Self-adaptive active driving circuit for Si / SiC hybrid device

Abstract

The application discloses a kind of adaptive active drive circuit for Si / SiC hybrid device, including adjustable delay drive circuit and adaptive switching current detection circuit.The adjustable delay drive circuit is based on PWM signal, and the working mechanism of switching state of device triggered by threshold voltage through the gate charge-discharge action of different stages of PWM signal is cooperated to realize the collaborative switching of Si / SiC hybrid device, and the off-delay duration is adjusted by changing control voltage;The adaptive switching current detection circuit collects the fluctuating switching current of Si / SiC hybrid device, and the fluctuating switching current is converted into a preliminary stable voltage signal through the working mechanism of fast charging and slow discharging, and then the low amplitude signal is amplified to the voltage order of the adaptive later stage.The application meets the driving demand of Si / SiC hybrid device, improves the flexibility and reliability of single drive circuit, effectively optimizes device switching loss, and expands the application scenario of single drive circuit.

Description

Technical Field

[0001] This invention belongs to the field of driving circuit technology, specifically relating to an adaptive active driving circuit for Si / SiC hybrid devices. Background Technology

[0002] As a wide-bandgap semiconductor material, SiC-based MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) offer higher switching speeds, providing a strong impetus for the development of modern power electronic converters towards higher frequencies. However, due to limitations in manufacturing processes, the current-carrying capacity advantage of SiC MOSFETs is not significant. Si IGBTs, on the other hand, possess strong current-carrying capacity due to their conductance modulation mechanism. The concept of Si / SiC hybrid devices combines the high switching speed of SiC MOSFETs with the strong current-carrying capacity of Si IGBTs, driving improvements in converter power density and power loss.

[0003] Dual-degree-of-freedom gate control provides greater flexibility for the application of Si / SiC hybrid devices. However, the switching losses of Si / SiC hybrid devices initially decrease and then increase with increasing turn-off delay time. Therefore, turn-off delay time becomes an important drive control parameter in this gate control mode. To save circuit costs and reduce control complexity, existing technologies use single-drive circuits for Si / SiC hybrid devices. These circuits operate by receiving a PWM (Pulse-Width Modulation) control signal and outputting a drive voltage to the common gate of the SiC MOSFET and Si IGBT through a fixed gate resistor. Simultaneously, a fixed-duration turn-off delay is generated using an RC (Resistor-Capacitor) delay unit. After the capacitor has fully charged and discharged, the drive signal triggers the hybrid device to turn off, thus achieving synchronous switching control of the two devices. However, limited by the fixed RC delay circuit, the turn-off delay time generated by the single-drive circuit cannot be flexibly adjusted. This also limits the application of single-drive circuits in various scenarios. Summary of the Invention

[0004] This invention provides an adaptive active driving circuit for Si / SiC hybrid devices, which solves the problem that the turn-off delay time generated by the single driving circuit in the prior art cannot be flexibly adjusted, and realizes the flexible adjustment of the circuit, so that the active driving circuit can be applied to a variety of scenarios.

[0005] The present invention provides an adaptive active driving circuit for Si / SiC hybrid devices, comprising: an adjustable delay driving circuit and an adaptive switching current detection circuit;

[0006] The adaptive switching current detection circuit includes a current acquisition section and a signal amplification section. The current acquisition section acquires the switching current signal of the Si / SiC hybrid device by connecting a sampling resistor in series in the current loop of the Si / SiC hybrid device. The signal amplification section amplifies the sampled switching current signal and converts it into a control voltage. ;

[0007] The adjustable delay drive circuit includes a drive control section and a delay adjustment section. The drive control section receives an external PWM signal and adjusts the delay by turning on the drive resistor. Turn off the drive resistor To achieve low voltage MOSFET The gate charging and discharging control, thereby controlling the coordinated switching operation of the Si IGBT and SiC MOSFET; the delay adjustment section receives the control voltage output by the adaptive switching current detection circuit. Feedback signal, through the first MOSFET Second MOSFET Changes in conduction characteristics of low-voltage MOSFETs Timing of gate-source voltage changes;

[0008] The control voltage Feedback is sent to the delay adjustment section of the adjustable delay drive circuit, which dynamically adjusts the turn-off delay time of the SiC MOSFET relative to the Si IGBT.

