Turn-off circuit, driving circuit, IGCT, electrical apparatus and turn-off method

Abstract

Provided in the present disclosure are a turn-off circuit, a driving circuit, an IGCT, an electrical apparatus and a turn-off method. The turn-off circuit comprises: a control device, which is configured to output a first control signal in a first stage, and output a second control signal in a second stage subsequent to the first stage, wherein the first stage comprises at least part of a voltage build-up stage within a turn-off stage of a gate commutated thyristor, and the at least part of the voltage build-up stage is subsequent to and adjacent to a commutation stage within the turn-off stage; and a voltage regulation circuit, which is configured to apply, after receiving the first control signal and in the first stage, a first reverse bias voltage to a PN junction formed by a second doped region and a first doped region, and apply in the second stage a second reverse bias voltage to the PN junction after receiving the second control signal, wherein the voltage value of the first reverse bias voltage is greater than or equal to a breakdown voltage threshold value of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold value of the PN junction.

Description

Turn-off circuit, drive circuit, IGCT, electrical device and turn-off method

[0001] Cross-reference to Related Applications

[0002] This application is based on the application with CN application number 202411116959.1 and application date 2024-08-14, and the application with CN application number 202510531279.4 and application date 2025-04-25, and claims priority thereto, the disclosure of which is incorporated herein in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of power electronics, in particular to a turn-off circuit, a drive circuit, an IGCT, an electrical device and a turn-off method. BACKGROUND

[0004] An integrated gate commutated thyristor (IGCT) is a device composed of a gate commutated thyristor (GCT), a tube package structure and a drive circuit.

[0005] FIG. 1 is a connection topology diagram of an electrode terminal of a gate commutated thyristor chip and a drive circuit in the related art. FIG. 1 shows the connection topology of the GCT and the drive circuit in the related art. As shown in FIG. 1, the GCT chip includes three lead terminals, i.e., a first lead terminal, a second lead terminal and a control terminal; the drive circuit mainly includes a turn-on loop and a turn-off loop.

[0006] FIG. 2 is a schematic diagram showing the working state of a gate commutated thyristor. As shown in FIG. 2, the working state of the GCT chip is divided into a conduction state, a turn-off state and a blocking state. In the conduction state, there is current inside the device, and the device does not substantially bear voltage across the terminals; in the blocking state, there is substantially no current inside the device, and the device directly bears voltage across the terminals; the turn-off state is a switching process of the device before the conduction state and the blocking state. The three states are constantly rotated to realize the conduction and turn-off of the main loop current.

[0007] As shown in FIG. 2, the turn-off state includes a commutation phase and a voltage build-up phase. In the commutation phase, the current originally flowing from the first lead terminal is switched to flow from the control terminal. That is, in the commutation phase, the cathode current is commutated to the gate, which is a "preparation" state at this time, there is current inside the device, and the device still does not bear voltage. In the voltage build-up phase, the voltage between the first lead terminal and the second lead terminal rises and stabilizes to the bus voltage, and the current inside the chip gradually decays to zero. That is, the voltage build-up phase is a process of gradually establishing the voltage across the terminals of the device, and the current inside the device gradually decays to 0.

[0008] The drive circuit is a core component for controlling the state transition of the GCT chip. The turn-on loop in the drive circuit controls the semiconductor to turn on by injecting a trigger current into the control electrode of the GCT chip. The turn-off loop in the drive circuit forces the current originally flowing from the first anode to commutate to flow from the control electrode by applying a reverse bias voltage to the PN junction between the control electrode and the first anode, so that the PN junction between the first anode and the control electrode of the GCT chip is reversely cut off, and then the voltage between the first anode and the second anode of the GCT chip is safely established, and the current in the chip decays to zero, and the chip successfully enters the blocking state. SUMMARY

[0009] According to one aspect of the present disclosure, a turn-off circuit for a gate-commutated thyristor is provided, wherein the gate-commutated thyristor includes a first anode, a second anode and a control electrode, wherein a first doping region connected to the first anode has an opposite conductivity type to a second doping region connected to the control electrode, the turn-off circuit includes: a control device configured to output a first control signal in a first phase and output a second control signal in a second phase after the first phase, wherein the first phase includes at least a part of a voltage establishment phase in a turn-off phase of the gate-commutated thyristor, the at least part of the voltage establishment phase is after and adjacent to a commutation phase in the turn-off phase; and a voltage regulation circuit configured to, after receiving the first control signal, apply a first reverse bias voltage to a PN junction formed by the second doping region and the first doping region through the control electrode and the first anode in the first phase, and after receiving the second control signal, apply a second reverse bias voltage to the PN junction in the second phase, wherein the voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

[0010] In some embodiments, the first phase further includes the commutation phase.

[0011] In some embodiments, the turn-off circuit further includes: a current detection device configured to detect a current value of a current flowing through the second anode and transmit the current value to the control device, wherein the control device is further configured to output the first control signal to the voltage regulation circuit in response to the current value being greater than a current threshold, and output the second control signal to the voltage regulation circuit in response to the current value being less than or equal to the current threshold.

[0012] In some embodiments, the current threshold is a current value of a predetermined percentage of a maximum current flowing through the second anode.

[0013] In some embodiments, the first stage corresponds to a predetermined duration.

[0014] In some embodiments, the voltage regulating circuit comprises: a first voltage source, wherein a voltage value of the first voltage source is the second reverse bias voltage; a second voltage source, wherein a sum of a voltage value of the second voltage source and the voltage value of the first voltage source is the first reverse bias voltage; a first switching device, a first end of the first switching device is electrically connected to the control electrode of the gate-commutated thyristor, a second end of the first switching device is electrically connected to a first end of the first voltage source, a control end of the first switching device is electrically connected to the control device; a second switching device, a first end of the second switching device is electrically connected to the first lead electrode of the gate-commutated thyristor, a second end of the second switching device is electrically connected to a second end of the first voltage source and a first end of the second voltage source, a control end of the second switching device is electrically connected to the control device; and a third switching device, a first end of the third switching device is electrically connected to the first lead electrode of the gate-commutated thyristor, a second end of the third switching device is electrically connected to a second end of the second voltage source, a control end of the third switching device is electrically connected to the control device.

[0015] In some embodiments, the first control signal comprises a first sub-control signal, a second sub-control signal and a third sub-control signal; the control device is configured to output the first sub-control signal to the first switching device to make the first switching device conductive, output the second sub-control signal to the second switching device to make the second switching device non-conductive, and output the third sub-control signal to the third switching device to make the third switching device conductive in the first stage.

[0016] In some embodiments, the control device is configured to output the first sub-control signal, the second sub-control signal and the third sub-control signal simultaneously.

[0017] In some embodiments, the second control signal comprises a fourth sub-control signal, a fifth sub-control signal and a sixth sub-control signal; the control device is configured to output the fourth sub-control signal to the first switching device to make the first switching device conductive, output the fifth sub-control signal to the second switching device to make the second switching device conductive, and output the sixth sub-control signal to the third switching device to make the third switching device non-conductive in the second stage.

[0018] In some embodiments, the control device is configured to output the fourth sub-control signal, the fifth sub-control signal and the sixth sub-control signal simultaneously.

[0019] In some embodiments, the second doped region is of P-type, the first doped region is of N-type, the first end of the first voltage source is a negative terminal, the second end of the first voltage source is a positive terminal, the first end of the second voltage source is a negative terminal, and the second end of the second voltage source is a positive terminal.

[0020] In some embodiments, the second doped region is of N-type, the first doped region is of P-type, the first end of the first voltage source is a positive terminal, the second end of the first voltage source is a negative terminal, the first end of the second voltage source is a positive terminal, and the second end of the second voltage source is a negative terminal.

[0021] In some embodiments, the voltage regulating circuit comprises: a first voltage source, wherein a voltage value of the first voltage source is the second reverse bias voltage; a second voltage source, wherein a sum of the voltage value of the second voltage source and the voltage value of the first voltage source is the first reverse bias voltage; a first switching device, a first end of the first switching device is electrically connected to the control electrode of the gate-commutated thyristor, a second end of the first switching device is electrically connected to a first end of the first voltage source, and a control end of the first switching device is electrically connected to the control device; a unidirectional conduction device, a first end of the unidirectional conduction device is electrically connected to the first draw-out electrode of the gate-commutated thyristor, a second end of the unidirectional conduction device is electrically connected to a second end of the first voltage source and a first end of the second voltage source; and a second switching device, a first end of the second switching device is electrically connected to the first draw-out electrode of the gate-commutated thyristor, a second end of the second switching device is electrically connected to a second end of the second voltage source, and a control end of the second switching device is electrically connected to the control device.

[0022] In some embodiments, the first control signal comprises a first sub-control signal and a second sub-control signal; the control device is configured to output the first sub-control signal to the first switching device in the first stage to make the first switching device conductive, and output the second sub-control signal to the second switching device in the first stage to make the second switching device conductive.

[0023] In some embodiments, the control device is configured to output the first sub-control signal and the second sub-control signal simultaneously.

[0024] In some embodiments, the second control signal comprises a third sub-control signal and a fourth sub-control signal; the control device is configured to output the third sub-control signal to the first switching device in the second phase to make the first switching device conductive, and output the fourth sub-control signal to the second switching device in the second phase to make the second switching device non-conductive.

[0025] In some embodiments, the control device is configured to output the third sub-control signal and the fourth sub-control signal simultaneously.

[0026] In some embodiments, the second doped region is of P-type, the first doped region is of N-type, the first end of the unidirectional conduction device is a negative terminal, the second end of the unidirectional conduction device is a positive terminal, the first end of the first voltage source is a negative terminal, the second end of the first voltage source is a positive terminal, the first end of the second voltage source is a negative terminal, and the second end of the second voltage source is a positive terminal.

[0027] In some embodiments, the second doped region is of N-type, the first doped region is of P-type, the first end of the unidirectional conduction device is a positive terminal, the second end of the unidirectional conduction device is a negative terminal, the first end of the first voltage source is a positive terminal, the second end of the first voltage source is a negative terminal, the first end of the second voltage source is a positive terminal, and the second end of the second voltage source is a negative terminal.

[0028] In some embodiments, the control device is further configured to output a control signal to the voltage regulation circuit, wherein the control signal comprises the first control signal or the second control signal; the voltage regulation circuit comprises a control sub-circuit, a pressure-bearing adjustable switching element, and a voltage source, wherein a first end of the pressure-bearing adjustable switching element is electrically connected to a control electrode of the gate-commutated thyristor, a second end of the pressure-bearing adjustable switching element is electrically connected to a first end of the voltage source, and a control end of the pressure-bearing adjustable switching element is electrically connected to the control sub-circuit.

[0029] A second end of the voltage source is electrically connected to a first outgoing electrode of the gate-commutated thyristor, and the control sub-circuit is configured to control the pressure-bearing adjustable switching element to be conductive or non-conductive, or to be clamped at a predetermined voltage, based on the control signal.

[0030] In some embodiments, the control sub-circuit comprises a first sub-circuit configured to control the pressure-bearing adjustable switching element to be conductive or non-conductive, and a second sub-circuit configured to control the pressure-bearing adjustable switching element to be clamped at a predetermined voltage.

[0031] In some embodiments, the first sub-circuit comprises: a first switch device, a first end of the first switch device is electrically connected to a first voltage terminal, a second end of the first switch device is electrically connected to a control terminal of the pressure-bearing adjustable switch element, and a control terminal of the first switch device is electrically connected to the control device; a first resistor, a first end of the first resistor is electrically connected to the first voltage terminal, and a second end of the first resistor is electrically connected to the control terminal of the pressure-bearing adjustable switch element; and a second switch device, a first end of the second switch device is electrically connected to a second voltage terminal, a second end of the second switch device is electrically connected to the control terminal of the pressure-bearing adjustable switch element, and a control terminal of the second switch device is electrically connected to the control device; wherein a voltage level of the first voltage terminal is less than a voltage level of the second voltage terminal.

[0032] In some embodiments, the first sub-circuit further comprises: a second resistor arranged between the second end of the first switch device and the control terminal of the pressure-bearing adjustable switch element; and / or a third resistor arranged between the second end of the second switch device and the control terminal of the pressure-bearing adjustable switch element.

