CN210724183U

CN210724183U - IGBT overcurrent and short circuit protection circuit

Info

Publication number: CN210724183U
Application number: CN201922053722.4U
Authority: CN
Inventors: 吴琼; 黄鹏辉; 丁祥根; 李育; 李靖恺
Original assignee: Shanghai Automobile Gear Works
Current assignee: Shanghai Automobile Gear Works
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2020-06-09
Anticipated expiration: 2029-11-25

Abstract

An IGBT over-current and short-circuit protection circuit, comprising: the IGBT with the current sampling device is connected with the desaturation detection circuit and the overcurrent detection circuit which are connected in parallel, and then is connected with the logic gate control circuit, the two-stage turn-off circuit and the soft turn-off circuit in series in sequence, and the logic gate control circuit is utilized to carry out Vge voltage control when short circuit or overcurrent occurs, so that short circuit protection and overcurrent protection are carried out on the IGBT. The utility model discloses compare traditional drive circuit scheme, optimized the two-stage of demarcation mode and turn-offed, adopted pure hardware mode, the parameter that the dynamic adjustment two-stage was turn-offed to soft turn-offeing mode has been combined, control Vge's maximum voltage to second level turn-offeing voltage. The combination mode effectively overcomes the defects of traditional two-stage turn-off and soft turn-off, intelligently controls the size of Vge according to the actual value of Ic, reduces the voltage spike of Vce, and ensures the normal work of the IGBT.

Description

IGBT overcurrent and short circuit protection circuit

Technical Field

The utility model relates to a technique in motor drive control field specifically is a protection circuit that IGBT overflows and short circuit.

Background

When the IGBT is short-circuited, if loop inductance is small, current rises fast, the IGBT can be desaturated, once the IGBT exits a saturation area, loss can rise hundreds of times, and time for allowing the state to last is very harsh; if the loop inductance is large, the current climbs very slowly, and the IGBT cannot be desaturated, but the current is much higher than the current under normal working conditions, so that after a plurality of switching cycles, the loss of the IGBT is very high, the junction temperature also rapidly rises, and failure is caused. In both cases, the gate is found by the driver and turned off in time.

The high-performance IGBT driving circuit can reduce the switching delay and the switching loss, so that the IGBT can obtain better switching-on and switching-off performance, and can quickly make a protection action when overcurrent or short-circuit faults occur, thereby avoiding the situations of exceeding the thermal limit, the seizure effect and exceeding the voltage resistance of devices, and ensuring the safe and reliable switching-off of the IGBT. In the prior art, two methods are mainly adopted to improve the switching characteristic of a driving circuit, one method is to adopt a single register to carry out two-stage turn-off, but the generated Vce voltage spike is large; the other is that a soft turn-off mode is directly adopted, but the Vce value obtained by the mode is larger than that obtained by the first mode.

SUMMERY OF THE UTILITY MODEL

The utility model discloses not enough to the above-mentioned that prior art exists, provide a protection circuit that IGBT overflows and short circuit, through the mode that dynamic settings two-stage shut-off level and soft turn-off combined together, utilize platform voltage and duration that the nimble control two-stage of hardware circuit was turn-off, then speed and time when the mode control twice Vge voltage of turning off through soft is suddenly changed, and then the speed that control current descends, restrain the peak value of Vce voltage, protection IGBT.

The utility model discloses a realize through following technical scheme:

the utility model discloses a: take current sampling device's IGBT, move back saturation detection circuitry, overflow detection circuitry, logic gate control circuit, two-stage turn-off circuit and soft turn-off circuit, wherein: the IGBT is connected with the desaturation detection circuit and the overcurrent detection circuit which are connected in parallel, and then is sequentially connected with the logic gate control circuit, the two-stage turn-off circuit and the soft turn-off circuit in series, and the logic gate control circuit is used for carrying out Vge voltage control when short circuit or overcurrent occurs, so that short circuit protection and overcurrent protection are carried out on the IGBT.

