CN211266458U

CN211266458U - SiC IGBT driving and protecting system

Info

Publication number: CN211266458U
Application number: CN202020114335.7U
Authority: CN
Inventors: 刘蕾; 徐启轮; 苑红伟; 周政
Original assignee: Hefei JEE Power System Co Ltd
Current assignee: Hefei JEE Power System Co Ltd
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2020-08-14
Anticipated expiration: 2030-01-19

Abstract

The utility model discloses a SiC IGBT driving and protecting system, which comprises an integrated control unit, wherein a driving unit, a Miller clamping unit and a short circuit soft turn-off unit are integrated outside the control unit; an output pin VO of the driving unit is connected with a grid IGBT _ HG of the IGBT through a driving circuit; an output pin MC of the Miller clamping unit is connected with a grid IGBT _ HG of the IGBT through a driving level detection circuit; the emitter IGBT _ HE and the collector IGBT _ HC of the IGBT are connected through a short circuit detection circuit, the output end of the short circuit detection circuit is connected with a detection pin DESAT of a short circuit soft turn-off unit, and an output control pin SSD of the short circuit soft turn-off unit is connected with a gate IGBT _ HG of the IGBT. According to the scheme, the Miller clamping function and the soft turn-off function are separated according to the characteristics of the SiC IGBT module, an external circuit is simplified, and the Miller clamping and soft turn-off functions are realized according to the working area of the SiC module.

Description

SiC IGBT driving and protecting system

Technical Field

The utility model relates to a SiC IGBT device, in particular to SiC IGBT drive and protection system.

Background

When the SiC IGBT module in the motor controller has Vce overvoltage, short circuit, drive overvoltage and drive undervoltage faults, the four faults are detected. No matter which fault phenomenon occurs, the motor controller can enter an active protection state; the driving signal of the IGBT enters the FO state, and the PWM signal is closed to ensure the safety of the vehicle; the prior art scheme includes:

(1) the method comprises the following steps that Vce overvoltage fault is carried out, the voltage of the SiC IGBT module when spike voltage is generated between a source electrode and a drain electrode is compared with active clamping, when the voltage between the source electrode and the drain electrode is larger than the active clamping voltage, the active clamping function acts, and the source electrode-drain electrode voltage is clamped between the active clamping action voltages;

(2) driving an undervoltage fault, when the controller works normally, monitoring a driving level in real time by a driving chip of six three-phase bridge arms of the SiC IGBT module, judging by the driving chip, when the driving level is lower than a set threshold value, enabling a control part of the driving chip to act, closing a PWM (pulse-width modulation) wave of the driving chip, enabling the controller to enter an ACS (auto-switching) mode, and enabling the driving chip to report the undervoltage fault;

(3) and when the controller works normally due to short circuit fault, the driving chip monitors the SiC IGBT module in real time through the DESAT pin. When the source electrode-drain voltage of the SiC IGBT is increased, the DESAT pin generates a voltage value, if the voltage value exceeds the threshold voltage of the DESAT pin, the driving chip enters a short-circuit state, FO is reported, PWM waves are closed, the controller enters the ASC module, and damage to circuits and devices due to overlarge current is avoided.

The prior art mainly has the following defects:

(1) the existing driving chip has a magnetic isolation scheme 1EDI20H12AH-FB of Yingfei and a capacitive isolation scheme UCC21750 of TI, the two schemes realize positive voltage 15V driving by reducing the transmission delay of PWM signals of the original secondary side and increasing CMI, and a CLAMP pin is used for monitoring driving waveforms and realizing a Miller CLAMP function when the driving chip is normally turned off. When short-circuit fault occurs, the 1EDI20H12AH-FB controls PWM wave through a driving chip and directly closes the PWM wave to enter an FO state; the UCC21750 controls the CLAMP pin through the driving chip, and generates a high-resistance state in the turn-off process so as to close the source-drain stage of the SiC module.

(3) When the existing driver outputs high-level pulse through VO, the existing driver is connected to IGBT _ HG through a P-type triode, and at the moment, the P-type triode is conducted to generate 0.7V voltage drop. The gate-drain of the P-type transistor generates a large voltage during the turn-off of the IGBT and damages the P-type transistor.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the purpose is: a positive 18V driving level is used when a driving chip is normally driven, Miller clamping is achieved through an MC pin when a PWM wave is normally turned off, and the PWM wave is turned off in a high-resistance state that the SSD pin is turned off when a short-circuit fault occurs.