[0033] In some embodiments, the second sub-circuit comprises one or more clamping sub-circuits, wherein each clamping sub-circuit comprises: a third switch device, a first end of the third switch device is electrically connected to the control terminal of the pressure-bearing adjustable switch element, and a control terminal of the third switch device is electrically connected to the control device; a first diode, a negative terminal of the first diode is electrically connected to a second end of the third switch device; and a voltage stabilizing diode, a positive terminal of the voltage stabilizing diode is electrically connected to a positive terminal of the first diode, and a negative terminal of the voltage stabilizing diode is electrically connected to a first end of the pressure-bearing adjustable switch element.

[0034] In some embodiments, the voltage stabilizing diode is an avalanche breakdown diode; and / or the pressure-bearing adjustable switch element comprises a metal-oxide-semiconductor field-effect transistor.

[0035] In some embodiments, the one or more clamping sub-circuits comprise a plurality of clamping sub-circuits, and the breakdown voltage thresholds of the voltage stabilizing diodes in the plurality of clamping sub-circuits are not equal.

[0036] In some embodiments, the control device is configured to control the first switching device to turn on, control the second switching device to turn off, and control all third switching devices in the one or more clamping sub-circuits to turn off when the gate-commutated thyristor enters the turn-on phase; control the first switching device to turn off, control the second switching device to turn on, and control all third switching devices in the one or more clamping sub-circuits to turn off when the gate-commutated thyristor enters the turn-off phase; and control the first switching device to turn off, control the second switching device to turn off, and control one third switching device in the one or more clamping sub-circuits to turn on when the gate-commutated thyristor enters the blocking phase.

[0037] In some embodiments, the first control signal comprises a first sub-control signal, a second sub-control signal, and a third sub-control signal; the control device is configured to output the first sub-control signal to the first switching device to control the first switching device to turn off, output the second sub-control signal to the second switching device to control the second switching device to turn on, and output the third sub-control signal to all third switching devices in the one or more clamping sub-circuits to control all third switching devices to turn off; and / or the second control signal comprises a fourth sub-control signal, a fifth sub-control signal, and a sixth sub-control signal; the control device is configured to output the fourth sub-control signal to the first switching device to control the first switching device to turn off, output the fifth sub-control signal to the second switching device to control the second switching device to turn off, and output the sixth sub-control signal to one third switching device in the one or more clamping sub-circuits to control the one third switching device to turn on.

[0038] In some embodiments, the voltage of the voltage source is greater than the breakdown voltage threshold of the PN junction.

[0039] According to another aspect of the present disclosure, a turn-off circuit is provided, wherein the turn-off circuit is used for a gate-commutated thyristor, the gate-commutated thyristor comprising a first draw-out electrode, a second draw-out electrode and a control electrode, the turn-off circuit comprising: a control device and a voltage regulating circuit; the control device is configured to output a control signal to the voltage regulating circuit; the voltage regulating circuit comprises: a control sub-circuit, a pressure-bearing adjustable switching element and a voltage source, wherein a first end of the pressure-bearing adjustable switching element is electrically connected to the control electrode of the gate-commutated thyristor, a second end of the pressure-bearing adjustable switching element is electrically connected to a first end of the voltage source, a control end of the pressure-bearing adjustable switching element is electrically connected to the control sub-circuit, a second end of the voltage source is electrically connected to the first draw-out electrode of the gate-commutated thyristor, and the control sub-circuit is configured to control the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage based on the control signal.

[0040] In some embodiments, the control sub-circuit comprises: a first sub-circuit configured to control the pressure-bearing adjustable switching element to be turned on or turned off; and a second sub-circuit configured to control the pressure-bearing adjustable switching element to be clamped at a predetermined voltage.

[0041] In some embodiments, the first sub-circuit comprises: a first switching device, a first end of the first switching device being electrically connected to a first voltage terminal, a second end of the first switching device being electrically connected to the control end of the pressure-bearing adjustable switching element, and a control end of the first switching device being electrically connected to the control device; a first resistor, a first end of the first resistor being electrically connected to the first voltage terminal, and a second end of the first resistor being electrically connected to the control end of the pressure-bearing adjustable switching element; and a second switching device, a first end of the second switching device being electrically connected to a second voltage terminal, a second end of the second switching device being electrically connected to the control end of the pressure-bearing adjustable switching element, and a control end of the second switching device being electrically connected to the control device; wherein a voltage level of the first voltage terminal is less than a voltage level of the second voltage terminal.

[0042] In some embodiments, the first sub-circuit further comprises: a second resistor arranged between the second end of the first switching device and the control end of the pressure-bearing adjustable switching element; and / or a third resistor arranged between the second end of the second switching device and the control end of the pressure-bearing adjustable switching element.

[0043] In some embodiments, the second sub-circuit comprises one or more clamping sub-circuits, wherein each clamping sub-circuit comprises: a third switching device, a first end of the third switching device being electrically connected to a control end of the pressure-bearing adjustable switching element, a control end of the third switching device being electrically connected to the control device; a first diode, a negative end of the first diode being electrically connected to a second end of the third switching device; and a voltage stabilizing diode, a positive end of the voltage stabilizing diode being electrically connected to a positive end of the first diode, a negative end of the voltage stabilizing diode being electrically connected to a first end of the pressure-bearing adjustable switching element.

[0044] In some embodiments, the voltage stabilizing diode is an avalanche breakdown diode; and / or the pressure-bearing adjustable switching element comprises a metal-oxide-semiconductor field-effect transistor.

[0045] In some embodiments, the one or more clamping sub-circuits comprise a plurality of clamping sub-circuits, and breakdown voltage thresholds of the voltage stabilizing diodes in the plurality of clamping sub-circuits are not equal.

[0046] In some embodiments, the control device is configured to: when the gate-commutated thyristor enters an on phase, control the first switching device to be on, control the second switching device to be off, and control all third switching devices in the one or more clamping sub-circuits to be off; when the gate-commutated thyristor enters an off phase, control the first switching device to be off, control the second switching device to be on, and control all third switching devices in the one or more clamping sub-circuits to be off; and when the gate-commutated thyristor enters a blocking phase, control the first switching device to be off, control the second switching device to be off, and control one third switching device in the one or more clamping sub-circuits to be on.

[0047] According to another aspect of the present disclosure, there is provided a drive circuit for a gate-commutated thyristor, comprising: an off circuit as previously described.

[0048] According to another aspect of the present disclosure, there is provided an integrated gate-commutated thyristor, comprising: an off circuit as previously described.

[0049] According to another aspect of the present disclosure, there is provided an electrical device, comprising: an integrated gate-commutated thyristor as previously described.

[0050] According to another aspect of the present disclosure, there is provided a turn-off method for a gate-commutated thyristor, wherein the gate-commutated thyristor comprises a first gate electrode, a second gate electrode and a control electrode, wherein a conductivity type of a first doped region connected to the first gate electrode is opposite to a conductivity type of a second doped region connected to the control electrode, the turn-off method comprising: applying, by the control electrode and the first gate electrode, a first reverse bias voltage to a PN junction formed by the second doped region and the first doped region in a first phase, wherein the first phase comprises at least a part of a voltage build-up phase in a turn-off phase of the gate-commutated thyristor, the at least part of the voltage build-up phase is after and adjacent to a commutation phase in the turn-off phase, a voltage value of the first reverse bias voltage is greater than or equal to a breakdown voltage threshold of the PN junction; and applying a second reverse bias voltage to the PN junction in a second phase after the first phase, wherein a voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

[0051] In some embodiments, the first phase further comprises the commutation phase.

[0052] In some embodiments, the applying the first reverse bias voltage to the PN junction in the first phase comprises: in response to a current value of a current flowing through the second gate electrode being greater than a current threshold, applying the first reverse bias voltage to the PN junction; and the applying the second reverse bias voltage to the PN junction in the second phase after the first phase comprises: in response to the current value of the current flowing through the second gate electrode being less than or equal to the current threshold, applying the second reverse bias voltage to the PN junction.

[0053] In some embodiments, the current threshold is a current value of a predetermined percentage of a maximum current value of the current flowing through the second gate electrode.

[0054] In some embodiments, the first phase corresponds to a predetermined time duration.

[0055] According to another aspect of the present disclosure, there is provided a turn-off method based on the turn-off circuit as previously described, comprising: when the gate-commutated thyristor enters a turn-on phase, controlling the first switching device to be turned on, controlling the second switching device to be turned off, and controlling all third switching devices in the one or more clamping sub-circuits to be turned off; when the gate-commutated thyristor enters a turn-off phase, controlling the first switching device to be turned off, controlling the second switching device to be turned on, and controlling all third switching devices in the one or more clamping sub-circuits to be turned off; when the gate-commutated thyristor enters a blocking phase, controlling the first switching device to be turned off, controlling the second switching device to be turned off, and controlling one third switching device in the one or more clamping sub-circuits to be turned on.

[0056] Other features and advantages of the present disclosure will be apparent from the detailed description of the exemplary embodiments thereof, which is described in connection with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0057] The accompanying drawings, which form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0058] The present disclosure can be understood more readily by reference to the following detailed description, taken in connection with the accompanying drawings, in which:

[0059] FIG. 1 is a connection topology diagram of an electrode terminal of a gate-commutated thyristor chip and a driving circuit in the related art;

[0060] FIG. 2 is a diagram illustrating the working states of the gate-commutated thyristor;

[0061] FIG. 3 is a graph illustrating the relationship between the current, the voltage and the time of the gate-commutated thyristor in different working stages;

[0062] FIG. 4 is a diagram illustrating the structure of the gate-commutated thyristor according to some embodiments of the present disclosure;

[0063] FIG. 5 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some embodiments of the present disclosure;

[0064] FIG. 6 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some other embodiments of the present disclosure;

[0065] FIG. 7 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some other embodiments of the present disclosure;

[0066] FIG. 8 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some other embodiments of the present disclosure;

[0067] FIG. 9 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some other embodiments of the present disclosure;

[0068] FIG. 10 is a connection diagram of a turn-off circuit for the gate-commutated thyristor according to some other embodiments of the present disclosure;

[0069] FIG. 11 is a flowchart of a turn-off method for the gate-commutated thyristor according to some embodiments of the present disclosure;

[0070] FIG. 12 is a graph illustrating the relationship between the current, the voltage and the time of the gate-commutated thyristor according to some embodiments of the present disclosure;

[0071] FIG. 13 is a graph showing the relationship between current, voltage and time of a gate-commutated thyristor in the related art;

[0072] FIG. 14 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some embodiments of the present disclosure;

[0073] FIG. 15 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure;

[0074] FIG. 16 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure;

[0075] FIG. 17 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure;

[0076] FIG. 18 is a flowchart showing a turn-off method according to some embodiments of the present disclosure.

[0077] It should be noted that the sizes of the parts shown in the drawings are not drawn in accordance with actual proportions, and the positions, ranges, etc. of the parts shown in the drawings are sometimes not indicative of actual positions, ranges, etc. In addition, like reference numerals indicate similar elements throughout the drawings. DETAILED DESCRIPTION

[0078] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses. The disclosure can be implemented in numerous different forms, not just the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the disclosure to those skilled in the art. It should be noted that the relative arrangement of the components and steps set forth in these embodiments, the components of the materials, numerical expressions, and numerical values are to be interpreted as merely exemplary, and not as a limitation unless specifically stated otherwise.

[0079] The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different parts. The terms "include", "comprise", and similar terms mean that the elements before the terms encompass the elements listed after the terms, and do not exclude the possibility of also encompassing other elements. "Up", "down", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0080] In the present disclosure, when it is described that a specific device is located between a first device and a second device, there can or can not be an intervening device between the specific device and the first device or the second device. When it is described that a specific device is connected to another device, the specific device can be directly connected to the other device without an intervening device, or can not be directly connected to the other device with an intervening device.

[0081] All terms used in the present disclosure, including technical or scientific terms, have the same meanings as those understood by a person having ordinary knowledge in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense, unless specifically so defined herein.

[0082] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate.

[0083] In the voltage build-up phase, the PN junction between the control electrode and the first draw-out electrode of the GCT chip will directly bear the full voltage of the turn-off capacitor bank in the turn-off circuit. The reverse bias voltage that the PN junction between the control electrode and the first draw-out electrode can withstand has a breakdown voltage threshold. When the reverse bias voltage that the PN junction between the control electrode and the first draw-out electrode bears exceeds the breakdown voltage threshold, a high current density avalanche current will be generated inside the PN junction, which, if not controlled, will cause the PN junction between the control electrode and the first draw-out electrode to burn out, thereby causing the chip to be damaged.

[0084] In the related art, the voltage applied to the turn-off capacitor bank is set to be lower than the breakdown voltage threshold of the PN junction between the control electrode and the first draw-out electrode, regardless of whether the GCT chip is in a turn-off state or a blocking state.

