Resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit

Abstract

The invention relates to the field of driving of power electronic devices, and provides a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit, which comprises an upper bridge arm unit and a lower bridge arm unit, and is characterized in that the upper bridge arm unit and the lower bridge arm unit respectively comprise a driving loop, a resonance-assisted branch, a low-impedance loop and a SiC MOSFET which are connected in sequence, the low-impedance loop comprises an NPN triode Q1, a PNP triode Q2, a diode D2 connected with an emitting electrode and a grid electrode of the NPN triode Q1, a diode D3 connected with an emitting electrode and a grid electrode of the PNP triode Q2, and a capacitor C8 of which one end is connected with a collector electrode of the NPN triode Q1 and a collector electrode of the PNP triode Q2 and the other end is connected with a source electrode, and a base electrode of the NPN triode Q1 and a base electrode of the PNP triode Q2 are connected with the resistance module; according to the invention, the Miller current is shunted, and the positive and negative voltage spikes are suppressed.

Description

Technical Field

[0001] The present invention relates to the technical field of driving power electronic devices, and in particular to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit. Background Art

[0002] Wide bandgap semiconductor device SiC MOSFET (SiC Metal-Oxide-Semiconductor Field-Effect Transistor) is widely used in smart grid, new energy vehicles, photovoltaic inverters and other fields due to its advantages of high switching speed, low conduction loss and high temperature resistance. As the switching frequency and speed increase, the device will generate a larger d v / d t and d i / d t , and there are parasitic parameters in the devices and circuits, which leads to crosstalk between the upper bridge arm unit and the lower bridge arm unit.

[0003] The impact of crosstalk can only be weakened but not eliminated fundamentally. In addition to optimizing circuit layout and improving device packaging structure, the driving side of high-power SiC MOSFET devices is a hot topic of current research. The driving design to suppress crosstalk is mainly divided into the following two categories: changing the gate drive resistance and realizing multi-level gate drive voltage. Changing the gate drive resistance will increase the switching speed and loss. Multi-level gate drive voltage mainly suppresses positive crosstalk by using negative voltage and suppresses negative crosstalk by zero voltage, but active devices and external control signals will increase the difficulty and complexity of control. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit to achieve Miller current shunting and suppress positive and negative voltage spikes.

[0005] The present invention provides a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit, comprising: an upper bridge arm unit and a lower bridge arm unit, wherein the upper bridge arm unit and the lower bridge arm unit each comprise a driving circuit, a resonance-assisted branch, a low-impedance circuit and a SiC MOSFET connected in sequence, wherein the SiC MOSFETs of the upper bridge arm unit and the lower bridge arm unit are connected in series; the low-impedance circuit comprises a diode D 2 ,diode D 3 ,capacitance C 8 、NPN transistor Q1 、PNP transistor Q 2 and resistor modules, the NPN transistor Q 1 The base of the PNP transistor Q 2 The base of the NPN transistor is connected to the resistor module. Q 1 The emitter and diode D 2 The anode of the diode is connected D 2 The cathode of the SiC MOSFET is connected to the gate of the PNP transistor. Q 2 The emitter of the diode D 3 The cathode of the diode is connected D 3 The anode of the SiC MOSFET is connected to the gate of the capacitor C 8 One end of the NPN transistor Q 1 The collector of the PNP transistor Q 2 The collector connection of the capacitor C 8 The other end is connected to the source of the SiC MOSFET.