The technical scheme of the utility model is that:

a SiC IGBT driving and protecting system comprises an integrated control unit, wherein a driving unit, a Miller clamping unit and a short-circuit soft turn-off unit are integrated outside the control unit; an output pin VO of the driving unit is connected with a grid IGBT _ HG of the IGBT through a driving circuit; an output pin MC of the Miller clamping unit is connected with a grid IGBT _ HG of the IGBT through a driving level detection circuit; the emitter IGBT _ HE and the collector IGBT _ HC of the IGBT are connected through a short circuit detection circuit, the output end of the short circuit detection circuit is connected with a detection pin DESAT of a short circuit soft turn-off unit, and an output control pin SSD of the short circuit soft turn-off unit is connected with a gate IGBT _ HG of the IGBT.

Preferably, the miller clamping unit comprises a switch tube T4 and a comparator U5, the driving level detection circuit comprises a resistor R6, a gate IGBT _ HG of the IGBT is connected with a pin MC through R6, the pin MC and the VEE2 are respectively connected with two ends of the switch tube T4 and two-phase input ends of the comparator U5, an output end of the comparator U5 is connected with the control unit, when the driving level is detected to be lower than +2V of the VEE2 level, the control unit controls the switch tube T4 to be turned on, so that the potential of the IGBT _ HG is the same as the potential at the VEE2, and the IGBT is turned off.

Preferably, the short circuit detection circuit comprises a capacitor C1, diodes D1, D2 and a resistor R1, wherein the capacitor C1, the resistor R1 and the diode D2 are sequentially connected in series, one end of the capacitor C1 is connected with an IGBT _ HE, a cathode of the diode D2 is connected with an IGBT _ HC, the diode D1 is connected with the capacitor C1 in parallel, and a common node of the capacitor C1 and the resistor R1 serves as an output end to be connected with a pin DESAT.

Preferably, the short-circuit soft turn-off unit comprises switch tubes T1 and T5, a comparator U3 and a not gate U4, pins DESAT and VE are respectively connected with two ends of the switch tube T1 and two-phase input ends of the comparator U3, an output end of the comparator U3 is connected with the control unit, and the control unit is connected with a control end of the switch tube T1 through the not gate U4; the control unit is connected with a control switch tube T5, two ends of the T5 are respectively connected with a pin SSD and a VEE2, and the pin SSD is directly connected with a grid IGBT _ HG of the IGBT.

Preferably, the driving circuit comprises a P-type triode Q1, an N-type triode Q2, resistors R2-R5, and diodes D3 and D4, wherein one end of the resistor R2 is connected to the driving pin VO, the other end of the resistor R2 is connected to the bases of the triodes Q1 and Q2, the collectors of the triodes Q1 and Q2 are connected to the power supply terminal VCC2 and the pin VEE2, the emitters are in common junction, the resistor R3 is connected between the emitter and the base of the common junction, the cathodes of the diodes D3 and D4 are in common junction, the resistors R4 and R5 are connected in parallel, the anode of the diode D3 is connected to the emitter of the diode, and the anode of the diode D4 is connected to the.

Preferably, the driving unit comprises two switching tubes T2 and T3 which are connected in series, the switching tubes T2 and T3 are connected with a pin VO in a common junction mode, the other end of the switching tube T2 is connected with VCC2, and the other end of the switching tube T3 is connected with VEE 2.

The utility model has the advantages that:

1. the utility model discloses the scheme separates Miller's clamp function and soft turn-off function according to the characteristic of SiC IGBT module, simplifies the external circuit, realizes Miller's clamp and soft turn-off function according to the work area of SiC module;

2. the utility model discloses the scheme reduces when the SiC IGBT module is opened because the voltage difference value that Q1 produced to effectively protect Q1 triode, prevent to lead to drive circuit to damage because grid-drain voltage punctures.

Drawings

The invention will be further described with reference to the following drawings and examples:

fig. 1 is a schematic diagram of the SiC IGBT driving and protecting system of the present invention.