[0009] Preferably, the drive control section includes a drive chip. Turn on the drive resistor Turn off the drive resistor Low-voltage MOSFET The turn-on drive resistor Turn off the drive resistor One end is connected to the driver chip One end is connected; the turn-on driving resistor and the shutdown drive resistor The other end is connected to a low-voltage MOSFET The source pin is connected to the gate pin of the Si IGBT; the driver chip The positive power supply terminal is connected to VCC, the negative power supply terminal is connected to -VEE, and the input terminal is used to receive external PWM signals.

[0010] Preferably, the delay adjustment section includes a delay resistor. First MOSFET Second MOSFET The first MOSFET Second MOSFET It is a back-to-back structure, the first MOSFET Second MOSFET common gate pin and control voltage The negative terminal is connected; the first MOSFET The drain pin of the low-voltage MOSFET source pin, control voltage The positive terminal is connected; the low-voltage MOSFET The drain pin is connected to the gate pin of the SiC MOSFET; the low-voltage MOSFET Gate pin, second MOSFET drain pin and delay resistor One end is connected; the delay resistor The other end is connected to the source pin of the SiC MOSFET.

[0011] Preferably, the adaptive switching current detection circuit includes a current acquisition section and a signal amplification section; the input terminal of the current acquisition section acquires the switching current signal of the Si / SiC hybrid device through a sampling resistor, the output terminal of the current acquisition section is electrically connected to the input terminal of the signal amplification section, and the output terminal of the signal amplification section serves as the output terminal of the adaptive switching current detection circuit and is connected to the feedback terminal of the adjustable delay drive circuit.

[0012] Preferably, the current acquisition section includes a high-speed precision operational amplifier. Sampling resistor proportional resistor proportional resistor proportional resistor proportional resistor ,diode Charging and discharging capacitors and discharge resistor The proportional resistor proportional resistor proportional resistor and proportional resistor Constructing a high-speed precision operational amplifier The feedback network; the sampling resistor The voltage across the Si / SiC hybrid device is differentially input to the high-speed precision operational amplifier in the current loop connected in series. The input terminal of the high-speed precision operational amplifier; The output terminal is connected to a diode With charging and discharging capacitors One end is connected to the charging / discharging capacitor. The other end is grounded, and the discharge resistor With charging and discharging capacitors in parallel.

[0013] Preferably, the signal amplification section includes a high-speed precision operational amplifier. proportional resistor proportional resistor proportional resistor proportional resistor and bias voltage The high-speed precision operational amplifier The input terminal is connected to the output terminal of the current acquisition section, and the proportional resistor... proportional resistor proportional resistor proportional resistor Building high-speed precision operational amplifiers Addition and subtraction amplification feedback network, Access to high-speed precision operational amplifier The negative polarity input terminal.

[0014] Preferably, the charging and discharging capacitor in the current acquisition section The charging time constant is less than the discharging time constant, and the charging / discharging capacitor... and the discharge resistor The value of determines the charging and discharging capacitor. The time constant.

[0015] Preferably, the operation of the adjustable delay drive circuit is as follows:

[0016] When the PWM signal is low, the low-voltage MOSFET The gate-source voltage is -VEE, and the low-voltage MOSFET When in the ON state, both the Si IGBT and SiC MOSFET are OFF;

[0017] When the rising edge of the PWM arrives, the driver chip The output positive voltage is turned on by the drive resistor. Give low voltage MOSFET The input capacitor discharges in reverse, simultaneously charging the gate of the Si / SiC hybrid device to the on-state; when the low-voltage MOSFET When the gate-source voltage drops below the threshold voltage, the low-voltage MOSFET Turn off, Si IGBT and SiCMOSFET turn on;

[0018] When the falling edge of the PWM arrives, the driver chip The output negative voltage is turned off by the drive resistor. Give low voltage MOSFET The input capacitor is reverse-charged, and simultaneously the gate-emitter voltage of the Si IGBT is reduced by the turn-off drive resistor. Discharge to VEE, Si IGBT turns off; when the low-voltage MOSFET When the gate-source voltage rises to its threshold voltage, the low-voltage MOSFET When the SiC MOSFET is turned on, the gate-source voltage of the SiC MOSFET begins to discharge, and when the SiC MOSFET is turned off, it is turned off.