[0006] According to a resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the resonant auxiliary branch includes a resistor R 1 ,capacitance C 7 ,diode D 4 ,diode D 6 ,inductance L 1 ,diode D 5 ,resistance R 4 , Zener diodes and capacitors C 9 , the capacitor C 7 One end of the capacitor is connected to the output end of the driving circuit, and the capacitor C 7 The other end is connected to the resistor module. R 1 and the diodeD 4 In parallel with the capacitor C 7 Both ends of the diode D 6 The cathode is connected to the resistor module, and the diode D 6 The anode and the inductor L 1 In series, the inductor L 1 One end of the diode is connected to the source of the SiC MOSFET; D 5 The anode of the diode is connected to the resistor module. D 5 The cathode and the resistor R 4 One end of the resistor is connected R 4 The other end of the capacitor is connected to the source of the SiC MOSFET; C 9 and the Zener diode is connected in parallel with the resistor R 4 The anode of the voltage stabilizing diode is connected to the source of the SiC MOSFET, and the cathode of the voltage stabilizing diode is connected to the diode D 5 anode connection.

[0007] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive circuit includes a power supply module, a pulse control module and a drive module, the output end of the power supply module supplies power to the drive module, the output end of the drive module is connected to the resonance-assisted branch, and the pulse control module is connected to both sides of the drive module.

[0008] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the pulse control module adopts pulse width modulation technology for control.

[0009] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive circuit also includes a capacitor C 4 , the capacitor C 4 The module is connected to both sides of the driving module and is connected in parallel with the pulse control module.

[0010] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive module includes an ACPL-P346 optical coupler.

[0011] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive circuit also includes a capacitor C 1 , the capacitor C 1 In parallel with the power module, the capacitor C 1 The end closest to the negative terminal of the power supply is grounded.

[0012] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the resistor module includes a driving resistor R 2 , driving resistance R 3 and diode D 1 , the driving resistance R 2 One end of the drive resistor is connected to the resonant auxiliary branch. R 2 The other end of the drive resistor R 3 One end of the drive resistor is connected R 3 The other end of the diode is connected to the gate of the SiC MOSFET. D 1 With the driving resistor R 3 Set in parallel, the diodes D 1 The anode of the SiC MOSFET is connected to the gate of the diode D 1 The cathode and the driving resistor R 2 connect.

[0013] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the SiC MOSFET includes a MOSFET, a gate-drain parasitic capacitor C gd , gate-source parasitic capacitance C gs and drain-source parasitic capacitance C ds , the gate-drain parasitic capacitance C gdThe two ends of the MOSFET are connected to the gate and drain, and the gate-source parasitic capacitance C gs The two ends of the MOSFET are connected to the gate and source, and the drain-source parasitic capacitance C ds The two ends of the MOSFET are connected to the drain and source.

[0014] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the source of the MOSFET of the upper bridge arm unit is connected to the drain of the MOSFET of the lower bridge arm unit.

[0015] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: According to the resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit of the embodiment of the present invention, by setting the NPN transistor Q 1 and the PNP transistor Q 2 After parallel connection with capacitor C 8 It is connected to one end of the circuit to shunt the Miller current and reduce the positive and negative gate-source voltage spikes without the need for external control. When protecting the device, the switching speed and switching loss will not increase significantly.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention.

[0019] Figure 2 It is a switching timing waveform diagram of a SiCMOSFET half-bridge circuit of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention.

[0020] FIG3( a ) is one of the working schematic diagrams of the SiC MOSFET gate drive circuit of the upper bridge arm unit of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention in various time periods.

[0021] FIG3( b ) is a second schematic diagram of the operation of the SiC MOSFET gate drive circuit of the upper bridge arm unit of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention in various time periods.

[0022] FIG3( c ) is a third schematic diagram of the operation of the SiC MOSFET gate drive circuit of the upper bridge arm unit of the resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention in various time periods.

[0023] FIG4( a ) is a comparison diagram of simulation results of negative peak voltages of an upper arm unit of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention and a traditional driving circuit.

[0024] FIG4( b ) is a comparison diagram of simulation results of the forward peak voltage of an upper bridge arm unit of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention and a traditional driving circuit. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0026] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0027] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0028] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0029] Figure 1 It is a structural schematic diagram of a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention.