[0085] FIG. 3 is a graph showing the relationship between current, voltage, and time of a gate-commutated thyristor in different working phases. FIG. 3 shows the relationship between the current flowing through the first draw-out electrode (e.g., cathode current) I k , the current flowing through the control electrode (i.e., gate current) I g , the current flowing through the second draw-out electrode (e.g., anode current) I a , and the voltage between the second draw-out electrode and the first draw-out electrode V a and time. As shown in FIG. 3, the horizontal axis is time (unit: seconds), and the vertical axis is voltage (unit: volts) and current (unit: amperes). The on state (or on phase) 21, the commutation phase 22, the voltage build-up phase 23, and the blocking state (or blocking phase) 24 are shown in FIG. 3.

[0086] In the related art, as can be seen from FIG. 3, in the commutation phase, the current I k decreases, the current I g flowing through the control electrode increases; in the voltage build-up phase, the voltage V a between the second draw-out electrode and the first draw-out electrode gradually increases, the current I a flowing through the second draw-out electrode gradually decreases to 0 after a period of time after the commutation phase and the voltage build-up phase starts.

[0087] The inventor of the present disclosure finds that, as shown in FIG. 3, in the voltage build-up phase, there can be a period of time in which the voltage V a between the second draw-out electrode and the first draw-out electrode rapidly rises, and the current I a still maintains a large current, at which time the phenomenon of the current commuted to the control electrode (i.e., the current flowing through the control electrode) being commuted back to the current flowing from the first draw-out electrode occurs, i.e., the PN junction between the control electrode and the first draw-out electrode can be re-opened in the off state, causing the GCT chip to fail to turn off. This results in a low off ability of the IGCT in the related art.

[0088] The mechanism of the above-mentioned PN junction re-opening process is that, in the voltage build-up phase, due to the voltage drop in other parts of the chip (e.g., a P-type base region in the chip) caused by the large current during the turn-off process, the reverse bias voltage on the PN junction between the control electrode and the first draw-out electrode decreases, and when it decreases to about 0, the PN junction cannot guarantee the reverse bias state, at which time the chip is re-opened, causing the turn-off to fail, and further causing the chip to be damaged.

[0089] The inventor of the present disclosure finds that, in the IGCT, increasing the voltage of the turn-off capacitor bank in the turn-off loop has a beneficial effect on the improvement of the turn-off ability of the device, and especially increasing the voltage of the turn-off capacitor bank in the voltage build-up phase can effectively suppress the GCT chip turn-off failure caused by the PN junction between the control electrode and the first draw-out electrode possibly being re-opened in the off state. This can be understood as increasing the total voltage on the loop by increasing the voltage (i.e., the reverse bias voltage) of the turn-off capacitor bank, and thus even if there is a large voltage drop in other parts of the chip, the above-mentioned PN junction can still be maintained in the reverse bias state.

[0090] In view of this, an embodiment of the present disclosure provides a turn-off circuit for a gate-commutated thyristor to improve the off ability of the IGCT.

[0091] FIG. 4 is a structural schematic diagram of a gate-commutated thyristor according to some embodiments of the present disclosure. As shown in FIG. 4, the gate-commutated thyristor includes a first doped region 411, a second doped region 412, a third doped region 413, and a fourth doped region 414. The first doped region 411 is adjacent to the second doped region 412, the second doped region 412 is adjacent to the third doped region 413, and the third doped region 413 is adjacent to the fourth doped region 414. The conduction type of the first doped region 411 is opposite to the conduction type of the second doped region 412, the conduction type of the second doped region 412 is opposite to the conduction type of the third doped region 413, and the conduction type of the third doped region 413 is opposite to the conduction type of the fourth doped region 414. For example, the conduction type of the fourth doped region 414 is P-type, the conduction type of the third doped region 413 is N-type, the conduction type of the second doped region 412 is P-type, and the conduction type of the first doped region 411 is N-type, i.e., the gate-commutated thyristor is a PNPN-type gate-commutated thyristor. For another example, the conduction type of the fourth doped region 414 is N-type, the conduction type of the third doped region 413 is P-type, the conduction type of the second doped region 412 is N-type, and the conduction type of the first doped region 411 is P-type, i.e., the gate-commutated thyristor is a NPNP-type gate-commutated thyristor.

[0092] As shown in FIG. 4, the gate-commutated thyristor further includes a first gate electrode 401, a second gate electrode 402, and a control electrode 403. The first gate electrode 401 is connected to the first doped region 411, the second gate electrode 402 is connected to the fourth doped region 414, and the control electrode 403 is connected to the second doped region 412. The conduction type of the first doped region 411 connected to the first gate electrode 401 is opposite to the conduction type of the second doped region 412 connected to the control electrode 403. The conduction type of the second doped region 412 connected to the control electrode 403 is the same as the conduction type of the fourth doped region 414 connected to the second gate electrode 402.

[0093] FIG. 5 is a connection schematic diagram of a turn-off circuit for a gate-commutated thyristor according to some embodiments of the present disclosure. The gate-commutated thyristor (GCT) is the gate-commutated thyristor as shown in FIG. 4. As shown in FIG. 5, the turn-off circuit 50 includes a control device 51 and a voltage regulating circuit 52. The control device is electrically connected to the voltage regulating circuit 52, and the voltage regulating circuit 52 is electrically connected to the first gate electrode 401 and the control electrode 403 of the GCT, respectively.

[0094] The control device 51 is configured to output a first control signal in a first stage, and output a second control signal in a second stage after the first stage. The first stage includes at least a part of a voltage build-up stage in an off stage of the gate-commutated thyristor. For example, the first stage is the at least a part of the voltage build-up stage. Here, the at least a part of the voltage build-up stage is after and adjacent to a commutation stage in the off stage. That is, the at least a part of the voltage build-up stage here is a process immediately after the commutation stage. The at least a part of the voltage build-up stage can be a part of the voltage build-up stage after and adjacent to the commutation stage, or can be the entire voltage build-up stage. For example, the control device 51 can be a control chip (for example, a logic chip), a controller, or a control circuit, etc.

[0095] The voltage regulation circuit 52 is configured to apply a first reverse bias voltage to a PN junction formed by the second doped region and the first doped region through the control electrode and the first draw-out electrode in the first stage after receiving the first control signal, and apply a second reverse bias voltage to the PN junction in the second stage after receiving the second control signal. Here, the voltage value of the first reverse bias voltage is greater than or equal to a breakdown voltage threshold of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction. Here, the breakdown voltage threshold is a voltage value at which the PN junction transitions from a high dynamic resistance to a low dynamic resistance, and a phenomenon of a sharp increase in reverse current occurs.

[0096] That is, in the at least a part of the voltage build-up stage, the first reverse bias voltage is applied to the PN junction formed by the second doped region and the first doped region. Since the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, the current flowing through the control electrode in the off stage of the GCT can be sufficiently maintained without being easily commutated back to the first draw-out electrode from the control electrode. In the at least a part of the voltage build-up stage, that is, in a stage in which the PN junction between the control electrode and the first draw-out electrode is easily reopened in the related art, the first reverse bias voltage greater than or equal to the breakdown voltage threshold of the PN junction, when applied to the PN junction, can reduce the possibility of reopening of the PN junction, and thus reduce the possibility of failure of the GCT chip to be turned off.

[0097] Of course, in the first stage described above, the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, which causes the PN junction to generate a reverse avalanche current. However, since the total duration of the at least a part of the voltage build-up stage is short, the duration of the breakdown phenomenon is short, and thus the breakdown phenomenon does not cause damage to the gate-commutated thyristor.

[0098] In the second stage, the voltage between the second and the first electrodes (as shown in FIG. 3) has risen to a relatively large voltage and the current flowing through the second electrode has decayed to a relatively small current, at which time a second reverse bias voltage is applied to the PN junction, the voltage value of the second reverse bias voltage being less than the breakdown voltage threshold of the PN junction, and the PN junction is not easily re-opened. Moreover, since the reverse bias voltage applied to the PN junction is reduced to a voltage less than the breakdown voltage threshold of the PN junction, the breakdown phenomenon described above can be prevented from lasting for a long time, thereby reducing the possibility of damage to the GCT due to a long time in the breakdown state.

[0099] That is, the above-described turn-off circuit can reduce the possibility of re-opening of the PN junction between the control electrode and the first electrode of the GCT in the off state, and reduce the possibility of damage to the GCT due to a long time in the breakdown state.

[0100] Thus, a turn-off circuit for a gate-commutated thyristor according to some embodiments of the present disclosure is provided. The gate-commutated thyristor includes a first electrode, a second electrode, and a control electrode, wherein the conductivity type of a first doped region connected to the first electrode is opposite to the conductivity type of a second doped region connected to the control electrode. The turn-off circuit includes: a control device configured to output a first control signal in a first stage and output a second control signal in a second stage after the first stage, wherein the first stage includes at least a portion of a voltage build-up stage in a turn-off stage of the gate-commutated thyristor, the at least a portion of the voltage build-up stage being after and adjacent to a commutation stage in the turn-off stage; and a voltage regulation circuit configured to, upon receiving the first control signal, apply a first reverse bias voltage to a PN junction formed by the second doped region and the first doped region through the control electrode and the first electrode in the first stage, and upon receiving the second control signal, apply a second reverse bias voltage to the PN junction in the second stage, wherein the voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction. The turn-off circuit can reduce the possibility of re-opening of the PN junction between the control electrode and the first electrode of the GCT in the off state, thereby improving the turn-off capability of the IGCT.

[0101] In some embodiments, the first stage includes the at least a portion of the voltage build-up stage and the commutation stage. For example, the first stage consists of the at least a portion of the voltage build-up stage and the commutation stage. That is, the control device outputs the first control signal in the at least a portion of the voltage build-up stage and the commutation stage, so that the voltage regulation circuit applies the first reverse bias voltage to the PN junction in the at least a portion of the voltage build-up stage and the commutation stage. Here, the commutation stage is also included in the first stage, which can facilitate the application of the first reverse bias voltage.

[0102] It should be noted that although the first stage includes the at least part of the voltage build-up stage and the commutation stage, since the total duration of the at least part of the voltage build-up stage and the commutation stage is very short (for example, even if the duration covers the entire turn-off process, i.e. including the commutation stage and the entire voltage build-up stage, the total duration is only in the order of microseconds), the above breakdown phenomenon during the first stage lasts for a very short time, and thus the breakdown phenomenon does not cause damage to the gate-commutated thyristor.

[0103] Regarding the determination of the above first stage and second stage, the determination can be made by means of current detection or time setting.

[0104] For example, FIG. 10 is a connection schematic diagram of a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure.

[0105] As shown in FIG. 10, the turn-off circuit 50' includes a control device 51 and a voltage regulating circuit 52. The turn-off circuit 50' further includes a current detection device 53. For example, the current detection device 53 is a current meter. The current detection device 53 is electrically connected to the second lead-out electrode 402 of the GCT and the control device 51, respectively.

[0106] The current detection device 53 is configured to detect a current value of the current flowing through the second lead-out electrode 402 and transmit the current value to the control device 51. The control device 51 is further configured to output a first control signal to the voltage regulating circuit 52 in response to the current value being greater than a current threshold value, and output a second control signal to the voltage regulating circuit 52 in response to the current value being less than or equal to the current threshold value.

[0107] For example, the current threshold value is a current value that is a predetermined percentage of the maximum current value flowing through the second lead-out electrode. For example, the predetermined percentage ranges from 0 to 40%. For example, when the GCT chip internal current decays to less than 40% of the maximum current, the voltage regulating circuit applies a second reverse bias voltage to the above-mentioned PN junction. Of course, those skilled in the art can understand that the range of the predetermined percentage is only exemplary, and can be set according to actual conditions or actual needs, and the scope of the present disclosure is not limited to the specific value of the predetermined percentage.

[0108] In the above embodiments, by detecting the current value of the current flowing through the second lead-out electrode, the decay of the current can be determined according to the current value, and the above-mentioned first stage and second stage can be determined according to the size relationship between the current value and the current threshold value, so as to achieve the purpose of outputting the first control signal and the second control signal to the voltage regulating circuit.

[0109] For example, the first stage corresponds to a predetermined time length. That is, the first stage can be set to a predetermined time length in the control device. In this way, the control device 51 can output the first control signal for a predetermined time length and output the second control signal after the predetermined time length. In this way, the first control signal and the second control signal can be output simply and conveniently.

