short circuit state from the normal operating state. In the second type of short circuit fault, the collector current ic will rise rapidly, and Vce will rise from the on-state voltage drop Vcesat during normal operation to the bus voltage Vdc.

[0032] Figure 3 This is a schematic diagram of the Vce desaturation detection circuit for a type of short circuit, as per the relevant scheme. Figure 3 It can demonstrate relevant solutions for Vce desaturation detection methods in a type of short circuit. For example... Figure 3 As shown, a Vce desaturation detection circuit for a type of short circuit includes: IGBT Q1, transistor Q0, capacitor Ca, resistor Rm, diodes D1 and D2, a 1.4mA current source, a 150uA current source, and comparator A1. The gate G of IGBT Q1 receives the drive signal. The collector C of IGBT Q1 is connected to the cathode of diode D2, and the transmitter E of IGBT Q1 is grounded. The 1.4mA current source is connected to the non-inverting input V+ of comparator A1, and the 150uA 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 grounded through capacitor Ca and also connected to the anode of diode D1 through resistor Rm; the cathode of diode D1 is connected to the anode of diode D2. The 150uA current source is also grounded after passing through resistor Rthx.

[0033] The relevant solutions address a type of short-circuit Vce desaturation detection method, such as... Figure 3As shown, the voltage at the inverting input V- of comparator A1 serves as the reference voltage for comparator A1. Specifically, the voltage value is the constant current source current of 150uA multiplied by the resistor Rthx. When the voltage at the non-inverting input V+ of comparator A1 is greater than the voltage at the inverting input V-, comparator A1 outputs a high level, triggering Class I short-circuit protection. Transistor Q0 is an NPN transistor. When the drive signal for IGBT Q1 is low, IGBT Q1 is not conducting, and transistor Q0 is conducting. At this time, the non-inverting input V+ of comparator A1 is grounded, and the voltage at the non-inverting input V+ of comparator A1 is less than the voltage at the inverting input V-, so comparator A1 outputs a low level, ensuring that Class I short-circuit protection is not triggered when IGBT Q1 is not conducting. If IGBT Q1 is normally turned on, its collector voltage is the forward voltage drop, typically around 2V. The voltage at the non-inverting input V+ of comparator A1 equals the forward voltage drop of IGBT Q1 plus the voltage drops of the two high-voltage diodes (e.g., diodes D1 and D2) and the voltage drop of the 1.4mA constant current source through resistor Rm. This voltage is lower than the reference voltage of comparator A1, i.e., the voltage at the inverting input V- of comparator A1, so comparator A1 outputs a low level. If a Class I short circuit has occurred when IGBT Q1 is turned on, its collector voltage is the bus voltage. The high-voltage diodes (e.g., diodes D1 and D2) are reverse-biased and cut off. The 1.4mA constant current source charges capacitor Ca. After a certain time, the voltage at the non-inverting input V+ of comparator A1 exceeds the voltage at the inverting input V- of comparator A1, causing comparator A1 to flip and output a low level, triggering short-circuit protection. However, when the IGBT (such as IGBT Q1) is normally turned on, from the time the IGBT receives a high-level signal at the gate to the time the IGBT turns on, the collector-emitter voltage Vce of the IGBT needs time to drop from the bus voltage to the turn-on voltage drop. This time can be regarded as a detection blind zone, and false triggering of faults is likely to occur within the detection blind zone.

[0034] Therefore, the present invention proposes a protection device for a frequency converter, specifically a short-circuit protection device for a frequency converter IGBT, which directly completes the fault detection and protection of IGBT short circuit through the drive board. It realizes fault detection and timely protection for Class I and Class II short circuits on the drive 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. See also Figure 1The diagram shows a structural schematic of an embodiment of the device of the present invention. The frequency converter has an inverter terminal and a drive board. The inverter terminal has an IGBT module, and the drive board has a drive chip. The output terminal of the drive chip is used to provide a drive signal to the gate of the IGBT module, specifically, to provide a drive signal to the gate of the IGBT module to control the switching of the IGBT module. The short-circuit fault of the IGBT module includes: a Class I short-circuit fault or a Class II short-circuit fault. Figure 4 This is a schematic diagram of the IGBT short-circuit detection and protection circuit of the present invention. The IGBT module is as follows: Figure 4 The IGBT transistor Q1 is shown. 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] The first detection unit is disposed between the emitter of the IGBT module and the input terminal of the driver chip. It is used to detect whether a type I short circuit fault has occurred in the IGBT module. When a type I short circuit fault is detected in the IGBT module, it outputs a type I short circuit fault signal to the input terminal of the driver chip so that the driver chip performs drive shutdown, specifically, it shuts down the drive signal output to the gate of the IGBT module.