[0030] The present invention provides a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit, such as Figure 1 As shown, the resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit includes: an upper bridge arm unit and a lower bridge arm unit, each of which includes a driving circuit, a resonance-assisted branch, a low-impedance circuit and a SiC MOSFET connected in sequence, and the SiC MOSFETs of the upper bridge arm unit and the lower bridge arm unit are connected in series; the low-impedance circuit includes a diode D 2 ,diode D 3 ,capacitance C 8 、NPN transistor Q 1 、PNP transistor Q 2 and resistor modules, the NPN transistor Q 1 The base of the PNP transistor Q 2 The base of the NPN transistor is connected to the resistor module. Q 1 The emitter and diodeD 2 The anode of the diode is connected D 2 The cathode of the SiC MOSFET is connected to the gate of the PNP transistor. Q 2 The emitter of the diode D 3 The cathode of the diode is connected D 3 The anode of the SiC MOSFET is connected to the gate of the capacitor C 8 One end of the NPN transistor Q 1 The collector of the PNP transistor Q 2 The collector connection of the capacitor C 8 The other end is connected to the source of the SiC MOSFET.

[0031] In this embodiment, by setting the NPN transistor Q 1 and the PNP transistor Q 2 After parallel connection with capacitor C 8 It is connected to one end of the circuit to shunt the Miller current and reduce the positive and negative gate-source voltage spikes without the need for external control. When protecting the device, the switching speed and switching loss will not increase significantly.

[0032] According to some preferred embodiments of the present invention, a low impedance loop is used to shunt the Miller current, thereby increasing the capacitance of the gate-source electrode and reducing the positive and negative voltage spikes between the gate-source electrode.

[0033] According to some preferred embodiments of the present invention, the low impedance loop includes an NPN transistor connected at both ends of the resistor module. Q 1 and diode D 2 Open the anti-crosstalk branch and the PNP transistor connected to both ends of the resistor module Q 2 and diode D 3 Turn off the anti-crosstalk branch and match the capacitor C 8 , through the capacitor C 8 Diversion.

[0034] According to some embodiments of the present invention, a resistance module in the driving part is used for design, two diodes and two transistors are connected in series with a capacitor to form a low-impedance loop, and the transistor is connected at both ends of the resistance module. When the voltage difference at both ends of the resistance module reaches the turn-on voltage of the transistor, the transistor-connected capacitor branch is turned on, so that the low-impedance branch is connected in parallel to the gate-source of the SiCMOSFET device, shunting the Miller current and reducing the positive and negative gate-source voltage spikes. No external control is required, and the switching speed and switching loss will not increase significantly when protecting the device.

[0035] According to a resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, Figure 1 As shown, the resonant auxiliary branch includes a resistor R 1 ,capacitance C 7 ,diode D 4 ,diode D 6 ,inductance L 1 ,diode D 5 ,resistance R 4 , Zener diodes and capacitors C 9 , the capacitor C 7 One end of the capacitor is connected to the output end of the driving circuit, and the capacitor C 7 The other end is connected to the resistor module. R 1 and the diode D 4 In parallel with the capacitor C 7 Both ends of the diode D 6 The cathode is connected to the resistor module, and the diode D 6 The anode and the inductor L 1 In series, the inductor L 1 One end of the diode is connected to the source of the SiC MOSFET; D 5 The anode of the diode is connected to the resistor module. D 5 The cathode and the resistor R 4 One end of the resistor is connected R4 The other end of the capacitor is connected to the source of the SiC MOSFET; C 9 and the Zener diode is connected in parallel with the resistor R 4 The anode of the voltage stabilizing diode is connected to the source of the SiC MOSFET, and the cathode of the voltage stabilizing diode is connected to the diode D 5 anode connection.

