Multi-stage amplification controlled igbt driving circuit and control method thereof

Abstract

The application discloses a kind of multistage amplification control IGBT drive circuit and control method thereof, including input signal photoelectric coupler isolation module, input signal multistage amplification control module, push-pull amplifier circuit module and overcurrent detection protection module.Photoelectric coupler isolation module is isolated input PWM signal by photoelectric coupler;Multistage amplification control module carries out multistage amplification and level conversion to isolated signal by the cascaded conduction relationship of multistage triode, and outputs intermediate PWM signal;Push-pull amplifier circuit module carries out push-pull amplification using push-pull triode, and outputs PWM drive signal to IGBT gate;When overcurrent is detected, overcurrent detection protection module triggers protection trigger triode and signal clamping triode to conduct, and the output signal of photoelectric coupler isolation module is clamped to drive power supply.The application improves driving capacity and level conversion capacity, and realizes the overcurrent protection of fast linkage, improves circuit reliability.

Description

Technical Field

[0001] This invention belongs to the field of power circuit driving technology, specifically relating to a multi-stage amplification control IGBT driving circuit and its control method. Background Technology

[0002] An insulated-gate bipolar transistor (IGBT) is a three-terminal composite semiconductor device consisting of a gate, collector, and emitter. It combines the advantages of power transistors and electric field-effect transistors, and its on / off state is controlled by the gate voltage. It features high input impedance and low conduction loss characteristics, and is widely used in photovoltaic inverters, new energy vehicle electronic control systems, and industrial frequency conversion equipment.

[0003] The high-frequency characteristics of IGBT devices make their drive circuits susceptible to parasitic parameters, leading to gate-source voltage waveform oscillations and drain-source voltage overshoot. Therefore, high demands are placed on the drive circuit: a high gate drive voltage is required to ensure smooth device turn-on; a negative voltage is needed for turn-off to prevent false triggering; fast rise and fall edges are required, along with a sufficiently large drive current to overcome gate capacitance and accommodate high-frequency switching; furthermore, high-frequency operation can easily cause bridge arm crosstalk, necessitating methods such as Miller clamping to limit voltage spikes.

[0004] Currently, drive circuits for high-power IGBTs typically employ negative voltage turn-off combined with Miller clamping. Miller clamping is generally divided into active Miller clamping and passive Miller clamping: Active Miller clamping involves a separate branch at the gate controlled by a transistor, which conducts during the IGBT's turn-off cycle, directly connecting the negative voltage source to the gate to lower the gate voltage during turn-off; Passive Miller clamping uses a Zener diode connected in parallel between the gate and source. When the Miller phenomenon occurs and a voltage spike is generated at the gate, the Zener diode is reverse-broken down, forming a low-impedance loop that bypasses the Miller current.

[0005] However, this existing drive circuit has the following drawbacks in practical applications: Existing circuits mostly employ single-stage control, which has limited driving capability and relatively small driving current. In high-voltage, high-power, or high-frequency switching applications, single-stage control struggles to rapidly charge and discharge the gate capacitor, prolonging the capacitor charging time, increasing unnecessary switching losses, and exhibiting poor stability at high frequencies.

[0006] Existing circuits have limited level conversion capabilities and impose certain requirements on the voltage amplitude of the input PWM signal, making them difficult to flexibly adapt to control signal applications with various level standards.

[0007] Existing circuits lack integrated drive and protection loops, and usually require the addition of external circuits to achieve functions such as overcurrent protection. This not only increases the complexity of the circuit, but also makes it difficult to guarantee the response speed of protection actions and the reliability of linkage control when overcurrent occurs. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing IGBT drive circuits in achieving efficient and reliable IGBT drive, thereby providing an IGBT drive circuit with multi-stage amplification control and its control method.

