Driving circuit, driving system and control method of silicon carbide device

Abstract

The invention provides a driving circuit, a driving system and a control method of a silicon carbide device, and the circuit comprises a driving module which is used for generating a driving signal; the switch module comprises a plurality of switch devices, the input end of the switch module is used for inputting power supply voltage, the control end of the switch module is electrically connected with the driving module, the output end of the switch module is used for being electrically connected with the silicon carbide device, and the power supply voltage is used for generating driving current of the silicon carbide device; the driving signal is used for controlling each switching device in the switching module to be switched on or switched off, so that each path in the switching module is switched on or switched off, and the driving current transmitted to the silicon carbide device is different under the condition that the switched-on paths in the switching module are different. According to the circuit, the problems of transient voltage overshoot and large switching loss can be avoided under different working conditions, and the problem that the service life of a silicon carbide device is shortened due to voltage overshoot damage and too large switching loss is avoided, so that the use reliability of the silicon carbide device is improved.

Description

Technical Field

[0001] The present application relates to the field of silicon carbide device control, and in particular, to a driving circuit of a silicon carbide device, a driving system of a silicon carbide device, and a control method of the driving circuit of a silicon carbide device. Background Art

[0002] As a third-generation semiconductor material, SiC has a wider bandgap, higher thermal conductivity, higher radiation resistance, and greater electron saturation drift rate. During the switching process, SiC power modules are prone to voltage and current overshoots due to parasitic parameters introduced by device packaging, PCB wiring, application circuits, and the device's own junction capacitance.

[0003] The existing technology can effectively suppress voltage and current overshoot by detecting the gate voltage of the SiC power module during the switching stage and dynamically adjusting the gate resistance according to different voltage values, but it will increase switching losses. The control method and circuit implementation are relatively complex and will be disturbed by the gate loop oscillation during the switching process, resulting in erroneous responses. Summary of the invention

[0004] The main purpose of the present application is to provide a driving circuit of a silicon carbide device, a driving system of a silicon carbide device, and a control method for the driving circuit of a silicon carbide device, so as to at least solve the problem in the prior art that the driving circuit of the SiC power module has transient current overshoot and switching loss during the switching process and is difficult to optimize simultaneously.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a driving circuit of a silicon carbide device is provided, including: a driving module, used to generate a driving signal; a switching module, including multiple switching devices, the input end of the switching module is used to input a power supply voltage, the control end of the switching module is electrically connected to the driving module, and the output end of the switching module is used to be electrically connected to the silicon carbide device, wherein the power supply voltage is used to generate a driving current for the silicon carbide device, and the driving signal is used to control each switching device in the switching module to be turned on or off, so that each path in the switching module is turned on or off, and when different paths are turned on in the switching module, the driving current transmitted to the silicon carbide device is different.

[0006] Optionally, the drive signal includes a first drive signal, a second drive signal, a third drive signal, a fourth drive signal, a fifth drive signal and a sixth drive signal, and the drive module includes: a drive chip, an input end of the drive chip is used to input a PWM signal, a first output end of the drive chip is used to output a first drive signal and is electrically connected to the first input end of the switch module, and a second output end of the drive chip is used to output a second drive signal and is electrically connected to the second input end of the switch module; a first optocoupler device, a first output end of the first optocoupler device is used to output a third drive signal and is electrically connected to the first control end of the switch module, and a second output end of the first optocoupler device is used to output a fourth drive signal and is electrically connected to the second control end of the switch module; a second optocoupler device, a first output end of the second optocoupler device is used to output a fifth drive signal and is electrically connected to the third control end of the switch module, and a second output end of the second optocoupler device is used to output a sixth drive signal and is electrically connected to the fourth control end of the switch module.

[0007] Optionally, the power supply voltage includes a positive power supply voltage and a negative power supply voltage, and the switch module includes: a first switch unit, a first input end of the first switch unit is used to input the positive power supply voltage, a second input end of the first switch unit is electrically connected to the first output end of the driver chip, a control end of the first switch unit is electrically connected to the first output end of the first optocoupler device, and an output end of the first switch unit is electrically connected to the silicon carbide device; a second switch unit, a first input end of the second switch unit is used to input the positive power supply voltage, a second input end of the second switch unit is electrically connected to the first output end of the driver chip, a control end of the second switch unit is electrically connected to the second output end of the first optocoupler device, and a second switch unit The output end of the element is electrically connected to the silicon carbide device; a third switch unit, the first input end of the third switch unit is used to input the negative power supply voltage, the second input end of the third switch unit is electrically connected to the second output end of the driving chip, the control end of the third switch unit is electrically connected to the first output end of the second optocoupler device, and the output end of the third switch unit is electrically connected to the silicon carbide device; a fourth switch unit, the first input end of the fourth switch unit is used to input the negative power supply voltage, the second input end of the fourth switch unit is electrically connected to the second output end of the driving chip, the control end of the fourth switch unit is electrically connected to the second output end of the second optocoupler device, and the output end of the fourth switch unit is electrically connected to the silicon carbide device.

