Driving circuit control method and device, processor and readable storage medium

Abstract

The invention discloses a driving circuit control method and device, a processor and a readable storage medium. The method comprises the following steps: acquiring an initial current flowing through a device in a driving circuit; responding to the condition that the initial current is greater than or equal to the current threshold, acquiring induced voltage generated when the initial current flows through a source parasitic inductor in the driving circuit; determining an on state of a device in the driving circuit based on the induced voltage; in response to the open state being a normal open state, a short-circuit current change state and an induced voltage state of a device in the driving circuit are obtained, the short-circuit current change state is used for indicating that short-circuit current is in a rising state or a stable state, and the induced voltage state is used for indicating that the short-circuit current is in a stable state; the induced voltage state is used for indicating that a source parasitic inductor in the driving circuit is in a voltage state or a non-voltage state; and controlling the working strategy of the driving circuit based on the short-circuit current change state and the induced voltage state. The technical problem that effective protection cannot be carried out when the driving circuit breaks down is solved.

Description

Technical Field

[0001] The present invention relates to the field of drive circuit control technology, and in particular to a drive circuit control method, device, processor and readable storage medium. Background Art

[0002] At present, the third-generation power semiconductor devices represented by silicon carbide (SiC) devices have significant advantages of high voltage resistance, high temperature resistance, high frequency and low loss. Compared with Si IGBT, they have smaller on-resistance and almost no tail current, showing great potential in high-power and high-frequency applications. SiC devices can use higher switching frequencies, and the requirements for energy storage components such as filters and inductors and capacitors are greatly reduced, thereby reducing the size of the equipment and improving power density. However, the high switching speed and high dV / dt characteristics of SiC MOSFET also put higher requirements on the gate drive circuit, requiring reliable gate drive to achieve optimal performance and ensure reliability.

[0003] In the related art, the existing drive circuit usually adopts fixed voltage or current drive, uses push-pull circuit to amplify the drive current, and charges and discharges the SiC MOSFET gate through the external gate resistor. By increasing or decreasing the external gate resistor, the switching speed can be slowed down or accelerated, but at the same time, the switching loss will increase or bring additional voltage / current stress, making it difficult to balance the switching speed, switching loss and electromagnetic interference requirements. Therefore, there is a technical problem that the drive circuit cannot be effectively protected when a fault occurs.

[0004] Currently, no effective solution has been proposed to the technical problem that the drive circuit cannot be effectively protected when a fault occurs. Summary of the invention

[0005] The embodiments of the present invention provide a control method, device, processor and readable storage medium of a driving circuit, so as to at least solve the technical problem that effective protection cannot be performed when a driving circuit fails.

[0006] According to one aspect of an embodiment of the present invention, a control method for a driving circuit is provided. The method may include: obtaining an initial current flowing through a device in the driving circuit; in response to the initial current being greater than or equal to a current threshold, obtaining an induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit; determining the on-state of the device in the driving circuit based on the induced voltage; in response to the on-state being a normal on-state, obtaining a short-circuit current change state and an induced voltage state of the device in the driving circuit, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; based on the short-circuit current change state and the induced voltage state, controlling the working strategy of the driving circuit.

[0007] Optionally, determining the on-state of the device in the driving circuit based on the induced voltage includes: in response to the induced voltage being greater than a voltage threshold, determining that the on-state of the device in the driving circuit is a normal on-state.

[0008] Optionally, based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled, including: determining the operating state of the device in the driving circuit based on the short-circuit current change state and the induced voltage state; and controlling the working strategy of the driving circuit based on the operating state.

[0009] Optionally, based on the short-circuit current change state and the induced voltage state, the operating state of the device in the driving circuit is determined, including: in response to the short-circuit current change state being a stable state and the induced voltage state being a no-voltage state, determining that the operating state of the device in the driving circuit is a normal operating state; in response to the short-circuit current change state being a rising state and the induced voltage state being a voltage-appearing state, determining that the operating state of the device in the driving circuit is a fault state.

[0010] Optionally, the control method of the driving circuit also includes: in response to the operating state of the device in the driving circuit being a normal operating state, controlling the working strategy of the driving circuit to switch the driving power supply; in response to the operating state of the device in the driving circuit being a fault state, controlling the driving circuit to stop working.

[0011] Optionally, the control method of the driving circuit further includes: in response to the operating state of the device in the driving circuit being a fault state, generating and outputting a fault signal of the driving circuit.

[0012] According to another aspect of an embodiment of the present invention, a control device for a driving circuit is also provided. The device may include: a first acquisition unit, for acquiring an initial current flowing through a device in the driving circuit; a second acquisition unit, for acquiring an induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit in response to the initial current being greater than or equal to a current threshold; a determination unit, for determining the on-state of the device in the driving circuit based on the induced voltage; a third acquisition unit, for acquiring a short-circuit current change state and an induced voltage state of the device in the driving circuit in response to the on-state being a normal on-state, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a voltage-free state; and a control unit, for controlling the working strategy of the driving circuit based on the short-circuit current change state and the induced voltage state.