[0037] The second detection unit is disposed between the collector of the IGBT module and the input terminal of the driver chip. It is used to detect whether the IGBT module has a type II short circuit fault. When a type II short circuit fault is detected in the IGBT module, it outputs a type II short circuit fault signal to the input terminal of the driver chip so that the driver chip performs a drive shutdown, specifically, it shuts down the drive signal output to the gate of the IGBT module.

[0038] The solution proposed in this invention is applicable to the field of frequency converter control. Specifically, this invention provides a short-circuit protection scheme for IGBTs in frequency converters, which is a short-circuit detection and protection scheme for high-power frequency converter IGBTs. It directly completes the fault detection and protection of IGBT short circuits through the drive board, achieving fault detection and timely protection for both Class I and Class II short circuits on the drive board, without false alarms.

[0039] In some embodiments, the frequency converter also has a main control board; wherein, the protection device of the frequency converter is further used to determine the short circuit fault type 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 disposed 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 first type of short circuit fault to the first input terminal of the main control board, so that the main control board determines the type of short circuit fault of the IGBT module as a first type of short circuit fault based on the signal of the first type of short circuit fault.

[0041] The second detection unit is also disposed 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 of short circuit fault to the second input terminal of the main control board, so that the main control board determines the type of short circuit fault of the IGBT module as a second type of short circuit fault based on the signal of the second type of short circuit fault.

[0042] In this invention, the drive fault signal is directly sent to the drive chip to achieve drive shutdown, eliminating the need for feedback to the main control board for main board shutdown. This enables rapid shutdown upon short circuit detection, improving product reliability. Furthermore, this invention can detect both Class I and Class II short circuits, allowing for separate detection and sending fault signals to the main control board. This facilitates fault location and cause analysis after 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 and the second emitter of the IGBT module. The first emitter of the IGBT module is as follows: Figure 4 The auxiliary emitter E shown, the second emitter of the IGBT module is as follows Figure 4 The power emitter PE shown is an example of a parasitic inductor module. Figure 4 The parasitic inductance L shown; the first detection unit includes: a negative reference voltage module, a first comparison module, and a first logic processing module, wherein the negative reference voltage module is as follows: Figure 4 The voltage Vref3 shown is provided by the module, and the first comparison module is as follows: Figure 4 The comparator U3 and the first logic processing module shown are as follows: Figure 4 The NOT gate U4 and AND gate AND2 are shown.

[0044] The first emitter of the IGBT module is grounded; the second emitter of the IGBT module is connected to the non-inverting input of the first comparator module, and is used to provide the voltage of the second emitter of the IGBT module to the non-inverting input of the first comparator module.

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

[0046] The first comparison module is used to compare a preset negative reference voltage with the voltage of the second emitter of the IGBT module to obtain a first comparison result, such as... Figure 4 The signal U3-out shown is connected to the input of the first logic processing module; the output of the first comparison module is connected to the input 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 on whether the IGBT module has experienced a type I short circuit fault.

[0048] The present invention achieves a type of short-circuit protection by detecting and processing the voltage of the IGBT emitter parasitic inductance through a circuit. In this invention, short-circuit protection is achieved through the detection and processing of the voltage of the IGBT emitter parasitic inductance. Compared with related solutions, the present invention avoids the drawbacks of short-circuit protection blind spots that easily lead to false alarms, making short-circuit detection and protection more accurate and timely.