[0019] Preferably, the control voltage in the adjustable delay drive circuit The larger the value, the lower the voltage of the MOSFET. The lower the minimum gate-source voltage, the better; for the same charging capacity, a low-voltage MOSFET... The longer it takes to reach the threshold voltage, the longer the turn-off delay time of the SiC MOSFET. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This invention provides a schematic flowchart of an adaptive active driving circuit for Si / SiC hybrid devices.

[0022] Figure 2 A schematic diagram of an adjustable delay drive circuit for an adaptive active drive circuit of Si / SiC hybrid devices provided by the present invention.

[0023] Figure 3 The present invention provides a simulation waveform diagram of the switching process of an adaptive active drive circuit for Si / SiC hybrid devices.

[0024] Figure 4 A schematic diagram of the switching current acquisition section of an adaptive active drive circuit for Si / SiC hybrid devices provided by the present invention.

[0025] Figure 5 The present invention provides an input / output waveform diagram for an adaptive active driving circuit for Si / SiC hybrid devices. Detailed Implementation

[0026] To facilitate a clearer understanding of the objectives, technical solutions, and advantages of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art can easily understand other advantages and effects of this invention from the content disclosed in this specification.

[0027] This invention can also be implemented or applied through other different specific examples, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of this invention.

[0028] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0029] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Secondly, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0030] Combination Figure 1 The present invention describes an adaptive active driving circuit for Si / SiC hybrid devices, comprising: an adjustable delay driving circuit and an adaptive switching current detection circuit;

[0031] The adaptive switching current detection circuit includes a current acquisition section and a signal amplification section. The current acquisition section acquires the switching current signal of the Si / SiC hybrid device by connecting a sampling resistor in series in the current loop of the Si / SiC hybrid device. The signal amplification section amplifies the sampled switching current signal and converts it into a control voltage. ;

[0032] The adjustable delay drive circuit includes a drive control section and a delay adjustment section. The drive control section receives an external PWM signal and adjusts the delay by turning on the drive resistor. Turn off the drive resistor To achieve low voltage MOSFET The gate charging and discharging control, thereby controlling the coordinated switching operation of the Si IGBT and SiC MOSFET; the delay adjustment section receives the control voltage output by the adaptive switching current detection circuit. Feedback signal, through the first MOSFET Second MOSFET Changes in conduction characteristics of low-voltage MOSFETs Timing of gate-source voltage changes;

[0033] The control voltage Feedback is sent to the delay adjustment section of the adjustable delay drive circuit, which dynamically adjusts the turn-off delay time of the SiC MOSFET relative to the Si IGBT.

[0034] Combination Figure 2 This invention describes an adjustable delay drive circuit portion of an adaptive active drive circuit for Si / SiC hybrid devices.

[0035] The adjustable delay drive circuit includes a drive control section and a delay adjustment section, the drive control section including a drive chip. Turn on the drive resistor Turn off the drive resistor Low-voltage MOSFET The turn-on drive resistor Turn off the drive resistor One end is connected to the driver chip One end is connected; the turn-on driving resistor and the shutdown drive resistor The other end is connected to a low-voltage MOSFET The source pin is connected to the gate pin of the Si IGBT; the driver chip The positive power supply terminal is connected to VCC, the negative power supply terminal is connected to -VEE, and the input terminal is used to receive external PWM signals.