[0036] In this embodiment, the resonant auxiliary branch adopts resistor and capacitor voltage division, and the inductor and capacitor resonance generates a multi-level gate drive voltage to prevent the positive crosstalk from causing the SiC MOSFET device to be mis-turned on and the negative crosstalk between the upper bridge arm unit and the lower bridge arm unit during the negative voltage aggravated shutdown transient, which causes the SiC MOSFET device to break down in reverse. A method combining the resonant auxiliary branch and the low-impedance loop is adopted, and the positive and negative drive voltages are obtained by voltage division using passive devices such as capacitors and resistors, and then a voltage slightly higher than the zero level is obtained through inductor and capacitor resonance, so as to realize the multi-level gate drive voltage. When positive crosstalk occurs, it is suppressed by negative voltage, and when negative crosstalk occurs, it is suppressed by zero voltage, so as to prevent the negative crosstalk between the upper bridge arm unit and the lower bridge arm unit during the negative voltage aggravated shutdown transient, which causes the negative crosstalk between the upper bridge arm unit and the lower bridge arm unit to exceed the negative withstand voltage value of the switch tube and break down, without adding an additional voltage source, and saving costs.

[0037] According to a resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, Figure 1 As shown, the driving circuit includes a power supply module, a pulse control module and a driving module. The output end of the power supply module supplies power to the driving module, the output end of the driving module is connected to the resonant auxiliary branch, and the pulse control module is connected to both sides of the driving module.

[0038] In this embodiment, the pulse control module is connected to both sides of the driving module to realize the control of turning on and off the SiCMOSFET device.

[0039] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the pulse control module adopts pulse width modulation technology for control.

[0040] In this embodiment, pulse width modulation technology is used to digitize the analog signal and then control the level of the output signal through pulse widths with different duty cycles.

[0041] According to some embodiments of the present invention, the width modulation technology for control (Pulse-Width Modulation, PWM) includes PWM1 mode and PWM2 mode. PWM1 mode: when the duty cycle is 0, a low level is output, when the duty cycle is 100%, a high level is output, and when the duty cycle is 1%, a 1% high level is output. The period of its output pulse remains unchanged, but the width of the pulse changes with the duty cycle; PWM2 mode: when the duty cycle is 0, a low level is output, when the duty cycle is 100%, a high level is output, and when the duty cycle is 1%, a 99% low level is output. The period and pulse width of its output pulse both change with the duty cycle.

[0042] According to some preferred embodiments of the present invention, the pulse control module adopts PWM1 mode.

[0043] According to a resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, Figure 1 As shown, the driving circuit also includes a capacitor C 4 , the capacitor C 4 The module is connected to both sides of the driving module and is connected in parallel with the pulse control module.

[0044] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive module includes an ACPL-P346 optical coupler.

[0045] In this embodiment, an ACPL-P346 optical coupler is used to control the on and off of the SiC MOSFET device. According to some embodiments of the present invention, an ACPL-P346 optocoupler is used to provide voltage and high peak output current, which is suitable for directly driving SiC MOSFET at high frequency to achieve high efficiency conversion.

[0046] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive circuit also includes a capacitor C 1 , the capacitor C 1 In parallel with the power module, the capacitor C 1 The end closest to the negative terminal of the power supply is grounded.

[0047] According to a resonant auxiliary low impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, Figure 1 As shown, the resistance module includes a driving resistance R 2 , driving resistanceR 3 and diode D 1 , the driving resistance R 2 One end of the drive resistor is connected to the resonant auxiliary branch. R 2 The other end of the drive resistor R 3 One end of the drive resistor is connected R 3 The other end of the diode is connected to the gate of the SiC MOSFET. D 1 With the driving resistor R 3 Set in parallel, the diodes D 1 The anode of the SiC MOSFET is connected to the gate of the diode D 1 The cathode and the driving resistor R 2 connect.

[0048] In this embodiment, by setting the diode D 1 , control the resistance size of the resistance module.

[0049] According to some embodiments of the present invention, the diode D 1 On, current flows only through the driving resistor R 2 ,diode D 1 Off, current flows through the drive resistor R 2 and drive resistance R 3 , relative to the diode D 1 On state, resistance increases.

