IGBT drive circuit based on push-pull structure

Abstract

The utility model provides an IGBT driving circuit based on a push-pull structure, and relates to the technical field of power electronic device driving, and the IGBT driving circuit comprises an optocoupler isolation module which is used for receiving a control signal and providing electrical isolation output; the push-pull driving module comprises an NPN type triode Q1 and a PNP type triode Q2 which are complementary and symmetrical; the push-pull driving module is configured as follows: when the optocoupler is conducted, Q1 is saturated and conducted, Q2 is cut off, and a driving current charges an IGBT grid electrode through R2; when the optocoupler is turned off, the Q2 is saturated and turned on, the Q1 is turned off, and the driving current flows through the R3 to discharge the grid electrode of the IGBT. Bidirectional driving current is provided through a push-pull structure, the charge charging and discharging speed of the IGBT grid electrode is increased, the switching loss is reduced, bidirectional driving current is provided through a switch-on resistor R2 and a switch-off resistor R3, the resistance value of the switch-on resistor R2 is selected to be small, the purpose of reducing switch-on loss Eon is achieved, the resistance value of the switch-off resistor R3 is selected to be large, and the purpose of reducing switch-off Vce is achieved.

Description

Technical Field

[0001] This utility model relates to the field of power electronic device drive technology, and in particular to an IGBT drive circuit based on a push-pull structure. Background Technology

[0002] In IGBT applications, the driver circuit, as a critical control module, directly affects the IGBT's performance and reliability. Current technologies commonly employ a single optocoupler drive scheme, which uses opto-isolation to isolate the control signal from the power circuit. However, single optocoupler drives have the following drawbacks:

[0003] 1. Insufficient driving capability: When driving high-current IGBT modules, the optocoupler output current is limited, making it difficult to provide sufficient gate charging current, which leads to a decrease in switching speed;

[0004] 2. High switching losses: A single drive resistor cannot optimize both the turn-on and turn-off processes, and the switching losses increase significantly with increasing current.

[0005] 3. High risk of oscillation: Parasitic inductance and current can easily cause high-frequency oscillations, threatening system stability.

[0006] To avoid these drawbacks, an IGBT drive circuit is needed that is suitable for controlling IGBT modules in high-current, high-frequency operating scenarios, so as to improve the driving capability and reduce switching losses. Utility Model Content

[0007] In view of this, in order to solve the problems of insufficient driving capability, slow switching speed, and oscillation caused by parasitic parameters when driving high-current IGBT modules, the purpose of this utility model is to propose an IGBT driving circuit based on a push-pull structure. It uses optocouplers to achieve electrical isolation between the control signal and the driving circuit, and consists of a push-pull circuit composed of complementary symmetrical NPN and PNP transistors (or MOSFETs) to amplify the driving signal. By optimizing the driving stage design, the driving current capability is improved, and the turn-on and turn-off gate resistors are separated to reduce turn-on losses and reduce the Vce voltage spike during turn-off.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] To achieve the above objectives, this utility model provides an IGBT drive circuit based on a push-pull structure, comprising:

[0010] Optical isolation module, used to receive control signals and provide electrical isolation output;

[0011] The push-pull driver module includes a complementary symmetrical NPN transistor Q1 and a PNP transistor Q2. The push-pull driver module is configured as follows:

[0012] When the optocoupler is turned on, Q1 is saturated and Q2 is turned off, and the drive current charges the IGBT gate through R2.

[0013] When the optocoupler is turned off, Q2 is saturated and Q1 is turned off, and the drive current discharges through R3 to the IGBT gate.

[0014] As a further embodiment of this utility model, the base of Q1 is connected to the output terminal of the optocoupler isolation module through the first current-limiting resistor R1, the emitter is grounded, and the collector is connected to the gate of the IGBT through the turn-on resistor R2.

[0015] The base of Q2 is connected to the output terminal of the optocoupler isolation module through the third current-limiting resistor R4, the emitter is connected to the power supply Vcc through the fourth current-limiting resistor R5, and the collector is connected to the gate of the IGBT through the turn-off resistor R3.

[0016] As a further embodiment of this utility model, the optocoupler isolation module adopts a high-speed optocoupler chip, the high-speed optocoupler chip model is TLP5701, the peak output current is ±0.6A, and the input terminal and the control signal terminal are connected through a current-limiting resistor R6.

[0017] As a further embodiment of this invention, the resistance of the turn-on resistor R2 is 2Ω to 10Ω, and it is used to adjust the turn-on speed of the IGBT.

[0018] As a further embodiment of this invention, the resistance of the turn-off resistor R3 is 10Ω to 30Ω, which is used to suppress the Vce voltage spike during turn-off.

