Driving circuit, sub-module and current converter

Abstract

The invention provides a driving circuit, a sub-module and a current converter. The drive circuit can realize short-circuit protection of the switch tube through the short-circuit protection branch, and can realize overcurrent protection of the switch tube through the overcurrent protection branch. In other words, different kinds of protection are adopted for the short-circuit fault and the over-current fault of the switching tube, reliable driving of the switching tube is achieved, and the reliability of the driving circuit is improved. The short-circuit protection threshold voltage and the over-current protection threshold voltage are adjustable, and driving protection of multi-stage threshold voltage can be realized for the switch tube.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a drive circuit, a submodule and a converter. Background Art

[0002] With the rapid development of semiconductor technology, insulated gate bipolar transistors (IGBT) and other switching tubes have been widely used in different fields such as flexible DC transmission, rail transportation, aerospace and new energy vehicles. Since the working state of the switching tube will affect the performance of the submodule and it needs to be driven by the driving circuit to work, the driving and reliable protection of the switching tube become very important.

[0003] The driving circuit for driving the switch tube provided by the related art generally realizes short circuit protection or overcurrent protection of the switch tube through a driving module, a charging capacitor and a charging resistor. In other words, the driving circuit provided by the related art can only realize single fault protection of the switch tube, and it is difficult to realize reliable protection of the switch tube, that is, the reliability of the driving circuit is low. Summary of the invention

[0004] In order to solve the problem of low reliability of the driving circuit in the prior art, the present application provides a driving circuit, which may include a short-circuit protection branch, an overcurrent protection branch, a selection module and a driving module.

[0005] The short-circuit protection branch is used to output a first voltage according to the voltage between the collector and the emitter of the switch tube.

[0006] The overcurrent protection branch is used to output a second voltage according to the voltage between the collector and the emitter.

[0007] The selection module is used to select the first voltage or the second voltage for the driving module.

[0008] The driving module is used to drive the switch tube according to the first voltage or the second voltage.

[0009] Optionally, the input ends of the short-circuit protection branch and the overcurrent protection branch are respectively connected to the collector of the switching tube, the output end of the short-circuit protection branch is connected to the first input end of the selection module, the output end of the overcurrent protection branch is connected to the second input end of the selection module, the output end of the selection module is connected to the input end of the driving module, and the output end of the driving module is connected to the gate of the switching tube.

[0010] In some possible implementations, the short-circuit protection branch includes a first resistor, a second resistor, a third resistor, a first capacitor, a first transistor, a first comparator, a fourth resistor, a fifth resistor, and a sixth resistor.

[0011] The first end of the first resistor is connected to the power supply, the second end of the first resistor and the first end of the second resistor are both connected to the first end of the third resistor, the second end of the second resistor is connected to the ground, the second end of the third resistor, the first end of the first capacitor, the collector of the first transistor and the non-inverting input end of the first comparator are all connected to the collector of the switch tube, the second end of the first capacitor and the emitter of the first transistor are both connected to the ground, the gate of the first transistor is connected to the output end of the driving module, the first end of the fourth resistor is used to receive the working voltage, the second end of the fourth resistor and the first end of the fifth resistor are both connected to the inverting input end of the first comparator, the second end of the fifth resistor is connected to the ground, and the output end of the first comparator is connected to the first input end of the selection module through the sixth resistor.

[0012] It is conceivable that the driving module can drive the first transistor according to the switching state of the switch tube.

[0013] In some other possible implementations, the overcurrent protection branch includes a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a second transistor, a second comparator, a tenth resistor, an eleventh resistor, and a twelfth resistor.

[0014] The first end of the seventh resistor is connected to the power supply, the second end of the seventh resistor and the first end of the eighth resistor are both connected to the first end of the ninth resistor, the second end of the eighth resistor is connected to the ground, the second end of the ninth resistor, the first end of the second capacitor, the collector of the second transistor and the in-phase input end of the second comparator are all connected to the collector of the switch tube, the second end of the second capacitor and the emitter of the second transistor are both connected to the ground, the gate of the second transistor is connected to the output end of the driving module, the first end of the tenth resistor is used to receive the working voltage, the second end of the tenth resistor and the first end of the eleventh resistor are both connected to the inverting input end of the second comparator, the second end of the eleventh resistor is connected to the ground, and the output end of the second comparator is connected to the second input end of the selection module through the twelfth resistor.

[0015] It is conceivable that the driving module can drive the second transistor according to the switching state of the switch tube.