[0013] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the control method of the driving circuit in the embodiment of the present invention.

[0014] According to another aspect of an embodiment of the present invention, a processor is further provided, wherein the processor is used to run a program, wherein the control method of the driving circuit in the embodiment of the present invention is executed when the program is run.

[0015] According to another aspect of the embodiments of the present invention, a computer program product is provided, which includes computer instructions, and when the computer instructions are executed by a processor, the control method of the driving circuit in the embodiments of the present invention is implemented.

[0016] In an embodiment of the present invention, an initial current flowing through a device in a driving circuit is obtained; in response to the initial current being greater than or equal to a current threshold, an induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained; based on the induced voltage, the on-state of the device in the driving circuit is determined; in response to the on-state being a normal on-state, the short-circuit current change state and the induced voltage state of the device in the driving circuit are obtained, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled. That is, the present invention determines the on-state of the device in the driving circuit by obtaining the initial current flowing through the device in the driving circuit, thereby controlling the driving circuit according to the on-state, the short-circuit current change state and the induced voltage state, thereby solving the technical problem that the driving circuit cannot be effectively protected when a fault occurs, and achieving the technical effect of effectively protecting the driving circuit when a fault occurs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 is a flow chart of a control method of a driving circuit according to an embodiment of the present invention;

[0019] Figure 2 is a schematic diagram of a conventional SiC MOSFET passive drive circuit according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of an existing variable driving voltage type active gate driving circuit according to an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of an existing variable drive voltage type active gate drive waveform according to an embodiment of the present invention;

[0022] FIG5 is a schematic diagram of a source parasitic inductance voltage detection method according to an embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of a two-stage gate drive circuit according to an embodiment of the present invention;

[0024] 7 is a schematic diagram of a working waveform of a two-stage turn-on gate drive circuit according to an embodiment of the present invention;

[0025] Figure 8 is a schematic diagram of short-circuit characteristic waveforms under different driving voltages according to an embodiment of the present invention;

[0026] Fig. 9 is a schematic diagram of a control device of a driving circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, functional component or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, functional components or devices.

[0029] According to an embodiment of the present invention, an embodiment of a control method for a driving circuit is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0030] Figure 1 is a flow chart of a control method of a driving circuit according to an embodiment of the present invention. Figure 1 As shown, the method may include the following steps:

[0031] Step S101, obtaining an initial current flowing through a device in a driving circuit.

[0032] In the technical solution provided in the above step S101 of the present invention, the initial current may also be referred to as the current flowing through the device.

[0033] In this embodiment, the initial current flowing through the device in the driving circuit is obtained. For example, the initial current flowing through the device in the driving circuit is obtained by using an ammeter or an oscilloscope. This is only an illustrative example and does not limit the specific method of obtaining the initial current flowing through the device in the driving circuit.

[0034] Step S102 , in response to the initial current being greater than or equal to a current threshold, obtaining an induced voltage generated by the initial current flowing through a source parasitic inductance in a driving circuit.

[0035] In the technical solution provided in the above step S102 of the present invention, the current threshold may also be referred to as a load current value or a turn-on threshold, and the induced voltage may also be referred to as an induced voltage value.

[0036] In this embodiment, after the initial current flowing through the device in the driving circuit is obtained in step S101, when the initial current is greater than or equal to the current threshold, the induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained.

[0037] For example, when the current reaches the load current value, the drain-source voltage across the device begins to drop, and the induced voltage value generated by the current flowing through the source parasitic inductance is detected by sampling.

[0038] Step S103: determining the on state of the device in the driving circuit based on the induced voltage.

[0039] In the technical solution provided in the above step S103 of the present invention, the activation state may also be referred to as activation status.

[0040] In this embodiment, after the induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained in step S102, the on state of the device in the driving circuit is determined according to the induced voltage.

[0041] Optionally, the induced voltage is compared with a voltage threshold, and when the induced voltage is greater than the voltage threshold, it is determined that the on-state of the device in the driving circuit is a normal on-state.

[0042] For example, assuming that the voltage threshold is +15V, when the induced voltage is +16V, since +16V>+15V, that is, the induced voltage is greater than the voltage threshold, based on this, it can be determined that the on-state of the device in the driving circuit is a normal on-state.

[0043] Step S104, in response to the on-state being the normal on-state, obtaining a short-circuit current change state and an induced voltage state of the device in the driving circuit.

[0044] In the technical solution provided in the above step S104 of the present invention, the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state.