[0019] As a further embodiment of this utility model, the push-pull drive module further includes:

[0020] The base voltage divider resistor network, including the sixth current-limiting resistor R7 and the seventh current-limiting resistor R8 connected in series, is connected between the optocoupler output and the base of Q2 to adjust the conduction threshold of Q2.

[0021] As a further embodiment of this invention, a Zener diode D1 is connected in parallel between the gate and emitter of the IGBT to limit the gate voltage amplitude.

[0022] As a further embodiment of this invention, the turn-on resistor R2 and the turn-off resistor R3 are independently adjustable, used to reduce R2 to reduce turn-on loss (Eon) and increase R3 to reduce turn-off loss (Eoff) and Vce spike.

[0023] As a further embodiment of this invention, transistors Q1 and Q2 in the push-pull drive module can be replaced with MOSFETs, wherein:

[0024] The source of the N-channel MOSFET Q1 is grounded, and its drain is connected to the gate of the IGBT through R2.

[0025] The source of the P-channel MOSFET Q2 is connected to the power supply Vcc, and the drain is connected to the gate of the IGBT through R3.

[0026] As a further embodiment of this invention, the driving circuit also includes a bootstrap power supply module, comprising a bootstrap diode D2 and a bootstrap capacitor C1, for maintaining the conduction voltage of Q2 under high voltage conditions.

[0027] Compared with existing technologies, the IGBT driving circuit based on a push-pull structure proposed in this utility model solves several technical bottlenecks of traditional single optocoupler driving schemes in high-current, high-frequency scenarios by optimizing the driver stage design and gate resistor separation technology, and has the following beneficial effects:

[0028] 1. The IGBT drive circuit based on the push-pull structure of this utility model adopts complementary symmetrical NPN and PNP transistors (or MOSFETs) to form a push-pull circuit. It realizes bidirectional drive current amplification through the switching characteristics of bipolar transistors. Compared with the traditional single optocoupler drive, the push-pull structure can provide higher gate charging and discharging current (such as ±0.6A peak current), meet the fast switching requirements of high current IGBT modules, and is especially suitable for high voltage and high power application scenarios (such as new energy inverters, motor drives, etc.), and the driving capability is significantly improved.

[0029] 2. Switching losses are significantly reduced. By independently setting a low-resistance turn-on resistor, the IGBT gate charging speed is accelerated, shortening the turn-on time and reducing turn-on losses (Eon) compared to traditional solutions. A high-resistance turn-off resistor is used to slow down the gate discharge rate, suppressing Vce voltage spikes and reducing turn-off losses (Eoff), while also reducing electromagnetic interference (EMI) during turn-off. Furthermore, the push-pull structure effectively counteracts high-frequency oscillations caused by parasitic inductance and capacitance through the dynamic complementary conduction of complementary transistors. Combined with a separate resistor design, the switching transient response is further optimized, avoiding the risk of IGBT mis-turn-on or breakdown due to parasitic parameters, thus improving system reliability.

[0030] 3. This invention provides bidirectional drive current through a push-pull structure, accelerating the charging and discharging speed of the IGBT gate charge and reducing switching losses. Furthermore, the turn-on resistor R2 has a significant impact on the turn-on loss Eon, while the turn-off resistor R3 has a smaller impact on the turn-off loss Eof. By using bidirectional drive current through the turn-on resistor R2 and the turn-off resistor R3, the value of the turn-on resistor R2 is chosen to be small to reduce the turn-on loss Eon, while the value of the turn-off resistor R3 is chosen to be large to reduce the turn-off loss Vce.

[0031] In summary, this invention, through the synergistic design of a push-pull structure and a separate gate resistor, improves driving capability while optimizing switching performance, solving the core pain points of insufficient driving, high losses, and high oscillation risk in traditional solutions. It is suitable for high-power IGBT control scenarios in fields such as new energy vehicles, industrial frequency converters, and power electronic equipment, and has significant value in energy saving, consumption reduction, and reliability improvement.

[0032] These or other aspects of this application will become more apparent from the following description of embodiments. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the application. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the accompanying drawings used in the description of the exemplary embodiments or related technologies will be briefly introduced below. The drawings are used to provide a further understanding of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain this utility model and do not constitute a limitation on this utility model. In the drawings:

[0034] Figure 1 This is a three-dimensional structural diagram of an IGBT driving circuit based on a push-pull structure according to an embodiment of the present invention.

[0035] Figure 2 This is a top view of the limiting frame in an IGBT drive circuit based on a push-pull structure according to an embodiment of the present invention. Detailed Implementation

[0036] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0037] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model are further described in detail below with reference to specific examples and the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit this application.