[0110] FIG. 6 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some embodiments of the present disclosure. As shown in FIG. 6, the turn-off circuit includes a control device 51 and a voltage regulating circuit. A specific circuit structure of the voltage regulating circuit will be described in detail below in conjunction with FIG. 6.

[0111] As shown in FIG. 6, the voltage regulating circuit includes a first voltage source 610, a second voltage source 620, a first switching device 521, a second switching device 522, and a third switching device 523.

[0112] The voltage value of the first voltage source 610 is a second reverse bias voltage. For example, the voltage value of the first voltage source ranges from 12V to 23V. Of course, those skilled in the art can understand that the range of the voltage value of the first voltage source is only exemplary, and the scope of the present disclosure is not limited thereto. The voltage value of the first voltage source can be set according to actual needs or actual conditions.

[0113] The sum of the voltage value of the second voltage source 620 and the voltage value of the first voltage source 610 is a first reverse bias voltage. That is, the sum of the voltages of the first voltage source and the second voltage source in series is the first reverse bias voltage. For example, the voltage value of the second voltage source ranges from 0V to 60V. Of course, those skilled in the art can understand that the range of the voltage value of the second voltage source is only exemplary, and the scope of the present disclosure is not limited thereto. The voltage value of the second voltage source can be set according to actual needs or actual conditions.

[0114] For example, the first voltage source and the second voltage source can each be a capacitor. That is, the first voltage source and the second voltage source are a capacitor bank. Of course, those skilled in the art can understand that the first voltage source and the second voltage source can also be other types of voltage sources, and the scope of the present disclosure is not limited thereto.

[0115] The first end of the first switching device 521 is electrically connected to the control electrode 403 of the gate-commutated thyristor GCT, the second end of the first switching device 521 is electrically connected to the first end of the first voltage source 610, and the control end of the first switching device 521 is electrically connected to the control device 51. For example, the control end of the first switching device 521 is electrically connected to the first output end of the control device 51.

[0116] The first end of the second switching device 522 is electrically connected to the first outgoing pole 401 of the gate-commutated thyristor GCT, the second end of the second switching device 522 is electrically connected to the second end of the first voltage source 610 and the first end of the second voltage source 620, and the control end of the second switching device 522 is electrically connected to the control device 51. For example, the control end of the second switching device 522 is electrically connected to the second output end of the control device 51.

[0117] The first end of the third switching device 523 is electrically connected to the first outgoing pole 401 of the gate-commutated thyristor GCT, the second end of the third switching device 523 is electrically connected to the second end of the second voltage source 620, and the control end of the third switching device 523 is electrically connected to the control device 51. For example, the control end of the third switching device 523 is electrically connected to the third output end of the control device 51.

[0118] The first switching device, the second switching device, and the third switching device are not specific and can be interchangeable with each other.

[0119] So far, the specific structure of the voltage regulating circuit according to some embodiments of the present disclosure has been described.

[0120] In some embodiments, the first control signal described above includes a first sub-control signal, a second sub-control signal, and a third sub-control signal. The control device 51 is configured to output the first sub-control signal to the first switching device to make the first switching device conductive in the first stage, output the second sub-control signal to the second switching device to make the second switching device non-conductive in the first stage, and output the third sub-control signal to the third switching device to make the third switching device conductive in the first stage. In this way, by outputting the first sub-control signal, the second sub-control signal, and the third sub-control signal by the control device, the first switching device is made conductive, the second switching device is made non-conductive, and the third switching device is made conductive, so that the first voltage source and the second voltage source are connected in series, so that the voltage regulating circuit applies a sum of the voltage value of the second voltage source 620 and the voltage value of the first voltage source 610 to the PN junction formed by the second doped region and the first doped region through the control electrode and the first outgoing pole in the first stage, that is, the first reverse bias voltage described above.

[0121] For example, the control device 51 is configured to output the first sub-control signal, the second sub-control signal, and the third sub-control signal simultaneously. That is, the control device 51 outputs the first sub-control signal to the first switching device, outputs the second sub-control signal to the second switching device, and outputs the third sub-control signal to the third switching device simultaneously in the first stage. In this way, the first switching device is made conductive, the second switching device is made non-conductive, and the third switching device is made conductive simultaneously, so that the voltage regulating circuit applies the first reverse bias voltage to the PN junction described above through the control electrode and the first outgoing pole in the first stage.

[0122] In other embodiments, the second control signal includes a fourth sub-control signal, a fifth sub-control signal and a sixth sub-control signal. The control device 51 is configured to output the fourth sub-control signal to the first switching device in the second stage to make the first switching device conductive, output the fifth sub-control signal to the second switching device in the second stage to make the second switching device conductive, and output the sixth sub-control signal to the third switching device in the second stage to make the third switching device non-conductive. In this way, by the control device outputting the fourth sub-control signal, the fifth sub-control signal and the sixth sub-control signal, the first switching device is made conductive, the second switching device is made conductive, and the third switching device is made non-conductive, so that the voltage regulating circuit applies, in the second stage, through the control electrode and the first drawn electrode, only the voltage value of the first voltage source 610 to the PN junction formed by the second doped region and the first doped region, i.e. the second reverse bias voltage described above.

[0123] For example, the control device 51 is configured to output the fourth sub-control signal, the fifth sub-control signal and the sixth sub-control signal simultaneously. That is, the control device 51 outputs the fourth sub-control signal to the first switching device, outputs the fifth sub-control signal to the second switching device, and outputs the sixth sub-control signal to the third switching device simultaneously in the second stage. In this way, the first switching device is made conductive, the second switching device is made conductive, and the third switching device is made non-conductive simultaneously, so that the voltage regulating circuit applies, in the second stage, through the control electrode and the first drawn electrode, the second reverse bias voltage to the PN junction described above.

[0124] In some embodiments, the second doped region is of P-type and the first doped region is of N-type. That is, the control electrode is an electrode drawn from a P-type region, and the first drawn electrode is an electrode drawn from an N-type region. In this case, the first end of the first voltage source is a negative terminal, the second end of the first voltage source is a positive terminal, the first end of the second voltage source is a negative terminal, and the second end of the second voltage source is a positive terminal. In this way, the arrangement of the two voltage sources of the voltage regulating circuit in the turn-off circuit for a PNPN-type GCT is achieved.

[0125] In other embodiments, the second doped region is of N-type and the first doped region is of P-type. That is, the control electrode is an electrode drawn from an N-type region, and the first drawn electrode is an electrode drawn from a P-type region. In this case, the first end of the first voltage source is a positive terminal, the second end of the first voltage source is a negative terminal, the first end of the second voltage source is a positive terminal, and the second end of the second voltage source is a negative terminal. In this way, the arrangement of the two voltage sources of the voltage regulating circuit in the turn-off circuit for a NPNP-type GCT is achieved.

[0126] In some embodiments, the first, second and third switching devices described above comprise MOS transistors (i.e. MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or the like. For example, the MOS transistors can be NMOS transistors (N-type MOS transistors) or PMOS transistors (P-type MOS transistors).

[0127] For example, FIG. 7 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure. As can be seen from FIG. 7, the first, second and third switching devices 521, 522 and 523 are MOS transistors, the gates of which are used as control terminals and are electrically connected to the control device 51, respectively. For example, the MOS transistors are NMOS transistors.

[0128] Of course, those skilled in the art will understand that the first, second and third switching devices described above can also use other types of switching devices, and the scope of the present disclosure is not limited thereto.

[0129] FIG. 8 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure. As shown in FIG. 8, the turn-off circuit comprises a control device 51 and a voltage regulating circuit. Another specific circuit structure of the voltage regulating circuit will be described in detail below in conjunction with FIG. 8.

[0130] As shown in FIG. 8, the voltage regulating circuit comprises a first voltage source 610, a second voltage source 620, a first switching device 541, a unidirectional conduction device 543 and a second switching device 542.

[0131] The voltage value of the first voltage source 610 is the second reverse bias voltage. For example, the voltage value of the first voltage source ranges from 12V to 23V. Of course, those skilled in the art will understand that the range of the voltage value of the first voltage source is only exemplary, and the scope of the present disclosure is not limited thereto. The voltage value of the first voltage source can be set according to actual needs or actual circumstances.

[0132] The sum of the voltage value of the second voltage source 620 and the voltage value of the first voltage source 610 is the first reverse bias voltage. That is, the sum of the voltages of the first voltage source and the second voltage source in series is the first reverse bias voltage. For example, the voltage value of the second voltage source ranges from 0V to 60V. Of course, those skilled in the art will understand that the range of the voltage value of the second voltage source is only exemplary, and the scope of the present disclosure is not limited thereto. The voltage value of the second voltage source can be set according to actual needs or actual circumstances.

[0133] For example, the first voltage source and the second voltage source can each employ a capacitor. That is, the first voltage source and the second voltage source employ a capacitor bank. Of course, those skilled in the art will appreciate that the first voltage source and the second voltage source can also employ other types of voltage sources, and the scope of the present disclosure is not limited in this regard.

[0134] The first end of the first switching device 541 is electrically connected to the control electrode 403 of the gate-commutated thyristor GCT, the second end of the first switching device 541 is electrically connected to the first end of the first voltage source 610, and the control end of the first switching device 541 is electrically connected to the control device 51. For example, the control end of the first switching device 541 is electrically connected to the first output end of the control device 51.

[0135] The first end of the unidirectional conduction device 543 is electrically connected to the first draw-out electrode 401 of the gate-commutated thyristor GCT, the second end of the unidirectional conduction device 543 is electrically connected to the second end of the first voltage source 610 and the first end of the second voltage source 620.

[0136] The first end of the second switching device 542 is electrically connected to the first draw-out electrode 401 of the gate-commutated thyristor GCT, the second end of the second switching device 542 is electrically connected to the second end of the second voltage source 620, and the control end of the second switching device 542 is electrically connected to the control device 51. For example, the control end of the second switching device 542 is electrically connected to the second output end of the control device 51.

[0137] The first switching device and the second switching device are not specific and can be interchangeable with each other.

[0138] So far, the specific structure of the voltage regulating circuit according to some other embodiments of the present disclosure has been described. Compared with the voltage regulating circuit shown in FIG. 6, the voltage regulating circuit shown in FIG. 8 reduces one switching device, so that the control device reduces the output of one sub-control signal, so that the circuit is more convenient to implement.

[0139] In some embodiments, the first control signal includes a first sub-control signal and a second sub-control signal. The control device 51 is configured to output the first sub-control signal to the first switching device to make the first switching device conductive in the first stage, and output the second sub-control signal to the second switching device to make the second switching device conductive in the first stage. In this way, by outputting the first sub-control signal and the second sub-control signal by the control device, the first switching device and the second switching device are both made to conduct, and the first voltage source and the second voltage source are connected in series, so that the voltage regulating circuit applies the sum of the voltage value of the second voltage source 620 and the voltage value of the first voltage source 610 to the PN junction formed by the second doped region and the first doped region through the control electrode and the first draw-out electrode in the first stage, that is, the first reverse bias voltage described above.

[0140] For example, the control device 51 is configured to output the first sub-control signal and the second sub-control signal simultaneously. That is, the control device 51 outputs the first sub-control signal to the first switching device and outputs the second sub-control signal to the second switching device simultaneously in the first stage. This simultaneously causes the first switching device and the second switching device to be turned on, so that the voltage adjustment circuit applies the first reverse bias voltage to the PN junction through the control electrode and the first drawn electrode in the first stage.

[0141] In other embodiments, the second control signal includes a third sub-control signal and a fourth sub-control signal. The control device 51 is configured to output the third sub-control signal to the first switching device to cause the first switching device to be turned on in the second stage, and output the fourth sub-control signal to the second switching device to cause the second switching device to be turned off in the second stage. In this way, the third sub-control signal and the fourth sub-control signal are output by the control device to cause the first switching device to be turned on and the second switching device to be turned off, so that the voltage adjustment circuit applies only the voltage value of the first voltage source 610, i.e., the second reverse bias voltage described above, to the PN junction formed by the second doped region and the first doped region through the control electrode and the first drawn electrode in the second stage.

[0142] For example, the control device 51 is configured to output the third sub-control signal and the fourth sub-control signal simultaneously. That is, the control device 51 outputs the third sub-control signal to the first switching device and outputs the fourth sub-control signal to the second switching device simultaneously in the second stage. This simultaneously causes the first switching device to be turned on and the second switching device to be turned off, so that the voltage adjustment circuit applies the second reverse bias voltage to the PN junction through the control electrode and the first drawn electrode in the second stage.