[0045] In this embodiment, after the on-state of the device in the driving circuit is determined in step S103, when the on-state is a normal on-state, the short-circuit current change state and the induced voltage state of the device in the driving circuit are acquired.

[0046] For example, by acquiring the short-circuit current and the induced voltage of a device in the driving circuit over a period of time, the short-circuit current change state and the induced voltage state are determined.

[0047] Step S105, controlling the working strategy of the driving circuit based on the short-circuit current change state and the induced voltage state.

[0048] In the technical solution provided in the above step S105 of the present invention, after the short-circuit current change state and the induced voltage state of the device in the driving circuit are obtained in step S104, the working strategy of the driving circuit is controlled according to the short-circuit current change state and the induced voltage state.

[0049] In this embodiment, the operating state of the device in the driving circuit is determined according to the short-circuit current change state and the induced voltage state, so that the working strategy of the driving circuit is controlled according to the operating state.

[0050] Optionally, when the short-circuit current change state is a stable state and the induced voltage state is a no-voltage state, the operation state of the device in the drive circuit is determined to be a normal operation state. The stable state may also be referred to as a current stable state, and the no-voltage state may also be referred to as the disappearance of the induced voltage.

[0051] Optionally, when the short-circuit current change state is a continuous rising state and the induced voltage state is a voltage state, it is determined that the operation state of the device in the driving circuit is a fault state. The voltage state may be that the induced voltage is continuously generated on the source parasitic inductance.

[0052] Optionally, when the operating state of the device in the driving circuit is a normal operating state, the working strategy of controlling the driving circuit is to switch the driving power supply.

[0053] For example, when the device current is stable and the induced voltage disappears, the gate drive power supply is switched to provide VCC drive voltage to the device gate, so that the device is turned on quickly, ensuring high turn-on speed and low turn-on loss of the device.

[0054] Optionally, the operating state of the device in the driving circuit is a fault state, and the driving circuit is controlled to stop working. The fault state may also be referred to as a hard switch short circuit fault.

[0055] For example, the short-circuit current of the device will continue to rise, and the induced voltage will continue to be generated on the source parasitic inductance. If the status monitoring circuit can still detect the induced voltage signal after being turned on for a period of time, it is determined that a hard switching short-circuit fault has occurred in the device.

[0056] It should be noted that the above embodiments can be executed by a control device of a driving circuit.

[0057] In the above steps S101 to S105 of the present invention, the initial current flowing through the device in the driving circuit is obtained; in response to the initial current being greater than or equal to the current threshold, the induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained; based on the induced voltage, the on-state of the device in the driving circuit is determined; in response to the on-state being the normal on-state, the short-circuit current change state and the induced voltage state of the device in the driving circuit are obtained, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled. That is to say, the present invention determines the on-state of the device in the driving circuit by obtaining the initial current flowing through the device in the driving circuit, thereby controlling the driving circuit according to the on-state, the short-circuit current change state and the induced voltage state, thereby solving the technical problem that the driving circuit cannot be effectively protected when a fault occurs, and achieving the technical effect of effectively protecting the driving circuit when a fault occurs.

[0058] The above method of this embodiment is further introduced below.

[0059] As an optional embodiment, determining the on-state of a device in the driving circuit based on the induced voltage includes: in response to the induced voltage being greater than a voltage threshold, determining that the on-state of the device in the driving circuit is a normal on-state.

[0060] In this embodiment, when the induced voltage is greater than the voltage threshold, it indicates that the driving circuit is turned on. Based on this, it can be determined that the turn-on state of the device in the driving circuit is a normal turn-on state.

[0061] Optionally, by detecting the on-state of a device in the driving circuit, fast and efficient device state detection and driving phase switching can be achieved.

[0062] As an optional implementation method, the working strategy of the driving circuit is controlled based on the short-circuit current change state and the induced voltage state, including: determining the operating state of the device in the driving circuit based on the short-circuit current change state and the induced voltage state; and controlling the working strategy of the driving circuit based on the operating state.

[0063] In this embodiment, the operating state of the device in the driving circuit is determined according to the short-circuit current change state and the induced voltage state; thus, the working strategy of the driving circuit is controlled according to the operating state.

[0064] Optionally, by determining the operating status of the device in the driving circuit, it can be determined whether the device has a hard switch short circuit fault, which is convenient for taking corresponding protective measures in time when the device fails to achieve short circuit protection for the device.

[0065] As an optional implementation method, the operating state of the device in the driving circuit is determined based on the short-circuit current change state and the induced voltage state, including: in response to the short-circuit current change state being a stable state and the induced voltage state being a no-voltage state, determining that the operating state of the device in the driving circuit is a normal operating state; in response to the short-circuit current change state being a rising state and the induced voltage state being a voltage-existing state, determining that the operating state of the device in the driving circuit is a fault state.