[0016] Furthermore, the driving circuit also includes a charging module. The charging module includes a third capacitor and a thirteenth resistor.

[0017] The first end of the thirteenth resistor is connected to the output end of the selection module, the second end of the thirteenth resistor and the first end of the third capacitor are both connected to the input end of the driving module, and the second end of the third capacitor is connected to the ground end.

[0018] In a possible implementation, when the switch tube is short-circuited, the drive circuit can be used to:

[0019] The first capacitor is charged through the power supply and the third resistor. When the voltage of the first capacitor reaches the short-circuit protection threshold voltage, the first comparator outputs a high level to charge the third capacitor. When the voltage of the third capacitor reaches the driving protection threshold voltage, the third comparator of the driving module outputs a high level to the driving unit in the driving module, and the driving unit drives the switch tube to turn off.

[0020] In another possible implementation, when the switch tube is overcurrent, the drive circuit is used to:

[0021] The second capacitor is charged through the power supply and the ninth resistor. When the voltage of the second capacitor reaches the overcurrent protection threshold voltage, the second comparator outputs a high level to charge the third capacitor. When the voltage of the third capacitor reaches the driving protection threshold voltage, the third comparator of the driving module outputs a high level to the driving unit in the driving module, and the driving unit drives the switch tube to turn off.

[0022] Exemplarily, the short-circuit protection branch includes a first capacitor, and the overcurrent protection branch includes a second capacitor. The capacitance of the first capacitor is smaller than the capacitance of the second capacitor.

[0023] Optionally, the selection module uses a logic OR gate.

[0024] In another aspect, the present application further provides a submodule, comprising a circuit board and the above-mentioned driving circuit. The driving circuit is arranged on the circuit board.

[0025] On the other hand, the present application also provides a converter, which may include the above-mentioned sub-module.

[0026] Optionally, the converter may be a voltage source converter or a modular multilevel converter, etc.

[0027] Compared with the prior art, the beneficial effects of this application are:

[0028] The driving circuit provided in the present application can realize short-circuit protection of the switch tube through the short-circuit protection branch, and can realize overcurrent protection of the switch tube through the overcurrent protection branch. That is, the present application adopts different protections for the two different faults of the short-circuit fault and the overcurrent fault of the switch tube, realizes reliable driving of the switch tube, and improves the reliability of the driving circuit.

[0029] The present application provides an adjustable short-circuit protection threshold voltage for the inverting input terminal of the first comparator through a voltage divider circuit formed by the fourth resistor and the fifth resistor, and provides an adjustable overcurrent protection threshold voltage for the inverting input terminal of the second comparator through a voltage divider circuit formed by the tenth resistor and the eleventh resistor. In other words, the short-circuit protection threshold voltage and the overcurrent protection threshold voltage of the present application are both adjustable, and multi-level threshold voltage drive protection can be achieved for the switch tube, and it is not easy to cause false protection due to driving at different voltage levels.

[0030] In the present application, both the short-circuit protection branch and the overcurrent protection branch are analog circuits, that is, the present application does not require the provision of a digital chip, and the cost of the driving circuit is relatively low.

[0031] In the present application, the capacitance of the first capacitor is smaller than that of the second capacitor. The smaller capacitance of the first capacitor can reduce the short-circuit protection blanking time and improve the reliability of the short-circuit protection. The larger capacitance of the second capacitor can increase the overcurrent protection blanking time and minimize the probability of false protection caused by large parasitic parameter overcurrent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 is a schematic structural diagram of a driving circuit in an embodiment of the present application;

[0034] Figure 2 Another schematic structural diagram of the driving circuit in the embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0036] The terms "first", "second", etc. in the specification embodiments, claims, and drawings of the present application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, including a series of steps or units. The method, system, product, or device 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.

[0037] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0038] The embodiment of the present application provides a driving circuit for driving a switch tube. Figure 1 As shown, the driving circuit 10 may include a short-circuit protection branch 1 , an overcurrent protection branch 2 , a selection module 3 and a driving module 4 .

[0039] Optionally, the short-circuit protection branch 1 is used to output a first voltage (which can be represented by V1) according to the voltage (which can be represented by Vce) between the collector and the emitter of the switch tube (hereinafter taking IGBT as an example).

[0040] The overcurrent protection branch 2 is used to output a second voltage (which can be represented by V2) according to the voltage Vce between the collector and the emitter.

[0041] The selection module 3 (which may be a logic OR gate, etc.) is used to select the first voltage V1 or the second voltage V2 to give to the driving module 4 .