[0008] Optionally, the first switch unit includes: a first switch device, a first end of the first switch device is electrically connected to the first output end of the driver chip, and a control end of the first switch device is electrically connected to the first output end of the first optocoupler device; a second switch device, a control end of the second switch device is electrically connected to the second end of the first switch device, and the first end of the second switch device is used to input the positive power supply voltage; a first resistor, a first end of the first resistor is electrically connected to the second end of the second switch device, and the second end of the first resistor is electrically connected to the silicon carbide device; and / or, the second switch unit includes: a third switch device, a first end of the third switch device is electrically connected to the first output end of the driver chip, and the control end of the third switch device is electrically connected to the second output end of the second optocoupler device; a fourth switch device, a control end of the fourth switch device is electrically connected to the second end of the third switch device, and the first end of the fourth switch device is used to input the positive power supply voltage; a second resistor, a first end of the second resistor is electrically connected to the second end of the fourth switch device, and the second end of the second resistor is electrically connected to the silicon carbide device.

[0009] Optionally, the second switch device and the fourth switch device are both NMOS devices.

[0010] Optionally, the third switch unit includes: a fifth switch device, a first end of the fifth switch device is electrically connected to the second output end of the driver chip, and a control end of the fifth switch device is electrically connected to the first output end of the second optocoupler device; a sixth switch device, a control end of the sixth switch device is electrically connected to the second end of the fifth switch device, and the first end of the sixth switch device is used to input the negative power supply voltage; a third resistor, a first end of the third resistor is electrically connected to the second end of the sixth switch device, and the second end of the third resistor is electrically connected to the silicon carbide device; and / or, the fourth switch unit includes: a seventh switch device, a first end of the seventh switch device is electrically connected to the second output end of the driver chip, and the control end of the seventh switch device is electrically connected to the second output end of the second optocoupler device; an eighth switch device, a control end of the eighth switch device is electrically connected to the second end of the seventh switch device, and the first end of the eighth switch device is used to input the negative power supply voltage; a fourth resistor, a first end of the fourth resistor is electrically connected to the second end of the eighth switch device, and the second end of the fourth resistor is electrically connected to the silicon carbide device.

[0011] Optionally, the sixth switching device and the eighth switching device are both PMOS devices.

[0012] According to another aspect of the present application, a driving system for a silicon carbide device is provided, comprising: a silicon carbide device; and a driving circuit for any one of the silicon carbide devices, electrically connected to the silicon carbide device.

[0013] According to another aspect of the present application, a method for controlling a drive circuit of any one of the silicon carbide devices is provided, comprising: obtaining a state of charge of a high-voltage power battery of a vehicle, wherein the high-voltage power battery is electrically connected to the silicon carbide device; and according to the state of charge of the high-voltage power battery, controlling the drive circuit of the silicon carbide device to output a corresponding drive current, wherein the drive current is inversely proportional to the state of charge of the high-voltage power battery.

[0014] Optionally, according to the state of charge of the high-voltage power battery, the drive circuit of the silicon carbide device is controlled to output a corresponding drive current, including: when the state of charge of the high-voltage power battery is greater than or equal to a first preset value, the drive circuit of the silicon carbide device is controlled to output a first drive current, and the first drive current is less than or equal to a first current value; when the state of charge of the high-voltage power battery is greater than or equal to a second preset value and less than the first preset value, the drive circuit of the silicon carbide device is controlled to output a second drive current, and the second drive current is greater than the first current value and less than or equal to the second current value; when the state of charge of the high-voltage power battery is less than the second preset value, the drive circuit of the silicon carbide device is controlled to output a third drive current, and the third drive current is greater than the second current value.

[0015] Applying the technical solution of the present application, the driving circuit of the above silicon carbide device includes: a driving module for generating a driving signal; a switch module including a plurality of switching devices, the input end of the switch module is used to input a power supply voltage, the control end of the switch module is electrically connected to the driving module, and the output end of the switch module is used to electrically connect to the silicon carbide device, wherein the power supply voltage is used to generate the driving current of the silicon carbide device, and the driving signal is used to control each switching device in the switch module to be turned on or off, so that each path in the switch module is turned on or off, and when the paths turned on in the switch module are different, the driving current transmitted to the silicon carbide device is different. The circuit can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device from being damaged by voltage overshoot and the shortening of service life caused by too large switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A schematic structural diagram of a driving circuit of a silicon carbide device provided in an embodiment of the present application is shown;

[0018] Figure 2 A schematic structural diagram of another driving circuit of a silicon carbide device provided according to an embodiment of the present application is shown;

[0019] Figure 3 A schematic structural diagram of another driving circuit of a silicon carbide device provided according to an embodiment of the present application is shown;

[0020] Figure 4 A schematic structural diagram of another driving circuit of a silicon carbide device provided according to an embodiment of the present application is shown;

[0021] Figure 5 A schematic structural diagram of a driving system for a silicon carbide device provided according to an embodiment of the present application is shown;

[0022] Figure 6 A schematic flow chart of a method for controlling a driving circuit of a silicon carbide device provided according to an embodiment of the present application is shown.