[0009] An IGBT driver circuit with multi-stage amplification control includes an input signal optocoupler isolation module, an input signal multi-stage amplification control module, a push-pull amplifier circuit module, and an overcurrent detection and protection module. The input signal optocoupler isolation module includes a first optocoupler U1, the signal input terminal of the first optocoupler U1 is connected to the PWM signal input, and the signal output terminal is connected to the input signal multi-stage amplification control module; The input signal multi-stage amplification control module includes a second transistor Q2, a third transistor Q3, a sixth transistor Q6, and a seventh transistor Q7. The base of the second transistor Q2 is connected to the signal output terminal of the first optocoupler U1, its collector is connected to the driving power supply DP+, and its emitter is connected to the base of the seventh transistor Q7. The collector of the seventh transistor Q7 is connected to the signal output terminal of the first optocoupler U1, and its emitter is connected to the negative voltage power supply DP-. The base of the third transistor Q3 is connected to the collector of the second transistor Q2, its emitter is connected to the negative voltage power supply DP-, and its collector is connected to the base of the sixth transistor Q6. The emitter of the sixth transistor Q6 is connected to the negative voltage power supply DP-, and its collector forms an intermediate PWM signal output terminal. The push-pull amplifier circuit module includes a fourth transistor Q4 and a fifth transistor Q5; the bases of the fourth transistor Q4 and the fifth transistor Q5 are connected to the intermediate PWM signal output terminal, the collector of the fourth transistor Q4 is connected to the driving power supply DP+, the collector of the fifth transistor Q5 is connected to the negative voltage power supply DP-, and the emitters of the fourth transistor Q4 and the fifth transistor Q5 are connected to form a PWM driving signal output terminal to connect to the IGBT gate; The overcurrent detection and protection module includes an eighth transistor Q8 and a ninth transistor Q9; the voltage VCE between the collector and emitter of the IGBT is connected to the base of the eighth transistor Q8; the collector of the eighth transistor Q8 is connected to the base of the ninth transistor Q9, and the collector of the ninth transistor Q9 is connected to the signal output terminal of the first optocoupler U1, which is used to clamp the output signal of the first optocoupler U1 to the drive power supply DP+ during overcurrent.

[0010] Furthermore, the input signal multi-stage amplification control module also includes a first transistor Q1 and an eleventh transistor Q11; The bases of the first transistor Q1 and the eleventh transistor Q11 are connected to the signal output terminal of the first optocoupler U1, and the emitters are connected to the driving power supply DP+. The collector of the first transistor Q1 is connected to the intermediate PWM signal output terminal. The collector of the eleventh transistor Q11 is connected to the voltage VCE between the collector and emitter of the IGBT.

[0011] Furthermore, the push-pull amplifier circuit module also includes a first decoupling capacitor C1, a second decoupling capacitor C2, and a Zener diode D3; The first decoupling capacitor C1 is connected between the drive power supply DP+ and the negative voltage power supply DP-. The first end of the second decoupling capacitor C2 is connected to the base of the fourth transistor Q4 and the fifth transistor Q5, and the second end is connected to the negative voltage power supply DP-. The negative terminal of the Zener diode D3 is connected to the base of the fourth transistor Q4 and the fifth transistor Q5, and the positive terminal is connected to the negative voltage power supply DP-.

[0012] Furthermore, the overcurrent detection and protection module also includes a thirteenth transistor Q10; The base of the thirteenth transistor Q10 is connected to the fault signal output terminal, the emitter is connected to the negative voltage power supply DP-, and the collector is connected to the base of the eighth transistor Q8.

[0013] Furthermore, it also includes a fourth diode D4, the anode of which is connected to the voltage VCE between the collector and emitter of the IGBT, and the cathode is connected to the intermediate PWM signal output terminal.

[0014] A control method for an IGBT drive circuit based on the above-mentioned multi-stage amplification control is characterized by comprising the following steps: The input signal optocoupler isolation module receives the external PWM input signal, which is then isolated by the first optocoupler U1 and output to the input signal multi-stage amplification and control module. The input signal multi-stage amplification control module utilizes the cascaded conduction relationship of the second transistor Q2, the third transistor Q3, the sixth transistor Q6, and the seventh transistor Q7 to perform multi-stage amplification and level conversion on the isolated signal, and output the intermediate PWM signal; The push-pull amplifier circuit module receives the intermediate PWM signal, uses the fourth transistor Q4 and the fifth transistor Q5 for push-pull amplification, and outputs the PWM drive signal to the IGBT gate. The overcurrent detection and protection module detects the voltage VCE between the collector and emitter of the IGBT. When VCE exceeds the preset threshold, it triggers the eighth transistor Q8 to turn on, which in turn turns on the ninth transistor Q9, connecting the signal output terminal of the first optocoupler U1 to the drive power supply DP+.

