IGBT drive circuit and electrical equipment

Abstract

The embodiment of the present invention discloses an IGBT drive circuit and an electrical device, wherein the IGBT drive circuit comprises: a hardware drive subcircuit, a soft switch subcircuit and a pull-down resistor; the hardware drive subcircuit comprises a power pin, a ground pin and a drive output pin; the soft switch subcircuit comprises an input pin, a ground pin and an output pin; the power pin of the hardware drive subcircuit is connected to a power supply, the drive output pin of the hardware drive subcircuit is connected to the input pin of the soft switch subcircuit, the ground pin of the hardware drive subcircuit, the ground pin of the soft switch subcircuit, the first end of the pull-down resistor and the source of the IGBT are all grounded; the output pin of the soft switch subcircuit is connected to the second end of the pull-down resistor and the gate of the IGBT. Through the soft switch subcircuit, two Cge discharge channels are formed, which can quickly exit deep saturation, realize the adjustable hard switch and soft switch curves of the IGBT, and make the IGBT drive circuit applicable to the use requirements of various electronic devices.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of circuit technology, and in particular to an IGBT drive circuit and an electrical device. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor) is widely used in the field of power electronics due to its high power level, wide switching frequency range and fully controllable insulated gate characteristics.

[0003] During the use of IGBT, if it is turned off too quickly, it may generate excessive voltage between the drain and the source, thereby damaging the IGBT, and if the du / dt is too large, it is easy to cause EMC interference. For this reason, when turning off the IGBT, the gate drive voltage is controlled to drop to 0V or negative voltage at a certain rate, that is, a soft shutdown strategy is adopted for the IGBT. The existing soft shutdown can be achieved through an integrated driver chip (such as Aavgo's HCPL-316J) or through a discrete component circuit.

[0004] The existing soft shutdown is realized by integrated driver chip and discrete component circuit. Although the soft shutdown is realized, the soft shutdown curve is not adjustable and the applicability to different electrical equipment is not strong. Summary of the invention

[0005] The invention provides an IGBT drive circuit and an electrical device to solve the technical problems that the soft shut-off curve of the existing IGBT drive circuit is not adjustable and the applicability to different electrical devices is not strong.

[0006] In a first aspect, an embodiment of the present invention provides an IGBT driving circuit for driving an IGBT, comprising: a hardware driving subcircuit, a soft switching subcircuit and a pull-down resistor; the hardware driving subcircuit comprises a power pin, a ground pin and a driving output pin; the soft switching subcircuit comprises an input pin, a ground pin and an output pin;

[0007] The power pin of the hardware driving subcircuit is connected to the power supply, the driving output pin of the hardware driving subcircuit is connected to the input pin of the soft switching subcircuit, the ground pin of the hardware driving subcircuit, the ground pin of the soft switching subcircuit, the first end of the pull-down resistor and the source of the IGBT are all grounded; the output pin of the soft switching subcircuit is connected to the second end of the pull-down resistor and the gate of the IGBT.

[0008] Further, the soft switch subcircuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a first diode and a first transistor;

[0009] The first end of the first resistor and the first end of the first capacitor are both connected to the drive output pin of the hardware drive sub-circuit; the second end of the first resistor, the cathode of the first diode, the first end of the third resistor and the emitter of the first transistor are all connected to the gate of the IGBT; the second end of the first capacitor is connected to the first end of the second resistor; the second end of the second resistor is connected to the anode of the first diode, the second end of the third resistor and the base of the first transistor; the collector of the first transistor is connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

[0010] Furthermore, the resistance of the second resistor is 100-1000 times the resistance of the first resistor.

[0011] Furthermore, the resistance of the second resistor is 500 times the resistance of the first resistor.

[0012] Furthermore, it also includes a TVS tube or a voltage regulator tube, the cathode of the TVS tube or the voltage regulator tube is connected to the second end of the pull-down resistor, and the anode of the TVS tube or the voltage regulator tube is grounded.

[0013] Furthermore, the hardware driving subcircuit is an integrated driving chip.

[0014] Furthermore, the model of the integrated driver chip is IR4427, TLP350 or UCC27511.

[0015] Furthermore, the hardware driving sub-circuit is a discrete component circuit.

[0016] Furthermore, the hardware driving subcircuit is connected to the soft switching subcircuit via a twisted pair cable.

[0017] In a second aspect, an embodiment of the present invention provides an electrical device, comprising the IGBT driving circuit described in any one of the first aspects.