[0023] The above drawings include the following reference numerals:

[0024] 01. Driving circuit of silicon carbide device; 10. Driving module; 11. Driving chip; 12. First optocoupler device; 13. Second optocoupler device; 20. Switch module; 21. First switch unit; 211. First switch device; 212. Second switch device; 22. Second switch unit; 221. Third switch device; 222. Fourth switch device; 23. Third switch unit; 231. Fifth switch device; 232. Sixth switch device; 24. Fourth switch unit; 241. Seventh switch device; 242. Eighth switch device; 30. Silicon carbide device; R1. First resistor; R2. Second resistor; R3. Third resistor; R4. Fourth resistor. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising 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, products or devices.

[0028] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0029] Silicon carbide devices (SiC for short): As the third-generation semiconductor material, SiC has a wider bandgap, higher thermal conductivity, higher radiation resistance, and a larger electron saturation drift rate.

[0030] Transient overshoot: During the switching process of the power module, voltage and current overshoots are easily generated due to parasitic parameters introduced by device packaging, PCB wiring, application circuits, and the junction capacitance of the device itself.

[0031] Switching loss: Switching loss includes turn-on loss and turn-off loss. Turn-on loss refers to the power loss generated when the power tube switches from cut-off to conduction; turn-off loss refers to the power loss generated when the power tube switches from conduction to cut-off;

[0032] Metal-Oxide-Semiconductor Field-EffectTransistor: Metal-Oxide-Semiconductor Field-EffectTransistor, referred to as MOS tube;

[0033] P-type metal-oxide-semiconductor field-effect transistor: P-channel metal-oxide-semiconductorfield-effect transistor, referred to as PMOS;

[0034] N-type metal oxide semiconductor field effect transistor: N-channel metal-oxide-semiconductorfield-effect transistor, referred to as NMOS.

[0035] As introduced in the background technology, in the prior art, by detecting the gate voltage of the SiC power module during the switching stage, dynamically adjusting the gate resistance according to different voltage values, the voltage and current overshoot can be effectively suppressed, but the switching loss will increase. The control method and circuit implementation are relatively complex, and will be disturbed by the gate loop oscillation during the switching process, resulting in an erroneous response. In addition, the purpose of the scheme in the prior art is to reduce the probability of voltage and current overshoot occurring during the SiC switching process, and it is impossible to take into account the purpose of reducing switching losses. On the contrary, increasing the driving resistance will increase the switching loss. The above scheme adjusts the driving resistance in the driving parameter, judges the different stages of the switching process according to the gate voltage, and selects different gate resistances at different stages to reduce the impact of voltage and current overshoot. Since the switching speed of SiC itself is relatively fast, adjusting the gate resistance in each switching process will reduce the switching speed, and the advantage of SiC's high switching speed cannot be brought into play, and the oscillation of the gate will bring unexpected adjustments, thereby affecting the final control effect.

[0036] In order to solve the problem in the prior art that the driving circuit of the SiC power module has transient current overshoot and switching loss during the switching process and is difficult to optimize simultaneously, the embodiments of the present application provide a driving circuit of a silicon carbide device, a driving system of a silicon carbide device, and a control method for the driving circuit of a silicon carbide device.

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0038] Figure 1 is a schematic diagram of a driving circuit of a silicon carbide device according to an embodiment of the present invention, such as Figure 1 As shown, the driving circuit of the silicon carbide device includes: a driving module 10, which is used to generate a driving signal; a switch module 20, which includes multiple switching devices, the input end of the above-mentioned switch module 20 is used to input a power supply voltage, the control end of the above-mentioned switch module 20 is electrically connected to the above-mentioned drive module 10, and the output end of the above-mentioned switch module 20 is used to be electrically connected to the silicon carbide device 30, wherein the above-mentioned power supply voltage is used to generate the driving current of the above-mentioned silicon carbide device 30, and the above-mentioned driving signal is used to control the conduction or cut-off of each switching device in the above-mentioned switch module 20, so that each path in the above-mentioned switch module 20 is turned on or off, and when the paths turned on in the above-mentioned switch module 20 are different, the driving current transmitted to the above-mentioned silicon carbide device 30 is different.

[0039] The driving circuit of the silicon carbide device of the present application includes: a driving module for generating a driving signal; a switch module including a plurality of switching devices, the input end of the switch module is used to input a power supply voltage, the control end of the switch module is electrically connected to the driving module, and the output end of the switch module is used to electrically connect to the silicon carbide device, wherein the power supply voltage is used to generate the driving current of the silicon carbide device, and the driving signal is used to control each switching device in the switch module to be turned on or off, so that each path in the switch module is turned on or off, and when the paths turned on in the switch module are different, the driving current transmitted to the silicon carbide device is different. The circuit can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device from being damaged by voltage overshoot and the shortening of service life caused by too large switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0040] The above embodiment is mainly used to solve the shortcomings of the SiC power module drive circuit in the switching process, that is, the transient overshoot phenomenon and the switching loss are difficult to optimize at the same time, by dynamically adjusting the current driving the SiC switch under different working conditions to achieve a balance between the low transient overshoot and low switching loss of SiC. The drive circuit has a simple structure and is easy to implement, and can suppress the overshoot and oscillation of voltage and current during the SiC switching process while maintaining low switching losses.