[0015] Furthermore, when the first optocoupler U1 outputs a low-level signal, the second transistor Q2 is turned on, and the third transistor Q3 and the seventh transistor Q7 are also turned on. The seventh transistor Q7 provides a freewheeling circuit, and the turn-on of the third transistor Q3 connects the base of the sixth transistor Q6 to the negative voltage power supply DP-, thus turning it off. When the first optocoupler U1 outputs a high-level signal, the second transistor Q2 is turned off, the third transistor Q3 is turned off, and the base of the sixth transistor Q6 is connected to the driving power supply DP+ through a resistor, thus turning it on. The negative voltage power supply DP- is output to the intermediate PWM signal via the sixth transistor Q6.

[0016] Furthermore, when the first optocoupler U1 outputs a low-level signal, the first transistor Q1 and the eleventh transistor Q11 are turned on, and the drive power supply DP+ is output to the intermediate PWM signal through the first transistor Q1.

[0017] Furthermore, when the intermediate PWM signal is at a positive level, the fourth transistor Q4 is turned on, and the driving power supply DP+ is connected to the PWM driving signal output terminal; when the intermediate PWM signal is at a negative level, the fifth transistor Q5 is turned on, and the negative voltage power supply DP- is connected to the PWM driving signal output terminal; during the IGBT turn-off cycle, the fifth transistor Q5 connects the IGBT gate to the negative voltage power supply DP-.

[0018] Furthermore, when an overcurrent occurs, the voltage VCE between the collector and emitter of the IGBT increases, causing the eighth transistor Q8 to conduct, which in turn lowers the base voltage of the ninth transistor Q9, causing Q9 to conduct. The drive power supply DP+ is connected to the signal output terminal of the first optocoupler U1 through the ninth transistor Q9. The voltage at the fault signal output terminal is pulled low, causing the thirteenth transistor Q10 to conduct, forming a loop from the drive power supply DP+ to the negative voltage power supply DP-.

[0019] Beneficial Effects: This invention discloses a multi-stage amplification control IGBT driving circuit and its control method. It employs a multi-stage input signal amplification control module containing multiple transistors, using the cascaded conduction relationship of these transistors to amplify and level-convert the input signal in multiple stages. This structure overcomes the limitation of small drive current in existing single-stage control circuits, achieving extremely high current gain and enabling the output of large drive current. It is suitable not only for high-voltage, high-power applications but also possesses excellent level-conversion capabilities, meeting the amplitude requirements of various input signals.

[0020] The push-pull amplifier circuit module of this invention utilizes two transistors to form a push-pull structure, resulting in a low output impedance of the drive circuit, enabling it to provide a large output current and strong load-driving capability. Furthermore, during the IGBT's turn-off cycle, the lower push-pull transistor conducts, directly connecting the IGBT gate to a negative voltage power supply without an intermediate turn-off resistor. This allows the gate voltage to be pulled very low, effectively mitigating the Miller effect and preventing the IGBT from mis-turning on.