[0143] In some embodiments, the second doped region is of P-type and the first doped region is of N-type. That is, the control electrode is an electrode drawn from a P-type region, and the first drawn electrode is an electrode drawn from an N-type region. In this case, the first end of the unidirectional conduction device is a negative electrode end, the second end of the unidirectional conduction device is a positive electrode end, the first end of the first voltage source is a negative electrode end, the second end of the first voltage source is a positive electrode end, the first end of the second voltage source is a negative electrode end, and the second end of the second voltage source is a positive electrode end. This achieves the arrangement of the unidirectional conduction device of the voltage adjustment circuit and the two voltage sources in the turn-off circuit for a PNPN-type GCT.

[0144] In other embodiments, the second doped region is of N-type and the first doped region is of P-type. That is, the control electrode is an electrode drawn from the N-type region and the first electrode is an electrode drawn from the P-type region. In this case, the first end of the unidirectional conduction device is the positive end, the second end of the unidirectional conduction device is the negative end, the first end of the first voltage source is the positive end, the second end of the first voltage source is the negative end, the first end of the second voltage source is the positive end, and the second end of the second voltage source is the negative end. This achieves the arrangement of the unidirectional conduction device and the two voltage sources in the voltage regulating circuit for the turn-off circuit of the NPNP GCT.

[0145] In some embodiments, the first and second switching devices described above comprise MOS transistors or the like, and the unidirectional conduction device described above comprises a diode or the like. For example, the MOS transistors can be NMOS transistors or PMOS transistors.

[0146] Figure 9 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to other embodiments of the present disclosure. As can be seen from Figure 9, the first and second switching devices 541 and 542 are MOS transistors. The gates of these MOS transistors are connected to the control device 51 as control ends. For example, the MOS transistors are NMOS transistors. As can be seen from Figure 9, the unidirectional conduction device 543 is a diode.

[0147] Of course, those skilled in the art will understand that the first and second switching devices described above can also be other types of switching devices, and the unidirectional conduction device can also be other types of unidirectional conduction devices, and the scope of the present disclosure is not limited thereto.

[0148] It should be noted that the voltage regulating circuit according to some embodiments of the present disclosure has been described above, but the specific structure of the voltage regulating circuit described above is only exemplary, and the scope of the present disclosure is not limited thereto, and embodiments of the present disclosure can also use other circuit structures of the voltage regulating circuit as long as the above functions of the voltage regulating circuit are achieved.

[0149] In embodiments of the present disclosure, during at least part of the voltage build-up phase of the turn-off state, the PN junction between the control electrode and the first electrode of the GCT chip operates in a breakdown state. That is, during at least part of the voltage build-up phase, the semiconductor PN junction formed by the adjacent semiconductor regions having opposite conductivity types, which are respectively connected to the first electrode of the GCT and the control electrode of the GCT chip, directly withstands a voltage value exceeding the breakdown voltage threshold thereof. The PN junction between the control electrode and the first electrode of the GCT chip has a breakdown current.

[0150] The turn-off circuit uses a voltage build-up stage to raise the voltage of the turn-off capacitor bank to improve the turn-off capability of the IGCT, and through a multi-level fast-acting drive design, limits the breakdown time of the PN junction between the control electrode and the first anode electrode, controls the avalanche current heat production, to ensure the safety of the GCT chip in the turn-off state as much as possible. The above-mentioned turn-off circuit can as much as possible solve the problem of chip damage caused by the re-forward opening of the PN junction between the control electrode and the first anode electrode during the turn-off process in the related art.

[0151] In some embodiments of the present disclosure, a driving circuit for a gate-commutated thyristor is also provided, which includes the turn-off circuit as described above.

[0152] In some embodiments of the present disclosure, an integrated gate-commutated thyristor is also provided, which includes the turn-off circuit as described above.

[0153] In some embodiments of the present disclosure, an electrical device is also provided, which includes the integrated gate-commutated thyristor as described above.

[0154] FIG. 11 is a flow chart illustrating a turn-off method for a gate-commutated thyristor according to some embodiments of the present disclosure. The gate-commutated thyristor includes a first anode electrode, a second anode electrode, and a control electrode, wherein the conductivity type of a first doped region connected to the first anode electrode is opposite to the conductivity type of a second doped region connected to the control electrode. As shown in FIG. 11, the turn-off method includes steps S1110-S1120.

[0155] At step S1110, a first reverse bias voltage is applied to a PN junction formed by the second doped region and the first doped region through the control electrode and the first anode electrode in a first stage. The first stage includes at least a part of a voltage build-up stage in a turn-off stage of the gate-commutated thyristor. The at least part of the voltage build-up stage is after and adjacent to a commutation stage in the turn-off stage. The voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction.

[0156] At step S1120, a second reverse bias voltage is applied to the PN junction in a second stage after the first stage. The voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

[0157] So far, the method for turning off the gate-commutated thyristor according to some embodiments of the present disclosure is provided. In the method, the first reverse bias voltage is applied to the PN junction in the first stage, and the second reverse bias voltage is applied to the PN junction in the second stage after the first stage, wherein the voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction. In this way, the possibility of the PN junction between the control electrode and the first gate electrode of the gate-commutated thyristor being re-opened in the off state can be reduced, thereby improving the turn-off capability of the IGCT.

[0158] In some embodiments, the first stage further includes the commutation stage.

[0159] In some embodiments, the applying of the first reverse bias voltage to the PN junction in the first stage includes: in response to the current value of the current flowing through the second gate electrode being greater than the current threshold, applying the first reverse bias voltage to the PN junction; and the applying of the second reverse bias voltage to the PN junction in the second stage after the first stage includes: in response to the current value of the current flowing through the second gate electrode being less than or equal to the current threshold, applying the second reverse bias voltage to the PN junction.

[0160] For example, the current threshold is a current value that is a predetermined percentage of the maximum current value of the current flowing through the second gate electrode.

[0161] In other embodiments, the duration corresponding to the first stage is a predetermined duration.

[0162] FIG. 12 is a graph showing the relationship between the current, voltage and time of the gate-commutated thyristor according to some embodiments of the present disclosure. FIG. 13 is a graph showing the relationship between the current, voltage and time of the gate-commutated thyristor in the related art.

[0163] In FIGS. 12 and 13, the relationship between the current (e.g., cathode current) I k flowing through the first gate electrode, the current (e.g., anode current) I a flowing through the second gate electrode, and the voltage V ak between the second gate electrode and the first gate electrode, and the time is shown. As shown in FIGS. 12 and 13, the abscissa is time (unit: microsecond), and the ordinate is voltage V (unit: volt) and current I (unit: ampere).

[0164] Here, the same GCT chip is used in the experiment, and first, the GCT chip is experimented with the turn-off circuit according to the embodiments of the present disclosure to obtain the graph shown in FIG. 12, and then the GCT chip is experimented with the turn-off circuit in the related art to obtain the graph shown in FIG. 13.

[0165] As can be seen from FIG. 12, when the turn-off circuit according to the embodiments of the present disclosure is used to turn off the current of 8000 A, the voltage Vak Successful establishment, successful turn-off. That is, by increasing the reverse bias voltage of the PN junction during at least part of the voltage establishment phase, the possibility of the PN junction being re-opened can be reduced, thereby improving the turn-off capability of the IGCT.

[0166] As can be seen from FIG. 13, when the related-art turn-off circuit is used to turn off a current of 5500 A, the voltage V ak After the voltage is established to 2000 V, the voltage drops, and the turn-off fails. This is because, during the voltage establishment phase, the PN junction of the GCT chip is re-opened, resulting in a failure of voltage establishment.

[0167] In the turn-off circuit and the turn-off method according to the embodiments of the present disclosure, the turn-off capacitor group voltage is increased during the anode voltage establishment phase, so that the PN junction between the control electrode and the first extraction electrode works in a breakdown state. Compared with the reverse blocking working state of the PN junction between the control electrode and the first extraction electrode in the related art, the failure of the GCT chip caused by the re-opening of the PN junction between the control electrode and the first extraction electrode in the turn-off state can be effectively inhibited.

[0168] The test results show that the turn-off method according to the embodiments of the present disclosure can effectively improve the turn-off capability of the same GCT chip by more than 46%. In addition, 11000 times of PN junction breakdown experiments between the control electrode and the first extraction electrode are carried out based on the above-mentioned circuit topology, and the performance of the GCT chip does not deteriorate obviously before and after the experiments.

[0169] In the related-art turn-off process, the switch component is turned on to enable the capacitor group to apply a reverse bias voltage to the control electrode, so as to force the device load current to commutate from the first extraction electrode to the control electrode, thereby naturally turning off the device. However, in the related art, it is difficult to balance the reliability of the GCT turn-off and the safety of the PN junction between the control electrode and the first extraction electrode.

[0170] Specifically, the inventors of the present disclosure find that, in the related art, in the turn-off technology of the IGCT, the capacitor group adopts a constant capacitor voltage value. However, if the voltage of the capacitor group is low, the GCT device may not have sufficient commutation capability, and thus the GCT device may be easily turned off; if the voltage of the capacitor group is high, the PN junction between the control electrode and the first extraction electrode of the GCT device may be broken down for a long time, and thus the PN junction may be burned out, resulting in a device failure, and it is difficult to balance the reliability of the GCT turn-off and the safety of the PN junction between the control electrode and the first extraction electrode.

[0171] In view of this, the embodiments of the present disclosure provide a turn-off circuit for a gate-commutated thyristor, so as to balance the reliability of the GCT turn-off and the safety of the PN junction between the control electrode and the first extraction electrode as much as possible.

[0172] FIG. 14 is a connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some embodiments of the present disclosure. The turn-off circuit is used for a gate-commutated thyristor including a first draw-out electrode, a second draw-out electrode, and a control electrode. As shown in FIG. 14, the turn-off circuit 50 includes a control device 51 and a voltage regulating circuit 52.

[0173] The control device 51 is configured to output a control signal to the voltage regulating circuit 52.

[0174] The voltage regulating circuit 52 includes a control sub-circuit 120, a pressure-bearing adjustable switching element 110, and a voltage source V C The first end of the pressure-bearing adjustable switching element 110 is electrically connected to the control electrode 403 of the gate-commutated thyristor GCT, the second end of the pressure-bearing adjustable switching element 110 is electrically connected to the first end (e.g., the negative end) of the voltage source V C The control end of the pressure-bearing adjustable switching element 110 is electrically connected to the control sub-circuit 120. The second end (e.g., the positive end) of the voltage source V C is electrically connected to the first draw-out electrode 401 of the gate-commutated thyristor GCT. For example, the voltage source V C includes a capacitor. For example, the voltage source V C is a capacitor bank.

[0175] In some embodiments, the pressure-bearing adjustable switching element 110 includes a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). For example, the pressure-bearing adjustable switching element is an N-channel Metal Oxide Semiconductor (NMOS) transistor. For another example, the pressure-bearing adjustable switching element is a P-channel Metal Oxide Semiconductor (PMOS) transistor. Here, the pressure-bearing adjustable switching element is a switching element with saturation characteristics.

[0176] It should be noted that the pressure-bearing adjustable switching element of the embodiments of the present disclosure is not limited to the above-mentioned types of switching elements, and a suitable switching element with saturation characteristics can be selected as the pressure-bearing adjustable switching element as needed.

[0177] The control sub-circuit 120 is electrically connected with the control device 51. The control sub-circuit 120 can receive a control signal from the control device 51. The control sub-circuit 120 is configured to control the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage, based on the control signal. In this way, the pressure-bearing adjustable switching element can be in a turned-on state, a turned-off state, or clamped at a predetermined voltage, so that the PN junction between the control electrode and the first anode electrode of the GCT can be at different voltages, so that the GCT can be in different states (for example, a turned-on state, a turned-off state, or a blocking state, etc.).

