IGBT (Insulated Gate Bipolar Translator) fast turn-off voltage-stabilizing driving circuit based on Miller capacitance suppression

Abstract

The utility model discloses an IGBT fast turn-off voltage stabilization drive circuit based on Miller capacitance suppression, which relates to the technical field of power electronics and comprises a two-stage IGBT drive circuit composed of an upper layer circuit and a lower layer circuit. Each of the upper layer circuit and the lower layer circuit comprises a driving chip, a divider resistor, an overcurrent resistor, a filter capacitor and an IGBT (Insulated Gate Bipolar Translator); the divider resistor is connected between grid electrodes of the driving chip IGBT, two ends of the divider resistor are also connected in parallel with a current limiting loop, the grid electrodes of the IGBT are connected with the bidirectional voltage-regulator tube, and the overcurrent resistor and the filter capacitor are connected in parallel and are connected between the bidirectional voltage-regulator tube and the emitter electrode of the IGBT. By adding the current-limiting loop channel and the voltage-regulator tube which are rapidly turned off in the circuit, the misconduction phenomenon caused by the Miller effect can be effectively inhibited, the normal turn-off of the IGBT is ensured, the switching performance of the IGBT is improved, and the reliability and the stability of the circuit are improved.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to an IGBT (Insulated Gate Bipolar Transistor) fast turn-off voltage regulation drive circuit based on Miller capacitance suppression. Background Technology

[0002] In IGBT (Insulated Gate Bipolar Transistor) applications, especially during high-power and high-frequency switching, the impact of Miller capacitance (Cgc) on the circuit cannot be ignored. During IGBT switching, particularly in the turn-off phase, Miller capacitance acts on the gate through displacement current, causing an increase in gate voltage, which may lead to mis-turn-on of the IGBT. This phenomenon is known as the Miller effect, and it typically causes high voltage spikes in the circuit, resulting in unnecessary losses or circuit failure.

[0003] Most IGBT driver circuits on the market currently use optocoupler driving, which is sufficient for most conventional applications. However, in harsh operating environments, especially when there is a large stray inductance or excessive capacitance in the circuit, the Miller effect can cause more severe false turn-on problems. Therefore, there is an urgent need for an improved IGBT driver circuit that can effectively suppress voltage spikes caused by Miller capacitance and ensure reliable IGBT turn-off. Utility Model Content

[0004] The purpose of this invention is to provide an IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression. This circuit is a fast turn-off voltage regulation drive circuit used to suppress the misleading turn-on problem caused by Miller capacitance in the IGBT (Insulated Gate Bipolar Transistor) drive circuit. By adding components such as a fast turn-off channel, a Zener diode, and a loop resistor to the existing drive circuit, the turn-off process of the IGBT is accelerated, and the misleading turn-on problem caused by Miller capacitance is effectively suppressed.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This invention provides an IGBT fast turn-off regulated driving circuit based on Miller capacitance suppression, comprising a two-stage IGBT driving circuit consisting of an upper-level circuit (first stage) and a lower-level circuit (second stage). Both the upper and lower-level circuits include a driving chip, voltage divider resistors, overcurrent resistors, filter capacitors, and IGBTs (Insulated Gate Bipolar Transistors). The voltage divider resistors are connected between the gates of the IGBTs in the driving chip, and a current-limiting loop is connected in parallel across the voltage divider resistors. The gates of the IGBTs are connected to bidirectional Zener diodes. The overcurrent resistors and filter capacitors are connected in parallel between the bidirectional Zener diodes and the emitters of the IGBTs. The two IGBTs in the two-stage IGBT driving circuit are connected in a bridge arm configuration, with the emitters of the upper-level IGBTs and the collectors of the lower-level IGBTs directly connected, forming the midpoint of the bridge arm. The collector of the upper-level IGBT is connected to a positive DC power supply, and the emitter of the lower-level IGBT is connected to a negative DC power supply.

[0007] As a further embodiment of this utility model, the current limiting loop is composed of interconnected current limiting resistors and diodes. In the current limiting loop, the anode of the diode is connected to the current limiting resistor, and the cathode of the diode is connected to the junction of the gate of the IGBT and the voltage divider resistor.