[0041] In some instances, such as Figure 2 As shown, the driving signal includes a first driving signal, a second driving signal, a third driving signal, a fourth driving signal, a fifth driving signal and a sixth driving signal. The driving module 10 includes: a driving chip 11, the input end of the driving chip 11 is used to input a PWM signal, the first output end of the driving chip 11 is used to output the first driving signal and is electrically connected to the first input end of the switch module 20, and the second output end of the driving chip 11 is used to output the second driving signal and is electrically connected to the second input end of the switch module 20; a first optocoupler 12, the first output end of the first optocoupler 12 is used to output the third driving signal and is electrically connected to the first control end of the switch module 20, and the second output end of the first optocoupler 12 is used to output the fourth driving signal and is electrically connected to the second control end of the switch module 20; a second optocoupler 13, the first output end of the second optocoupler 13 is used to output the fifth driving signal and is electrically connected to the third control end of the switch module 20, and the second output end of the second optocoupler 13 is used to output the sixth driving signal and is electrically connected to the fourth control end of the switch module 20.

[0042] Among them, the switch module includes four paths, two paths for controlling the conduction of the silicon carbide device, and two paths for controlling the shutdown of the silicon carbide device. The opening and closing of each path are controlled by the driving signal output by the driving chip and the external signal output by the first optocoupler device and the second optocoupler device. According to the different working conditions of the silicon carbide device, the driving signal controls the conduction of different paths, and the size of the driving current of the silicon carbide device is different, thereby controlling the conduction or shutdown of the silicon carbide device, and further controlling the speed of the conduction or shutdown of the silicon carbide device.

[0043] In some instances, such as Figure 3 As shown, the power supply voltage includes a positive power supply voltage VCC and a negative power supply voltage VEE, and the switch module 20 includes: a first switch unit 21, a first input end of the first switch unit 21 is used to input the positive power supply voltage VCC, a second input end of the first switch unit 21 is electrically connected to a first output end of the driver chip 11, a control end of the first switch unit 21 is electrically connected to a first output end of the first optocoupler device 12, and an output end of the first switch unit 21 is electrically connected to the silicon carbide device 30; a second switch unit 22, a first input end of the second switch unit 22 is used to input the positive power supply voltage VCC, a second input end of the second switch unit 22 is electrically connected to a first output end of the driver chip 11, a control end of the second switch unit 22 is electrically connected to a second output end of the first optocoupler device 12, and the second switch unit The output end of the third switch unit 22 is electrically connected to the silicon carbide device 30; a third switch unit 23, the first input end of the third switch unit 23 is used to input the negative power supply voltage VEE, the second input end of the third switch unit 23 is electrically connected to the second output end of the driving chip 11, the control end of the third switch unit 23 is electrically connected to the first output end of the second optocoupler device 13, and the output end of the third switch unit 23 is electrically connected to the silicon carbide device 30; a fourth switch unit 24, the first input end of the fourth switch unit 24 is used to input the negative power supply voltage VEE, the second input end of the fourth switch unit 24 is electrically connected to the second output end of the driving chip 11, the control end of the fourth switch unit 24 is electrically connected to the second output end of the second optocoupler device 13, and the output end of the fourth switch unit 24 is electrically connected to the silicon carbide device 30.

[0044] Among them, the path where the first switch unit and the second switch unit are located is the path for controlling the conduction of the silicon carbide device, and the path where the third switch unit and the fourth switch unit are located is the path for controlling the shutdown of the silicon carbide device. SiC has a smaller gate capacitance than IGBT, and the required driving power is significantly smaller, but the magnitude of the driving current is closely related to the operating speed of the switching device. In order to meet the needs of SiC high-frequency switching, it is necessary to select a driver chip with a larger output peak current. The peak output current of the current mainstream driver chip ranges from a few amperes to tens of amperes.

[0045] In addition, the two paths, the path where the first switch unit is located and the path where the second switch unit is located, control the conduction of the silicon carbide device, and can control the drive current input into the silicon carbide device. In the three cases where only the path where the first switch unit is located is turned on, only the path where the second switch unit is located is turned on, and the path where the first switch unit is located and the path where the second switch unit is located are both turned on, the output drive current is different. The two paths, the path where the third switch unit is located and the path where the fourth switch unit is located, control the cutoff of the silicon carbide device, and can control the drive current input into the silicon carbide device. In the three cases where only the path where the third switch unit is located is turned on, only the path where the fourth switch unit is located is turned on, and the path where the third switch unit and the path where the fourth switch unit are located are both turned on, the output drive current is different.