[0038] It should be noted that all uses of the terms "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two different entities or different parameters with the same name. Therefore, "first" and "second" are merely for convenience of expression and should not be construed as limiting the embodiments of this utility model. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as other steps or units inherent in a process, method, system, product, or device that includes a series of steps or units.

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0041] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0042] See Figure 1 and Figure 2 As shown, an embodiment of this utility model provides an IGBT driving circuit based on a push-pull structure, including an optocoupler isolation module and a push-pull driving module. The optocoupler isolation module is used to receive control signals and provide electrical isolation output. The push-pull driving module includes complementary symmetrical NPN transistor Q1 and PNP transistor Q2. The base of Q1 is connected to the output terminal of the optocoupler isolation module through a first current-limiting resistor R1, the emitter is grounded, and the collector is connected to the gate of the IGBT through an on-resistor R2. The base of Q2 is connected to the output terminal of the optocoupler isolation module through a third current-limiting resistor R4, the emitter is connected to the power supply Vcc through a fourth current-limiting resistor R5, and the collector is connected to the gate of the IGBT through a off-resistor R3.

[0043] In this embodiment, the push-pull drive module is configured such that when the optocoupler is turned on, Q1 is saturated and Q2 is turned off, and the drive current charges the IGBT gate through R2.

[0044] When the optocoupler is turned off, Q2 is saturated and Q1 is turned off, and the drive current discharges through R3 to the IGBT gate.

[0045] This invention relates to an IGBT drive circuit based on a push-pull structure. The push-pull circuit is composed of complementary symmetrical NPN and PNP transistors (or MOSFETs). It achieves bidirectional drive current amplification through the switching characteristics of bipolar transistors. Compared with traditional single optocoupler drive, the push-pull structure can provide higher gate charging and discharging current (such as ±0.6A peak current), meeting the fast switching requirements of high-current IGBT modules. It is especially suitable for high-voltage and high-power applications (such as new energy inverters, motor drives, etc.), and the driving capability is significantly improved.

[0046] In this embodiment, the optocoupler isolation module uses a high-speed optocoupler chip, model TLP5701, with an output peak current of ±0.6A. The input terminal and the control signal terminal are connected through a current-limiting resistor R6. The turn-on resistor R2 has a resistance of 2Ω to 10Ω and is used to adjust the IGBT turn-on speed; the turn-off resistor R3 has a resistance of 10Ω to 30Ω and is used to suppress Vce voltage spikes during turn-off.

[0047] In some embodiments, the push-pull drive module further includes: a base voltage divider resistor network, comprising a sixth current-limiting resistor R7 and a seventh current-limiting resistor R8 connected in series, connected between the optocoupler output terminal and the base of Q2, for adjusting the conduction threshold of Q2. A Zener diode D1 is connected in parallel between the gate and emitter of the IGBT for limiting the gate voltage amplitude.

[0048] In this embodiment, the turn-on resistor R2 and the turn-off resistor R3 are adjusted independently to reduce R2 to decrease the turn-on loss (Eon) and increase R3 to reduce the turn-off loss (Eoff) and Vce spike.

[0049] This invention provides bidirectional drive current through a push-pull structure, accelerating the charging and discharging speed of the IGBT gate charge and reducing switching losses. Furthermore, from... Figure 2 The curve of IGBT switching loss versus gate resistance shows that the turn-on resistor R2 has a significant impact on the turn-on loss Eon, while the turn-off resistor R3 has a small impact on the turn-off loss Eof. Specifically, the turn-on loss Eon = f(R... G ), Turn-off loss Eof=f(R) G ), V GE =±15V, I C =300A, V CE =600V; The bidirectional current is driven by the turn-on resistor R2 and the turn-off resistor R3. The value of the turn-on resistor R2 is selected to reduce the turn-on loss Eon, and the value of the turn-off resistor R3 is selected to reduce the turn-off loss Vce.

[0050] In some embodiments, transistors Q1 and Q2 in the push-pull drive module can be replaced with MOSFETs, wherein:

[0051] The source of the N-channel MOSFET Q1 is grounded, and its drain is connected to the gate of the IGBT through R2.

[0052] The source of the P-channel MOSFET Q2 is connected to the power supply Vcc, and the drain is connected to the gate of the IGBT through R3.

[0053] In some embodiments, the driving circuit further includes a bootstrap power supply module, comprising a bootstrap diode D2 and a bootstrap capacitor C1, for maintaining the conduction voltage of Q2 under high voltage conditions.