[0036] The delay adjustment section includes a delay resistor. First MOSFET Second MOSFET The first MOSFET Second MOSFET It is a back-to-back structure, the first MOSFET Second MOSFET common gate pin and control voltage The negative terminal is connected; the first MOSFET The drain pin of the low-voltage MOSFET source pin, control voltage The positive terminal is connected; the low-voltage MOSFET The drain pin is connected to the gate pin of the SiC MOSFET; the low-voltage MOSFET Gate pin, second MOSFET drain pin and delay resistor One end is connected; the delay resistor The other end is connected to the source pin of the SiC MOSFET.

[0037] Combination Figure 3 The adjustable delay drive circuit operates as follows: when the PWM signal is low, the low-voltage MOSFET... The gate-source voltage is -VEE, and the low-voltage MOSFET When in the ON state, both the Si IGBT and SiC MOSFET are OFF;

[0038] When the rising edge of the PWM arrives, the driver chip The output positive voltage is turned on by the drive resistor. Give low voltage MOSFET The input capacitor discharges in reverse, simultaneously charging the gate of the Si / SiC hybrid device to the on-state; when the low-voltage MOSFET When the gate-source voltage drops below the threshold voltage, the low-voltage MOSFET Turn off, Si IGBT and SiCMOSFET turn on;

[0039] When the falling edge of the PWM arrives, the driver chip The output negative voltage is turned off by the drive resistor. Give low voltage MOSFET The input capacitor is reverse-charged, and simultaneously the gate-emitter voltage of the Si IGBT is reduced by the turn-off drive resistor. Discharge to VEE, Si IGBT turns off; when the low-voltage MOSFET When the gate-source voltage rises to its threshold voltage, the low-voltage MOSFET When the SiC MOSFET is turned on, the gate-source voltage of the SiC MOSFET begins to discharge, and when the SiC MOSFET is turned off, it is turned off.

[0040] Control voltage with current feedback The size affects the low voltage MOSFET The lowest possible gate-source voltage. A higher control voltage means a lower gate-source voltage. For the same charging capability, a low-voltage MOSFET... The longer it takes to reach the threshold voltage, the longer the turn-off delay time of the SiC MOSFET.

[0041] In a stable circuit state, when the rising edge of the PWM arrives, the first MOSFET... Second MOSFET The charging process of the gate-drain voltage can be represented as:

[0042]

[0043] In the formula, Indicates the second MOSFET The gate-drain voltage at time t. Indicates the second MOSFET of The gate-drain voltage at time t.

[0044] Based on the principle of circuit equivalence, the relationship between its gate-source voltage and gate-drain voltage can be approximately proportional:

[0045]

[0046] In the formula, k is a constant. For the first MOSFET or second MOSFET The gate-source voltage at time t.

[0047] Meanwhile, low-voltage MOSFET The discharge and reverse charging process can be represented as:

[0048]

[0049] The time constant is:

[0050]

[0051] In the formula, It is a time constant. Equivalent capacitance;

[0052] When the first MOSFET Second MOSFET When the gate-source voltage reaches its threshold voltage, the low-voltage MOSFET Reverse charging stops, reaching its minimum gate-source voltage. .

[0053] When the falling edge of the PWM arrives, the low-voltage MOSFET can be derived based on circuit principles. The expression for the gate-source voltage is:

[0054]

[0055] Low voltage MOSFET The time to reach the Miller voltage is the turn-off delay time, and its calculation formula is as follows:

[0056]

[0057] In the formula, To disable the delay time, Low voltage MOSFET Gate-source Miller voltage, for Low-voltage MOSFET at time The actual gate-source voltage, Low voltage MOSFET The reference time for the gate charging process.

[0058] Combination Figure 4 This invention describes an adaptive switching current detection circuit for an adaptive active drive circuit of a Si / SiC hybrid device, including a current acquisition section and a signal amplification section.

[0059] The input terminal of the current acquisition section acquires the switching current signal of the Si / SiC hybrid device through a sampling resistor. The output terminal of the current acquisition section is electrically connected to the input terminal of the signal amplification section. The output terminal of the signal amplification section serves as the output terminal of the adaptive switching current detection circuit and is connected to the feedback terminal of the adjustable delay drive circuit.