[0066] In this embodiment, when the short-circuit current change state is a stable state and the induced voltage state is a no-voltage state, it indicates that the device has not suffered a hard-switch short-circuit fault, based on which it can be determined that the operating state of the device in the drive circuit is a normal operating state; when the short-circuit current change state is a rising state and the induced voltage state is a voltage state, it indicates that the device has suffered a hard-switch short-circuit fault, based on which it can be determined that the operating state of the device in the drive circuit is a fault state.

[0067] Optionally, according to the switching characteristics and short-circuit characteristics of the SiC MOSFET, appropriate gate drive voltages are selected and applied to the turn-on process of the drive circuit, thereby protecting the device from hard switching short-circuit faults while ensuring high turn-on speed and low turn-on loss of the device.

[0068] As an optional implementation method, the control method of the driving circuit also includes: in response to the operating state of the device in the driving circuit being a normal operating state, controlling the working strategy of the driving circuit to switch the driving power supply; in response to the operating state of the device in the driving circuit being a fault state, controlling the driving circuit to stop working.

[0069] In this embodiment, when the operating state of the device in the driving circuit is a normal operating state, the working strategy of controlling the driving circuit is to switch the driving power supply; when the operating state of the device in the driving circuit is a fault state, the driving circuit is controlled to stop working.

[0070] Optionally, when the operating state of the device in the driving circuit is a normal operating state, if the device is turned on normally without a short-circuit fault, the device current stabilizes at a certain moment, and after detecting that the induced voltage disappears, the gate drive power supply is switched to provide a VCC drive voltage to the gate of the device, so that the device is turned on quickly, thereby ensuring a high turn-on speed and low turn-on loss of the device.

[0071] Optionally, if a hard switch short circuit fault occurs during the turn-on phase, the short circuit current of the device will continue to rise, and an induced voltage will continue to be generated on the source parasitic inductance. If the status monitoring circuit can still detect the induced voltage signal after being turned on for a period of time, it is determined that a hard switch short circuit fault has occurred in the device, and a fault signal is sent to the FPGA to quickly shut down the device, thereby achieving short-circuit protection for the device.

[0072] As an optional embodiment, the control method of the driving circuit further includes: in response to the operating state of the device in the driving circuit being a fault state, generating and outputting a fault signal of the driving circuit.

[0073] In this embodiment, when the operating state of the device in the driving circuit is a fault state, a fault signal of the driving circuit is generated and output.

[0074] For example, when the operating state of a device in the driving circuit is a fault state, a fault signal of the driving circuit is generated, and a fault signal is sent to the FPGA to quickly shut down the device, thereby achieving short-circuit protection for the device.

[0075] It should be noted that the above embodiments can be executed by a control device of a driving circuit.

[0076] In this embodiment, the initial current flowing through the device in the driving circuit is obtained; in response to the initial current being greater than or equal to the current threshold, the induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained; based on the induced voltage, the on-state of the device in the driving circuit is determined; in response to the on-state being the normal on-state, the short-circuit current change state and the induced voltage state of the device in the driving circuit are obtained, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled. That is to say, the present invention determines the on-state of the device in the driving circuit by obtaining the initial current flowing through the device in the driving circuit, thereby controlling the driving circuit according to the on-state, the short-circuit current change state and the induced voltage state, thereby solving the technical problem that the driving circuit cannot be effectively protected when a fault occurs, and achieving the technical effect of effectively protecting the driving circuit when a fault occurs.

[0077] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0078] At present, the third-generation power semiconductor devices represented by SiC devices have significant advantages of high voltage resistance, high temperature resistance, high frequency and low loss. Compared with Si IGBT, they have smaller on-resistance and almost no tail current, showing great potential in high-power and high-frequency applications. SiC devices can use higher switching frequencies, and the requirements for energy storage components such as filters and inductors and capacitors are greatly reduced, thereby reducing the size of the equipment and improving power density. However, the high switching speed and high dV / dt characteristics of SiC MOSFET also place higher requirements on the gate drive circuit, requiring a reliable gate drive to achieve optimal performance and ensure reliability.

[0079] In the related art, the existing drive circuit usually adopts a fixed voltage or current drive, uses a push-pull circuit to amplify the drive current, and charges and discharges the SiC MOSFET gate through an external gate resistor. By increasing or decreasing the external gate resistor, the switching speed can be slowed down or accelerated, but at the same time, the switching loss will increase or bring additional voltage / current stress, making it difficult to balance the switching speed, switching loss and electromagnetic interference requirements. Therefore, there is a technical problem that the drive circuit cannot be effectively protected when a fault occurs. In view of the technical problem that the drive circuit cannot be effectively protected when a fault occurs, no effective solution has been proposed.