[0054] In this invention, switching losses are significantly reduced. By independently setting a low-resistance turn-on resistor, the IGBT gate charging speed is accelerated, shortening the turn-on time and reducing turn-on losses (Eon) compared to traditional solutions. A high-resistance turn-off resistor is used to slow down the gate discharge rate, suppressing Vce voltage spikes and reducing turn-off losses (Eoff), while also reducing electromagnetic interference (EMI) during turn-off. Furthermore, the push-pull structure effectively counteracts high-frequency oscillations caused by parasitic inductance and capacitance through the dynamic complementary conduction of complementary transistors. Combined with a separate resistor design, the switching transient response is further optimized, avoiding the risk of IGBT mis-turn-on or breakdown due to parasitic parameters and improving system reliability.

[0055] In summary, this utility model presents an IGBT drive circuit based on a push-pull structure. It employs optocouplers to achieve electrical isolation between the control signal and the drive circuit. A push-pull circuit, composed of complementary symmetrical NPN and PNP transistors (or MOSFETs), amplifies the drive signal. By optimizing the drive stage design, the drive current capability is improved. Separating the turn-on and turn-off gate resistors reduces turn-on losses and the turn-off Vce voltage spike. The push-pull circuit, composed of complementary symmetrical NPN (Q1) and PNP (Q2) transistors with selectable current, amplifies the drive signal. Through the synergistic design of the push-pull structure and the separated gate resistors, the drive capability is enhanced while the switching performance is optimized. This solves the core pain points of traditional solutions, such as insufficient drive, high losses, and high oscillation risk. It is suitable for high-power IGBT control scenarios in fields such as new energy vehicles, industrial frequency converters, and power electronic equipment, and has significant value in energy saving, consumption reduction, and reliability improvement.

[0056] The above are exemplary embodiments disclosed in this utility model. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this utility model as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this utility model may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0057] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the framework of the present invention, technical features of the above embodiments or different embodiments can also be combined, and many other variations of different aspects of the present invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An IGBT driving circuit based on a push-pull structure, characterized in that, include: Optical isolation module, used to receive control signals and provide electrical isolation output; The push-pull driver module includes a complementary symmetrical NPN transistor Q1 and a PNP transistor Q2. The push-pull driver module is configured as follows: When the optocoupler is turned on, Q1 is saturated and Q2 is turned off, and the drive current charges the IGBT gate through R2. When the optocoupler is turned off, Q2 is saturated and Q1 is turned off, and the drive current discharges through R3 to the IGBT gate.

2. The IGBT drive circuit based on a push-pull structure as described in claim 1, characterized in that, The base of Q1 is connected to the output terminal of the optocoupler isolation module through the first current-limiting resistor R1, the emitter is grounded, and the collector is connected to the gate of the IGBT through the turn-on resistor R2. The base of Q2 is connected to the output terminal of the optocoupler isolation module through the third current-limiting resistor R4, the emitter is connected to the power supply Vcc through the fourth current-limiting resistor R5, and the collector is connected to the gate of the IGBT through the turn-off resistor R3.

3. The IGBT drive circuit based on a push-pull structure as described in claim 2, characterized in that, The optocoupler isolation module uses a high-speed optocoupler chip, model TLP5701, with a peak output current of ±0.6A. The input terminal and the control signal terminal are connected through a current-limiting resistor R6.

4. The IGBT drive circuit based on a push-pull structure as described in claim 2, characterized in that, The resistance of the turn-on resistor R2 is 2Ω to 10Ω, and it is used to adjust the turn-on speed of the IGBT.

5. The IGBT drive circuit based on a push-pull structure as described in claim 4, characterized in that, The resistance of the turn-off resistor R3 is 10Ω to 30Ω, and it is used to suppress the Vce voltage spike when the circuit is turned off.

6. The IGBT drive circuit based on a push-pull structure as described in claim 1, characterized in that, The push-pull drive module also includes: The base voltage divider resistor network, including the sixth current-limiting resistor R7 and the seventh current-limiting resistor R8 connected in series, is connected between the optocoupler output and the base of Q2 to adjust the conduction threshold of Q2.

7. The IGBT drive circuit based on a push-pull structure as described in claim 6, characterized in that, A Zener diode D1 is connected in parallel between the gate and emitter of the IGBT to limit the gate voltage amplitude.

8. The IGBT drive circuit based on a push-pull structure as described in claim 1, characterized in that, The transistors Q1 and Q2 in the push-pull drive module can be replaced with MOSFETs, wherein: The source of the N-channel MOSFET Q1 is grounded, and its drain is connected to the gate of the IGBT through R2. The source of the P-channel MOSFET Q2 is connected to the power supply Vcc, and the drain is connected to the gate of the IGBT through R3.

9. The IGBT drive circuit based on a push-pull structure as described in claim 1, characterized in that, The driving circuit also includes a bootstrap power supply module, which includes a bootstrap diode D2 and a bootstrap capacitor C1, used to maintain the conduction voltage of Q2 under high voltage conditions.

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