[0046] In some instances, such as Figure 4 As shown, the first switch unit 21 includes: a first switch device 211, a first end of the first switch device 211 is electrically connected to the first output end of the driving chip 11, and a control end of the first switch device 211 is electrically connected to the first output end of the first optocoupler device 12; a second switch device 212, a control end of the second switch device 212 is electrically connected to the second end of the first switch device 211, and a first end of the second switch device 212 is used to input the positive power supply voltage VCC; a first resistor R1, a first end of the first resistor R1 is electrically connected to the second end of the second switch device 212, and a second end of the first resistor R1 is electrically connected to the silicon carbide device 30; And / or, the second switch unit 22 includes: a third switch device 221, a first end of the third switch device 221 is electrically connected to the first output end of the driver chip 11, and a control end of the third switch device 221 is electrically connected to the second output end of the second optocoupler device 13; a fourth switch device 222, a control end of the fourth switch device 222 is electrically connected to the second end of the third switch device 221, and a first end of the fourth switch device 222 is used to input the positive power supply voltage VCC; a second resistor R2, a first end of the second resistor R2 is electrically connected to the second end of the fourth switch device 222, and a second end of the second resistor R2 is electrically connected to the silicon carbide device 30.

[0047] The resistance values ​​of the first resistor and the second resistor are related to the model of the silicon carbide device. Generally, the resistance values ​​of the first resistor and the second resistor are less than 5 ohms. The first path is turned on or off by controlling the first switch device and the second switch device to be turned on or off, and the second path is turned on or off by controlling the third switch device and the fourth switch device to be turned on or off.

[0048] In some instances, a PWMH signal is input into the first input terminal of the driver chip, a PWML signal is input into the second input terminal of the driver chip, and a high level is input into the first terminal of the first switching device and the third switching device at the first output terminal of the driver chip. When the first optocoupler device controls the first switching device to be turned on by a high level (or a low level) and controls the third switching device to be turned off by a low level (or a high level), the second switching device is turned on and the fourth switching device is turned off, and only the first path is turned on at this time; when the first optocoupler device controls the third switching device to be turned on by a high level (or a low level) and controls the first switching device to be turned off by a low level (or a high level), the fourth switching device is turned on and the second switching device is turned off, and only the second path is turned on at this time; when the first optocoupler device controls the first switching device and the third switching device to be turned on by a high level (or a low level), both the second switching device and the fourth switching device are turned on, and both the first path and the second path are turned on.

[0049] In some examples, when only the first path is turned on, the driving current of the silicon carbide device is 5A, when only the second path is turned on, the driving current of the silicon carbide device is 10A, and when both the first path and the second path are turned on, the driving current of the silicon carbide device is 15A.

[0050] In some instances, such as Figure 4 As shown, the second switch device 212 and the fourth switch device 222 are both NMOS devices.

[0051] The first switch device and the third switch device may be transistors or MOS tubes, and the second switch device and the fourth switch device may be replaced by push-pull circuits to achieve the same effect.

[0052] In some instances, such as Figure 4As shown, the third switch unit 23 includes: a fifth switch device 231, a first end of the fifth switch device 231 is electrically connected to the second output end of the driving chip 11, and a control end of the fifth switch device 231 is electrically connected to the first output end of the second optocoupler device 13; a sixth switch device 232, a control end of the sixth switch device 232 is electrically connected to the second end of the fifth switch device 231, and a first end of the sixth switch device 232 is used to input the negative power supply voltage VEE; a third resistor R3, a first end of the third resistor R3 is electrically connected to the second end of the sixth switch device 232, and a second end of the third resistor R3 is electrically connected to the silicon carbide device 30; And / or, the fourth switch unit 24 includes: a seventh switch device 241, a first end of the seventh switch device 241 is electrically connected to the second output end of the driving chip 11, and a control end of the seventh switch device 241 is electrically connected to the second output end of the second optocoupler device 13; an eighth switch device 242, a control end of the eighth switch device 242 is electrically connected to the second end of the seventh switch device 241, and a first end of the eighth switch device 242 is used to input the negative power supply voltage VEE; a fourth resistor R4, a first end of the fourth resistor R4 is electrically connected to the second end of the eighth switch device 242, and a second end of the fourth resistor R4 is electrically connected to the silicon carbide device 30.

[0053] The resistance values ​​of the third resistor and the fourth resistor are related to the model of the silicon carbide device, and the resistance values ​​of the first resistor and the second resistor are twice that of the third resistor and the fourth resistor. The conduction or cutoff of the third path is controlled by controlling the conduction or cutoff of the fifth switch device and the sixth switch device, and the conduction or cutoff of the fourth path is controlled by controlling the conduction or cutoff of the seventh switch device and the eighth switch device.

[0054] In some examples, a PWMH signal is input to the first input terminal of the driver chip, and a PWML signal is input to the second input terminal of the driver chip, wherein the PWMH signal is the high-level signal portion of the PWM, and the PWML signal is the low-level signal portion of the PWM. The second output terminal of the driver chip inputs a low level to the first terminals of the fifth switch device and the seventh switch device. When the second optocoupler device controls the fifth switch device to be turned on by a high level (or a low level) and controls the seventh switch device to be turned off by a low level (or a high level), the sixth switch device is turned on and the eighth switch device is turned off, and only the third path is turned on at this time; when the second optocoupler device controls the seventh switch device to be turned on by a high level (or a low level) and controls the fifth switch device to be turned off by a low level (or a high level), the eighth switch device is turned on and the sixth switch device is turned off, and only the fourth path is turned on at this time; when the second optocoupler device controls the fifth switch device and the seventh switch device to be turned on by a high level (or a low level), the sixth switch device and the eighth switch device are both turned on, and both the third path and the fourth path are turned on.