[0080] However, the embodiment of the present invention proposes a control method for opening the SIC module driving circuit in two stages, where a current flows through the device by conduction, and when the current reaches the load current value, the drain-source voltage V ds The voltage of the induced voltage generated by the sampling detection current flowing through the source parasitic inductance can indirectly indicate the current condition flowing through the device, that is, reflect the on-state of the device. When the device is fully turned on, the current flowing through the device reaches the load current value and tends to be stable. At this time, the induced voltage disappears. The on-state of the device can be judged by detecting whether the induced voltage disappears within a period of time. This solves the technical problem that the drive circuit cannot be effectively protected when a fault occurs, and achieves the technical effect of effectively protecting the drive circuit when a fault occurs.

[0081] The embodiments of the present invention are further described below.

[0082] Figure 2 is a schematic diagram of an existing SiC MOSFET passive drive circuit according to an embodiment of the present invention, such as Figure 2 As shown, traditional passive gate drive circuits usually use fixed voltage or current drive, usually use push-pull circuits to amplify the drive current, and charge and discharge the SiC MOSFET gate through an external gate resistor. By increasing or decreasing the external gate resistor, the switching speed can be slowed down or accelerated, but at the same time it will increase the switching loss or bring additional voltage / current stress. Therefore, it is difficult for traditional passive gate drives to balance the requirements of switching speed, switching loss and electromagnetic interference.

[0083] Figure 3 is a schematic diagram of an existing variable drive voltage type active gate drive circuit according to an embodiment of the present invention, such as Figure 3As shown, the existing active drive circuits are mainly variable gate resistance type, variable drive voltage type and current source type drive. The basic principle of the variable gate resistance type circuit is to change the drive current size of each stage of the switching transient by dynamically adjusting the equivalent external gate resistance value of the drive loop, and to regulate the turn-on and turn-off speed of the SiC device in stages to achieve the smallest switching loss and the smallest voltage / current stress as much as possible. The variable drive voltage type selects different gate drive voltages in different switching stages to control the device switching speed in stages.

[0084] In this embodiment, Figure 2 Taking the variable drive voltage type active gate drive circuit as an example, two drive power supplies of 20V and 5V are usually used to generate four gate drive voltages (i.e. +20, +15, 0 and -5V), which are connected to the device gate and auxiliary source respectively.

[0085] Optionally, +20V / -5V is used as the normal driving voltage, and +15V and 0V are used as the intermediate driving voltages to optimize the switching performance of the SiC MOSFET.

[0086] Figure 4 FIG. 1 is a schematic diagram of an existing variable drive voltage type active gate drive waveform according to an embodiment of the present invention. The control waveform of the variable drive voltage type active gate drive circuit during the switching process is as follows: Figure 4 As shown, during the opening phase, the pulse width modulation signal (PWM signal for short) is at t 0 When the gate voltage changes to high level, the gate first applies a 20V drive voltage to generate a high drive current to charge the gate input capacitance of the device. The gate-source voltage V gs Start to rise.

[0087] Optionally, t 1 Gate-source voltage V gs After reaching the turn-on threshold, the device drain current I d Start to rise; after the set time delay t d1 After that, the driving power supply is adjusted to apply a +15V driving voltage to suppress the turn-on current spike; t 2 Moment I d Reaching load current I L The level of V gs Reaching the Miller platform voltage, the device drain-source voltage V ds Start to decline until t 3 Moment I d When the device becomes stable, it turns on normally, and the gate drive voltage is switched back to +20V. At time t4, the device is fully turned on.

[0088] Optionally, the turn-on process can adjust the current and voltage slope of the turn-on transient by applying different positive gate drive voltages, which can effectively reduce the turn-on current oscillation peak and optimize the switching performance; the turn-off stage is similar to the turn-on stage.

[0089] Alternatively, although SiC MOSFET has low switching loss, high switching frequency, high withstand voltage and excellent temperature characteristics, under the same rated current capacity, SiC MOSFET chip area is small and current density is high, which leads to weak short-circuit tolerance of SiC MOSFET; when a short-circuit fault occurs, due to the small on-resistance of SiC MOSFET, the rising rate of short-circuit current and the short-circuit current peak are large. If the device is not protected from short-circuit in a short time, it will cause damage to the device or even equipment. The short-circuit protection capability of the device should also be an important part of the active gate drive circuit design.

[0090] Optionally, the optimization points of the currently commonly used active drive circuit compared to the passive drive circuit are mainly to increase the switching speed, reduce the switching loss, and suppress the amplitude of the switching transient voltage and current. Since the driving withstand voltage of the commonly used SiC devices on the market does not exceed +25V, a +20V drive voltage is usually selected in the turn-on stage to ensure a high turn-on speed. However, according to the working characteristic curve of SiC MOSFET, when the gate is turned on by applying a +20V drive voltage, if a hard switch short circuit fault occurs, the short-circuit current flowing through the device will rise rapidly. In a short time, the short-circuit current will reach dozens of times the rated current of the device, which is not conducive to the rapid short-circuit protection of the device and will cause irreversible damage to the device. At the same time, obvious surge voltage and oscillation will be generated when the large current is turned off. The existing active drive circuit does not have any protection measures against hard switch faults in the turn-on stage.