[0021] The overcurrent detection and protection module of this invention detects the voltage VCE between the collector and emitter of the IGBT. When an overcurrent occurs, it triggers the protection transistor to conduct, which in turn turns on the signal clamping transistor. The signal clamping transistor directly clamps the signal output of the optocoupler isolation module to the drive power supply, isolating the positive level portion of the intermediate PWM signal at the signal source, thus keeping the IGBT quickly turned off. This solution directly links the overcurrent protection with the output of the pre-optocoupler isolation module, achieving a fast-response integrated protection action without the need for additional external protection circuitry, significantly improving the overall stability and reliability of the circuit. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the module structure of the present invention; Figure 2 This is the circuit schematic diagram of the present invention. Detailed Implementation

[0024] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0025] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] Reference Figure 1 and Figure 2 As shown, this embodiment provides a multi-stage amplification control IGBT driver circuit and its control method. The driver circuit consists of an input signal optocoupler isolation module, an input signal multi-stage amplification control module, a push-pull amplifier circuit module, and an overcurrent detection and protection module. Through the coordinated operation of these modules, the circuit can not only perform multi-stage amplification and level conversion of the input signal, outputting a large drive current to adapt to high-voltage and high-power applications, but also quickly isolate the drive signal from the signal source and latch the fault state when an overcurrent occurs, significantly improving the overall driving capability and reliability.

[0028] In the input signal optocoupler isolation module, the A4504 chip is specifically used as the first optocoupler U1. Port 8 of this chip is connected to the DC drive power supply DP+, port 5 is connected to the negative voltage power supply DP-, and port 6 serves as the signal output port. A decoupling capacitor C3 is connected between the positive and negative voltage sources to eliminate high-frequency harmonics and stabilize the voltage. The chip's input is connected to the DC source VCC and the input PWM signal JN-. When the optocoupler chip detects that the input signal JN- is low, the internal LED lights up, and a low-level signal is output from port 6 after optocoupler isolation; when JN- is high, the LED turns off, and a high-level signal is output from port 6, thus achieving electrical isolation and level transmission between the control signal and the power stage.

[0029] The signal output from the first optocoupler U1 is input to a multi-stage amplification control module via resistor R1. This module includes transistors Q2, Q3, Q6, and Q7, as well as transistors Q1 and Q11. The base of transistor Q2 is connected to the signal output terminal of U1, its collector is connected to the drive power supply DP+ via resistor R3, and its emitter is connected to the base of transistor Q7. The collector of transistor Q7 is connected to the signal output terminal of U1 via resistor R5, and its emitter is connected to the negative voltage power supply DP-. The base of transistor Q3 is connected to the collector of transistor Q2, its emitter is connected to the negative voltage power supply DP-, and its collector is connected to the base of transistor Q6. The emitter of transistor Q6 is connected to the negative voltage power supply DP-, and its collector forms the intermediate PWM signal output terminal. The bases of the first transistor Q1 and the eleventh transistor Q11 are connected to the signal output terminal of U1, and their emitters are connected to the drive power supply DP+. The collector of the first transistor Q1 is connected to the intermediate PWM signal output terminal; the collector of the eleventh transistor Q11 is connected to the voltage VCE between the collector and emitter of the IGBT.

[0030] In the multi-stage amplification control module, the tenth resistor R10 is connected to the base of the third transistor Q3 and the negative voltage power supply DP-. The common cathode of the first diode is connected to the signal output terminal of U1, and the two anodes are connected to the base and collector of the first transistor Q1, respectively. The collector of the first transistor Q1 is connected to the intermediate PWM signal output terminal via the sixth resistor R6. The collector of the sixth transistor Q6 forms the intermediate PWM signal output terminal via the eighth resistor R8.

[0031] When this multi-stage amplification control module is working, if U1 outputs a low-level signal, the second transistor Q2 turns on. The drive power supply DP+ is input through Q2 to the gates of the third transistor Q3 and the seventh transistor Q7, triggering them to turn on. The seventh transistor Q7 provides a freewheeling circuit for the input signal. The third transistor Q3 turns on, causing the gate of the sixth transistor Q6 to be directly connected to the negative voltage power supply DP-. At this time, both the gate and emitter of Q6 are connected to DP-, and the voltage difference is zero, so the sixth transistor Q6 is cut off. Simultaneously, there is a voltage difference between the emitter and gate of the first transistor Q1 and the eleventh transistor Q11, causing them to turn on. The drive power supply DP+ outputs through the two branches of Q1 and Q11 respectively, and the intermediate PWM signal outputs a high level at this time.