[0055] In some examples, when only the third path is turned on, the driving current of the silicon carbide device is -5A, when only the fourth path is turned on, the driving current of the silicon carbide device is -10A, and when both the third path and the fourth path are turned on, the driving current of the silicon carbide device is -15A.

[0056] In some instances, such as Figure 4 As shown, the sixth switch device 232 and the eighth switch device 242 are both PMOS devices.

[0057] Among them, the fifth switch device and the seventh switch device can be transistors or MOS tubes, and the sixth switch device and the eighth switch device can be replaced by push-pull circuits to achieve the same effect.

[0058] The switch of the SiC power device in the above-mentioned drive circuit is still controlled by the drive chip. Under different working conditions, the control signal from the control board controls the switching of the first switch device, the third switch device, the fifth switch device and the seventh switch device through the first optocoupler device and the second spectrum device, thereby controlling the on and off of the gate drive path to achieve adjustable drive current.

[0059] Figure 5 is a schematic diagram of a structure of a driving system of a silicon carbide device according to an embodiment of the present invention, such as Figure 5 As shown, the driving system of the silicon carbide device includes: a silicon carbide device 30; and any one of the driving circuits 01 of the above-mentioned silicon carbide devices, which is electrically connected to the above-mentioned silicon carbide device 30.

[0060] The driving system of the silicon carbide device of the present application includes: a silicon carbide device; a driving circuit of any silicon carbide device, electrically connected to the silicon carbide device. The system can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device being damaged by voltage overshoot and the shortening of its service life due to large switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0061] Figure 6 is a flow chart of a control method of a driving circuit of a silicon carbide device according to an embodiment of the present invention, such as Figure 6 As shown, the method comprises the following steps:

[0062] Step S101, obtaining the state of charge of a high-voltage power battery of the vehicle, wherein the high-voltage power battery is electrically connected to the silicon carbide device;

[0063] Step S102, according to the charge state of the high-voltage power battery, controlling the drive circuit of the silicon carbide device to output a corresponding drive current, wherein the drive current is inversely proportional to the charge state of the high-voltage power battery.

[0064] The control method of the driving circuit of the above-mentioned silicon carbide device of the present application includes: obtaining the state of charge of the high-voltage power battery of the whole vehicle, the high-voltage power battery is electrically connected to the silicon carbide device; according to the state of charge of the high-voltage power battery, controlling the driving circuit of the silicon carbide device to output a corresponding driving current, wherein the driving current is inversely proportional to the state of charge of the high-voltage power battery. This method can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device being damaged by voltage overshoot and the shortening of its service life caused by excessive switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0065] According to the state of charge of the high-voltage power battery, controlling the drive circuit of the silicon carbide device to output a corresponding drive current comprises the following steps:

[0066] Step S1021, when the state of charge of the high-voltage power battery is greater than or equal to a first preset value, controlling the drive circuit of the silicon carbide device to output a first drive current, wherein the first drive current is less than or equal to a first current value;

[0067] Step S1022, when the state of charge of the high-voltage power battery is greater than or equal to a second preset value and less than the first preset value, controlling the drive circuit of the silicon carbide device to output a second drive current, wherein the second drive current is greater than the first current value and less than or equal to the second current value;

[0068] Step S1023, when the state of charge of the high-voltage power battery is less than the second preset value, controlling the drive circuit of the silicon carbide device to output a third drive current, wherein the third drive current is greater than the second current value.

[0069] The first preset value may be 90%, the second preset value may be 80%, the first current value may be 6A, and the current value may be 14A.

[0070] In some instances, such as Figure 4 As shown, the driver chip selection does not need to select a chip with a large peak output current. The driving current source and the MOS tube on the gate path, in order to make the adjustable range of the driving current wider and combine the driving current requirements of SiC under different working conditions, the second switch device 212 and the fourth switch device 222 on the driving path support 5A and 10A current output respectively. Three working modes can be selected, only the second switch device 212 is turned on, only the fourth switch device 222 is turned on, and the second switch device 212 and the fourth switch device 222 are turned on at the same time, which can meet the driving current requirements of 5A, 10A, and 15A. When the high-voltage power battery of the whole vehicle is fully charged and the charge state is above 90%, the first consideration at this time is the possibility of device damage caused by voltage overshoot during the switching process. At this time, the second switch device 212 should be turned on and the fourth switch device 222 should be turned off, so that the gate drive current value is 5A, so as to reduce the voltage overshoot to the limit as much as possible. When the state of charge of the vehicle is 80% to 90%, the first consideration is the possibility of device damage caused by voltage overshoot during the switching process. At this time, the fourth switch device 222 should be turned on and the second switch device 212 should be turned off, so that the gate drive current value is 10A, so as to reduce the voltage overshoot to the limit as much as possible. As the battery capacity decreases, the upper limit of the voltage overshoot value decreases, and there is no risk of exceeding the limit range. At this time, the gate current value can be increased to reduce the switching loss, that is, when the state of charge of the vehicle is less than 80%, the second switch device 212 and the fourth switch device 222 are turned on at the same time, so that the gate drive current value is 15A, so as to achieve the purpose of improving the reliability of SiC use. Among them, the situation where the second switch device 212 and the fourth switch device 222 are turned on at the same time includes more than 70% of the battery use time, which has a significant effect on reducing switching losses and improving the reliability of SiC use.