[0091] Optionally, in view of the shortcomings of existing active drive circuits that, when a hard switch short circuit fault occurs when the device is turned on, the short circuit current rising rate flowing through the device is fast and the short circuit current peak is large, which can easily cause device aging and damage, the present invention proposes a two-stage turn-on SiC module drive circuit and a control method thereof, which can achieve the limitation of the short circuit current rising rate and the short circuit current peak when a hard switch short circuit fault occurs in the device, as well as the detection and protection of the hard switch short circuit fault, while ensuring the high turn-on speed and low turn-on loss of the device.

[0092] Fig. 5 is a schematic diagram of a source parasitic inductance voltage detection method according to an embodiment of the present invention. As shown in Fig. 5, for the gate drive circuit design of SiC devices, the selection of gate drive voltage is one of the most important contents. The magnitude of the gate drive voltage determines the turn-on speed of the SiC device and the short-circuit current rise rate (peak value).

[0093] Alternatively, the current SiC MOSFET turn-on drive voltage is mainly between +18V and +20V. Using a +18V drive voltage can effectively reduce the conduction loss and reduce the gate-source voltage V gs Risk of damage caused by overshoot; some SiC MOSFETs are also recommended to use +20V as the driving voltage, especially when a lower on-resistance R is required. dson To achieve higher energy efficiency in applications.

[0094] Optionally, when a hard switch short circuit failure occurs, the short circuit current flowing through the device will rise rapidly. Using a +15V driving voltage can effectively reduce the rising rate of the short circuit current, so that the short circuit current peak value is reduced by 50% compared to the +20V driving voltage, effectively reducing the short circuit stress protection device.

[0095] Optionally, for an active gate drive circuit, a device state monitoring circuit is an important part for achieving efficient and precise control, accurately detecting the device state and providing timely feedback to control gate drive parameters to optimize the switching process of the device.

[0096] Optionally, for a SiC device with an auxiliary source pin in a Kelvin package, the switching state of the device can be determined by detecting the induced voltage on the source parasitic inductance between the auxiliary source and the power source pins. It is easy to integrate, has a simple structure, and does not need to withstand a high bus voltage. The specific working principle is shown in Figure 5: In the turn-on phase of the SiC device, the device is first turned on to generate current flowing through the device. When the current reaches the load current value, the drain-source voltage V ds The induced voltage value generated by sampling the detection current flowing through the source parasitic inductance can indirectly indicate the current condition flowing through the device, that is, reflect the device's turn-on condition. When the device is fully turned on, the current flowing through the device reaches the load current value and tends to be stable. At this time, the induced voltage disappears. The conduction condition of the device can be judged by detecting whether the induced voltage disappears within a period of time.

[0097] Figure 6 Schematic diagram of a two-stage gate drive circuit according to an embodiment of the present invention. Figure 6 As shown, it includes a gate drive circuit, a control circuit and a device status monitoring circuit. During the turn-on phase, the device turn-on status is monitored to control the switching access of the two gate drive power supplies, thereby realizing a two-stage turn-on process of two drive voltages.

[0098] Optionally, the SiC MOSFET is turned on by controlling the turn-on through a two-stage turn-on driving strategy, which limits the rising rate and peak value of the short-circuit current while ensuring high turn-on speed and low turn-on loss, thereby realizing detection and protection of hard switching faults occurring during the turn-on process.

[0099] FIG7 is a schematic diagram of a two-stage gate drive circuit operation waveform according to an embodiment of the present invention. As shown in FIG7, when the input PWM signal controls the device to be turned on, it enters the first stage of the turn-on: t 0 The driving power supply is connected at the moment to provide Vmid driving voltage to charge the gate of the device. 1 At this moment, the gate-source voltage reaches the turn-on threshold, the device is turned on and the current flowing through it generates an induced voltage on the source parasitic inductance, and the status monitoring circuit starts working.

[0100] Optionally, if the device is turned on normally without short circuit failure, until t 3 When the device current is stable at this moment, after detecting that the induced voltage disappears, the gate drive power supply is switched to provide VCC drive voltage to the device gate, so that the device is turned on quickly, ensuring high turn-on speed and low turn-on loss of the device.