[0178] So far, the turn-off circuit according to some embodiments of the present disclosure has been provided. The turn-off circuit is used for a gate-commutated thyristor, the gate-commutated thyristor includes a first anode electrode, a second anode electrode, and a control electrode, and the turn-off circuit includes: a control device and a voltage regulating circuit; the control device is configured to output a control signal to the voltage regulating circuit; the voltage regulating circuit includes: a control sub-circuit, a pressure-bearing adjustable switching element, and a voltage source, wherein a first end of the pressure-bearing adjustable switching element is electrically connected to the control electrode of the gate-commutated thyristor, a second end of the pressure-bearing adjustable switching element is electrically connected to a first end of the voltage source, a control end of the pressure-bearing adjustable switching element is electrically connected to the control sub-circuit, a second end of the voltage source is electrically connected to the first anode electrode of the gate-commutated thyristor, and the control sub-circuit is configured to control the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage, based on the control signal. In the turn-off circuit, the control device outputs the control signal to the control sub-circuit, so that the control sub-circuit controls the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage, based on the control signal, so that the PN junction between the control electrode and the first anode electrode of the GCT can be at different voltages. In this way, when it is necessary to improve the reliability of device turn-off, that is, to improve the commutation capability of the GCT device, the above-mentioned PN junction can be at a larger reverse bias voltage, and in order to prevent the PN junction from being broken down for a long time, the above-mentioned PN junction can be changed from bearing a larger reverse bias voltage to bearing a smaller reverse bias voltage, so that the safety of the PN junction between the control electrode and the first anode electrode can be improved. In this way, the reliability of GCT turn-off and the safety of the PN junction between the control electrode and the first anode electrode can be taken into account as much as possible, so that the reliability of device turn-off and the safety of the PN junction can be improved.

[0179] FIG. 15 is a connection schematic diagram of a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure. FIG. 15 shows a voltage regulating circuit including a control sub-circuit 120, a pressure-bearing adjustable switching element 110, and a voltage source V CFor example, the pressure-bearing adjustable switching element 110 is an NMOS transistor. It should be noted that the control device is not shown in FIG. 15, but as previously described, the turn-off circuit further includes the control device.

[0180] As shown in FIG. 15, the control sub-circuit 120 includes a first sub-circuit 121 and a second sub-circuit 122. The first sub-circuit 121 can be configured to control the pressure-bearing adjustable switching element 110 to be turned on or turned off. For example, the first sub-circuit 121 is configured to apply a high-level or low-level control signal to the control end (e.g., the gate of a MOSFET) of the pressure-bearing adjustable switching element to control the pressure-bearing adjustable switching element to be turned on or turned off. The second sub-circuit 122 is configured to control the pressure-bearing adjustable switching element 110 to be clamped at a predetermined voltage. For example, the second sub-circuit 122 is configured to control the pressure-bearing adjustable switching element to enter a saturation state, in which the voltage at which the pressure-bearing adjustable switching element is clamped is equal to the difference between the voltage of the voltage source and the voltage that the PN junction can withstand. In this way, the pressure-bearing adjustable switching element is controlled.

[0181] In some embodiments, as shown in FIG. 15, the first sub-circuit 121 includes a first switching device S drv1 , a first resistor R1, and a second switching device S drv2 .

[0182] The first end of the first switching device S drv1 is electrically connected to the first voltage end 101. The second end of the first switching device S drv1 is electrically connected to the control end (e.g., the gate) of the pressure-bearing adjustable switching element 110. The control end of the first switching device S drv1 is electrically connected to the control device (not shown in FIG. 15). For example, the first switching device S drv1 is an NMOS transistor. For another example, the first switching device S drv1 is a PMOS transistor. The scope of the present disclosure is not limited to the specific type of the first switching device.

[0183] The first end of the first resistor R1 is electrically connected to the first voltage end 101, and the second end of the first resistor R1 is electrically connected to the control end of the pressure-bearing adjustable switching element 110.

[0184] For example, the resistance value of the first resistor R1 can range from 1 kΩ (kilo-ohm) to 10 kΩ. However, it should be noted that the range of the resistance value of the first resistor here is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the first resistor.

[0185] The first end of the second switching device S drv2 is electrically connected to the second voltage end 102. The second end of the second switching device S drv2The second end of [it] is electrically connected to the control end of the pressure-bearing adjustable switch element 110. The second switching device S drv2 's control end is electrically connected to the control device. For example, the second switching device S drv2 is a PMOS transistor. Again, for example, the second switching device S drv2 is an NMOS transistor. The scope of the present disclosure is not limited to the specific type of the second switching device.

[0186] For example, the voltage level of the first voltage terminal 101 is less than (i.e., lower than) the voltage level of the second voltage terminal 102. For example, the first voltage terminal 101 is a ground terminal, and the second voltage terminal 102 is a power supply voltage terminal, and this second voltage terminal 102 can be used to increase the driving voltage V drive .

[0187] FIG. 16 is a schematic connection diagram showing a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure. As shown in FIG. 16, the first sub-circuit 121 includes: the first switching device S drv1 , the first resistor R1 and the second switching device S drv2 .

[0188] In some embodiments, as shown in FIG. 16, the first sub-circuit 121 may further include a second resistor R2. The second resistor R2 is disposed between the second end of the first switching device S drv1 and the control end of the pressure-bearing adjustable switch element 110. That is, the first end of the second resistor R2 is electrically connected to the second end of the first switching device S drv1 , and the second end of the second resistor R2 is electrically connected to the control end of the pressure-bearing adjustable switch element 110.

[0189] For example, the range of the resistance value of the second resistor R2 can be 0 < R1 ≤ 200 ohms. For example, the resistance value of the second resistor R2 is 1 ohm. However, it should be noted that here, the range of the resistance value of the second resistor is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the second resistor.

[0190] In some embodiments, the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2.

[0191] In some embodiments, as shown in FIG. 16, the first sub-circuit 121 may further include a third resistor R3. The third resistor R3 is disposed between the second end of the second switching device S drv2 and the control end of the pressure-bearing adjustable switch element 110. That is, the first end of the third resistor R3 is electrically connected to the second end of the second switching device S drv2 , and the second end of the third resistor R3 is electrically connected to the control end of the pressure-bearing adjustable switch element 110.

[0192] For example, the resistance value of the third resistor R3 can range from 0 < R3≤ 200 ohms. For example, the resistance value of the third resistor R3 is 1 ohm. However, it should be noted that the range of the resistance value of the third resistor here is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the third resistor.

[0193] In some embodiments, the resistance value of the first resistor R1 is greater than the resistance value of the third resistor R3.

[0194] In some embodiments, the resistance value of the second resistor R2 is equal to the resistance value of the third resistor R3.

[0195] The second resistor R2 and the third resistor R3 described above can be used to adjust the turn-off speed and the turn-on speed of the pressure-bearing adjustable switch element 110. For example, when the first switch device S drv1 is turned on and the second switch device S drv2 is turned off, the low level of the first voltage terminal 101 is applied to the control terminal of the pressure-bearing adjustable switch element 110, so that the pressure-bearing adjustable switch element 110 (here, the pressure-bearing adjustable switch element 110 is selected as an NMOS transistor) is turned off, and the second resistor R2 with different resistance values can make the pressure-bearing adjustable switch element 110 have different turn-off speeds. For another example, when the first switch device S drv1 is turned off and the second switch device S drv2 is turned on, the high level of the second voltage terminal 102 is applied to the control terminal of the pressure-bearing adjustable switch element 110 (here, the pressure-bearing adjustable switch element 110 is selected as an NMOS transistor), so that the pressure-bearing adjustable switch element 110 is turned on, and the third resistor R3 with different resistance values can make the pressure-bearing adjustable switch element 110 have different turn-on speeds.

[0196] It should be noted that the second resistor R2 and the third resistor R3 described above are both optional. For example, the second resistor R2 and the third resistor R3 can not be provided in the first sub-circuit 121 (as shown in FIG. 15), or one of the second resistor R2 and the third resistor R3 can be provided in the first sub-circuit 121, or the second resistor R2 and the third resistor R3 can be provided in the first sub-circuit 121 (as shown in FIG. 16).

[0197] In some embodiments, the second sub-circuit 122 includes one or more clamping sub-circuits. For example, one clamping sub-circuit is shown in FIG. 15 and FIG. 16. As shown in FIG. 15 or FIG. 16, the clamping sub-circuit includes a third switch device S aux1, the first diode D1 and the voltage stabilizing diode TVS1. Here, in order to distinguish from the voltage stabilizing diode, the diode D1 can be referred to as the first diode, or the diode D1 can also be referred to as the auxiliary diode. In addition, the voltage stabilizing diode can be referred to as the second diode.

[0198] The third switching device S aux1 is electrically connected to the control end of the pressure-bearing adjustable switching element 110. The control end of the third switching device S aux1 is electrically connected to a control device (not shown in both FIG. 15 and FIG. 16). For example, the third switching device S aux1 is an NMOS transistor. For another example, the third switching device S aux1 is a PMOS transistor. The scope of the present disclosure is not limited to the specific type of the third switching device.

[0199] The negative end of the first diode D1 is electrically connected to the second end of the third switching device S aux1 .

[0200] The positive end of the voltage stabilizing diode TVS1 is electrically connected to the positive end of the first diode D1. The negative end of the voltage stabilizing diode TVS1 is electrically connected to the first end of the pressure-bearing adjustable switching element 110. That is, the negative end of the voltage stabilizing diode TVS1 is electrically connected to the control electrode 403 of the GCT.

[0201] For example, the voltage stabilizing diode TVS1 is an avalanche breakdown diode. It should be noted that the voltage stabilizing diode of the embodiments of the present disclosure can also use other types of voltage stabilizing diodes, and therefore the scope of the present disclosure is not limited to this.

[0202] The control device can be used to output corresponding control signals to the first switching device, the second switching device and the third switching device respectively, so as to control the conduction or turn-off of the first switching device, the second switching device and the third switching device, and then the conduction or turn-off of the pressure-bearing adjustable switching element, or the pressure-bearing adjustable switching element being clamped at a predetermined voltage can be controlled.

[0203] In some embodiments, in the case that the second sub-circuit only includes one clamping sub-circuit, the control device is configured to control the first switching device to be turned on, control the second switching device to be turned off, and control the third switching device to be turned off when the gate-commutated thyristor enters the conduction phase; control the first switching device to be turned off, control the second switching device to be turned on, and control the third switching device to be turned off when the gate-commutated thyristor enters the turn-off phase; and control the first switching device to be turned off, control the second switching device to be turned off, and control the third switching device to be turned on when the gate-commutated thyristor enters the blocking phase.

[0204] Next, the pressure-bearing adjustable switching element 110, the first switching device S drv1and the third switching device S aux1 is an NMOS transistor, the second switching device S drv2 is a PMOS transistor. The working process of the turn-off circuit is described as an example.

[0205] For example, when the GCT enters the on stage, the control device outputs a control signal (for example, a high-level signal) to the first switching device S drv1 , so that the first switching device S drv1 is turned on; the control device outputs a control signal (for example, a high-level signal) to the second switching device S drv2 , so that the second switching device S drv2 is turned off; in addition, the control device outputs a control signal (for example, a low-level signal) to the third switching device S aux1 , so that the third switching device S aux1 is turned off. In this way, the low level of the first voltage terminal 101 is applied to the control terminal of the pressure-adjustable switching element 110, so that the pressure-adjustable switching element 110 is maintained in the off state. In this way, the reverse bias voltage of the voltage source V C is not applied to the PN junction between the control electrode and the first lead electrode of the GCT, and thus the GCT can enter the on stage or be maintained in the on state.

[0206] For another example, when the GCT enters the off stage, the control device outputs a control signal (for example, a low-level signal) to the first switching device S drv1 , so that the first switching device S drv1 is turned off; the control device outputs a control signal (for example, a low-level signal) to the second switching device S drv2 , so that the second switching device S drv2 is turned on; in addition, the control device outputs a control signal (for example, a low-level signal) to the third switching device S aux1 , so that the third switching device S aux1 is turned off. In this way, the driving voltage V drive of the second voltage terminal 102 is applied to the control terminal of the pressure-adjustable switching element 110, so that the pressure-adjustable switching element 110 is maintained in the on state. In this way, the reverse bias voltage of the voltage source V C is applied to the PN junction between the control electrode and the first lead electrode of the GCT, and thus the GCT enters the off stage.

[0207] For another example, when the GCT enters the block stage, the control device outputs a control signal (for example, a low-level signal) to the first switching device S drv1 , so that the first switching device S drv1 is turned off; the control device outputs a control signal (for example, a low-level signal) to the second switching device S drv2Output a control signal (e.g., a high-level signal) to cause the second switching device S to... drv2 Turn off; in addition, the control device sends a signal to the third switching device S. aux1 Output a control signal (e.g., a high-level signal) to cause the third switching device S to... aux1 The circuit is turned on. Thus, using the clamping sub-circuit, the voltage of the adjustable voltage-bearing switching element 110 is clamped at a predetermined voltage, which is the sum of the breakdown voltage threshold (or breakdown threshold voltage) of the Zener diode TVS1 and the threshold voltage of the adjustable voltage-bearing switching element 110. This ensures that the reverse bias voltage (the difference between the voltage of the voltage source and the predetermined voltage) across the PN junction between the control electrode and the first lead of the GCT is lower than that of the voltage source V. C The voltage value. Thus, the GCT enters the blocking phase.