Technical effects

Compared with the prior art, the utility model discloses compare traditional drive circuit scheme, optimized the two-stage of demarcation mode and turn-offed, adopted pure hardware mode, the parameter that the dynamic adjustment two-stage was turn-offed to combined soft turn-offeing mode, control Vge's maximum voltage to second level turn-offed voltage, and second level turn-offed voltage to the rate of decline and the time of minimum voltage. The combination mode effectively overcomes the defects of traditional two-stage turn-off and soft turn-off, intelligently controls the size of Vge according to the actual value of Ic, reduces the voltage spike of Vce, and ensures the normal work of the IGBT.

Drawings

FIG. 1 is a schematic diagram of a drive module;

FIG. 2 is a desaturation detection circuit;

FIG. 3 is an over-current detection circuit;

FIG. 4 is a two-stage turn-off circuit;

FIG. 5 is a soft turn-off circuit;

FIG. 6 is a schematic diagram of gate voltage turn-off under protection;

FIG. 7 is a schematic diagram illustrating the effects of the embodiment;

in the figure: the circuit comprises a desaturation detection circuit A, an overcurrent detection circuit B, a logic gate control circuit C, a two-stage turn-off circuit D, a soft turn-off circuit E, first to second diodes 1 to 2, first to fifth comparators 3 to 7, first to eighth triodes 8 to 15, first to fourth logic gates 16 to 19, first to third capacitors 20 to 22, first to fifteenth resistors 23 to 37 and first to eighth pins a to h.

Detailed Description

As shown in fig. 1, the present embodiment includes: IGBT with current sampling device, desaturation detection circuit A, overcurrent detection circuit B, logic gate control circuit C, two-stage turn-off circuit D and soft turn-off circuit E, wherein: the IGBT is connected with a desaturation detection circuit A and an overcurrent detection circuit B which are connected in parallel, and then is sequentially connected with a logic gate control circuit C, a two-stage turn-off circuit D and a soft turn-off circuit E in series.

As shown in fig. 2, the desaturation detection circuit a includes: a first diode 1, a first resistor 23 and a first comparator 3, wherein: the first diode 1 is connected to the C port of the IGBT and is connected in turn to the first resistor 23 and the third pin C of the first comparator 3.

The first pin a of the first comparator 3 transmits a short-circuit fault signal, the fourth pin d thereof is provided with a first capacitor 20, a first triode 8 is arranged between the third pin c thereof and the first resistor 23, and the eighth pin h thereof is grounded.

And a first pin a of the first triode 8 is connected with the logic gate control circuit C.

As shown in fig. 3, the over-current detection circuit B includes: second to fourth resistors 24 to 26, a second capacitor 21 and a second comparator 4, wherein: the second to fourth resistors 24-26 are connected in series, and two ends of the second capacitor 21 are respectively connected to one end of the fourth resistor 26 and the third pin c of the second comparator 4.

The first pin a of the second comparator 4 transmits an overcurrent fault signal, the fourth pin d thereof is provided with a capacitor, and the eighth pin h thereof is grounded.

As shown in fig. 4, the two-stage shutdown circuit D includes: fifth to eighth resistors 27 to 30 connected in series to the first power source VCC1, ninth to twelfth resistors 31 to 34 connected in series to the second power source VCC2, third to fifth comparators 5 to 7, and second to fourth triodes 9 to 11, wherein: a first-stage current threshold value is set between every two adjacent resistors of the fifth to eighth resistors 27 to 30, which is three stages, represented by I1, I2 and I3, a Vge second-stage turn-off voltage value, represented by V1, V2 and V3, of a first pin a and a seventh pin g of the third comparator 5 are connected with a third pin C of the second triode 9, a first pin a of the second triode 9 is connected with a logic gate control circuit C, a first pin a and a seventh pin g of the fourth comparator 6 are connected with a third pin C of the third triode 10, a first pin a of the third triode 10 is connected with the logic gate control circuit C, a first pin a of the fifth comparator 7 is connected with a third pin C of the fourth triode 11, and a first pin a of the fourth triode 11 is connected with the logic gate control circuit C.

The third pin c of the third comparator 5 is inputted with I1, the second pin b thereof and the fifth pin e are inputted with Ic, and the sixth pin f thereof is inputted with I2.

The third pin c of the fourth comparator 6 is inputted with I2, the second pin b thereof and the fifth pin e thereof are inputted with Ic, and the sixth pin f thereof is inputted with I3.