[0032] When U1 outputs a high-level signal, since U1's port 8 is connected to DP+, the output high-level signal voltage is also DP+. The voltage difference between the emitter and gate of the second transistor Q2, the first transistor Q1, and the eleventh transistor Q11 is less than 0.7V, so these three transistors are cut off. Subsequently, the third transistor Q3 is also cut off. The gate of the sixth transistor Q6 is no longer directly connected to DP-, but is connected to the drive power supply DP+ through the fourth resistor R4, while its emitter is directly connected to DP-. There is a voltage difference between the gate and emitter, so the sixth transistor Q6 is turned on. The negative voltage power supply DP- is output to the intermediate PWM signal output after passing through the resistor, and at this time, the output is negative.

[0033] This multi-stage BJT control structure achieves extremely high current gain, ensuring that the switching transistor is in a state of deep saturation and rapid turn-off, which greatly improves the driving capability and overall performance stability.

[0034] The intermediate PWM signal output is then connected to a push-pull amplifier circuit module. This module mainly includes a fourth transistor Q4, a fifth transistor Q5, a first decoupling capacitor C1, a second decoupling capacitor C2, and a Zener diode D3. The first decoupling capacitor C1 is connected between the drive power supply DP+ and the negative power supply DP-. The first terminal of the second decoupling capacitor C2 is connected to the bases of the fourth transistor Q4 and the fifth transistor Q5, and the second terminal is connected to the negative power supply DP-. The cathode of the Zener diode D3 is connected to the bases of the fourth transistor Q4 and the fifth transistor Q5, and the anode is connected to the negative power supply DP-. D3 can be an 84C15 Zener diode with a reverse breakdown voltage of 15V. C1 and C2, as decoupling capacitors, provide a fast path for the input and output current during high-frequency switching of the devices, locally stabilize the voltage, eliminate high-order harmonics, and suppress common-mode noise. When a voltage spike occurs in the intermediate PWM signal, the second decoupling capacitor C2 momentarily presents a low-impedance current absorption charge, significantly mitigating the initial voltage spike. If the voltage rises above 15V, the Zener diode D3 quickly reverse-biased breaks down, providing a low-impedance circuit to clamp the voltage. The collector of the fourth transistor Q4 is connected to the drive power supply DP+, and the collector of the fifth transistor Q5 is connected to the negative power supply DP-. Their emitters are connected to form the PWM drive signal output terminal, which is connected to the IGBT gate. When the intermediate PWM signal is positive, the fourth transistor Q4 is turned on, and DP+ is connected to the output terminal to output a high level; when the intermediate PWM signal is negative, the fifth transistor Q5 is turned on, and DP- is connected to the output terminal to output a low level. The push-pull amplification structure results in a low output impedance, providing a large output current with low distortion. Especially during the IGBT turn-off cycle, the gate is directly connected to the negative power supply DP- through the fifth transistor Q5, without an intermediate turn-off resistor, pulling the gate voltage very low, effectively mitigating the Miller effect and preventing false turn-on. In addition, the circuit also includes a fourth diode D4, whose common anode is connected to the voltage VCE between the collector and emitter of the IGBT, and whose cathode is connected to the intermediate PWM signal output terminal, to provide an additional potential clamping and protection path.

[0035] In this embodiment, the overcurrent detection and protection module includes an eighth transistor Q8 and a ninth transistor Q9; the voltage VCE between the collector and emitter of the IGBT is connected to the base of the eighth transistor Q8; the collector of the eighth transistor Q8 is connected to the base of the ninth transistor Q9, and the collector of the ninth transistor Q9 is connected to the signal output terminal of the first optocoupler U1, used to clamp the output signal of the first optocoupler U1 to the drive power supply DP+ during overcurrent. The overcurrent detection and protection module also includes a thirteenth transistor Q10; the base of the thirteenth transistor Q10 is connected to the fault signal output terminal, the emitter is connected to the negative voltage power supply DP-, and the collector is connected to the base of the eighth transistor Q8.