[0050] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the SiC MOSFET includes a MOSFET, a gate-drain parasitic capacitor C gd , gate-source parasitic capacitance C gs and drain-source parasitic capacitance C ds , the gate-drain parasitic capacitance C gd The two ends of the MOSFET are connected to the gate and drain, and the gate-source parasitic capacitanceC gs The two ends of the MOSFET are connected to the gate and source, and the drain-source parasitic capacitance C ds The two ends of the MOSFET are connected to the drain and source.

[0051] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention, the drive circuit also includes a capacitor C 2 ,capacitance C 3 ,capacitance C 5 and capacitor C 6 , the capacitor C 2 One end of the capacitor is connected to the positive output end of the power module. C 2 The other end of the capacitor is connected to the NP end of the power module. C 3 One end of the capacitor is connected to the NP end of the power module. C 3 The other end of the capacitor is connected to the ground terminal of the power module. C 3 The other end of the capacitor is grounded. C 5 One end of the capacitor is connected to the positive electrode of the power supply of the driving module. C 5 The other end of the capacitor is connected to the source of the MOSFET. C 6 One end of the capacitor is connected to the positive power supply of the driving module and the positive output end of the power module. C 6 The other end is grounded.

[0052] According to a resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit provided by the present invention, the source of the MOSFET of the upper bridge arm unit is connected to the drain of the MOSFET of the lower bridge arm unit.

[0053] Figure 2It is a switching timing waveform diagram of a SiCMOSFET half-bridge circuit of a resonant assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention. Figure 3(a) is one of the working schematic diagrams of the SiC MOSFET gate drive circuit of the upper bridge arm unit of a resonant assisted low-impedance SiCMOSFET crosstalk suppression drive circuit provided by the present invention in various time periods. Figure 3(b) is a second working schematic diagram of the SiC MOSFET gate drive circuit of the upper bridge arm unit of a resonant assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention in various time periods. Figure 3(c) is a third working schematic diagram of the SiC MOSFET gate drive circuit of the upper bridge arm unit of a resonant assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention in various time periods. Taking the switching transient of the lower bridge arm unit as an example, the crosstalk suppression process of the upper bridge arm unit drive circuit is analyzed. Figure 2 To illustrate the working principle of the resonant assisted low impedance SiC MOSFET crosstalk suppression drive circuit, the details are as follows: t 0 -t 1 : Down tube Q L (SiC MOSFET of the lower bridge unit) is in full conduction state, and the upper tube Q H (SiC MOSFET of the upper bridge arm unit) is in a completely off state, the resonant auxiliary branch is turned on, and the inductor L 1 and capacitor C 7 Resonance, Capacitance C 7 The energy on the inductor L 1 transfer, as the capacitance C 7 Energy to Inductor L 1 Constantly transfer, capacitance C 7 The voltage continues to drop to 0V, and then the diode D 4 Under the clamping condition, the capacitor voltage maintains the forward voltage drop of a diode.

[0054] t 1 -t 4 : Down tube Q L Shutdown, upper tube Q H It is still in the fully off state, the resonant auxiliary branch is in the on state, and the gate-source voltage of the upper tube is within a diode D 4The forward conduction voltage drop value, when the current tube Q L When shut down, the upper tube Q H The voltage between the drain and source drops rapidly, and the current begins to discharge the Miller capacitor. The discharge current flows through the drive resistor. R 2 and drive resistance R 3 The voltage difference between the left high and the right low is formed, which raises the gate-source voltage of the upper tube and causes the transistor to Q 1 Series Capacitor C 8 The branch is turned on, forming a low impedance loop, and the discharge current flows through C 8 The current flow diagram is shown in Figure 3(a). When negative crosstalk occurs, the capacitor with a slight positive voltage C 7 The low impedance loop can effectively suppress the peak value of the negative spike and protect the gate from breakdown.