The third pin c of the fifth comparator 7 is input with I3, and the second pin b thereof is input with Ic.

As shown in fig. 2 and 4, the logic gate control circuit C includes: first to fourth logic gates 16 to 19, wherein: the fourth pin d of the first logic gate 16 is connected with the first pin a of the first triode 8, the first pin a and the second pin b thereof are connected with the pulse width modulator PWM, the fourth pins d of the second to fourth logic gates 17 to 19 are respectively connected with the first pins a of the corresponding second to fourth triodes 9 to 11, the first pins a thereof all transmit short-circuit fault signals, the second pins b thereof all transmit overcurrent fault signals, the third pins c thereof are all grounded, and the fifth pin e thereof is all connected with the first power supply VCC 1.

As shown in fig. 5, the soft shutdown circuit E includes: fifth to eighth triodes 12 to 15, a second diode 2 and thirteenth to fifteenth resistors 35 to 37, wherein: a first pin a of the eighth triode 15 receives an overcurrent fault signal or a short-circuit fault signal transmitted by the two-stage turn-off circuit D, a second pin b of the eighth triode 15 is connected with-8V voltage, a third pin c of the eighth triode 15 is connected with 15V voltage, thirteenth to fifteenth resistors 35 to 37 are connected in parallel and are respectively connected with second pins b of the corresponding fifth to seventh triodes 12 to 14, a first pin a of the seventh triode 14 is connected with a third pin c of the eighth triode 15, first pins a of the fifth triode 12 and the sixth triode 13 are both connected with a pulse width modulator PWM, one end of the second diode 2 is connected between the seventh triode 14 and the eighth triode 15, and the other end of the second diode is connected with the first pin a of the fifth triode 12.

And a third pin c of the fifth triode 12 is provided with 15V voltage.

And a voltage of-8V is set at the third pin c of the sixth triode 13.

The third pin c of the seventh triode 14 is provided with V1, V2 or V3.

The respective working processes of the circuits are as follows:

the desaturation detection circuit A: when the IGBT is turned off, the PWM input of the pulse width modulator is negative, the output of the first logic gate 16 is negative, the first triode 8 of the MOS tube is conducted, and no short-circuit fault signal is output; when the IGBT has a short-circuit fault, the first diode 1 is turned off, the first power supply VCC1 charges the first capacitor 22, the voltage of the third pin c of the first comparator 3 is greater than the threshold value of the voltage of the second pin b thereof, and a high-level short-circuit fault signal is output.

And an overcurrent detection circuit B: the current detection pin of the IGBT converts the collector current Ic of the IGBT into a voltage across the third resistor 25, and after filtering by the second resistor 24 and the second capacitor 21, the voltage is transmitted to the third pin c of the second comparator 4, and when the voltage value of the third pin c is greater than the overcurrent threshold value set by the second pin b, a high-level overcurrent fault signal is output.

Two-stage shutdown circuit D: when the over-current detection circuit B collects the Ic signal, and when the Ic value is between I1 and I2, the first pin a of the third comparator 5 outputs a high level, and in the logic gate control circuit C, if only one of the short-circuit fault signal or the over-current fault signal occurs, the short-circuit fault signal or the over-current fault signal passes through the second logic gate 17 and then outputs a low level, the second triode 9 is turned on, and the voltage V1 is output; when Ic is between I2 and I3, the first pin a of the fourth comparator 6 outputs a high level, the third transistor 10 is turned on, and the voltage V2 is output; when Ic is higher than I3, the first pin a of the fifth comparator 7 outputs a high level, the fourth transistor 11 is turned on, and the output voltage V3 is output.