[0008] As a further embodiment of this invention, the bypass connection of the bidirectional Zener diode is located at the midpoint of the bridge arm formed by the two IGBTs, and the output voltage Uout is taken between the emitter and collector of the two IGBTs.

[0009] As a further embodiment of this invention, in the two-stage IGBT drive circuit, the pin connected to the voltage divider resistor on the IGBT outputs a PWM waveform as the gate drive signal Uout.

[0010] As a further embodiment of this invention, the PWM output (Uout) of the IGBT pin is connected to the anode of the diode via a current-limiting resistor; the cathode of the diode is connected to the gate of the IGBT.

[0011] As a further embodiment of this utility model, the upper-layer circuit includes a driver chip U1, a voltage divider resistor R1, an overcurrent resistor R2, a filter capacitor C1, an IGBT-A, a bidirectional Zener diode TV1, a current-limiting resistor R5, and a diode D1; the voltage divider resistor R1 is connected between pin 5 of the driver chip U1 and the gate G1 of the IGBT-A, and the current-limiting resistor R5 and the diode D1 are connected in parallel with the voltage divider resistor R1; the gate G1 of the IGBT-A is connected to the bidirectional Zener diode TV1, and the bypass of the bidirectional Zener diode TV1 is connected at the midpoint of the two IGBTs; the overcurrent resistor R2 and the filter capacitor C1 are connected in parallel and connected between the bidirectional Zener diode TV1 and the emitter E1 of the IGBT-A.

[0012] As a further embodiment of this utility model, pin 6 of the driver chip U1 is connected to the VCC1 power supply for providing voltage, and pin 4 of the driver chip U1 is grounded to GND.

[0013] As a further embodiment of this utility model, the lower-level circuit includes a driver chip U2, a voltage divider resistor R3, an overcurrent resistor R4, a filter capacitor C2, an IGBT-B, a bidirectional Zener diode TV2, a current-limiting resistor R6, and a diode D2. The voltage divider resistor R3 is connected between pin 5 of the driver chip U2 and the gate G2 of the IGBT-B. The current-limiting resistor R6 and the diode D2 are connected in parallel with the voltage divider resistor R3. The gate G2 of the IGBT-B is connected to the bidirectional Zener diode TV2, and the bypass of the bidirectional Zener diode TV2 is connected at the midpoint of the two IGBTs. The overcurrent resistor R4 and the filter capacitor C2 are connected in parallel and connected between the bidirectional Zener diode TV2 and the emitter E2 of the IGBT-B.

[0014] As a further embodiment of this utility model, pin 6 of the driver chip U2 is connected to the VCC2 power supply for providing voltage, and pin 4 of the driver chip U2 is grounded to GND.

[0015] As a further embodiment of this utility model, the emitter E1 of IGBT-A in the upper circuit is directly connected to the collector C2 of IGBT-B in the lower circuit to form the midpoint of the bridge arm; the collector C1 of IGBT-A is connected to the positive terminal DC+ of the DC power supply, and the emitter E2 of IGBT-B is connected to the negative terminal DC- of the DC power supply.

[0016] As a further embodiment of this invention, the two-stage IGBT driving circuit also includes associated capacitors on the IGBT, including a gate-collector capacitor Cgc, a gate-emitter capacitor Cge, and a collector-emitter capacitor Cce; the gate-collector capacitor Cgc is a Miller capacitor connected between the gate and collector of the IGBT; the gate-emitter capacitor Cge is connected between the gate and emitter of the IGBT; and the collector-emitter capacitor Cce is connected between the collector and emitter of the IGBT.