[0018] The above-mentioned IGBT driving circuit and electrical equipment include: a hardware driving subcircuit, a soft switching subcircuit and a pull-down resistor; the hardware driving subcircuit includes a power pin, a ground pin and a driving output pin; the soft switching subcircuit includes an input pin, a ground pin and an output pin; the power pin of the hardware driving subcircuit is connected to the power supply, the driving output pin of the hardware driving subcircuit is connected to the input pin of the soft switching subcircuit, the ground pin of the hardware driving subcircuit, the ground pin of the soft switching subcircuit, the first end of the pull-down resistor and the source of the IGBT are all grounded; the output pin of the soft switching subcircuit is connected to the second end of the pull-down resistor and the gate of the IGBT. Through the soft switching subcircuit, two Cge discharge channels are formed, which can quickly exit deep saturation, realize the adjustable hard switching and soft switching curves of the IGBT, and make the IGBT driving circuit applicable to the use requirements of various electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A circuit structure diagram of an IGBT driving circuit provided in an embodiment of the present invention;

[0020] Figure 2 It is a circuit structure diagram of an IGBT driving circuit in the prior art;

[0021] Figure 3 It is a schematic diagram of the first loop of the IGBT drive circuit in this scheme;

[0022] Figure 4 It is a schematic diagram of the second loop of the IGBT driving circuit in this scheme;

[0023] Figure 5 Another circuit structure diagram of the IGBT driving circuit in this solution;

[0024] Figure 6 This is the turn-off curve diagram of the IGBT drive circuit in this solution. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0026] It should be noted that due to space limitations, this application description does not list all optional implementation methods. After reading this application description, those skilled in the art should be able to understand that as long as the technical features do not contradict each other, any combination of technical features can constitute an optional implementation method.

[0027] Please refer to Figure 1, which is a circuit structure diagram of an IGBT driving circuit provided in an embodiment of the present invention. As shown in the figure, the IGBT driving circuit is used to drive the IGBT T1, and specifically includes: a hardware driving subcircuit M1, a soft switching subcircuit P1 and a pull-down resistor R5; the hardware driving subcircuit M1 includes a power pin, a ground pin and a driving output pin; the soft switching subcircuit P1 includes an input pin, a ground pin and an output pin;

[0028] The power pin of the hardware driving sub-circuit M1 is connected to the power supply, the driving output pin of the hardware driving sub-circuit M1 is connected to the input pin of the soft switching sub-circuit P1, the ground pin of the hardware driving sub-circuit M1, the ground pin of the soft switching sub-circuit P1, the first end of the pull-down resistor R5 and the source of the IGBT T1 are all grounded; the output pin of the soft switching sub-circuit P1 is connected to the second end of the pull-down resistor R5 and the gate of the IGBT T1.

[0029] When the present solution is specifically implemented, the soft switch sub-circuit P1 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor Csoft, a first diode D1 and a first transistor Q1;

[0030] The first end of the first resistor R1 and the first end of the first capacitor Csoft are both connected to the drive output pin of the hardware drive sub-circuit M1; the second end of the first resistor R1, the cathode of the first diode D1, the first end of the third resistor R3 and the emitter of the first transistor Q1 are all connected to the gate of the IGBT T1; the second end of the first capacitor Csoft is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the anode of the first diode D1, the second end of the third resistor R3 and the base of the first transistor Q1; the collector of the first transistor Q1 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is grounded.

[0031] In the prior art, Figure 2 As shown, there is only one channel that is turned off, and the gate capacitance Cge is discharged through the lower tube of the totem pole circuit 1 to turn off the IGBT T1. The IGBT drive circuit implemented in this solution has two gate capacitance Cge discharge channels, which can quickly exit deep saturation, has a soft switching function, and has the effects of a shorter discharge loop.

[0032] When implementing this solution, the resistance of the second resistor R2 can be designed to be 100-1000 times the resistance of the first resistor R1, for example 100 times, 500 times, or 1000 times. Based on the resistance design of the first resistor R2 and the first resistor R1, the soft switch sub-circuit P1 is grounded when turned on, and since the second resistor R2 is much larger than the first resistor R1, the turned-on driving current is not affected.

[0033] Please refer to Figure 3 , Figure 4 and Figure 6 , which are the discharge channel of the first circuit, the discharge channel of the second circuit and the shutdown curve of the IGBT drive circuit in this scheme, respectively. Figure 3 The bold circuit in the middle indicates the first circuit. Figure 4 The bold circuit in the middle represents the second circuit. Figure 6 H represents the hard shutdown curve, and S represents the soft shutdown curve.

[0034] In the t0-t1 phase, drive becomes low level, and the IGBT Cge has a high level drive (such as 15V), so it is discharged through the first resistor R1, and a voltage of 15V is formed on the pull-down resistor R5, so current flows through the first capacitor Csoft, and the first transistor Q1 is turned on. At this time, Cge (specific parameters of gate capacitance) is discharged through the first transistor Q1 and the lower tube of the hardware drive sub-circuit M1 in two ways (respectively as Figure 3 and Figure 4 As shown in the figure), the IGBT can quickly exit the deep saturation of the internal transistor and prepare for shutdown.