[0036] Specifically, the voltage VCE between the collector and emitter of the IGBT is input through the twentieth resistor R20 and connected to the common anode of the fourth diode. The two cathodes of the fourth diode are connected to the drive power supply DP+ and the collector of the sixth transistor, respectively. One end of the twentieth resistor R20 is connected to DP- through the seventh capacitor C7 and to the anode of the fifth diode D5 Zener diode. The anode of the fifth diode D5 is connected to DP- through the seventeenth resistor R17 and the sixth capacitor, and to the base of the eighth transistor Q8. The emitter of the eighth transistor Q8 is connected to DP-, and its collector is connected to the base of the ninth transistor through the fourteenth resistor R14 and the thirteenth resistor. The collector of the ninth transistor Q9 is connected to the PWM signal output terminal of the input signal optocoupler isolation module. The cathode of the fifth diode D5 is connected to the collector of the thirteenth transistor through the sixteenth resistor R16 and the fifth capacitor C5. The other end of the fourteenth resistor is connected to the signal input terminal of the second optocoupler U2, and the output terminal of the second optocoupler U2 forms the FO+ drive fault indicator. The emitter of the ninth transistor Q9 is connected to DP+, the emitter of the thirteenth transistor Q10 is connected to DP+ through the fifteenth resistor R15, and the base is connected to the collector of the eighth transistor Q8 through the fourteenth resistor.

[0037] The overcurrent detection and protection module monitors the voltage VCE between the collector and emitter of the IGBT in real time. This module includes transistors Q8 (eighth), Q9 (ninth), and Q10 (thirteenth). After the VCE input circuit, it is connected to the base of transistor Q8 via a resistor and Zener diode D5. The Zener diode can be an MM3Z7V5ST1 with a reverse breakdown voltage of 7.5V. During normal operation, the VCE forward voltage drop is very small, typically only 1 to 2V, which is below the reverse breakdown voltage of the Zener diode, and the overcurrent protection circuit does not activate. When an overcurrent occurs, the current flowing through the IGBT or SiC MOSFET increases sharply, and VCE increases accordingly. When VCE exceeds 7.5V, the Zener diode breaks down, and the voltage reaches the base of transistor Q8 through the resistor and the Zener diode, making the voltage difference between its emitter and base greater than 0.7V, thus turning on transistor Q8. After transistor Q8 turns on, the circuit between the drive power supply DP+ and the negative voltage power supply DP- is connected through resistors R13 and R14, pulling down the base voltage of transistor Q9. Since the emitter of transistor Q9 is connected to the drive power supply DP+, its emitter junction is forward biased after its base voltage is pulled down, and transistor Q9 turns on. The collector of transistor Q9 is connected to the signal output terminal of the first optocoupler U1. The conduction of Q9 makes DP+ directly connected to the control circuit, clamping the output signal of the first optocoupler U1 to the drive power supply DP+ voltage. This linkage action immediately turns off the first transistor Q1 and the eleventh transistor Q11, which were originally in the on state, isolating the positive voltage part of the intermediate PWM signal, keeping the IGBT in the off state, and completing the protection action. At the same time, the voltage at the location of the fault light signal is pulled down, causing the left optocoupler isolation module to activate, pulling down the FO+ signal, and the fault indicator light illuminates. This fault light signal is also connected to the base of the thirteenth transistor Q10. The emitter of the thirteenth transistor Q10 is connected to the negative voltage power supply DP-, and its collector is connected to the base of the eighth transistor Q8. When the fault light signal is low, the voltage difference between the gate and emitter of the thirteenth transistor Q10 is greater than 0.7V, causing Q10 to conduct and providing a direct loop from DP+ to DP-. This loop keeps the eighth transistor Q8 conducting, maintaining the fault light signal at a low level, thus achieving the fault signal latching function. By integrating overcurrent detection, signal clamping, and status latching into one unit, highly reliable integrated linkage protection can be achieved without adding additional external protection circuitry.