[0060] The current acquisition section includes a high-speed precision operational amplifier. Sampling resistor proportional resistor proportional resistor proportional resistor proportional resistor ,diode Charging and discharging capacitors and discharge resistor The proportional resistor proportional resistor proportional resistor and proportional resistor Constructing a high-speed precision operational amplifier The feedback network; the sampling resistor The voltage across the Si / SiC hybrid device is differentially input to the high-speed precision operational amplifier in the current loop connected in series. The input terminal of the high-speed precision operational amplifier; The output terminal is connected to a diode With charging and discharging capacitors One end is connected to the charging / discharging capacitor. The other end is grounded, and the discharge resistor With charging and discharging capacitors in parallel;

[0061] Furthermore, the current acquisition section operates as follows: When the device is turned on, the device current rises, and the voltage drop across the sampling resistor increases. Diode D1 conducts, and the output voltage charges capacitor C1. The output voltage rises along with the input voltage. The specific current path diagram is shown in the figure. When the device is turned off, the device current decreases, and the voltage drop across the sampling resistor becomes 0. Since the voltage across the charging / discharging capacitor C1 cannot change abruptly, the cathode voltage of the diode is higher than the anode voltage, and the diode does not conduct. At this time, the capacitor discharges through the parallel discharge resistor. The specific current path diagram is shown in the figure. When the next turn-on occurs, the above process is repeated until the output voltage remains essentially constant.

[0062] Furthermore, the charging and discharging capacitor in the current acquisition section The charging time constant is smaller than the discharging time constant. In this invention, the PWM duty cycle used is 0.4-0.6, so when the current flowing through the device decreases, the output voltage is still higher than the input voltage. At this time, the diode is still not conducting, thus the capacitor is charged and discharged. Continue through the discharge resistor Discharge. The circuit reaches stability when the output voltage is lower than the input voltage. With reasonable values ​​for the discharge resistor and charging / discharging capacitor, the ripple of the charging / discharging capacitor can be largely ignored, approximating a steady-state value. Thus, the circuit achieves a steady-state output forward current value with the device switching current as input.

[0063] Assume the forward current flowing through the hybrid device is The voltage across the sampling resistor is According to Ohm's law, we can obtain:

[0064]

[0065] Based on the principles of virtual short and virtual open in differential amplifier circuits, the corresponding calculation formula can be obtained as follows:

[0066]

[0067] In the formula, For high-speed precision operational amplifiers The output voltage.

[0068] The charging and discharging of capacitor C1 is equivalent to a constant current charging process. This process is driven by the output current of the operational amplifier. The output of this stage of the circuit requires a voltage drop across a diode, calculated as follows:

[0069]

[0070] In the formula, This is the charging voltage input to the charging / discharging capacitor C1. This is the voltage drop across the diode.

[0071] Based on the definitions of current and voltage in a capacitor, the corresponding mathematical expression can be obtained, where This is the maximum output current of the op-amp:

[0072]

[0073] The discharge of capacitor C1 is equivalent to an RC discharge circuit. The mathematical expression for this process, based on the zero-input response of a first-order circuit, is as follows:

[0074]

[0075] Its time constant is shown below:

[0076]

[0077] The formula shows that in the current acquisition section, the values ​​of the charging / discharging capacitor C1 and the discharging resistor R5 are related to the time constant of the circuit, thus affecting the response speed of the current detection circuit and the degree of output voltage fluctuation. When the junction temperature or current approaches the edge of the safe range, the current detection response speed must be as fast as possible to prevent extreme conditions such as overheating or overcurrent. In this case, the capacitance value needs to be appropriately reduced to ensure a fast response. Therefore, temperature-sensitive capacitors and temperature-sensitive resistors can be used for adjustment. Alternatively, commercially available variable capacitors or variable resistors can be used to construct a feedback loop for control.

[0078] Furthermore, the signal amplification section includes a high-speed precision operational amplifier. proportional resistor proportional resistor proportional resistor proportional resistor and bias voltage The high-speed precision operational amplifier The input terminal is connected to the output terminal of the current acquisition section, and the proportional resistor... proportional resistor proportional resistor proportional resistor Building high-speed precision operational amplifiers Addition and subtraction amplification feedback network, Access to high-speed precision operational amplifier The negative polarity input terminal.