[0101] Optionally, if a hard switch short circuit fault occurs during the turn-on phase, the short circuit current of the device will continue to rise, and an induced voltage will continue to be generated on the source parasitic inductance. If the status monitoring circuit can still detect the induced voltage signal after being turned on for a period of time, it is determined that a hard switch short circuit fault has occurred in the device, and a fault signal is sent to the FPGA to quickly shut down the device, thereby achieving short-circuit protection for the device.

[0102] In this embodiment, two driving voltages are used in the opening stage to control the opening drive of the SiC device in stages. In the first opening stage, a small gate voltage is applied to drive the short-circuit current peak value and the short-circuit current growth rate when a hard switch short-circuit fault occurs, thereby greatly reducing the short-circuit stress on the SiC device and improving its reliability and life. In the second opening stage, a larger gate voltage is selected to drive the device, reduce the on-resistance of the device, increase the opening speed of the device, ensure the high opening speed of the SiC device, and make up for the opening delay and opening loss caused by the first opening stage.

[0103] Optionally, the present invention utilizes a parasitic inductance voltage detection circuit to monitor the on-state of the device, controls the two-stage switching of the gate drive circuit, and realizes fast and efficient device state detection and drive stage switching by setting a suitable detection threshold.

[0104] Optionally, Figure 8 is a schematic diagram of short-circuit characteristic waveforms under different driving voltages according to an embodiment of the present invention, such as Figure 8 As shown in Figure 2, the effect of the driving voltage on the short-circuit characteristics of SiC MOSFET is as follows: Figure 8As shown in the figure, different driving voltages have a significant impact on the on-resistance Rdson of SiC MOSFET, which in turn affects the rising rate of short-circuit current and the peak value of short-circuit current when a hard switch short-circuit fault occurs. Selecting a +15V driving voltage as the driving voltage for the first stage of opening can significantly reduce the rising rate of short-circuit current. Compared with a +20V driving voltage, the peak value of short-circuit current can be reduced by 50%, achieving short-circuit protection for the device.

[0105] In this embodiment, the current flows through the device by conduction. When the current reaches the load current value, the drain-source voltage V ds The voltage of the induced voltage generated by the sampling detection current flowing through the source parasitic inductance can indirectly indicate the current condition flowing through the device, that is, reflect the on-state of the device. When the device is fully turned on, the current flowing through the device reaches the load current value and tends to be stable. At this time, the induced voltage disappears. The on-state of the device can be judged by detecting whether the induced voltage disappears within a period of time. This solves the technical problem that the drive circuit cannot be effectively protected when a fault occurs, and achieves the technical effect of effectively protecting the drive circuit when a fault occurs.

[0106] According to an embodiment of the present invention, a control device for a drive circuit is further provided. It should be noted that the control device for a drive circuit can be used to execute the control method for a drive circuit in the method embodiment.

[0107] Fig. 9 is a schematic diagram of a control device of a drive circuit according to an embodiment of the present invention. Fig. 9 As shown, the control device 900 of the driving circuit may include: a first acquisition unit 901 , a second acquisition unit 902 , a determination unit 903 , a third acquisition unit 904 and a control unit 905 .

[0108] The first acquisition unit 901 is used to acquire the initial current flowing through the device in the driving circuit.

[0109] The second acquisition unit 902 is used for acquiring an induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit in response to the initial current being greater than or equal to the current threshold.

[0110] The determination unit 903 is used to determine the on state of the device in the driving circuit based on the induced voltage.

[0111] The third acquisition unit 904 is used to obtain the short-circuit current change state and the induced voltage state of the device in the driving circuit in response to the opening state being the normal opening state, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state.

[0112] The control unit 905 is used to control the working strategy of the driving circuit based on the short-circuit current change state and the induced voltage state.

[0113] Optionally, the determining unit 903 may include: a first determining module, configured to determine that the on-state of the device in the driving circuit is a normal on-state in response to the induced voltage being greater than a voltage threshold.

[0114] Optionally, the control unit 905 may include: a second determination module, used to determine the operating state of the device in the drive circuit based on the short-circuit current change state and the induced voltage state; and a control module, used to control the working strategy of the drive circuit based on the operating state.

[0115] Optionally, the second determination module may include: a first determination submodule, used to determine that the operating state of the device in the driving circuit is a normal operating state in response to the short-circuit current change state being a stable state and the induced voltage state being a no-voltage state; a second determination submodule, used to determine that the operating state of the device in the driving circuit is a fault state in response to the short-circuit current change state being a rising state and the induced voltage state being a voltage-existing state.

[0116] Optionally, the control device 900 of the driving circuit may further include: a first control unit, used to control the working strategy of the driving circuit to switch the driving power supply in response to the operating state of the device in the driving circuit being a normal operating state; and a second control unit, used to control the driving circuit to stop working in response to the operating state of the device in the driving circuit being a fault state.

[0117] Optionally, the control device 900 of the driving circuit may further include: an output unit, configured to generate and output a fault signal of the driving circuit in response to the operating state of a device in the driving circuit being a fault state.