[0049] In some implementations, the first logic processing module includes: a NOT logic module, a first AND logic module, and a negative reference voltage module, such as... Figure 4 The voltage Vref3 shown is provided by the module, and the first comparison module is as follows: Figure 4 The comparator U3 and the NOT logic module shown are as follows: Figure 4 The NOT gate U4 and the first AND logic module shown are as follows: Figure 4 The 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-logic module is used to perform non-logic processing based on the first comparison result to obtain a non-logic processing result.

[0052] The first AND logic module is used to perform AND logic processing based on the NOT logic processing result and the gate drive signal of the IGBT module to obtain the first logic processing result, such as... Figure 4 The signal shown is SO_2.

[0053] like Figure 4As shown, if a type I short circuit occurs before IGBT Q1 is turned on, the voltage across IGBT Q1 is the bus voltage, i.e., Vce = Vdc. When IGBT Q1 is turned on, the collector-emitter voltage Vce of IGBT Q1 drops slightly and then rises back to the bus voltage Vdc. The collector current ic of IGBT Q1 rises rapidly, generating a voltage Vpe across the parasitic inductance L between the power emitter PE and the auxiliary emitter E of IGBT Q1. The magnitude of voltage Vpe is related to the rate at which the current ic rises, i.e., Vpe = -L*dic / dt. This voltage is negative, and L is the inductance value of the parasitic inductance L. When voltage Vpe is less than voltage Vref3, the output signal U3-out of comparator U3 is low, the output signal U4-out of NOT gate U4 is high, the output of AND gate AND2 is high, and the output of OR gate OR1 is high, which is sent to the driver chip, triggering short-circuit protection and driving the shutdown. The main control board receives a high level output from AND gate AND2 and determines that a type of short circuit has occurred.

[0054] In this invention, a short-circuit detection and protection system is rapidly implemented via a driver board. Compared to related solutions, this invention avoids the drawbacks of blind spots in short-circuit protection that can easily lead to false alarms. This makes short-circuit detection and protection more accurate and timely, precisely identifying the short-circuit type and facilitating fault location and maintenance.

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

[0056] The voltage divider sampling module is used to acquire voltage from the collector of the IGBT module to obtain the collector voltage of the IGBT module; and input the collector voltage of the IGBT module to the inverting input terminal of the second comparator module and the non-inverting input terminal of the third comparator module respectively; the input terminal of the voltage divider sampling module is connected to the collector of the IGBT module; and the output terminal of the voltage divider sampling module is connected to the inverting input terminal of the second comparator module and the non-inverting input terminal of the third comparator module respectively.

[0057] The first reference voltage module is connected to the non-inverting input of the second comparison module, and is used to provide a preset first reference voltage to the non-inverting input of the second comparison module; the first reference voltage is as follows: Figure 4 The voltage Vref1 is shown. The second comparison module is used to process the voltage based on the preset first reference voltage and the collector voltage of the IGBT module to obtain a second comparison result.

[0058] A preset second reference voltage module is connected to the inverting input of the third comparison module, and is used to provide a preset second reference voltage to the non-inverting input of the third comparison module; the second reference voltage is as follows: Figure 4 The voltage Vref2 shown is used to process the voltage based on the preset second reference voltage and the collector voltage 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 on whether the IGBT module has experienced a type II short circuit fault.

[0060] The solution of the present invention processes the detection of Vce of IGBT through circuitry, so as to realize that the Vce drops to the on-state voltage drop as the enable condition for Vce detection. After the enable is completed, as long as Vce rises to a certain threshold due to short circuit, the Class II short circuit protection is triggered.

[0061] In this invention, the detection of Vce is processed by a circuit 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 it can directly determine whether a Class II short circuit has occurred and provide feedback, which facilitates fault location and maintenance.

[0062] In some embodiments, the second logic processing module includes: an SR trigger module and a second AND logic module, wherein the SR trigger module is as follows: Figure 4The SR processor S1 shown, the second AND logic module as follows Figure 4 The 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 used to perform SR triggering processing based on the second comparison result and the inverted signal of the gate drive signal of the IGBT module to obtain the triggering 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 shown is SO_1.