[0042] The driving module 4 is used to drive the IGBT according to the first voltage V1 or the second voltage V2.

[0043] Exemplarily, a plurality of diodes D may be provided between the input ends of the short-circuit protection branch 1 and the overcurrent protection branch 2 and the collector of the IGBT.

[0044] refer to Figure 1 The input ends of the short-circuit protection branch 1 and the overcurrent protection branch 2 are respectively connected to the collector of the IGBT through multiple diodes D, the output end of the short-circuit protection branch 1 is connected to the first input end of the selection module 3, the output end of the overcurrent protection branch 2 is connected to the second input end of the selection module 3, the output end of the selection module 3 is connected to the input end of the driving module 4, and the output end of the driving module 4 is connected to the gate of the IGBT.

[0045] In some embodiments, Figure 2As shown, the short-circuit protection branch 1 includes a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a first transistor T1, a first comparator COMP1, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6.

[0046] A first end of the first resistor R1 is connected to a power supply V, a second end of the first resistor R1 and a first end of the second resistor R2 are both connected to a first end of a third resistor R3, a second end of the second resistor R2 is connected to a ground terminal, a second end of the third resistor R3, a first end of the first capacitor C1, a collector of the first transistor T1 and a non-inverting input terminal of the first comparator COMP1 are all connected to a collector of the IGBT, a second end of the first capacitor C1 and an emitter of the first transistor T1 are both connected to a ground terminal, a gate of the first transistor T1 is connected to an output terminal of the driving module 4, a first end of the fourth resistor R4 is used to receive an operating voltage Vcc, a second end of the fourth resistor R4 and a first end of the fifth resistor R5 are both connected to an inverting input terminal of the first comparator COMP1, a second end of the fifth resistor R5 is connected to a ground terminal, and an output terminal of the first comparator COMP1 is connected to a first input terminal of the selection module 3 via a sixth resistor R6.

[0047] The first resistor R1 and the second resistor R2 form a voltage divider circuit. The voltage divided by the second resistor R2 is the cut-off voltage of the diode D connected in series with the IGBT when the short-circuit protection branch 1 determines that the IGBT is short-circuited (the voltage level can be set to be above 10V). The fourth resistor R4 and the fifth resistor R5 also form a voltage divider circuit, and the voltage divided by the fifth resistor R5 is the short-circuit protection threshold voltage (represented by Vth1).

[0048] It is conceivable that the driving module 4 can drive the first transistor T1 according to the switching state of the IGBT.

[0049] In other embodiments, the overcurrent protection branch 2 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a second capacitor C2, a second transistor T2, a second comparator COMP2, a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12.

[0050] A first end of the seventh resistor R7 is connected to the power supply V, a second end of the seventh resistor R7 and a first end of the eighth resistor R8 are both connected to a first end of the ninth resistor R9, a second end of the eighth resistor R8 is connected to the ground, a second end of the ninth resistor R9, a first end of the second capacitor C2, a collector of the second transistor T2 and a non-inverting input end of the second comparator COMP2 are all connected to the collector of the IGBT, a second end of the second capacitor C2 and an emitter of the second transistor T2 are both connected to the ground, a gate of the second transistor T2 is connected to the output end of the driving module 4, a first end of the tenth resistor R10 is used to receive a working voltage Vcc, a second end of the tenth resistor R10 and a first end of the eleventh resistor R11 are both connected to an inverting input end of the second comparator COMP2, a second end of the eleventh resistor R11 is connected to the ground, and an output end of the second comparator COMP2 is connected to a second input end of the selection module 3 through a twelfth resistor R12.

[0051] The seventh resistor R7 and the eighth resistor R8 form a voltage divider circuit, and the voltage divided by the eighth resistor R8 is the cut-off voltage (the voltage level can be set to be above 10V) of the diode D connected in series with the IGBT when the overcurrent protection branch 2 determines an IGBT overcurrent fault. The tenth resistor R10 and the eleventh resistor R11 also form a voltage divider circuit, and the voltage divided by the eleventh resistor R11 is the overcurrent protection threshold voltage (represented by Vth2).

[0052] It is conceivable that the driving module 4 can drive the second transistor T2 according to the switching state of the IGBT.

[0053] Optionally, the capacitance of the first capacitor C1 is smaller than the capacitance of the second capacitor C2. A smaller capacitance of the first capacitor C can reduce the short-circuit protection blanking time and improve the reliability of the short-circuit protection. A larger capacitance of the second capacitor C2 can increase the overcurrent protection blanking time and minimize the probability of false protection caused by large parasitic parameter overcurrent.