[0038] During operation, the external PWM input signal is first isolated and output through the first optocoupler U1. The multi-stage input signal amplification control module utilizes the cascaded conduction relationship of the second transistor Q2, the third transistor Q3, the sixth transistor Q6, and the seventh transistor Q7 to amplify and level-convert the isolated signal, outputting an intermediate PWM signal. The push-pull amplifier circuit module uses the fourth transistor Q4 and the fifth transistor Q5 for push-pull amplification, outputting the final PWM drive signal to the IGBT gate. The overcurrent detection and protection module continuously monitors the voltage VCE. Once an overcurrent occurs, it sequentially triggers the conduction of the eighth transistor Q8 and the ninth transistor Q9, clamping the signal output of the first optocoupler U1 to the drive power supply DP+, isolating the positive level portion of the intermediate PWM signal to keep the IGBT off, and achieving fault latching through the thirteenth transistor Q10.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A multi-stage amplification control IGBT drive circuit, characterized in that, It includes an input signal optocoupler isolation module, an input signal multi-stage amplification and control module, a push-pull amplifier circuit module, and an overcurrent detection and protection module; The input signal optocoupler isolation module includes a first optocoupler U1, the signal input terminal of the first optocoupler U1 is connected to the PWM signal input, and the signal output terminal is connected to the input signal multi-stage amplification control module; The input signal multi-stage amplification control module includes a second transistor Q2, a third transistor Q3, a sixth transistor Q6, and a seventh transistor Q7. The base of the second transistor Q2 is connected to the signal output terminal of the first optocoupler U1, its collector is connected to the driving power supply DP+, and its emitter is connected to the base of the seventh transistor Q7. The collector of the seventh transistor Q7 is connected to the signal output terminal of the first optocoupler U1, and its emitter is connected to the negative voltage power supply DP-. The base of the third transistor Q3 is connected to the collector of the second transistor Q2, its emitter is connected to the negative voltage power supply DP-, and its collector is connected to the base of the sixth transistor Q6. The emitter of the sixth transistor Q6 is connected to the negative voltage power supply DP-, and its collector forms an intermediate PWM signal output terminal. The push-pull amplifier circuit module includes a fourth transistor Q4 and a fifth transistor Q5; the bases of the fourth transistor Q4 and the fifth transistor Q5 are connected to the intermediate PWM signal output terminal, the collector of the fourth transistor Q4 is connected to the driving power supply DP+, the collector of the fifth transistor Q5 is connected to the negative voltage power supply DP-, and the emitters of the fourth transistor Q4 and the fifth transistor Q5 are connected to form a PWM driving signal output terminal to connect to the IGBT gate; The overcurrent detection and protection module includes an eighth transistor Q8 and a ninth transistor Q9; the voltage VCE between the collector and emitter of the IGBT is connected to the base of the eighth transistor Q8; the collector of the eighth transistor Q8 is connected to the base of the ninth transistor Q9, and the collector of the ninth transistor Q9 is connected to the signal output terminal of the first optocoupler U1, which is used to clamp the output signal of the first optocoupler U1 to the drive power supply DP+ during overcurrent.

2. The IGBT drive circuit with multi-stage amplification control according to claim 1, characterized in that, The input signal multi-stage amplification control module also includes a first transistor Q1 and an eleventh transistor Q11; The bases of the first transistor Q1 and the eleventh transistor Q11 are connected to the signal output terminal of the first optocoupler U1, and the emitters are connected to the driving power supply DP+. The collector of the first transistor Q1 is connected to the intermediate PWM signal output terminal. The collector of the eleventh transistor Q11 is connected to the voltage VCE between the collector and emitter of the IGBT.

3. The IGBT drive circuit with multi-stage amplification control according to claim 1, characterized in that, The push-pull amplifier circuit module also includes a first decoupling capacitor C1, a second decoupling capacitor C2, and a Zener diode D3; The first decoupling capacitor C1 is connected between the drive power supply DP+ and the negative voltage power supply DP-. The first end of the second decoupling capacitor C2 is connected to the base of the fourth transistor Q4 and the fifth transistor Q5, and the second end is connected to the negative voltage power supply DP-. The negative terminal of the Zener diode D3 is connected to the base of the fourth transistor Q4 and the fifth transistor Q5, and the positive terminal is connected to the negative voltage power supply DP-.