The soft-off circuit E: when the IGBT has an overcurrent fault or a short-circuit fault, the first pin a of the eighth triode 15 inputs a high level, the eighth triode 15 is turned on, the fifth triode 12 is clamped at-8V by the second diode 2, and the fifth triode 12 is turned off; since the PWM is at a high level, the sixth transistor 13 is turned off; since the eighth transistor 15 is turned on, the seventh transistor 14 is turned on; the gate of the IGBT is discharged from 15V to the voltage of the first logic gate 16, the second logic gate 17, or the third logic gate 18 by driving the fifteenth resistor 37, and the turn-off time of the IGBT is adjusted by reasonably adjusting the driving of the fifteenth resistor 37, where the adjustment process of this part is the process of the voltage 15V dropping to the voltage of the first logic gate 16, the second logic gate 17, or the third logic gate 18 in the first soft turn-off in fig. 6. When the IGBT recovers from the short-circuit fault, the over-current fault signal or the short-circuit fault signal is at a low level, the eighth transistor 15 is turned off, because the pulse width modulator PWM is at a low level at this time, the sixth transistor 13 is turned on, the fourteenth resistor 36 is driven to control the gate of the IGBT to discharge from the voltage of the first logic gate 16 or the second logic gate 17 or the third logic gate 18 to-8V, and the turn-off time of the IGBT is adjusted by appropriately adjusting and driving the fourteenth resistor 36, where the adjustment process of this part is a process in which the voltage of the second soft turn-off in fig. 6 drops from the voltage of the first logic gate 16 or the second logic gate 17 or the third logic gate 18 to-8V.

As shown in fig. 7, for the effect of the implementation of the combination of the two-stage shutdown and the soft shutdown, it can be seen from the diagram that the voltage Vce of the collector and the emitter has the effect of two-stage shutdown, and the voltage spike Vce is reduced.

The device overcomes the defects that in single two-stage turn-off, the voltage and the duration time of a turn-off platform of a single Vge need to be selected through calibration, the voltage values and the duration times of second-stage turn-off platforms of three different vges are selected in real time according to the Ic value, and the peak of Vce during first turn-off is reduced; meanwhile, the descending slope from the peak voltage of Vge to the second-stage turn-off voltage platform and the descending slope from the second-stage turn-off voltage platform to the lowest voltage are ensured by combining a soft turn-off mode, and the peak of Vce during the second turn-off is further reduced.

The device can select the voltage and the duration of the second-stage turn-off platform of the Vge in real time according to the actual collector current Ic value, and overcomes the defect that the single voltage and the single duration of the turn-off platform of the Vge are selected in a calibration mode at present. Meanwhile, the device combines secondary turn-off and soft turn-off together, and through building a hardware circuit, short circuit and overcurrent faults are quickly reflected, so that the descending slope from the peak voltage of Vge to the secondary turn-off voltage platform and the descending slope from the secondary turn-off voltage platform to the lowest voltage are slowed down, and the peak voltage of Vce is more favorably reduced.

When a short-circuit fault occurs, the desaturation detection circuit a detects the fault and outputs a high-level short-circuit fault signal through the pin a of the first comparator 3. When an overcurrent fault occurs, the overcurrent detection circuit B detects the fault and outputs a high-level overcurrent fault signal through the pin a of the second comparator 4. Then, the second triode 9, the third triode 10 and the fourth triode 11 are controlled to be conducted by the short-circuit fault signal or the over-current fault signal through the logic gate control circuit C. Then, in the two-stage turn-off circuit D, the magnitude of the two-stage turn-off voltage of Vge is determined according to the magnitude of the collector current Ic, when the Ic value is between I1 and I2, the two-stage turn-off voltage of Vge is V1, when the Ic value is between I2 and I3, the two-stage turn-off voltage of Vge is V2, and when the Ic value is higher than I3, the two-stage turn-off voltage of Vge is V3. Finally, through the soft turn-off circuit E, when the IGBT has overcurrent fault or short-circuit fault, any voltage of platform voltages V1/V2/V3 from 15V soft turn-off to two-stage turn-off is changed by Vge; at the moment, the collector current Ic is reduced, the IGBT is recovered from the short-circuit fault, the Vge voltage is turned off to-8V from any voltage of platform voltages V1/V2/V3 of two-stage turn-off in a soft mode, the Vge voltage is adjusted in real time according to the magnitude of the Ic current, and the magnitude, duration and voltage reduction time of two-stage turn-off voltage are controlled, so that the aim of reducing a Vce voltage spike is fulfilled, and the overcurrent and short-circuit protection effects are further achieved.