[0017] In the above technical solution, the IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression provided by this utility model has the following advantages:

[0018] In the drive circuit, the drive chips (U1, U2) control the gate current of the IGBT by outputting high and low level signals of the PWM wave. During the IGBT's switching process, especially during turn-off, voltage changes between the collector and emitter generate a displacement current at the gate caused by Miller capacitance. If not suppressed, this displacement current may cause the gate voltage to rise, leading to mis-turn-on of the IGBT. To suppress this mis-turn-on phenomenon, this invention provides an IGBT fast turn-off voltage-regulating drive circuit based on Miller capacitance suppression. By adding a current-limiting loop, a fast turn-off channel is provided, which can accelerate the IGBT's turn-off process and quickly eliminate the gate voltage. At the same time, the added bidirectional Zener diode provides voltage regulation. When the gate voltage is too high, the Zener diode automatically clamps it within a safe range to prevent mis-turn-on caused by excessive gate voltage. By adding a fast turn-off channel and a Zener diode to the drive circuit, the mis-turn-on phenomenon caused by the Miller effect can be effectively suppressed, ensuring the normal turn-off of the IGBT. This allows the circuit to remain stable even in high-frequency and harsh environments, avoiding circuit damage caused by voltage spikes. By optimizing the gate drive circuit, losses caused by misleading turn-on and overvoltage are reduced, improving the overall system efficiency. By adding a loop to accelerate turn-off, the response speed during IGBT turn-off is improved, the turn-off time is reduced, and the switching frequency is increased.

[0019] In summary, the IGBT fast turn-off regulated drive circuit based on Miller capacitance suppression provided by this utility model can effectively suppress the false turn-on problem caused by Miller capacitance, improve the switching performance of IGBT, and enhance the reliability and stability of the circuit. It is suitable for high-power and high-frequency IGBT drive applications, especially power conversion and switching control systems in harsh environments. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0021] Figure 1 This is a circuit diagram of an IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to this utility model.

[0022] Figure 2 This is a circuit diagram showing the parasitic capacitance in the PN junction of the IGBT in an IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to this utility model.

[0023] Figure 3This is a circuit diagram of a single drive circuit in an IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to this utility model.

[0024] Figure 4 This is a schematic diagram illustrating the five stages of high voltage leveling during the turn-on process of an IGBT fast turn-off regulated driving circuit based on Miller capacitance suppression, according to this utility model.

[0025] Figure 5 This is a schematic diagram illustrating the effect of Miller capacitance suppression on saturation voltage in an IGBT fast turn-off regulated driving circuit based on this invention.

[0026] Figure 6 This is a schematic diagram illustrating the effect of Miller capacitance suppression on short-circuit current in an IGBT fast turn-off regulated driving circuit according to this invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings.

[0028] To address the issue of mis-conduction caused by the Miller effect, which is exacerbated in harsh operating environments, especially when there is significant stray inductance or excessive capacitance in the circuit, this invention provides an IGBT fast turn-off regulated drive circuit based on Miller capacitance suppression. This circuit is designed to suppress mis-conduction caused by Miller capacitance in IGBT (Insulated Gate Bipolar Transistor) drive circuits. By adding specific components (such as a fast turn-off channel, a Zener diode, and a loop resistor) to the existing drive circuit, the IGBT turn-off process is accelerated, effectively suppressing mis-conduction caused by Miller capacitance. The drive circuit includes two main power supplies (VCC1 and VCC2), a drive chip U1, and two IGBTs. Through the addition of resistor R5, diode D1, and resistor R6, diode D2, and optimized loop connections, the IGBT turn-off process is accelerated, gate voltage is rapidly eliminated, ensuring a more stable and reliable IGBT switching process, reducing mis-conduction caused by the Miller effect, and improving system reliability.

[0029] 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.

[0030] like Figures 1 to 3As shown, this utility model embodiment provides an IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression, including a two-stage IGBT drive circuit consisting of an upper-level circuit (first stage) and a lower-level circuit (second stage). Both the upper-level and lower-level circuits include a driver chip, a voltage divider resistor, an overcurrent resistor, a filter capacitor, and an IGBT (Insulated Gate Bipolar Transistor). The voltage divider resistor is connected between the gates of the IGBT in the driver chip, and a current-limiting loop is connected in parallel across the voltage divider resistor. The gate of the IGBT is connected to a bidirectional Zener diode. The overcurrent resistor and the filter capacitor are connected in parallel between the bidirectional Zener diode and the emitter of the IGBT. The two IGBTs in the two-stage IGBT drive circuit are connected in a bridge arm configuration, with the emitter of the IGBT in the upper-level circuit and the collector of the IGBT in the lower-level circuit directly connected, forming the midpoint of the bridge arm. The collector of the IGBT in the upper-level circuit is connected to a positive DC power supply; the emitter of the IGBT in the lower-level circuit is connected to a negative DC power supply.