[0066] like Figure 4 As shown, before IGBT Q1 is turned on, the voltage across the IGBT device is the bus voltage, i.e., Vce = Vdc. After IGBT Q1 is turned on, the CE voltage Vce of IGBT Q1 is the IGBT's on-state voltage drop. The CE voltage Vce of IGBT Q1 is divided by resistors R1 and R2 to obtain voltage V0. Voltage V0 < voltage Vref1, the output signal U1-out of comparator U1 is high, the S input of SR flip-flop S1 is high, the R input is low, and the Q output of SR flip-flop S1 outputs a high level, enabling Class II short circuit detection. If a Class II short circuit occurs, IGBT Q1 exits the saturation region, and the CE voltage Vce of IGBT Q1 begins to rise. When voltage V0 is greater than voltage Vref2, the output signal U2-out of comparator U2 is high, the output of SR flip-flop S1 remains unchanged, the AND gate AND1 outputs a high level, and the OR gate OR1 outputs a high level to the driver chip, triggering short circuit protection and driving the shutdown. The main control board receives a high level output from AND gate AND1 and determines that a type II short circuit has occurred.

[0067] The solution of this invention quickly detects and protects against Class II short circuits through circuitry. 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, which facilitates fault location and maintenance.

[0068] In some embodiments, the voltage divider 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 module shown are as follows: Figure 4The diode D0 is shown.

[0069] In this configuration, the collector of the IGBT module is grounded via the first and second resistor modules; a preset positive DC power supply is connected to the cathode of the diode module; and the common terminal of the first and second resistor modules is connected to the anode of the diode module. This common terminal serves as the output terminal of the voltage divider sampling module, used to output the collector voltage of the IGBT module.

[0070] Existing solutions employ Vce desaturation circuits for detection in Class I short circuits and use current sensors to determine if the current exceeds a threshold for Class II short circuits. The solution of this invention, through an IGBT short circuit detection and protection circuit, can achieve rapid detection and protection against both Class I and Class II short circuits, and avoids the drawbacks of existing solutions where blind spots in short circuit protection easily lead to false alarms. Figure 4 As shown, the IGBT short-circuit detection and protection circuit proposed in this invention includes: an IGBT transistor Q1, resistors R1, R2, R3, R4, R5, R6, R7, and R8, a diode D0, comparators U1, U2, and U3, an SR flip-flop 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. Inside the IGBT transistor Q1, there are two emitters: a power emitter PE, typically used to connect to the main circuit; and an auxiliary emitter E, 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 transistor Q1.

[0071] In this configuration, the gate (G) of IGBT Q1 receives the drive signal output from the driver chip; the collector (C) of IGBT Q1 is connected to the cathode of the body diode of IGBT Q1; the auxiliary emitter (E) of IGBT Q1 is connected to the anode of the body diode of IGBT Q1, and the auxiliary emitter (E) is grounded (i.e., 0V potential). The auxiliary emitter (E) of IGBT Q1 is connected to the power emitter (PE) of IGBT Q1 via the parasitic inductance (L). The collector (C) of IGBT Q1 is grounded (i.e., 0V potential) 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] A 15V power supply is grounded (i.e., 0V potential) after passing through resistors R4 and R3. The common terminal of resistors R4 and R3 outputs voltage Vref1 to the non-inverting input of comparator U1; the common terminal of resistors R1 and R2 outputs voltage V0 to the inverting input of comparator U1. The output of comparator U1 outputs signal U1-out to the S input of SR flip-flop S1. The R input of SR flip-flop S1 receives the trigger signal, and the Q input of SR flip-flop S1 outputs signal S1-out to the first input of AND gate AND1. The common terminal of resistors R1 and R2 also outputs voltage V0 to the non-inverting input of comparator U2. A 15V power supply is grounded (i.e., 0V potential) after passing through resistors R5 and R6. The common terminal of resistors R5 and R6 outputs voltage Vref2 to the inverting input of comparator U2; the output of comparator U2 outputs signal U2-out to the second input of AND gate AND1. The output of AND1 can output signal SO_1. The output signal SO_1 of AND1 can be transmitted to the first input of the main control board; the output signal SO_1 of AND1 can also be input to the first input of OR1.