Detailed Description

As shown in fig. 1, the SiC IGBT driving and protecting system of the present invention includes an integrated control unit, which is further integrated with a driving unit, a miller clamping unit, and a short circuit soft turn-off unit; an output pin VO of the driving unit is connected with a grid IGBT _ HG of the IGBT through a driving circuit; an output pin MC of the Miller clamping unit is connected with a grid IGBT _ HG of the IGBT through a driving level detection circuit; the emitter IGBT _ HE and the collector IGBT _ HC of the IGBT are connected through a short circuit detection circuit, the output end of the short circuit detection circuit is connected with a detection pin DESAT of a short circuit soft turn-off unit, and an output control pin SSD of the short circuit soft turn-off unit is connected with a gate IGBT _ HG of the IGBT. The driving chip uses positive 18V driving level when driving normally, and the Miller clamp is realized through MC base pin when PWM ripples are normally shut off, and the PWM ripples are closed through the high resistance state that SSD base pin realized shutting off when short circuit fault takes place.

The Miller clamping unit comprises a switch tube T4 and a comparator U5, a driving level detection circuit comprises a resistor R6, a grid IGBT _ HG of the IGBT is connected with a pin MC through an R6, the pin MC and a VEE2 are respectively connected with two ends of a switch tube T4 and two-phase input ends of a comparator U5, the output end of the comparator U5 is connected with a Control unit, when the driving level is detected to be lower than +2V of the level of the VEE2, the MC pin triggers the Miller Control, the Control unit controls a switch tube T4 to be conducted, the potential of the IGBT _ HG is the same as the potential of the VEE2, and the IGBT is reliably turned off.

The short circuit detection circuit comprises a capacitor C1, diodes D1, D2 and a resistor R1, wherein the capacitor C1, the resistor R1 and the diode D2 are sequentially connected in series, one end of the capacitor C1 is connected with an IGBT _ HE, the cathode of the diode D2 is connected with an IGBT _ HC, the diode D1 is connected with the capacitor C1 in parallel, and the common node of the capacitor C1 and the resistor R1 serves as an output end to be connected with a base pin DESAT. The short-circuit soft turn-off unit comprises switch tubes T1 and T5, a comparator U3 and a NOT gate U4, pins DESAT and VE are respectively connected with two ends of the switch tube T1 and two-phase input ends of the comparator U3, the output end of the comparator U3 is connected with the control unit, and the control unit is connected with the control end of the switch tube T1 through the NOT gate U4; the control unit is connected with a control switch tube T5, two ends of the T5 are respectively connected with a pin SSD and a VEE2, and the pin SSD is directly connected with a grid IGBT _ HG of the IGBT. When the IGBT is short-circuited, the voltage between the source electrode and the drain electrode is increased, the voltage at the two ends of the C1 is increased, and when the DESAT pin detects that the level is higher than 7V, the control part turns off the VO output, and Q1 and Q2 are in a closed state. The Control part controls the conduction of the triode T5 through the SSD Control, so that the SiC IGBT _ HG is closed in a high-resistance state, and the peak voltage generated by the SiIGBT due to short circuit is low, so that the SiC IGBT cannot be damaged.

The driving circuit comprises triodes Q1 and Q2, resistors R2-R5, and diodes D3 and D4, wherein one end of a resistor R2 is connected with a driving pin VO, the other end of the resistor R2 is respectively connected with bases of the triodes Q1 and Q2, collectors of the triodes Q1 and Q2 are respectively connected with a power supply terminal VCC2 and a pin VEE2, emitters are in common junction, a resistor R3 is connected between an emitter and a base of the common junction, cathodes of the diodes D3 and D4 are in common junction, the resistors R4 and R5 are respectively connected in parallel, anodes of the D3 are connected with emitters of two triodes, and an anode of D4 is connected with a grid IGBT _ HG of. The driving unit comprises two switching tubes T2 and T3 which are connected in series, the switching tubes T2 and T3 are connected with a pin VO in a common junction mode, the other end of the switching tube T2 is connected with VCC2, and the other end of the switching tube T3 is connected with VEE 2.

When the SiIGBT normally works, the VO outputs high level, T2 is switched on, Q1 is switched on, T3 and Q2 are switched off, the level between IGBT _ HG and IGBT _ HE is 18V, and at the moment, the SiIGBT normally works. When VO outputs low level, T2 and Q1 are closed, T3 and Q2 are opened, the level between IGBT _ HG and IGBT _ HE is negative level, and the SiC IGBT is reliably turned off at the moment.