[0031] In this embodiment, the current-limiting loop consists of interconnected current-limiting resistors and diodes. The anode of the diode is connected to the current-limiting resistor, and the cathode is connected to the junction of the IGBT gate and the voltage divider resistor. The bypass of the bidirectional Zener diode is connected at the midpoint of the two IGBTs forming a bridge arm, and the output voltage Uout is taken between the emitters and collectors of the two IGBTs. The PWM output (Uout) of the IGBT pin is connected to the anode of the diode via the current-limiting resistor; the cathode of the diode is connected to the IGBT gate.

[0032] This invention relates to an IGBT fast turn-off voltage-regulated drive circuit based on Miller capacitance suppression. By adding a current-limiting loop, a fast turn-off channel is provided, which accelerates the IGBT turn-off process and quickly eliminates the gate voltage. Simultaneously, the added bidirectional Zener diode provides voltage regulation; when the gate voltage is too high, the Zener diode automatically clamps it within a safe range, preventing false turn-on caused by excessive gate voltage. By adding a fast turn-off channel and a Zener diode to the drive circuit, false turn-on caused by the Miller effect can be effectively suppressed, ensuring normal IGBT turn-off and maintaining circuit stability even in high-frequency and harsh environments, avoiding circuit damage caused by voltage spikes. Optimizing the gate drive circuit reduces losses due to false turn-on and overvoltage, improving the overall system efficiency. Adding an accelerated turn-off loop improves the IGBT turn-off response speed, reduces turn-off time, and increases the switching frequency.

[0033] See Figure 1 and Figure 3As shown, the upper-layer circuit includes a driver chip U1, a voltage divider resistor R1, an overcurrent resistor R2, a filter capacitor C1, an IGBT-A, a bidirectional Zener diode TV1, a current-limiting resistor R5, and a diode D1. The voltage divider resistor R1 is connected between pin 5 of the driver chip U1 and the gate G1 of the IGBT-A. The current-limiting resistor R5 and the diode D1 are connected in parallel with the voltage divider resistor R1. The gate G1 of the IGBT-A is connected to the bidirectional Zener diode TV1, and the bypass of the bidirectional Zener diode TV1 is connected at the midpoint of the two IGBTs. The overcurrent resistor R2 and the filter capacitor C1 are connected in parallel and connected between the bidirectional Zener diode TV1 and the emitter E1 of the IGBT-A.

[0034] Among them, pin 6 of the driver chip U1 is connected to the VCC1 power supply for providing voltage, and pin 4 of the driver chip U1 is grounded to GND.

[0035] See Figure 2 and Figure 3 As shown, the two-stage IGBT drive circuit also includes associated capacitors on the IGBT, including a gate-collector capacitor Cgc, a gate-emitter capacitor Cge, and a collector-emitter capacitor Cce. The gate-collector capacitor Cgc is a Miller capacitor connected between the gate and collector of the IGBT; the gate-emitter capacitor Cge is connected between the gate and emitter of the IGBT; and the collector-emitter capacitor Cce is connected between the collector and emitter of the IGBT.

[0036] See Figures 1 to 3 As shown, the lower-level circuit includes a driver chip U2, a voltage divider resistor R3, an overcurrent resistor R4, a filter capacitor C2, an IGBT-B, a bidirectional Zener diode TV2, a current-limiting resistor R6, and a diode D2. The voltage divider resistor R3 is connected between pin 5 of the driver chip U2 and the gate G2 of the IGBT-B. The current-limiting resistor R6 and the diode D2 are connected in parallel with the voltage divider resistor R3. The gate G2 of the IGBT-B is connected to the bidirectional Zener diode TV2, and the bypass of the bidirectional Zener diode TV2 is connected at the midpoint between the two IGBTs. The overcurrent resistor R4 and the filter capacitor C2 are connected in parallel and connected between the bidirectional Zener diode TV2 and the emitter E2 of the IGBT-B.