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

[0074] There are two types of short circuits: Type I short circuits occur before IGBT Q1 is turned on, and Type II short circuits occur after IGBT Q1 is turned on. The difference is that in Type I short circuits, the CE voltage Vce of IGBT Q1 does not drop to the on-state voltage drop, while in Type II short circuits, the CE voltage Vce of IGBT Q1 is at the on-state voltage drop before the short circuit occurs, and rises from the on-state voltage drop to the bus voltage Vdc when a Type II short circuit occurs. Therefore, in Type I short circuits, the voltage V0 obtained after the CE voltage Vce of IGBT Q1 is divided by resistors R1 and R2 is greater than the voltage Vref1. The output signal U1-out of comparator U1 is low, the output signal S1-out of SR flip-flop S1 is always low, and the output signal SO_1 of AND gate AND1 is always low. The Type II short circuit detection function will not be triggered. In a Class II short circuit, the rise rate of the collector current ic of IGBT Q1 is much smaller than that in a Class I short circuit. Therefore, the voltage Vpe is larger in a Class II short circuit. The output signal U3-out of comparator U3 is high, the output signal U4-out of NOT gate U4 is low, and the output of AND gate AND1 is low, so it will not trigger the Class I short circuit protection.

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

[0076] The present invention proposes a short-circuit detection and protection scheme for high-power frequency converter IGBTs, which directly completes the fault detection and protection of IGBT short circuits through the drive board, without the need for current sensors and main control board judgment to achieve shutdown. The drive board can detect two types of short circuits and realize drive protection.

[0077] In this system, the main control board acts as the host computer, responsible for sending drive signals to the drive board and receiving fault signals from the drive board. The drive board acts as the slave computer, receiving drive board signals from the main control board, processing them, and then driving the IGBTs to complete the inversion. It also transmits drive fault signals to the host computer's main control board. If the main control board detects two types of short circuits and implements drive protection, it needs to detect that the current exceeds a threshold or that the drive board sends a fault signal back to it. In this case, the main control board stops outputting drive signals, and the drive board stops working upon receiving the shutdown signal, thus shutting down the system. In this invention, if the drive board detects two types of short circuits and implements drive protection, it directly shuts down the IGBT upon detecting a fault, and simultaneously sends a fault signal back to the main control board. This invention's solution, with fault detection and protection completed by the drive board, provides more timely short-circuit protection and enhances the safety of the frequency converter.

[0078] In the solution of this invention, the fault detection and protection of IGBT short circuit is completed by the drive board, without the need for the current sensor and the main control board to realize the shutdown. The drive board can detect two types of short circuits and directly realize the shutdown, realizing timely and effective short circuit protection, protecting the safety of the components in the inverter cabinet, solving the problem of relying on the current sensor to realize the second type of short circuit protection in related solutions, and also solving the problem that the IGBT short circuit protection in related solutions is prone to false triggering of fault protection.

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

[0080] The output of the first detection unit is connected to the first input of the OR logic module; the output of the second detection unit is connected to the second input of the OR logic module; and the output of the OR logic module is connected to the input of the driver chip.

[0081] like Figure 4 As shown, when the output signal SO_1 of AND gate AND1 or the output signal SO_2 of AND gate AND2 is high, OR gate OR1 outputs a high level to the driver chip, triggering short-circuit protection and shutting down the drive of IGBT Q1. A drive signal identical to the gate signal (G) of IGBT Q1 is connected to the input of AND gate AND2, while a drive signal inversely phase to the gate signal (G) of IGBT Q1 is connected to the R input of SR flip-flop S1. This ensures that fault detection only functions when the drive signal to the gate signal (G) of IGBT Q1 is high. The CE voltage Vce of IGBT 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 present invention, by combining two detection schemes and processing the circuit, the false alarm problem caused by the short circuit protection blind zone in the relevant schemes is avoided, thereby achieving rapid protection against Class I and Class II short circuits.