[0035] In the t1-t2 phase, the level on Cge has dropped to Vth, the first capacitor Csoft is fully charged, and no longer provides base current for the first transistor Q1. The first transistor Q1 is turned off. At this time, the electricity of Cge is only discharged through the lower tube of the hardware driving sub-circuit M1 until Vgs is lower than Vth, and the IGBT enters the off state.

[0036] In the t2-t3 phase, the lower tube of the hardware driving sub-circuit M1 continues to discharge, and reliable low-level clamping is performed to ensure that the IGBT is in the off state.

[0037] When the present solution is implemented specifically, a TVS tube or a voltage regulator tube may be further included, wherein the cathode of the TVS tube or the voltage regulator tube is connected to the second end of the pull-down resistor, and the anode of the TVS tube or the voltage regulator tube is grounded.

[0038] The hardware drive subcircuit may be an integrated drive chip or a discrete component circuit. If it is an integrated drive chip, its model may be IR4427, TLP350 or UCC27511.

[0039] When the IGBT current is large and the volume is large, it needs to be placed separately on the busbar or radiator, and the drive circuit is placed in a distant control box. The distance is too far, so a twisted pair is required for connection, that is, the hardware drive subcircuit M1 and the soft switch subcircuit P1 are connected by a twisted pair. Figure 5 As shown, Z1 in the figure is a TVS tube or a voltage regulator tube. IGBT T1 is often used in the bridge arm of the inverter. The IGBT T1 with the upper and lower bridge arms is turned on alternately. When the gate of IGBT T1 generates a level due to the Miller effect, the first transistor Q1 is at the end close to IGBT T1, not at the end of the totem pole circuit, and does not need to pass through a twisted pair, providing a shorter discharge loop, faster response time, lower level clamping, and reducing mis-conduction, which is particularly effective in increasing the reliability of the IGBT when the upper and lower bridge arms are switched alternately.

[0040] The embodiment of the present invention further provides an electrical device, including the IGBT driving circuit described above, and having corresponding technical effects.

[0041] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of further restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0042] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An IGBT driving circuit, for driving an IGBT, characterized in that: include: Hardware driver subcircuit, soft switch subcircuit and pull-down resistor; The hardware drive subcircuit includes a power pin, a ground pin and a drive output pin; The soft switch subcircuit includes an input pin, a ground pin and an output pin, and includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a first diode and a first transistor, wherein the first end of the first resistor and the first end of the first capacitor are both connected to the drive output pin of the hardware drive subcircuit; the second end of the first resistor, the cathode of the first diode, the first end of the third resistor and the emitter of the first transistor are all connected to the gate of the IGBT; the second end of the first capacitor is connected to the first end of the second resistor; the second end of the second resistor is connected to the anode of the first diode, the second end of the third resistor and the base of the first transistor; the collector of the first transistor is connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded; The power pin of the hardware driving sub-circuit is connected to the power supply, the driving output pin of the hardware driving sub-circuit is connected to the input pin of the soft switching sub-circuit, the ground pin of the hardware driving sub-circuit, the ground pin of the soft switching sub-circuit, the first end of the pull-down resistor and the source of the IGBT are all grounded; the output pin of the soft switching sub-circuit is connected to the second end of the pull-down resistor and the gate of the IGBT, and the IGBT driving circuit includes two Cge discharge channels of the gate capacitor.

2. The IGBT driving circuit according to claim 1, characterized in that: The resistance of the second resistor is 100-1000 times the resistance of the first resistor.

3. The IGBT driving circuit according to claim 2, characterized in that: The resistance of the second resistor is 500 times the resistance of the first resistor.

4. The IGBT driving circuit according to any one of claims 1 to 3, characterized in that: It also includes a TVS tube or a voltage regulator tube, the cathode of the TVS tube or the voltage regulator tube is connected to the second end of the pull-down resistor, and the anode of the TVS tube or the voltage regulator tube is grounded.

5. The IGBT driving circuit according to any one of claims 1 to 3, characterized in that: The hardware driving sub-circuit is an integrated driving chip.

6. The IGBT driving circuit according to claim 5, characterized in that: The model of the integrated driver chip is IR4427, TLP350 or UCC27511.

7. The IGBT driving circuit according to any one of claims 1 to 3, characterized in that: The hardware driving subcircuit is a discrete component circuit.

8. The IGBT driving circuit according to any one of claims 1 to 3, characterized in that: The hardware driving subcircuit is connected to the soft switching subcircuit via a twisted pair cable.

9. Electrical equipment, characterized in that The invention comprises the IGBT driving circuit as described in any one of claims 1 to 8.

Images