[0037] Among them, pin 6 of the driver chip U2 is connected to the VCC2 power supply for providing voltage, and pin 4 of the driver chip U2 is grounded to GND.

[0038] In the upper circuit, the emitter E1 of IGBT-A is directly connected to the collector C2 of IGBT-B in the lower circuit to form the midpoint of the bridge arm; the collector C1 of IGBT-A is connected to the positive terminal DC+ of the DC power supply, and the emitter E2 of IGBT-B is connected to the negative terminal DC- of the DC power supply.

[0039] In this embodiment, see Figures 1 to 6 As shown, the turn-on and turn-off processes of the IGBT fast turn-off regulated drive circuit based on Miller capacitance suppression of this utility model are as follows:

[0040] 1. Activation process:

[0041] Phase 1: Dead Time (Vge) <Vge(th))

[0042] ■ PWM wave generates gate signal: The PWM wave signal is output from the fifth pin of the driver chip (U1, U2). The high level of the PWM wave signal is applied to the gate of the IGBT.

[0043] ■ Gate current charges Cge: The gate current begins to charge the gate-emitter capacitance Cge, causing the gate voltage Vge to rise.

[0044] ■ No change in collector-emitter voltage: When the gate voltage Vge is less than the threshold voltage Vge(th), the collector current Ice is zero, and the voltage (Vce) between the collector and emitter remains unchanged.

[0045] ■ This stage is called the "dead time," during which the IGBT has not yet been turned on and the current Ice is zero.

[0046] Phase Two: Miller Plateau Rise Phase (Vge > Vge(th), Vce ≈ Constant)

[0047] ■ Gate current continues to charge: As the gate voltage Vge continues to rise, the gate current not only charges Cge, but also begins to charge the gate-collector capacitance Cgc.

[0048] ■ Collector current begins to rise: Since the gate voltage has exceeded the threshold voltage Vge(th), the IGBT begins to conduct, and the collector current Ice begins to increase until it reaches the maximum load current Ic.

[0049] ■Impact of Diode Reverse Recovery Current: At this stage, due to the presence of diode reverse recovery current (especially during IGBT reverse recovery), this process differs from the turn-on process of a traditional MOSFET. Compared to MOSFETs, the turn-on of an IGBT requires consideration of the diode recovery effect.

[0050] ■ Miller Plateau: The gate voltage Vge reaches the "Miller plateau voltage" for a brief period of time (i.e., the gate voltage remains constant above Vge(th), and the gate current no longer increases). At this time, the collector current Ice is still increasing, but the gate voltage is stable, and the charging of the Miller capacitance (Cgc) ends.

[0051] Phase 3: The gate voltage remains at the Miller plateau (Vge is constant, Vce drops rapidly).

[0052] ■ Gate current continues to charge: The gate voltage remains at the Miller plateau voltage, while the gate current continues to charge, and charge accumulates in Cge and Cgc. At this point, the gate voltage Vge essentially stops rising and remains constant.

[0053] ■Vce begins to decrease rapidly: As the gate voltage stabilizes, the collector current Ice reaches its maximum value, and Vce begins to decrease rapidly. This process is very short, so the gate current will not increase significantly again.

[0054] Fourth stage: Vce gradually stabilizes, Miller capacitance effect increases (Vge remains constant, Vce slowly approaches steady state).

[0055] ■Vce decreases further: The gate voltage Vge continues to remain at the Miller plateau, the charging process of the gate current to Cgc remains stable, and Vce continues to decrease, gradually approaching the steady-state voltage.

[0056] ■ Increased Miller capacitance: As Vce decreases, the influence of Miller capacitance Cgc increases. At this time, the gate voltage Vge remains at the Miller plateau, and charge accumulates on the Miller capacitance, but the gate voltage and collector current remain basically stable.

[0057] Phase 5: IGBT fully activated (Vge increases, Ice reaches steady state)

[0058] ■ Gate current continues to charge: The gate voltage Vge continues to increase, starting to increase significantly, until the gate is fully charged and Vge reaches the operating voltage of the driver chip, and the IGBT is fully turned on.