Build the experiment of IGBT first kind short circuit for simulate IGBT short circuit and overflow fault, this utility model for traditional Vge turn-off mode, can be according to the Ic value of difference real-time regulation Vge's of difference size, and then make Vce appear the less turn-off voltage of two-stage, reduced Vce's spike voltage and Ic's electric current, specific effect picture is as shown in figure 7.

According to the device, the turn-off voltage of the Vge can be adjusted in real time according to the Ic, two-stage turn-off and soft turn-off modes built by a hardware circuit are combined, the turn-off voltage spike of the Vce is controlled, and the safety of the IGBT is guaranteed.

The foregoing embodiments may be modified in many different ways by those skilled in the art without departing from the spirit and scope of the invention, which is defined by the appended claims and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. An IGBT over-current and short circuit protection circuit, comprising: take current sampling device's IGBT, move back saturation detection circuitry, overflow detection circuitry, logic gate control circuit, two-stage turn-off circuit and soft turn-off circuit, wherein: the IGBT is connected with the desaturation detection circuit and the overcurrent detection circuit which are connected in parallel, and then is sequentially connected with the logic gate control circuit, the two-stage turn-off circuit and the soft turn-off circuit in series, and the logic gate control circuit is used for carrying out Vge voltage control when short circuit or overcurrent occurs, so that short circuit protection and overcurrent protection are carried out on the IGBT.

2. The IGBT overcurrent and short circuit protection circuit as set forth in claim 1, wherein the desaturation detection circuit includes: a first diode, a first resistor, and a first comparator, wherein: the first diode is connected with the port and is sequentially connected with the first resistor and the third pin of the first comparator;

a fourth pin of the first comparator is provided with a first capacitor, a first triode is arranged between a third pin of the first capacitor and the first resistor, and an eighth pin of the first capacitor is grounded;

and a first pin of the first triode is connected with the logic gate control circuit.

3. The IGBT overcurrent and short-circuit protection circuit as set forth in claim 1, wherein the overcurrent detection circuit includes: second to fourth resistors, a second capacitor, and a second comparator, wherein: the second resistor, the third resistor and the fourth resistor are connected in series, and the second capacitor is connected with the second pin of the second comparator in parallel;

and a fourth pin of the second comparator is provided with a capacitor, and an eighth pin of the second comparator is grounded.

4. The IGBT overcurrent and short circuit protection circuit of claim 1, wherein the two-stage turn-off circuit comprises: fifth to eighth resistors connected in series with the first power supply, ninth to twelfth resistors connected in series with the second power supply, third to fifth comparators, and second to fourth transistors, wherein: the first pin and the seventh pin of the third comparator are connected with the third pin of the second triode, the first pin of the second triode is connected with the logic gate control circuit, the first pin and the seventh pin of the fourth comparator are connected with the third pin of the third triode, the first pin of the third triode is connected with the logic gate control circuit, the first pin of the fifth comparator is connected with the third pin of the fourth triode, and the first pin of the fourth triode is connected with the logic gate control circuit.

5. The IGBT overcurrent and short circuit protection circuit as set forth in claim 1, wherein the logic gate control circuit includes: first to fourth logic gates, wherein: the fourth pin of the first logic gate is connected with the first pin of the first triode, the first pin and the second pin of the first logic gate are connected with the pulse width modulator, the fourth pins of the second to fourth logic gates are respectively connected with the first pins of the corresponding second to fourth triodes, the first pins of the second to fourth logic gates transmit short-circuit fault signals, the second pins of the second logic gates transmit over-current fault signals, the third pins of the second logic gates are grounded, and the fifth pins of the second logic gates are connected with the first power supply.

6. The IGBT overcurrent and short circuit protection circuit as set forth in claim 1, wherein the soft turn-off circuit includes: fifth to eighth triodes, a second diode and thirteenth to fifteenth resistors, wherein: the first pin of the eighth triode receives an overcurrent fault signal or a short-circuit fault signal transmitted by the two-stage turn-off circuit, the second pin of the eighth triode is connected with a voltage, the third pin of the eighth triode is connected with a voltage, the thirteenth resistor, the fifteenth resistor, the thirteenth resistor.