[0054] Continue to refer Figure 2 The driving circuit 10 further includes a charging module 5. The charging module 5 includes a third capacitor C3 and a thirteenth resistor R13.

[0055] A first end of the thirteenth resistor R13 is connected to the output end of the selection module 3 , a second end of the thirteenth resistor R13 and a first end of the third capacitor C3 are both connected to the input end of the driving module 4 , and a second end of the third capacitor C3 is connected to the ground end.

[0056] Optionally, the driving module 4 may be a driving chip, including a third comparator COMP3 and a driving unit 4, such as Figure 2The non-inverting input terminal of the third comparator COMP3 is connected to the thirteenth resistor R13 and the third capacitor C3, and the inverting input terminal of the third comparator COMP3 is used to receive the driving protection threshold voltage Vth, which can be 6.5V or the like.

[0057] In one example, during the IGBT shutdown process, the drive circuit 10 can be used for: the transistor T1 and the transistor T2 are both turned on, and the power supply V of the short-circuit protection branch 1 is bypassed by the transistor T1 (so the second capacitor C2 is not charged). Similarly, the power supply V of the overcurrent protection branch 2 is bypassed by the transistor T2 (so the third capacitor C3 is not charged). Since the voltage Vce between the collector and the emitter is relatively low, the first comparator COMP1 and the second comparator COMP2 are each clamped to a low potential at the same phase input terminal, so the first comparator COMP1 and the second comparator COMP2 are not flipped and both output a low level, the potential of the third capacitor C3 is clamped to a low level, and the third comparator COMP3 in the driving module 4 is not flipped.

[0058] In another example, during the IGBT turn-on process, the drive circuit 10 can be used to: the transistor T1 and the transistor T2 are both turned off, the IGBT enters the saturation region, the power supply of the short-circuit protection branch 1 flows through the resistor R1, multiple diodes D and the IGBT, and the power supply V of the overcurrent protection branch 2 flows through the resistor R3 and multiple diodes D and the IGBT, so a loop can be formed, and the third comparator COMP3 does not flip.

[0059] In another example, when the IGBT is short-circuited, the drive circuit 10 can be used to: the IGBT will exit the saturation region, the voltage Vce between the collector and the emitter will quickly rise to the bus voltage of the bus connected to the IGBT, the diode D will be turned off, the first capacitor C1 will be charged through the power supply V and the third resistor R3, and the voltage of the first capacitor C1 will rise linearly. Since the capacitance of the first capacitor C1 is small, the voltage of the first capacitor C1 can quickly reach the short-circuit protection threshold voltage Vth1. When the voltage of the first capacitor C1 reaches the short-circuit protection threshold voltage Vth1, the first comparator COMP1 flips the output high level to charge the third capacitor C3, and the voltage of the third capacitor C3 rises linearly. When the voltage of the third capacitor C3 reaches the driving protection threshold voltage (expressed by Vth), the third comparator COMP3 flips the output high level to the driving unit 41 in the driving module 4, and the driving unit 41 drives the IGBT to turn off.

[0060] In another example, when the IGBT is overcurrent, the drive circuit 10 is used to: cIn a short time, it rises to twice the rated current of the IGBT (at this time, Vce is low), the diode D is turned off, and the second capacitor C2 is charged through the power supply V and the ninth resistor R9. Since the capacitance of the second capacitor C2 is large, a certain charging time is required. When the voltage of the second capacitor C2 reaches the overcurrent protection threshold voltage Vth2, the second comparator COMP2 flips and outputs a high level to charge the third capacitor C3, and the voltage of the third capacitor C3 rises linearly. When the voltage of the third capacitor C3 reaches the driving protection threshold voltage Vth, the third comparator COMP3 of the driving module 4 flips and outputs a high level to the driving unit 41 in the driving module 4, and the driving unit 41 drives the IGBT to turn off.

[0061] The embodiment of the present application further provides a submodule, comprising a circuit board and the above-mentioned driving circuit 10. The driving circuit 10 is arranged on the circuit board.

[0062] An embodiment of the present application also provides a converter, which may include the above-mentioned sub-module.

[0063] Optionally, the converter may be a voltage source converter or a modular multilevel converter, etc., which is not limited in the embodiments of the present application.

[0064] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A driving circuit, characterized in that: It includes a short-circuit protection branch, an overcurrent protection branch, a selection module and a drive module; The short-circuit protection branch is used to: output a first voltage according to the voltage between the collector and the emitter of the switch tube; The overcurrent protection branch is used to: output a second voltage according to the voltage between the collector and the emitter; The selection module is used to: select the first voltage or the second voltage to the driving module; The driving module is used to drive the switch tube according to the first voltage or the second voltage.