[0208] In the above embodiment, the voltage across the switching element can be adjusted. Since the voltage of the voltage source is constant, the voltage across the PN junction between the control electrode and the first lead of the GCT changes in the opposite direction as the active voltage changes, thereby realizing the adjustment of the voltage across the PN junction between the control electrode and the first lead of the GCT by the turn-off circuit.

[0209] A control device outputs a control signal to the voltage regulation circuit to control the switching devices within the circuit to turn on or off. In this way, by adjusting the voltage actively applied to the switching components, the voltage applied to the power semiconductor device's turn-off circuit can be regulated. This solves the problem of unadjustable capacitor voltage in related technologies, reduces the complexity of the turn-off circuit, lowers costs, and improves circuit reliability.

[0210] Figure 17 is a schematic diagram illustrating the connection of a turn-off circuit for a gate-commutated thyristor according to some other embodiments of the present disclosure. Similar to the turn-off circuit shown in Figure 16, Figure 17 shows a voltage regulation circuit included in the turn-off circuit, which includes a control sub-circuit 120, a voltage-adjustable switching element 110, and a voltage source V. C For example, the pressure-adjustable switching element 110 is an NMOS transistor.

[0211] As shown in Figure 17, the control sub-circuit 120 includes a first sub-circuit 121 and a second sub-circuit 122. For example, the first sub-circuit 121 can be the first sub-circuit 121 shown in Figure 16, or it can be the first sub-circuit 121 shown in Figure 15. The first sub-circuit 121 has been described in detail above and will not be repeated here.

[0212] Different from the second sub-circuit shown in FIG. 16, the second sub-circuit shown in FIG. 17 includes multiple clamping sub-circuits. For example, the second sub-circuit includes N clamping sub-circuits, where N is a positive integer. Each clamping sub-circuit includes a third switching device, a first diode, and a voltage stabilizing diode. For example, FIG. 17 shows N third switching devices S aux1 to S auxN N first diodes D1 to D N and N voltage stabilizing diodes TVS1 to TVS N As shown in FIG. 17, the multiple clamping sub-circuits are connected in parallel between the control terminal and the first terminal of the pressure-bearing adjustable switching element 110.

[0213] For example, the N clamping sub-circuits include a 1st clamping sub-circuit to an Nth clamping sub-circuit. Here, the 1st clamping sub-circuit includes a third switching device S aux1 , a first diode D1, and a voltage stabilizing diode TVS1, the 2nd clamping sub-circuit includes a third switching device S aux2 , a first diode D2, and a voltage stabilizing diode TVS2, the Nth clamping sub-circuit includes a third switching device S auxN , a first diode D N , and a voltage stabilizing diode TVS N , and so on.

[0214] In the case where the second sub-circuit includes multiple clamping sub-circuits, the control device is configured to control the first switching device to be on, control the second switching device to be off, and control all the third switching devices of the multiple clamping sub-circuits to be off when the gate-commutated thyristor enters the on phase; control the first switching device to be off, control the second switching device to be on, and control all the third switching devices of the multiple clamping sub-circuits to be off when the gate-commutated thyristor enters the off phase; and control the first switching device to be off, control the second switching device to be off, and control one third switching device of the multiple clamping sub-circuits to be on when the gate-commutated thyristor enters the blocking phase, at which time, control the other third switching devices of the multiple clamping sub-circuits to be off.

[0215] That is, when a clamping sub-circuit is working (for example, when it is necessary to clamp the pressure-bearing adjustable switching element at a predetermined voltage), one third switching device of the multiple clamping sub-circuits needs to be on, and the other third switching devices need to be off.

[0216] In some embodiments, the one or more clamping sub-circuits include a plurality of clamping sub-circuits, and the breakdown voltage threshold values (i.e. the clamping values) of the zener diodes in the plurality of clamping sub-circuits are not equal. That is, the breakdown voltage threshold values of the plurality of zener diodes in the plurality of clamping sub-circuits are different from each other. In other words, the clamping voltages of the plurality of clamping sub-circuits are different from each other. In this way, the third switching devices of the corresponding clamping sub-circuits can be selected to be turned on while the third switching devices of the other remaining clamping sub-circuits are turned off, so as to clamp the voltage of the voltage-bearing adjustable switching element at a desired predetermined voltage.

[0217] For example, if the i-th (1≤i≤N, i is a positive integer) clamping sub-circuit is selected to be turned on to clamp the voltage of the voltage-bearing adjustable switching element at a predetermined voltage, in addition to turning off the first switching device S drv1 and turning off the second switching device S drv2 , the third switching device S auxi of the i-th clamping sub-circuit is turned on, and the third switching devices of the other clamping sub-circuits are turned off. Therefore, the voltage of the voltage-bearing adjustable switching element can be adjusted by controlling the third switching device of the i-th clamping sub-circuit to be turned on, so as to adjust the voltage across the control electrode and the first output electrode of the GCT chip.

[0218] In some embodiments, the control device can output the control signal based on the state of the optical signal to control the GCT to switch from the on state to the off state or from the blocking state to the on state.

[0219] In some embodiments, the control device can control the GCT to switch from the off state to the blocking state by a fixed time duration (or referred to as a predetermined time duration) or based on the measurement result of the current detection device at the second output electrode or the control electrode of the GCT (i.e. the magnitude of the current flowing through the second output electrode or the control electrode measured by the current detection device). For example, the GCT can be controlled to switch from the off state to the blocking state after a set fixed time duration (e.g. 5 microseconds) or after the current at the second output electrode of the GCT drops to a predetermined percentage (e.g. 40%) of the original current. Here, the predetermined percentage can be set according to actual needs, and the scope of the present disclosure is not limited to the specific value of the predetermined percentage.

[0220] In some embodiments, as described above, the control device 51 can be configured to output a first control signal in a first phase and output a second control signal in a second phase after the first phase. The first phase includes at least a part of the voltage establishment phase in the off phase of the gate-commutated thyristor, and the at least a part of the voltage establishment phase is adjacent to and after the commutation phase in the off phase. Here, the control signal described above includes the first control signal and the second control signal.

[0221] The voltage regulating circuit 52 can be configured to, after receiving the first control signal, apply a first reverse bias voltage to the PN junction formed by the second doped region and the first doped region through the control electrode and the first draw-out electrode in the first stage, and, after receiving the second control signal, apply a second reverse bias voltage to the PN junction in the second stage, wherein the voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, and the voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

[0222] That is, in the at least part of the voltage establishment stage, the first reverse bias voltage is applied to the PN junction formed by the second doped region and the first doped region. Since the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, the current of the GCT in the off stage can be sufficiently switched from flowing through the first draw-out electrode to flowing through the control electrode, and is not easily switched back from flowing through the control electrode to flowing through the first draw-out electrode. In the at least part of the voltage establishment stage, that is, in the stage in which the PN junction between the control electrode and the first draw-out electrode is easily reopened in the related art, the first reverse bias voltage greater than or equal to the breakdown voltage threshold of the PN junction applied to the PN junction can reduce the possibility of reopening of the PN junction and the possibility of failure of the GCT chip in the off state, even if a part of the voltage is distributed to the impedance of other parts.

[0223] Of course, in the first stage, the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction, which causes the PN junction to generate a reverse avalanche current. However, since the total duration of the at least part of the voltage establishment stage is short, the duration of the breakdown phenomenon is short, and thus the breakdown phenomenon does not cause damage to the gate commutated thyristor.

[0224] In the subsequent second stage, the voltage between the second draw-out electrode and the first draw-out electrode (as shown in FIG. 3) has risen to a relatively large voltage, and the second reverse bias voltage is applied to the PN junction at this time. The voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction, and the PN junction is not easily reopened. Moreover, since the reverse bias voltage applied to the PN junction is reduced to a voltage less than the breakdown voltage threshold of the PN junction, the breakdown phenomenon described above can be prevented from lasting for a long time, thereby reducing the possibility of damage to the GCT due to a long time in the breakdown state.

[0225] That is, the above-mentioned off circuit can reduce the possibility of reopening of the PN junction between the control electrode and the first draw-out electrode of the GCT in the off state, thereby improving the off ability of the IGCT, and reducing the possibility of damage to the GCT due to a long time in the breakdown state.

[0226] In some embodiments, the first stage further comprises a commutation stage.

[0227] In some embodiments, the voltage of the voltage source V C is greater than a breakdown voltage threshold of the PN junction between the control electrode and the first extraction electrode of the GCT.

[0228] In some embodiments, the first control signal comprises a first sub-control signal, a second sub-control signal and a third sub-control signal. The control device 51 can be configured to output the first sub-control signal to the first switching device to control the first switching device to be turned off, output the second sub-control signal to the second switching device to control the second switching device to be turned on, and output the third sub-control signal to all the third switching devices in the one or more clamping sub-circuits to control all the third switching devices to be turned off.

[0229] For example, taking the turn-off circuit shown in FIG. 15 or FIG. 16 as an example, in the first stage, the control device 51 outputs the first sub-control signal to the first switching device S drv1 to control the first switching device S drv1 to be turned off, outputs the second sub-control signal to the second switching device S drv2 to control the second switching device S drv2 to be turned on, and outputs the third sub-control signal to the third switching device S aux1 to control the third switching device S aux1 to be turned off. In this way, the driving voltage V drive of the second voltage terminal 102 is applied to the pressure-bearing adjustable switching element 110, so that the pressure-bearing adjustable switching element 110 is turned on, and the voltage of the voltage source V C is applied to the PN junction between the control electrode and the first extraction electrode of the GCT as a reverse bias voltage. Since the voltage of the voltage source V C can be set to a voltage greater than the breakdown voltage threshold of the PN junction between the control electrode and the first extraction electrode of the GCT, in this way, the first reverse bias voltage can be applied to the above-mentioned PN junction through the control electrode and the first extraction electrode in the first stage, and the voltage value of the first reverse bias voltage is greater than or equal to the breakdown voltage threshold of the PN junction.

[0230] In some embodiments, the second control signal comprises a fourth sub-control signal, a fifth sub-control signal and a sixth sub-control signal. The control device 51 can be configured to output the fourth sub-control signal to the first switching device to control the first switching device to be turned off, output the fifth sub-control signal to the second switching device to control the second switching device to be turned off, and output the sixth sub-control signal to one of the third switching devices in the one or more clamping sub-circuits to control the one of the third switching devices to be turned on.

[0231] Here, the situation regarding controlling the conduction of a third switching device in the above embodiments can be understood as follows: for the case where the second sub-circuit includes only one clamping sub-circuit, the third switching device in the clamping sub-circuit is controlled to conduct; for the case where the second sub-circuit includes multiple clamping sub-circuits, in addition to controlling the conduction of one third switching device in the multiple clamping sub-circuits, the other third switching devices in the multiple clamping sub-circuits are also controlled to turn off.

[0232] For example, taking the shutdown circuit shown in Figure 15 or Figure 16 as an example, in the second stage, the control device 51 can send a signal to the first switching device S. drv1 Output the fourth sub-control signal to control the first switching device S drv1 Turn off, to the second switching device S drv2 Output the fifth sub-control signal to control the second switching device S drv2 Turn off, and send to the third switching device S aux1 Output the sixth sub-control signal to control the third switching device S aux1 The circuit is turned on. Thus, using the clamping sub-circuit, the voltage of the adjustable voltage-bearing switching element 110 is clamped at a predetermined voltage, which is the sum of the breakdown voltage threshold of the Zener diode TVS1 and the threshold voltage of the adjustable voltage-bearing switching element 110. For example, this can be achieved by pre-setting the predetermined voltage and the voltage source V. C The voltage is such that the reverse bias voltage across the PN junction between the control electrode and the first lead of the GCT is less than the breakdown voltage threshold of the PN junction. This achieves the application of a second reverse bias voltage to the PN junction in the second stage, the value of which is less than the breakdown voltage threshold of the PN junction.