[0071] Specifically, the above steps can enable the controller to avoid transient voltage overshoot and large switching loss under different working conditions, avoid SiC damage due to voltage overshoot and shortened service life due to excessive switching loss, and improve the reliability of SiC. Reducing the voltage overshoot during the SiC switching process reduces the switching loss, increases the service life of the SiC power module, and solves the problem that it is difficult to simultaneously optimize the transient overshoot phenomenon and switching loss during the switching process.

[0072] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0073] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0074] 1) The driving circuit of the silicon carbide device of the present application includes: a driving module for generating a driving signal; a switch module including a plurality of switching devices, the input end of the switch module is used to input a power supply voltage, the control end of the switch module is electrically connected to the driving module, and the output end of the switch module is used to electrically connect to the silicon carbide device, wherein the power supply voltage is used to generate the driving current of the silicon carbide device, and the driving signal is used to control each switching device in the switch module to be turned on or off, so that each path in the switch module is turned on or off, and when the paths turned on in the switch module are different, the driving current transmitted to the silicon carbide device is different. The circuit can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device from being damaged by voltage overshoot and the shortening of service life caused by too large switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0075] 2) The driving system of the silicon carbide device of the present application comprises: a silicon carbide device; a driving circuit of any silicon carbide device, electrically connected to the silicon carbide device. The system can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device being damaged by voltage overshoot and the shortening of its service life due to excessive switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0076] 3) The control method of the driving circuit of the above-mentioned silicon carbide device of the present application includes: obtaining the state of charge of the high-voltage power battery of the whole vehicle, the high-voltage power battery is electrically connected to the silicon carbide device; according to the state of charge of the high-voltage power battery, controlling the driving circuit of the silicon carbide device to output a corresponding driving current, wherein the driving current is inversely proportional to the state of charge of the high-voltage power battery. This method can enable the controller to avoid the problems of transient voltage overshoot and large switching loss under different working conditions, avoid the silicon carbide device being damaged by voltage overshoot and the shortening of its service life caused by excessive switching loss, so as to improve the reliability of the silicon carbide device, and solve the problem that the driving circuit of the SiC power module in the prior art has transient current overshoot and switching loss during the switching process and is difficult to optimize at the same time.

[0077] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A driving circuit for a silicon carbide device, It is characterized in that include: A driving module, used for generating a driving signal; A switch module comprises a plurality of switch devices, wherein an input end of the switch module is used to input a power supply voltage, a control end of the switch module is electrically connected to the drive module, and an output end of the switch module is electrically connected to a silicon carbide device, wherein the power supply voltage is used to generate a drive current for the silicon carbide device, and the drive signal is used to control each switch device in the switch module to be turned on or off, thereby turning on or off each path in the switch module, and when different paths are turned on in the switch module, different drive currents are transmitted to the silicon carbide device.

2. The driving circuit of the silicon carbide device according to claim 1, It is characterized in that The driving signal includes a first driving signal, a second driving signal, a third driving signal, a fourth driving signal, a fifth driving signal and a sixth driving signal, and the driving module includes: A driving chip, wherein the input end of the driving chip is used to input a PWM signal, the first output end of the driving chip is used to output a first driving signal and is electrically connected to the first input end of the switch module, and the second output end of the driving chip is used to output a second driving signal and is electrically connected to the second input end of the switch module; a first optocoupler device, wherein a first output end of the first optocoupler device is used to output a third drive signal and is electrically connected to the first control end of the switch module, and a second output end of the first optocoupler device is used to output a fourth drive signal and is electrically connected to the second control end of the switch module; A second optocoupler device, wherein the first output end of the second optocoupler device is used to output a fifth drive signal and is electrically connected to the third control end of the switch module, and the second output end of the second optocoupler device is used to output a sixth drive signal and is electrically connected to the fourth control end of the switch module.