4. The IGBT drive circuit with multi-stage amplification control according to claim 1, characterized in that, The overcurrent detection and protection module also includes a thirteenth transistor Q10; The base of the thirteenth transistor Q10 is connected to the fault signal output terminal, the emitter is connected to the negative voltage power supply DP-, and the collector is connected to the base of the eighth transistor Q8.

5. The IGBT drive circuit with multi-stage amplification control according to claim 1, characterized in that, It also includes a fourth diode D4, the anode of which is connected to the voltage VCE between the collector and emitter of the IGBT, and the cathode is connected to the intermediate PWM signal output terminal.

6. A control method for an IGBT drive circuit based on the multi-stage amplification control described in any one of claims 1-5, characterized in that, Includes the following steps: The input signal optocoupler isolation module receives the external PWM input signal, which is then isolated by the first optocoupler U1 and output to the input signal multi-stage amplification and control module. The input signal multi-stage amplification control module utilizes the cascaded conduction relationship of the second transistor Q2, the third transistor Q3, the sixth transistor Q6, and the seventh transistor Q7 to perform multi-stage amplification and level conversion on the isolated signal, and output an intermediate PWM signal; The push-pull amplifier circuit module receives the intermediate PWM signal, uses the fourth transistor Q4 and the fifth transistor Q5 for push-pull amplification, and outputs the PWM drive signal to the IGBT gate. The overcurrent detection and protection module detects the voltage VCE between the collector and emitter of the IGBT. When VCE exceeds the preset threshold, it triggers the eighth transistor Q8 to conduct, which in turn turns on the ninth transistor Q9, connecting the signal output terminal of the first optocoupler U1 to the drive power supply DP+.

7. The control method for the IGBT drive circuit with multi-stage amplification control according to claim 6, characterized in that, When the first optocoupler U1 outputs a low-level signal, the second transistor Q2 is turned on, and the third transistor Q3 and the seventh transistor Q7 are also turned on. The seventh transistor Q7 provides a freewheeling circuit, and the turn-on of the third transistor Q3 connects the base of the sixth transistor Q6 to the negative voltage power supply DP-, thus turning it off. When the first optocoupler U1 outputs a high-level signal, the second transistor Q2 is turned off, the third transistor Q3 is turned off, and the base of the sixth transistor Q6 is connected to the driving power supply DP+ through a resistor, thus turning it on. The negative voltage power supply DP- is output to the intermediate PWM signal via the sixth transistor Q6.

8. The control method for the IGBT drive circuit with multi-stage amplification control according to claim 7, characterized in that, When the first optocoupler U1 outputs a low-level signal, the first transistor Q1 and the eleventh transistor Q11 are turned on, and the drive power supply DP+ is output to the intermediate PWM signal through the first transistor Q1.

9. The control method for the multi-stage amplification control IGBT drive circuit according to claim 6, characterized in that, When the intermediate PWM signal is at a positive level, the fourth transistor Q4 is turned on, and the driving power supply DP+ is connected to the PWM driving signal output terminal; when the intermediate PWM signal is at a negative level, the fifth transistor Q5 is turned on, and the negative voltage power supply DP- is connected to the PWM driving signal output terminal; during the IGBT turn-off cycle, the fifth transistor Q5 connects the IGBT gate to the negative voltage power supply DP-.

10. The control method for the IGBT drive circuit with multi-stage amplification control according to claim 6, characterized in that, When an overcurrent occurs, the voltage VCE between the collector and emitter of the IGBT increases, causing the eighth transistor Q8 to conduct. This pulls down the base voltage of the ninth transistor Q9, causing Q9 to conduct as well. The drive power supply DP+ is connected to the signal output terminal of the first optocoupler U1 through the ninth transistor Q9. The voltage at the fault signal output terminal is pulled down, causing the thirteenth transistor Q10 to conduct, forming a loop from the drive power supply DP+ to the negative voltage power supply DP-.

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