[0059] ■ Gate Current Compensation: At this point, the collector current Ice has reached its steady-state value. The current Igc (the current caused by the discharge of Cgc) is compensated through the Miller capacitance to ensure the stability of the gate voltage. Specifically:

[0060] I G =I Driver +I gc =I Driver +C gc ·dV ce / dt

[0061] In the formula, I GI represents the gate current required. Driver Indicates the gate drive current, I gc This indicates the current used for charging the GC capacitor; C gc dV represents the capacitance between the G and C electrodes. ce / dt represents the rate of voltage change between the CE electrode and the capacitor electrode.

[0062] 2. Shutdown process:

[0063] When the IGBT is turned off, the Vce voltage jumps from a low level to a high level, resulting in a very large voltage change rate (dv / dt). This process generates a displacement current, affecting the IGBT's turn-off characteristics.

[0064] Displacement current and Miller capacitance:

[0065] ■ Displacement current: Due to the sudden rise of Vce, the Miller capacitance Cgc will generate a displacement current, which will flow through the gate resistor back to ground.

[0066] ■ Gate voltage rise: After the displacement current flows through the gate resistor, the gate voltage Vge will rise, which may cause the gate voltage to reach the threshold voltage Vge(th), thereby causing the IGBT to turn on falsely and increasing system losses.

[0067] Solution: Quickly shut down the channel:

[0068] ■ Diode D1 and Current-limiting Resistor R5: To prevent false turn-on due to displacement current caused by the Miller plateau, a fast turn-off channel (composed of diode D1 and current-limiting resistor R5) is added to the circuit design. This channel can quickly dissipate the charge released by the Miller capacitor and rapidly eliminate displacement current.

[0069] ■Increase negative voltage: At the same time, by increasing the negative voltage value, the displacement current of the Miller capacitor is consumed quickly, preventing the gate voltage from rising to the threshold voltage, thereby avoiding false turn-on.

[0070] The functions of bidirectional Zener diodes TV1 and TV2 are as follows:

[0071] ■ Automatic Voltage Regulation: Bidirectional Zener diodes TV1 and TV2 are used to ensure that the gate voltage of the IGBTs in the upper and lower layer circuits does not exceed the set maximum value. When the gate voltage exceeds the set voltage, the bidirectional Zener diodes will automatically activate the voltage regulation function to prevent instability caused by excessively high gate voltage.

[0072] ■ Stabilize Vge voltage: The Zener diode ensures that the gate voltage is always kept within a stable range, thereby effectively suppressing the Miller capacitance effect caused by gate voltage fluctuations and improving the switching performance of the IGBT.

[0073] See Figure 5 and Figure 6 As shown, bidirectional Zener diodes TV1 and TV2 are used to automatically regulate the gate voltage when it exceeds a set value. For IGBTs, the magnitude of Vge affects the magnitude of Vce(set). Specifically, regarding the effect on saturation voltage: as Vge increases, Vceat decreases; regarding the effect on short-circuit current: as Vge increases, Isc increases (tsc decreases), as... Figure 5 and Figure 6 The curve shown.

[0074] Therefore, in this circuit design, Miller capacitance suppression is achieved through the cooperation of fast turn-off channel diode D1, current-limiting resistor R5, and bidirectional Zener diodes TV1 and TV2. By increasing the negative voltage and designing a suitable circuit path, current displacement and charge accumulation are quickly eliminated, avoiding false turn-on caused by the Miller plateau, thereby improving the IGBT's turn-off speed and system stability. Simultaneously, by rationally designing each stage of the switching process, smooth IGBT turn-on and turn-off are ensured, reducing system losses and improving efficiency.

[0075] The IGBT fast turn-off regulated drive circuit based on Miller capacitance suppression provided by this utility model can effectively suppress the false turn-on problem caused by Miller capacitance, improve the switching performance of IGBT, and enhance the reliability and stability of the circuit. It is suitable for high-power and high-frequency IGBT drive applications, especially power conversion and switching control systems in harsh environments.