3. The driving circuit of the silicon carbide device according to claim 2, It is characterized in that The power supply voltage includes a positive power supply voltage and a negative power supply voltage, and the switch module includes: a first switch unit, wherein a first input terminal of the first switch unit is used to input the positive power supply voltage, a second input terminal of the first switch unit is electrically connected to a first output terminal of the driver chip, a control terminal of the first switch unit is electrically connected to a first output terminal of the first optocoupler device, and an output terminal of the first switch unit is electrically connected to the silicon carbide device; a second switch unit, wherein the first input terminal of the second switch unit is used to input the positive power supply voltage, the second input terminal of the second switch unit is electrically connected to the first output terminal of the driver chip, the control terminal of the second switch unit is electrically connected to the second output terminal of the first optocoupler device, and the output terminal of the second switch unit is electrically connected to the silicon carbide device; a third switch unit, wherein a first input end of the third switch unit is used to input the negative power supply voltage, a second input end of the third switch unit is electrically connected to a second output end of the driver chip, a control end of the third switch unit is electrically connected to a first output end of the second optocoupler device, and an output end of the third switch unit is electrically connected to the silicon carbide device; A fourth switch unit, wherein the first input end of the fourth switch unit is used to input the negative power supply voltage, the second input end of the fourth switch unit is electrically connected to the second output end of the driver chip, the control end of the fourth switch unit is electrically connected to the second output end of the second optocoupler device, and the output end of the fourth switch unit is electrically connected to the silicon carbide device.

4. The driving circuit of the silicon carbide device according to claim 3, It is characterized in that The first switch unit comprises: A first switch device, wherein a first end of the first switch device is electrically connected to a first output end of the driver chip, and a control end of the first switch device is electrically connected to a first output end of the first optocoupler device; a second switch device, wherein a control terminal of the second switch device is electrically connected to a second terminal of the first switch device, and a first terminal of the second switch device is used to input the positive power supply voltage; a first resistor, wherein a first end of the first resistor is electrically connected to a second end of the second switch device, and a second end of the first resistor is electrically connected to the silicon carbide device; And / or, the second switch unit includes: a third switch device, wherein a first end of the third switch device is electrically connected to the first output end of the driver chip, and a control end of the third switch device is electrically connected to the second output end of the second optocoupler device; a fourth switch device, wherein a control terminal of the fourth switch device is electrically connected to the second terminal of the third switch device, and a first terminal of the fourth switch device is used to input the positive power supply voltage; A second resistor, wherein a first end of the second resistor is electrically connected to a second end of the fourth switch device, and a second end of the second resistor is electrically connected to the silicon carbide device.

5. The driving circuit of the silicon carbide device according to claim 4, It is characterized in that The second switching device and the fourth switching device are both NMOS devices.

6. The driving circuit of the silicon carbide device according to claim 3, It is characterized in that The third switch unit comprises: a fifth switch device, wherein a first terminal of the fifth switch device is electrically connected to the second output terminal of the driver chip, and a control terminal of the fifth switch device is electrically connected to the first output terminal of the second optocoupler device; a sixth switch device, wherein a control terminal of the sixth switch device is electrically connected to the second terminal of the fifth switch device, and a first terminal of the sixth switch device is used to input the negative power supply voltage; a third resistor, wherein a first end of the third resistor is electrically connected to a second end of the sixth switching device, and a second end of the third resistor is electrically connected to the silicon carbide device; And / or, the fourth switch unit includes: a seventh switch device, wherein a first end of the seventh switch device is electrically connected to the second output end of the driving chip, and a control end of the seventh switch device is electrically connected to the second output end of the second optocoupler device; an eighth switch device, wherein a control terminal of the eighth switch device is electrically connected to a second terminal of the seventh switch device, and a first terminal of the eighth switch device is used to input the negative power supply voltage; A fourth resistor, wherein a first end of the fourth resistor is electrically connected to the second end of the eighth switching device, and a second end of the fourth resistor is electrically connected to the silicon carbide device.

7. The driving circuit of the silicon carbide device according to claim 6, It is characterized in that The sixth switching device and the eighth switching device are both PMOS devices.

8. A driving system for a silicon carbide device, It is characterized in that include: Silicon carbide devices; The driving circuit of the silicon carbide device according to any one of claims 1 to 7 is electrically connected to the silicon carbide device.

9. A method for controlling a driving circuit of a silicon carbide device according to any one of claims 1 to 7, It is characterized in that include: Obtaining a state of charge of a high-voltage power battery of the vehicle, wherein the high-voltage power battery is electrically connected to the silicon carbide device; According to the state of charge of the high-voltage power battery, the drive circuit of the silicon carbide device is controlled to output a corresponding drive current, wherein the drive current is inversely proportional to the state of charge of the high-voltage power battery.

10. The control method according to claim 9, It is characterized in that According to the state of charge of the high-voltage power battery, controlling the drive circuit of the silicon carbide device to output a corresponding drive current includes: When the state of charge of the high-voltage power battery is greater than or equal to a first preset value, controlling the drive circuit of the silicon carbide device to output a first drive current, where the first drive current is less than or equal to a first current value; When the state of charge of the high-voltage power battery is greater than or equal to a second preset value and less than the first preset value, controlling the drive circuit of the silicon carbide device to output a second drive current, wherein the second drive current is greater than the first current value and less than or equal to the second current value; When the state of charge of the high-voltage power battery is less than the second preset value, the drive circuit of the silicon carbide device is controlled to output a third drive current, and the third drive current is greater than the second current value.

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