[0118] In this embodiment, the initial current flowing through the device in the driving circuit is obtained; in response to the initial current being greater than or equal to the current threshold, the induced voltage generated by the initial current flowing through the source parasitic inductance in the driving circuit is obtained; based on the induced voltage, the on-state of the device in the driving circuit is determined; in response to the on-state being the normal on-state, the short-circuit current change state and the induced voltage state of the device in the driving circuit are obtained, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled. That is to say, the present invention determines the on-state of the device in the driving circuit by obtaining the initial current flowing through the device in the driving circuit, thereby controlling the driving circuit according to the on-state, the short-circuit current change state and the induced voltage state, thereby solving the technical problem that the driving circuit cannot be effectively protected when a fault occurs, and achieving the technical effect of effectively protecting the driving circuit when a fault occurs.

[0119] According to an embodiment of the present invention, a computer-readable storage medium is further provided. The storage medium includes a stored program, wherein the program executes the control method of the driving circuit in the method embodiment.

[0120] According to an embodiment of the present invention, a processor is further provided. The processor is used to run a program, wherein the control method of the driving circuit in the method embodiment is executed when the program is run.

[0121] According to an embodiment of the present invention, a computer program product is further provided. The computer program product includes computer instructions. When the computer instructions are executed by a processor, the control method of the driving circuit in the method embodiment is implemented.

[0122] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0123] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0124] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0125] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0126] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0127] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent functional component, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software functional component, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store program codes.

[0128] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A control method for a driving circuit, characterized in that: include: Obtaining an initial current flowing through a device in a driving circuit; In response to the initial current being greater than or equal to a current threshold, obtaining an induced voltage generated by the initial current flowing through a source parasitic inductance in the driving circuit; Determining a turn-on state of the device in the drive circuit based on the induced voltage; In response to the on-state being a normal on-state, acquiring a short-circuit current change state and an induced voltage state of the device in the drive circuit, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the drive circuit is in a voltage state or a no-voltage state; Based on the short-circuit current change state and the induced voltage state, the working strategy of the driving circuit is controlled.

2. The method according to claim 1, characterized in that Determining the on state of a device in the driving circuit based on the induced voltage includes: In response to the induced voltage being greater than a voltage threshold, determining that the on-state of the device in the driving circuit is the normal on-state.

3. The method according to claim 1, characterized in that: Based on the short-circuit current change state and the induced voltage state, controlling the working strategy of the driving circuit includes: Determining the operating state of the device in the drive circuit based on the short-circuit current change state and the induced voltage state; Based on the operating status, a working strategy of the driving circuit is controlled.

4. The method according to claim 3, characterized in that Determining the operating state of the device in the drive circuit based on the short-circuit current change state and the induced voltage state includes: In response to the short-circuit current change state being the stable state and the induced voltage state being the no-voltage state, determining that the operating state of the device in the drive circuit is a normal operating state; In response to the short-circuit current change state being the rising state and the induced voltage state being the voltage-existing state, it is determined that the operating state of the device in the drive circuit is a fault state.

5. The method according to claim 4, characterized in that The method further comprises: In response to the operating state of the device in the driving circuit being the normal operating state, controlling the working strategy of the driving circuit to switch the driving power supply; In response to the operating state of the device in the driving circuit being the fault state, the driving circuit is controlled to stop working.

6. The method according to any one of claims 1 to 5, characterized in that: The method further comprises: In response to the operating state of the device in the driving circuit being the fault state, a fault signal of the driving circuit is generated and outputted.

7. A control device for a drive circuit, characterized in that: include: A first acquisition unit, used to acquire an initial current flowing through a device in the driving circuit; A second acquisition unit, configured to acquire an induced voltage generated by the initial current flowing through a source parasitic inductance in the driving circuit in response to the initial current being greater than or equal to a current threshold; A determination unit, configured to determine a turn-on state of a device in the drive circuit based on the induced voltage; a third acquisition unit, configured to acquire a short-circuit current change state and an induced voltage state of the device in the driving circuit in response to the on-state being a normal on-state, wherein the short-circuit current change state is used to indicate that the short-circuit current is in a rising state or a stable state, and the induced voltage state is used to indicate that the source parasitic inductance in the driving circuit is in a voltage state or a no-voltage state; A control unit is used to control the working strategy of the driving circuit based on the short-circuit current change state and the induced voltage state.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed by a processor, the device where the storage medium is located is controlled to execute the method according to any one of claims 1 to 6.

9. A processor, characterized in that: The processor is used to run a program, wherein the program executes the method according to any one of claims 1 to 6 when running.

10. A computer program product, characterized in that The computer program product comprises computer instructions, which implement the method according to any one of claims 1 to 6 when executed by a processor.

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