[0055] t 4 -t 5 : Down tube Q L and top tube Q H All are turned off, and the single-phase upper bridge arm unit is in a dead zone state. At this time, there is no current in the drive circuit and the low-impedance circuit does not work.

[0056] t 5 -t 6 : Down tube Q L In the off state, the upper tube Q H As shown in Figure 3(b), the diode D 5 Conductivity, resistance and capacitance, passive components such as voltage divider, capacitor C 9 , the Zener diode simultaneously clamps the gate-source voltage to V C9 + V D5 Since the diode D 2 and D 3 It has unidirectional conductivity, so low impedance loops do not work.

[0057] t 6 -t 7 : Down tube Q L In the off state, the upper tube Q HIn the off state, the resonant auxiliary branch is turned on, and the inductor L 1 and capacitor C 7 Resonance, Capacitance C 7 The energy on the inductor L 1 By designing the energy transfer time, it is possible to provide negative voltage to suppress the positive crosstalk peak when the positive crosstalk comes.

[0058] t 7 -t 10 : Down tube Q L Open, put on the pipe Q H In the off state, the resonant auxiliary branch is in the on state. Q L When opening, the upper tube Q H The voltage between the drain and source rises rapidly, and the current begins to charge the Miller capacitor. The charging current flows through the driving resistor R 2 The voltage difference between the left low and the right high is formed, which raises the gate-source voltage of the upper tube and causes the transistor to Q 2 Series Capacitor C 8 The branch is turned on, forming a low impedance loop, and the charging current flows through C 8 The current flow diagram is shown in Figure 3(c). When positive crosstalk occurs, the capacitor with negative voltage C 7 The low impedance loop can effectively suppress the peak value of the positive spike and prevent the upper tube Q H Misleading conduction leads to short circuit of the upper bridge arm unit.

[0059] Figure 4 (a) is a comparison diagram of the simulation results of the negative peak voltage of the upper bridge arm unit of a resonant assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention and a traditional drive circuit. Figure 4 (b) is a comparison diagram of the simulation results of the positive peak voltage of the upper bridge arm unit of a resonant assisted low-impedance SiC MOSFET crosstalk suppression drive circuit provided by the present invention and a traditional drive circuit. In order to compare the effect of the present invention on suppressing the crosstalk of the upper bridge arm unit, this embodiment builds a double pulse test platform based on simulation software to compare the crosstalk suppression effect of the traditional drive circuit and the present invention. The device model used by SiC MOSFET is the C3M0040120D model provided by CREE. In this embodiment, the load inductance is 125μH, the bus capacitance is 320μF, and the bus voltage is 400V. As shown in the comparison result of Figure 4(a), the negative peak voltage of the conventional drive circuit is -7.67V, while the negative peak voltage of the optimized drive circuit is -1.56V; as shown in the comparison result of Figure 4(b), the positive peak voltage of the conventional drive circuit is 2.32V, while the positive peak voltage of the optimized drive circuit is -1.10V. The resonant auxiliary low impedance SiC MOSFET crosstalk suppression drive circuit proposed in the present invention has a good suppression effect on both positive and negative crosstalk, and only passive devices are used, no additional control signals are required, the structure is simple, and it is easy to implement.