[0079] The signal amplification section is based on an additive and subtractive amplifier circuit. The voltage signal input to the preamplifier is typically in the mV range; by changing the proportional resistor value, it can be amplified to a V-range voltage signal to meet the requirements of subsequent circuits. A bias voltage is also set at the negative terminal of the operational amplifier. This improves the flexibility of circuit design. The specific calculation formula is as follows:

[0080]

[0081] Combination Figure 5 This figure shows the simulation results of the adaptive switching current detection circuit, demonstrating that the circuit can convert fluctuating switching current into a stable and adaptable voltage signal, suitable for wide load applications. It uses a continuous square wave as the signal input to replace the device's switching current, taking the common power electronic converter switching frequency of 30kHz as the square wave frequency. To observe the feasibility of the designed circuit under wide load applications, the maximum value of the input signal was successively set to 400mV, 200mV, 100mV, and 300mV for simulation. The waveform exhibits periodic fluctuation characteristics of rapid rise and fall followed by stable holding. The output consists of four sets of stable DC voltage signals without significant ripple, and the output voltage amplitude is strictly positively correlated with the input square wave amplitude, achieving signal amplification from the mV to the V level. This waveform verifies that the adaptive switching current detection circuit can effectively suppress the overshoot oscillation of the switching current, converting the fluctuating switching current into a stable voltage signal suitable for subsequent circuit requirements.

[0082] This invention relates to an adaptive active drive circuit for Si / SiC hybrid devices, comprising an adjustable delay drive circuit and an adaptive switching current detection circuit. Addressing the shortcomings of existing single-drive circuits, such as non-adjustable turn-off delay and large switching current detection errors, the adaptive switching current detection circuit converts fluctuating switching current into a stable voltage through capacitor charging and discharging and signal amplification. This voltage then provides feedback control to the adjustable delay drive circuit, adjusting the low-voltage MOSFET. The circuit optimizes the charge / discharge timing to achieve adaptive adjustment of the turn-off delay in Si / SiC hybrid devices. This circuit is adaptable to a wide range of load scenarios, improving the operational flexibility and stability of the devices and expanding the application scope of single-drive circuits.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An adaptive active driving circuit for Si / SiC hybrid devices, characterized in that, include: Adjustable delay drive circuit and adaptive switching current detection circuit; The adaptive switching current detection circuit includes a current acquisition section and a signal amplification section. The current acquisition section acquires the switching current signal of the Si / SiC hybrid device by connecting a sampling resistor in series in the current loop of the Si / SiC hybrid device. The signal amplification section amplifies the sampled switching current signal and converts it into a control voltage. ; The adjustable delay drive circuit includes a drive control section and a delay adjustment section. The drive control section receives an external PWM signal and adjusts the delay by turning on the drive resistor. Turn off the drive resistor To achieve low voltage MOSFET The gate charging and discharging control, thereby controlling the coordinated switching operation of the Si IGBT and SiC MOSFET; the delay adjustment section receives the control voltage output by the adaptive switching current detection circuit. Feedback signal, through the first MOSFET Second MOSFET Changes in conduction characteristics of low-voltage MOSFETs The timing sequence of gate-source voltage changes; the drive control section includes a drive chip. Turn on the drive resistor Turn off the drive resistor Low-voltage MOSFET The turn-on drive resistor Turn off the drive resistor One end is connected to the driver chip One end is connected; the turn-on driving resistor and the shutdown drive resistor The other end is connected to a low-voltage MOSFET The source pin is connected to the gate pin of the Si IGBT; the driver chip The positive power supply terminal is connected to VCC, the negative power supply terminal is connected to -VEE, and the input terminal is used to receive external PWM signals; the delay adjustment section includes a delay resistor. First MOSFET Second MOSFET The first MOSFET Second MOSFET It is a back-to-back structure, the first MOSFET Second MOSFET common gate pin and control voltage The negative terminal is connected; the first MOSFET The drain pin of the low-voltage MOSFET source pin, control voltage The positive terminal is connected; the low-voltage MOSFET The drain pin is connected to the gate pin of the SiC MOSFET; the low-voltage MOSFET Gate pin, second MOSFET drain pin and delay resistor One end is connected; the delay resistor The other end is connected to the source pin of the SiC MOSFET; The control voltage Feedback is sent to the delay adjustment section of the adjustable delay drive circuit, which dynamically adjusts the turn-off delay time of the SiC MOSFET relative to the Si IGBT.

2. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 1, characterized in that, The adaptive switching current detection circuit includes a current acquisition section and a signal amplification section. The input terminal of the current acquisition section acquires the switching current signal of the Si / SiC hybrid device through a sampling resistor. The output terminal of the current acquisition section is electrically connected to the input terminal of the signal amplification section. The output terminal of the signal amplification section serves as the output terminal of the adaptive switching current detection circuit and is connected to the feedback terminal of the adjustable delay drive circuit.

3. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 2, characterized in that, The current acquisition section includes a high-speed precision operational amplifier. Sampling resistor proportional resistor proportional resistor proportional resistor proportional resistor ,diode Charging and discharging capacitors and discharge resistor The proportional resistor proportional resistor proportional resistor and proportional resistor Constructing a high-speed precision operational amplifier The feedback network; the sampling resistor The voltage across the Si / SiC hybrid device is differentially input to the high-speed precision operational amplifier in the current loop connected in series. The input terminal of the high-speed precision operational amplifier; The output terminal is connected to a diode With charging and discharging capacitors One end is connected to the charging / discharging capacitor. The other end is grounded, and the discharge resistor With charging and discharging capacitors in parallel.

4. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 2, characterized in that, The signal amplification section includes a high-speed precision operational amplifier. proportional resistor proportional resistor proportional resistor proportional resistor and bias voltage The high-speed precision operational amplifier The input terminal is connected to the output terminal of the current acquisition section, and the proportional resistor... proportional resistor proportional resistor proportional resistor Building high-speed precision operational amplifiers Addition and subtraction amplification feedback network, Access to high-speed precision operational amplifier The negative polarity input terminal.

5. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 3, characterized in that, The charging and discharging capacitor in the current acquisition section The charging time constant is less than the discharging time constant, and the charging / discharging capacitor... and the discharge resistor The value of determines the charging and discharging capacitor. The time constant.

6. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 1, characterized in that, The operation process of the adjustable delay drive circuit is as follows: When the PWM signal is low, the low-voltage MOSFET The gate-source voltage is -VEE, and the low-voltage MOSFET When in the ON state, both the Si IGBT and SiC MOSFET are OFF; When the rising edge of the PWM arrives, the driver chip The output positive voltage is turned on by the drive resistor. Give low voltage MOSFET The input capacitor discharges in reverse, simultaneously charging the gate of the Si / SiC hybrid device to the on-state; when the low-voltage MOSFET When the gate-source voltage drops below the threshold voltage, the low-voltage MOSFET Turn off, Si IGBT and SiCMOSFET turn on; When the falling edge of the PWM arrives, the driver chip The output negative voltage is turned off by the drive resistor. Give low voltage MOSFET The input capacitor is reverse-charged, and simultaneously the gate-emitter voltage of the Si IGBT is reduced by the turn-off drive resistor. Discharge to VEE, Si IGBT turns off; when the low-voltage MOSFET When the gate-source voltage rises to its threshold voltage, the low-voltage MOSFET When the SiC MOSFET is turned on, the gate-source voltage of the SiC MOSFET begins to discharge, and when the SiC MOSFET is turned off, it is turned off.

7. The adaptive active driving circuit for Si / SiC hybrid devices according to claim 1, characterized in that, Control voltage in the adjustable delay drive circuit The larger the value, the lower the voltage of the MOSFET. The lower the minimum gate-source voltage, the better; for the same charging capacity, a low-voltage MOSFET... The longer it takes to reach the threshold voltage, the longer the turn-off delay time of the SiC MOSFET.

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