[0083] In the solution of this invention, the parameter voltages are not limited to those in the above-described example design; the parameters can be adjusted and designed according to actual applications. For example, in the solution of this invention, the driver board voltage is 15V and -15V. The voltage is divided by a voltage divider resistor, and the resulting reference voltage Vref is compared with V0 and Vpe to determine whether a short circuit has occurred. If other common driver board reference voltages such as 15V and -10V, or 12V and -8V are involved in the actual application circuit, the voltage divider resistor can be adjusted and matched according to the actual application voltage to achieve short circuit detection and protection.

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

[0085] In this 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, facilitating fault location and cause analysis after a fault shutdown. Upon detecting a short circuit fault, the fault signal is sent to the driver chip. By enabling the driver chip, the output of the drive signal is directly controlled, eliminating the need for further processing of the fault signal before shutdown, resulting in faster short circuit protection. This invention includes two detection schemes for Class I and Class II short circuits. Both schemes operate when the IGBT drive signal is high. If a Class I short circuit has already occurred upon startup, short circuit protection is immediately initiated. If no fault has occurred upon startup, when the CE voltage Vce of IGBT Q1 reaches the on-state voltage drop after IGBT 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 employing the technical solution of this invention, an IGBT short-circuit fault detection circuit is installed on the drive board of the frequency converter to detect both Class I and Class II short-circuit faults in the IGBT. Upon detection of either a Class I or Class II short-circuit fault, the drive board shuts down the circuit. Thus, by installing the IGBT short-circuit fault detection circuit on the drive board of the frequency converter, rapid protection against both Class I and Class II short circuits is achieved.

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

[0088] Since the processing and functions implemented by the frequency converter in this embodiment are basically the same as those in the embodiments, principles and examples of the device, any details not covered in this embodiment can be found in the relevant descriptions in the foregoing embodiments, and will not be repeated here.

[0089] According to embodiments of the present invention, a protection method for a frequency converter is also provided, such as... Figure 5 The diagram shows a flowchart of an embodiment of the method of the present invention. The protection method for the frequency converter may include steps S110 to S120.

[0090] In step S110, the first detection unit detects whether a Type I short circuit fault has occurred in the IGBT module, and outputs a Type I short circuit fault signal if a Type I short circuit fault is detected in the IGBT module; and the second detection unit detects whether a Type II short circuit fault has occurred in the IGBT module, and outputs a Type II short circuit fault signal if a Type II short circuit fault is detected in the IGBT module.

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

[0092] The solution of this invention directly completes the fault detection and protection of IGBT short circuit through the driver board, realizing the fault detection and timely protection of Class I and Class II short circuits on the driver board, and avoiding false alarms.

[0093] In some embodiments, the inverter protection method of the present invention further includes: a process of determining the short-circuit fault type 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 is combined Figure 6 The schematic diagram shown is an embodiment of the method of the present invention for determining the short circuit fault type based on the signal of the first type of short circuit fault and the signal of the second type of short circuit fault. The process of determining the short circuit fault type based on the signal of the first type of short circuit fault and the signal of the second type of short circuit fault includes: steps S210 to S230.

[0095] Step S210: The signals of the first type of short circuit fault and the signals of the second type of short circuit fault are transmitted to the main control board of the frequency converter.

[0096] Step S220: The main control board determines that the short circuit fault of the IGBT module is a type of short circuit fault based on the signal of the type I short circuit fault.

[0097] Step S230: The main control board determines that the short circuit fault of the IGBT module is a type II short circuit fault based on the signal of the type II short circuit fault.

[0098] In this invention, the drive fault signal is directly sent to the drive chip to achieve drive shutdown, eliminating the need for feedback to the main control board for main board shutdown. This enables rapid shutdown upon short circuit detection, improving product reliability. Furthermore, this invention can detect both Class I and Class II short circuits, allowing for separate detection and sending fault signals to the main control board. This facilitates fault location and cause analysis after shutdown.