2. The driving circuit according to claim 1, characterized in that: The input ends of the short-circuit protection branch and the overcurrent protection branch are respectively connected to the collector of the switch tube, the output end of the short-circuit protection branch is connected to the first input end of the selection module, the output end of the overcurrent protection branch is connected to the second input end of the selection module, the output end of the selection module is connected to the input end of the drive module, and the output end of the drive module is connected to the gate of the switch tube.

3. The driving circuit according to claim 2, characterized in that: The short-circuit protection branch includes a first resistor, a second resistor, a third resistor, a first capacitor, a first transistor, a first comparator, a fourth resistor, a fifth resistor and a sixth resistor; The first end of the first resistor is connected to the power supply, the second end of the first resistor and the first end of the second resistor are both connected to the first end of the third resistor, the second end of the second resistor is connected to the ground, the second end of the third resistor, the first end of the first capacitor, the collector of the first transistor and the non-inverting input end of the first comparator are all connected to the collector of the switch tube, the second end of the first capacitor and the emitter of the first transistor are both connected to the ground, the gate of the first transistor is connected to the output end of the driving module, the first end of the fourth resistor is used to receive the working voltage, the second end of the fourth resistor and the first end of the fifth resistor are both connected to the inverting input end of the first comparator, the second end of the fifth resistor is connected to the ground, and the output end of the first comparator is connected to the first input end of the selection module through the sixth resistor.

4. The driving circuit according to claim 2, characterized in that: The overcurrent protection branch includes a seventh resistor, an eighth resistor, a ninth resistor, a second capacitor, a second triode, a second comparator, a tenth resistor, an eleventh resistor and a twelfth resistor; The first end of the seventh resistor is connected to the power supply, the second end of the seventh resistor and the first end of the eighth resistor are both connected to the first end of the ninth resistor, the second end of the eighth resistor is connected to the ground, the second end of the ninth resistor, the first end of the second capacitor, the collector of the second transistor and the non-inverting input end of the second comparator are all connected to the collector of the switch tube, the second end of the second capacitor and the emitter of the second transistor are both connected to the ground, the gate of the second transistor is connected to the output end of the driving module, the first end of the tenth resistor is used to receive the working voltage, the second end of the tenth resistor and the first end of the eleventh resistor are both connected to the inverting input end of the second comparator, the second end of the eleventh resistor is connected to the ground, and the output end of the second comparator is connected to the second input end of the selection module through the twelfth resistor.

5. The driving circuit according to claim 3 or 4, characterized in that: The driving circuit further includes a charging module; the charging module includes a third capacitor and a thirteenth resistor; The first end of the thirteenth resistor is connected to the output end of the selection module, the second end of the thirteenth resistor and the first end of the third capacitor are both connected to the input end of the driving module, and the second end of the third capacitor is connected to the ground end.

6. The driving circuit according to claim 5, characterized in that: In the case where the switch tube is short-circuited, the drive circuit is used to: The first capacitor is charged through the power supply and the third resistor. When the voltage of the first capacitor reaches a short-circuit protection threshold voltage, the first comparator outputs a high level to charge the third capacitor. When the voltage of the third capacitor reaches a driving protection threshold voltage, the third comparator of the driving module outputs a high level to the driving unit in the driving module, and the driving unit drives the switch tube to turn off.

7. The driving circuit according to claim 5, characterized in that: In the case of an overcurrent in the switch tube, the drive circuit is used to: The second capacitor is charged through the power supply and the ninth resistor, and the second comparator outputs a high level to charge the third capacitor when the voltage of the second capacitor reaches the overcurrent protection threshold voltage. When the voltage of the third capacitor reaches the driving protection threshold voltage, the third comparator of the driving module outputs a high level to the driving unit in the driving module, and the driving unit drives the switch tube to turn off.

8. The driving circuit according to claim 1, characterized in that: The short-circuit protection branch includes a first capacitor, and the overcurrent protection branch includes a second capacitor; The capacitance of the first capacitor is smaller than the capacitance of the second capacitor.

9. The driving circuit according to claim 1, characterized in that: The selection module adopts a logic OR gate.

10. A submodule, characterized in that: It comprises a circuit board and a driving circuit as claimed in any one of claims 1 to 9; the driving circuit is arranged on the circuit board.

11. A converter, characterized in that: Comprising the submodule as claimed in claim 10.

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