[0076] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A fast turn-off regulated driving circuit for IGBTs based on Miller capacitance suppression, characterized in that, The circuit comprises a two-stage IGBT driver circuit consisting of an upper-level circuit and a lower-level circuit. Each upper-level and lower-level circuit includes a driver chip, voltage divider resistors, overcurrent resistors, filter capacitors, and IGBTs. The voltage divider resistors are connected between the gates of the driver chip's IGBTs, and a current-limiting loop is connected in parallel across the voltage divider resistors. The gates of the IGBTs are connected to bidirectional Zener diodes. The overcurrent resistors and filter capacitors are connected in parallel between the bidirectional Zener diodes and the emitters of the IGBTs. The two IGBTs in the two-stage IGBT driver circuit are connected in a bridge arm configuration, with the emitters of the upper-level IGBTs and the collectors of the lower-level IGBTs directly connected, forming the midpoint of the bridge arm. The collector of the upper-level IGBT is connected to a positive DC power supply, and the emitter of the lower-level IGBT is connected to a negative DC power supply.

2. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 1, characterized in that, The current limiting loop consists of interconnected current limiting resistors and diodes. In the current limiting loop, the anode of the diode is connected to the current limiting resistor, and the cathode of the diode is connected to the junction of the gate of the IGBT and the voltage divider resistor.

3. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 2, characterized in that, The bypass connection of the bidirectional Zener diode is located at the midpoint of the bridge arm formed by the two IGBTs, and the output voltage Uout is taken between the emitter and collector of the two IGBTs.

4. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 3, characterized in that, In a two-stage IGBT drive circuit, the pin connected to the voltage divider resistor on the IGBT outputs a PWM waveform as the gate drive signal Uout.

5. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 4, characterized in that, The PWM output of the IGBT pin is connected to the anode of the diode via a current-limiting resistor; the cathode of the diode is connected to the gate of the IGBT.

6. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 1, characterized in that, The upper-layer circuit includes a driver chip U1, a voltage divider resistor R1, an overcurrent resistor R2, a filter capacitor C1, an IGBT-A, a bidirectional Zener diode TV1, a current-limiting resistor R5, and a diode D1. The voltage divider resistor R1 is connected between pin 5 of the driver chip U1 and the gate G1 of the IGBT-A. The current-limiting resistor R5 and the diode D1 are connected in parallel with the voltage divider resistor R1. The gate G1 of the IGBT-A is connected to the bidirectional Zener diode TV1, and the bypass of the bidirectional Zener diode TV1 is connected at the midpoint between the two IGBTs. The overcurrent resistor R2 and the filter capacitor C1 are connected in parallel and connected between the bidirectional Zener diode TV1 and the emitter E1 of the IGBT-A.

7. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 6, characterized in that, Pin 6 of the driver chip U1 is connected to the VCC1 power supply for providing voltage, and pin 4 of the driver chip U1 is grounded to GND.

8. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 6, characterized in that, The lower-level circuit includes a driver chip U2, a voltage divider resistor R3, an overcurrent resistor R4, a filter capacitor C2, an IGBT-B, a bidirectional Zener diode TV2, a current-limiting resistor R6, and a diode D2. The voltage divider resistor R3 is connected between pin 5 of the driver chip U2 and the gate G2 of the IGBT-B. The current-limiting resistor R6 and the diode D2 are connected in parallel with the voltage divider resistor R3. The gate G2 of the IGBT-B is connected to the bidirectional Zener diode TV2, and the bypass of the bidirectional Zener diode TV2 is connected at the midpoint between the two IGBTs. The overcurrent resistor R4 and the filter capacitor C2 are connected in parallel and connected between the bidirectional Zener diode TV2 and the emitter E2 of the IGBT-B.

9. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 8, characterized in that, Pin 6 of the driver chip U2 is connected to the VCC2 power supply for providing voltage, and pin 4 of the driver chip U2 is grounded to GND.

10. The IGBT fast turn-off voltage regulation drive circuit based on Miller capacitance suppression according to claim 8, characterized in that, In the upper circuit, the emitter E1 of IGBT-A is directly connected to the collector C2 of IGBT-B in the lower circuit to form the midpoint of the bridge arm; the collector C1 of IGBT-A is connected to the positive terminal DC+ of the DC power supply, and the emitter E2 of IGBT-B is connected to the negative terminal DC- of the DC power supply.

Images