[0099] Since the processing and functions implemented by the method in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned frequency converters, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0100] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0101] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A protection device for a frequency converter, characterized in that, The frequency converter has an inverter terminal and a drive board. The inverter terminal has an IGBT module, and the drive board has a drive chip. The output terminal 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 includes: a first detection unit and a second detection unit; wherein, The first detection unit is disposed at the emitter of the IGBT module and is used to detect whether a type I short circuit fault has occurred in the IGBT module. When a type I short circuit fault is detected in the IGBT module, the unit outputs a type I short circuit fault signal to the input terminal of the driver chip so that the driver chip can drive the shutdown signal. The second detection unit is disposed at the collector of the IGBT module and is used to detect whether the IGBT module has a type II short circuit fault. When a type II short circuit fault is detected in the IGBT module, the unit outputs a type II short circuit fault signal to the input terminal of the driver chip so that the driver chip can perform a drive shutdown. The second detection unit includes: a voltage divider 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 divider sampling module is used to sample voltage from the collector of the IGBT module to obtain the collector voltage of the IGBT module; and input the collector voltage 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 process the preset first reference voltage 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 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 a second logic processing result; the second logic processing result includes: a judgment result on whether the IGBT module has experienced a type II short circuit fault.

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 also used 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 the type of short circuit fault of the IGBT module as a first type of short circuit fault based on the signal of the first type of short circuit fault. The second detection unit is also used to output the signal of the second type of short circuit fault to the second input terminal of the main control board, so that the main control board can determine the type of short circuit fault of the IGBT module as a second type of short circuit fault based on the signal of the second type of 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 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 non-inverting input terminal of the first comparator 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 with a 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 gate drive signal of the IGBT module to obtain a first logic processing result; the first logic processing result includes: a judgment result on whether the IGBT module has experienced a type I short circuit fault.

4. The protection device for the frequency converter according to claim 3, characterized in that, The first logic processing module includes: a NOT 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-logic module 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 is used to perform AND logic processing based on the non-logic processing result and the gate drive signal of the IGBT module to obtain the first logic processing result.

5. The protection device for the frequency converter according to claim 1, 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 used to perform SR triggering processing based on the second comparison result and the inverted signal of the gate drive signal of the IGBT module to obtain the triggering 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.

6. The protection device for the frequency converter according to claim 1, characterized in that, 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 terminal of the first resistor module and the second resistor module is connected to the anode of the diode module. The common terminal of the first resistor module and the second resistor module serves as the output terminal of the voltage divider sampling module, used to output the collector voltage of the IGBT module.

7. The protection device for the frequency converter according to any one of claims 1, 2, 4 to 6, characterized in that, Also includes: Or a logic module; where, The output terminal of the first detection unit is connected to the first input terminal of the OR logic module; The output of the second detection unit is connected to the second input of the OR logic module; The output terminal of the OR logic module is connected to the input terminal of the driver chip.

8. The protection device for the frequency converter according to claim 3, characterized in that, Also includes: Or a logic module; where, The output terminal of the first detection unit is connected to the first input terminal of the OR logic module; The output of the second detection unit is connected to the second input of the OR logic module; The output terminal of the OR logic module is connected to the input terminal of the driver chip.

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

10. A protection method for a frequency converter corresponding to the protection device of the frequency converter as described in any one of claims 1 to 8, characterized in that, include: The first detection unit detects whether the IGBT module has a Class I short circuit fault, and outputs a Class I short circuit fault signal when the IGBT module is detected to have a Class I short circuit fault; the second detection unit detects whether the IGBT module has a Class II short circuit fault, and outputs a Class II short circuit fault signal when the IGBT module is detected to have a Class II short circuit fault. The driving chip is used to drive the shutdown waveform based on the signal of the first type of short circuit fault; and the driving chip is used to drive the shutdown waveform based on the signal of the second type of short circuit fault.

11. The protection method for a frequency converter according to claim 10, characterized in that, Also includes: The signals of the first type of short circuit fault and the signals of the second type of short circuit fault are respectively transmitted to the main control board of the frequency converter; Based on the signal of the first type of short circuit fault, the main control board determines that the short circuit fault of the IGBT module is a first type of short circuit fault. Based on the signal of the type II short circuit fault, the main control board determines that the short circuit fault of the IGBT module is a type II short circuit fault.

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