When the voltage regulator is normally switched on, the VO outputs a high-level pulse, the Q1 is switched on, the Q2 is switched off, at the moment, the VCC2 passes through the Q1, the D3 and the R5 to the IGBT _ HG, the level of the IGBT _ HG and the IGBT _ HE is +18V, and the voltage difference generated when the triode Q1 is switched on is eliminated through the resistor R3.

Diode D3 is used to protect P-type transistor Q1 from the gate-drain voltage of Q1 when the SiC IGBT is turned off, thereby preventing Q1 from being damaged. According to the scheme, when the SiC module is normally turned off, Q1 is turned off, Q2 is turned on, and current passes through D4, R4, Q2 to VEE2, so that high voltage generated at two ends of a grid electrode and a drain electrode of Q1 can be prevented from damaging Q1 when the SiC module is turned off.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All modifications made according to the spirit of the main technical scheme of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A SiC IGBT driving and protecting system is characterized by comprising an integrated control unit, wherein a driving unit, a Miller clamping unit and a short-circuit soft turn-off unit are integrated outside the control unit; an output pin VO of the driving unit is connected with a grid IGBT _ HG of the IGBT through a driving circuit; an output pin MC of the Miller clamping unit is connected with a grid IGBT _ HG of the IGBT through a driving level detection circuit; the emitter IGBT _ HE and the collector IGBT _ HC of the IGBT are connected through a short circuit detection circuit, the output end of the short circuit detection circuit is connected with a detection pin DESAT of a short circuit soft turn-off unit, and an output control pin SSD of the short circuit soft turn-off unit is connected with a gate IGBT _ HG of the IGBT.

2. The SiC IGBT driving and protection system of claim 1, wherein the Miller clamp unit comprises a switch tube T4 and a comparator U5, the driving level detection circuit comprises a resistor R6, a gate IGBT _ HG of the IGBT is connected with a pin MC through an R6, the pin MC and a VEE2 are respectively connected with two ends of a switch tube T4 and two-phase input ends of a comparator U5, an output end of the comparator U5 is connected with the control unit, when the driving level is detected to be lower than +2V of the VEE2 level, the control unit controls the switch tube T4 to be conducted, the potential of the IGBT _ HG is enabled to be the same as the potential at the VEE2, and the IGBT is turned off.

3. The SiC IGBT driving and protection system of claim 2, wherein the short circuit detection circuit comprises a capacitor C1, diodes D1, D2 and a resistor R1, the capacitor C1, the resistor R1 and the diode D2 are sequentially connected in series, one end of the capacitor C1 is connected with an IGBT _ HE, the cathode of the diode D2 is connected with an IGBT _ HC, the diode D1 is connected with the capacitor C1 in parallel, and the common node of the capacitor C1 and the resistor R1 serves as an output end to be connected with a DESAT pin.

4. The SiC IGBT driving and protecting system of claim 3, wherein the short-circuit soft turn-off unit comprises switch tubes T1 and T5, a comparator U3 and a NOT gate U4, pins DESAT and VE are respectively connected with two ends of the switch tube T1 and two phase input ends of the comparator U3, an output end of the comparator U3 is connected with the control unit, and the control unit is connected with a control end of the switch tube T1 through the NOT gate U4; the control unit is connected with a control switch tube T5, two ends of the T5 are respectively connected with a pin SSD and a VEE2, and the pin SSD is directly connected with a grid IGBT _ HG of the IGBT.

5. The SiC IGBT driving and protection system of claim 4, wherein the driving circuit comprises a P-type triode Q1, an N-type triode Q2, resistors R2-R5, and diodes D3 and D4, wherein one end of a resistor R2 is connected with the driving pin VO, the other end is connected with the bases of the triodes Q1 and Q2 respectively, the collectors of the triodes Q1 and Q2 are connected with the power supply terminal VCC2 and the pin VEE2 respectively, the emitters are in common junction, a resistor R3 is connected between the emitter and the base of the common junction, the cathodes of the diodes D3 and D4 are in common junction, the parallel resistors R4 and R5 are connected in parallel, the anode of the D3 is connected with the emitter of the triode, and the anode of the D4 is connected with the grid IGBT _ HG of the IGBT.

6. The SiC IGBT driving and protection system of claim 5, wherein the driving unit comprises two serially connected switching tubes T2 and T3, the switching tubes T2 and T3 are connected with a pin VO in a common junction mode, the other end of the switching tube T2 is connected with a VCC2, and the other end of the switching tube T3 is connected with a VEE 2.