[0060] Compared with the prior art, the resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit of the embodiment of the present invention has the following technical effects: The combination of a resonant auxiliary branch and a low-impedance loop effectively suppresses the crosstalk between the upper bridge arm unit and the lower bridge arm unit. While protecting the device, the switching speed and switching loss will not increase significantly. There is no need to add additional voltage sources and external controls, which saves costs and reduces circuit complexity.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit, characterized in that: It includes an upper bridge arm unit and a lower bridge arm unit, each of which includes a driving circuit, a resonant auxiliary branch, a low impedance circuit and a SiC MOSFET connected in sequence, and the SiC MOSFETs of the upper bridge arm unit and the lower bridge arm unit are connected in series; The low impedance loop includes a diode D 2. Diode D 3. Capacitor C 8. NPN transistor Q 1. PNP transistor Q 2 and resistor modules, the NPN transistor Q 1 base and the PNP transistor Q 2 is connected to the base of the resistor module, and the NPN transistor Q 1 emitter and diode D 2, the anode of the diode is connected D 2 is connected to the gate of the SiC MOSFET, and the PNP transistor Q 2 emitter and the diode D 3 cathode connection, the diode D The anode of 3 is connected to the gate of the SiCMOSFET, and the capacitor C One end of 8 is connected to the NPN transistor Q 1 collector and the PNP transistor Q 2 collector connection, the capacitor C The other end of 8 is connected to the source of the SiC MOSFET.

2. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 1, characterized in that: The resonant auxiliary branch includes a resistor R 1. Capacitor C 7. Diode D 4. Diode D 6. Inductor L 1. Diode D 5. Resistance R 4. Zener diode and capacitor C 9. The capacitor C One end of 7 is connected to the output end of the driving circuit, and the capacitor C The other end of 7 is connected to the resistor module. R 1 and the diode D 4 in parallel with the capacitor C 7, the diode D 6 cathode is connected to the resistor module, the diode D 6. The anode and the inductor L 1 in series, the inductor L One end of 1 is connected to the source of the SiC MOSFET; The diode D 5 is connected to the anode of the resistor module, and the diode D 5 cathode and the resistor R 4 is connected to one end of the resistor R The other end of 4 is connected to the source of the SiC MOSFET; The capacitor C 9 and the voltage zener diode are connected in parallel to the resistor R 4, the anode of the voltage zener diode is connected to the source of the SiC MOSFET, and the cathode of the voltage zener diode is connected to the diode D 5 anode connection.

3. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 1, characterized in that: The driving circuit includes a power supply module, a pulse control module and a driving module. The output end of the power supply module supplies power to the driving module. The output end of the driving module is connected to the resonant auxiliary branch. The pulse control module is connected to both sides of the driving module.

4. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 3, characterized in that: The pulse control module adopts pulse width modulation technology for control.

5. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 3, characterized in that: The driving circuit also includes a capacitor C 4 , the capacitor C 4 The module is connected to both sides of the driving module and is connected in parallel with the pulse control module.

6. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 3, characterized in that: The driving module includes an ACPL-P346 optical coupler.

7. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit according to claim 3, characterized in that: The driving circuit also includes a capacitor C 1 , the capacitor C 1 In parallel with the power module, the capacitor C 1 The end closest to the negative terminal of the power supply is grounded.

8. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression drive circuit according to claim 1, characterized in that: The resistance module includes a driving resistor R 2. Driving resistance R 3 and diode D 1. The driving resistance R 2 One end of the drive resistor is connected to the resonant auxiliary branch. R 2 and the other end of the driving resistor R 3 is connected to one end of the driving resistor R The other end of the diode 3 is connected to the gate of the SiC MOSFET. D 1 with the driving resistor R 3 parallel arrangement, the diode D 1 is connected to the gate of the SiC MOSFET, and the diode D 1 cathode and the driving resistor R 2Connect.

9. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit according to claim 1, characterized in that: SiC MOSFET includes MOSFET, gate-drain parasitic capacitance C gd , gate-source parasitic capacitance C gs and drain-source parasitic capacitance C ds , the gate-drain parasitic capacitance C gd The two ends of the MOSFET are connected to the gate and drain, and the gate-source parasitic capacitance C gs The two ends of the MOSFET are connected to the gate and source, and the drain-source parasitic capacitance C ds The two ends of the MOSFET are connected to the drain and source.

10. The resonance-assisted low-impedance SiC MOSFET crosstalk suppression driving circuit according to claim 9, characterized in that: The source of the MOSFET of the upper bridge arm unit is connected to the drain of the MOSFET of the lower bridge arm unit.

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