[0233] In some embodiments, the control device outputs a control signal to the voltage regulation circuit to control the voltage-adjustable switching element (i.e., a switching element with saturation characteristics) to operate in an ideal conduction state, so that the full voltage of the voltage source is applied to the PN junction between the control electrode and the first lead of the GCT to apply a first reverse bias voltage to the GCT; after a predetermined time or after the current of the GCT chip decays to less than a predetermined percentage of the maximum current (e.g., the predetermined percentage ranges from 0 to 40%), the control device controls the voltage regulation circuit to make the voltage-adjustable switching element operate in the saturation region, so that the actual withstand voltage of the PN junction is lower than the breakdown voltage threshold of the PN junction to apply a second reverse bias voltage to the GCT.

[0234] In some embodiments of this disclosure, a drive circuit for a gate-commutated thyristor is also provided, the drive circuit including the shutdown circuit as described above.

[0235] In some embodiments of this disclosure, an integrated gate-commutated thyristor is also provided, which includes the shutdown circuit described above.

[0236] In some embodiments of the present disclosure, there is also provided an electrical device comprising the integrated gate-commutated thyristor as described above.

[0237] FIG. 18 is a flow chart illustrating a turn-off method according to some embodiments of the present disclosure. The turn-off method can be implemented based on the turn-off circuit as described above. As shown in FIG. 18, the turn-off method comprises steps S910-S930.

[0238] At step S910, when the gate-commutated thyristor enters the on phase, the first switching device is controlled to be turned on, the second switching device is controlled to be turned off, and all the third switching devices in the one or more clamping sub-circuits are controlled to be turned off.

[0239] At step S920, when the gate-commutated thyristor enters the off phase, the first switching device is controlled to be turned off, the second switching device is controlled to be turned on, and all the third switching devices in the one or more clamping sub-circuits are controlled to be turned off.

[0240] At step S930, when the gate-commutated thyristor enters the block phase, the first switching device is controlled to be turned off, the second switching device is controlled to be turned off, and one of the third switching devices in the one or more clamping sub-circuits is controlled to be turned on. Here, for the case where the turn-off circuit only comprises one clamping sub-circuit, the third switching device of the clamping sub-circuit is controlled to be turned on; for the case where the turn-off circuit comprises multiple clamping sub-circuits, one of the third switching devices in the multiple clamping sub-circuits is controlled to be turned on, and the other third switching devices (i.e. the remaining third switching devices) in the multiple clamping sub-circuits are controlled to be turned off.

[0241] So far, a turn-off method based on the turn-off circuit as described above is provided. The turn-off method comprises: when the gate-commutated thyristor enters the on phase, the first switching device is controlled to be turned on, the second switching device is controlled to be turned off, and all the third switching devices in the one or more clamping sub-circuits are controlled to be turned off; when the gate-commutated thyristor enters the off phase, the first switching device is controlled to be turned off, the second switching device is controlled to be turned on, and all the third switching devices in the one or more clamping sub-circuits are controlled to be turned off; when the gate-commutated thyristor enters the block phase, the first switching device is controlled to be turned off, the second switching device is controlled to be turned off, and one of the third switching devices in the one or more clamping sub-circuits is controlled to be turned on. In this way, the control of the turning on or turning off of the switching devices in the voltage regulation circuit of the turn-off circuit is achieved, and thus the reliability of the GCT turn-off and the safety of the PN junction between the control electrode and the first lead-out electrode can be taken into account as much as possible, so that the reliability of the GCT turn-off and the safety of the PN junction can be improved.

[0242] In some embodiments, a conductivity type of the first doped region connected to the first anode is opposite to a conductivity type of the second doped region connected to the control electrode. The turn-off method can further include: in a first stage, applying, by the control electrode and the first anode, a first reverse bias voltage to a PN junction formed by the second doped region and the first doped region, wherein the first stage includes at least a part of a voltage build-up stage in a turn-off stage of the gate commutated thyristor, the at least a part of the voltage build-up stage is after and adjacent to a commutation stage in the turn-off stage, a voltage value of the first reverse bias voltage is greater than or equal to a breakdown voltage threshold of the PN junction; and in a second stage after the first stage, applying a second reverse bias voltage to the PN junction, wherein a voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

[0243] In some embodiments, the first stage further includes the commutation stage.

[0244] In some embodiments, in the first stage, applying, by the control electrode and the first anode, the first reverse bias voltage to the PN junction formed by the second doped region and the first doped region includes: controlling the first switching device to turn off, controlling the second switching device to turn on, and controlling all the third switching devices in the one or more clamping sub-circuits to turn off.

[0245] In some embodiments, in the second stage after the first stage, applying the second reverse bias voltage to the PN junction includes: controlling the first switching device to turn off, controlling the second switching device to turn off, and controlling one of the third switching devices in the one or more clamping sub-circuits to turn on.

[0246] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

[0247] Although some specific embodiments of the present disclosure have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A shutdown circuit, wherein, The turn-off circuit is used for a gate-commutated thyristor, the gate-commutated thyristor comprising a first electrode, a second electrode and a control electrode, wherein a first doping region connected to the first electrode has an opposite conductivity type to a second doping region connected to the control electrode, the turn-off circuit comprising: a control device configured to output a first control signal in a first phase and output a second control signal in a second phase after the first phase, wherein the first phase comprises at least a part of a voltage build-up phase in a turn-off phase of the gate-commutated thyristor, the at least part of the voltage build-up phase being after and adjacent to a commutation phase in the turn-off phase; and a voltage regulation circuit configured to apply, upon receiving the first control signal, a first reverse bias voltage to a PN junction formed by the second doping region and the first doping region through the control electrode and the first electrode in the first phase, and apply, upon receiving the second control signal, a second reverse bias voltage to the PN junction in the second phase, wherein the first reverse bias voltage has a voltage value greater than or equal to a breakdown voltage threshold of the PN junction, and the second reverse bias voltage has a voltage value less than the breakdown voltage threshold of the PN junction.

2. The turn-off circuit according to claim 1, wherein The first phase further comprises the commutation phase.

3. The turn-off circuit of claim 1 or 2, further comprising: a current detection device configured to detect a current value of a current flowing through the second electrode and transmit the current value to the control device, wherein the control device is further configured to output the first control signal to the voltage regulation circuit in response to the current value being greater than a current threshold, and output the second control signal to the voltage regulation circuit in response to the current value being less than or equal to the current threshold.

4. The turn-off circuit according to claim 3, wherein The current threshold is a current value of a predetermined percentage of a maximum current flowing through the second electrode.

5. The turn-off circuit of claim 1 or 2, wherein the first phase corresponds to a predetermined time length.

6. The turn-off circuit according to any one of claims 1 to 5, wherein The voltage regulation circuit comprises: a first voltage source, wherein the first voltage source has a voltage value of the second reverse bias voltage; a second voltage source, wherein a sum of a voltage value of the second voltage source and the voltage value of the first voltage source is the first reverse bias voltage; a first switching device, a first end of the first switching device being electrically connected to the control electrode of the gate-commutated thyristor, a second end of the first switching device being electrically connected to a first end of the first voltage source, and a control end of the first switching device being electrically connected to the control device; a second switching device, a first end of the second switching device being electrically connected to the first electrode of the gate-commutated thyristor, a second end of the second switching device being electrically connected to a second end of the first voltage source and a first end of the second voltage source, and a control end of the second switching device being electrically connected to the control device; and a third switching device, a first end of the third switching device being electrically connected to the control electrode of the gate-commutated thyristor, a second end of the third switching device being electrically connected to the second end of the first voltage source and the first end of the second voltage source, and a control end of the third switching device being electrically connected to the control device. A third switch device, a first end of the third switch device being electrically connected to the first outgoing pole of the gate-commutated thyristor, a second end of the third switch device being electrically connected to the second end of the second voltage source, and a control end of the third switch device being electrically connected to the control device.

7. The turn-off circuit according to claim 6, wherein: the first control signal comprises a first sub-control signal, a second sub-control signal and a third sub-control signal; the control device is configured to output the first sub-control signal to the first switch device to make the first switch device conductive, output the second sub-control signal to the second switch device to make the second switch device non-conductive, and output the third sub-control signal to the third switch device to make the third switch device conductive in the first phase.

8. The turn-off circuit according to claim 7, wherein: the control device is configured to output the first sub-control signal, the second sub-control signal and the third sub-control signal simultaneously.

9. The turn-off circuit according to any one of claims 6 to 8, wherein: the second control signal comprises a fourth sub-control signal, a fifth sub-control signal and a sixth sub-control signal; the control device is configured to output the fourth sub-control signal to the first switch device to make the first switch device conductive, output the fifth sub-control signal to the second switch device to make the second switch device conductive, and output the sixth sub-control signal to the third switch device to make the third switch device non-conductive in the second phase.

10. The turn-off circuit according to claim 9, wherein: the control device is configured to output the fourth sub-control signal, the fifth sub-control signal and the sixth sub-control signal simultaneously.

11. The turn-off circuit according to any one of claims 6 to 10, wherein: the second doped region is of P-type and the first doped region is of N-type, the first end of the first voltage source is a negative terminal, the second end of the first voltage source is a positive terminal, the first end of the second voltage source is a negative terminal, and the second end of the second voltage source is a positive terminal.

12. The turn-off circuit according to any one of claims 6 to 10, wherein: the second doped region is of N-type and the first doped region is of P-type, the first end of the first voltage source is a positive terminal, the second end of the first voltage source is a negative terminal, the first end of the second voltage source is a positive terminal, and the second end of the second voltage source is a negative terminal.

13. The turn-off circuit according to any one of claims 1 to 5, wherein the voltage regulating circuit comprises: a first voltage source, wherein the voltage value of the first voltage source is the second reverse bias voltage; a second voltage source, wherein the sum of the voltage value of the second voltage source and the voltage value of the first voltage source is the first reverse bias voltage; and a third voltage source, wherein the voltage value of the third voltage source is the first reverse bias voltage. a first switch device, a first end of the first switch device being electrically connected to the control electrode of the gate-commutated thyristor, a second end of the first switch device being electrically connected to a first end of the first voltage source, a control end of the first switch device being electrically connected to the control device; a unidirectional conduction device, a first end of the unidirectional conduction device being electrically connected to the first main electrode of the gate-commutated thyristor, a second end of the unidirectional conduction device being electrically connected to a second end of the first voltage source and a first end of the second voltage source; and a second switch device, a first end of the second switch device being electrically connected to the first main electrode of the gate-commutated thyristor, a second end of the second switch device being electrically connected to a second end of the second voltage source, a control end of the second switch device being electrically connected to the control device.

14. The turn-off circuit according to claim 13, wherein: the first control signal comprises a first sub-control signal and a second sub-control signal; the control device is configured to output the first sub-control signal to the first switch device to make the first switch device conductive in the first phase, and output the second sub-control signal to the second switch device to make the second switch device conductive in the first phase.

15. The turn-off circuit according to claim 14, wherein: the control device is configured to output the first sub-control signal and the second sub-control signal simultaneously.

16. The turn-off circuit according to any one of claims 13 to 15, wherein: the second control signal comprises a third sub-control signal and a fourth sub-control signal; the control device is configured to output the third sub-control signal to the first switch device to make the first switch device conductive in the second phase, and output the fourth sub-control signal to the second switch device to make the second switch device non-conductive in the second phase.

17. The turn-off circuit according to claim 16, wherein: the control device is configured to output the third sub-control signal and the fourth sub-control signal simultaneously.

18. The turn-off circuit according to any one of claims 13 to 17, wherein: the second doped region is of P-type, the first doped region is of N-type, the first end of the unidirectional conduction device is a negative terminal, the second end of the unidirectional conduction device is a positive terminal, the first end of the first voltage source is a negative terminal, the second end of the first voltage source is a positive terminal, the first end of the second voltage source is a negative terminal, and the second end of the second voltage source is a positive terminal.

19. The turn-off circuit according to any one of claims 13 to 17, wherein: the second doped region is of N-type, the first doped region is of P-type, the first end of the unidirectional conduction device is a positive terminal, the second end of the unidirectional conduction device is a negative terminal, the first end of the first voltage source is a positive terminal, the second end of the first voltage source is a negative terminal, the first end of the second voltage source is a positive terminal, and the second end of the second voltage source is a negative terminal.

20. The turn-off circuit according to any one of claims 1 to 5, wherein: the control device is further configured to output a control signal to the voltage regulating circuit, wherein the control signal comprises the first control signal or the second control signal; the voltage regulating circuit comprises a control sub-circuit, a pressure-bearing adjustable switching element, and a voltage source, wherein a first end of the pressure-bearing adjustable switching element is electrically connected to a control electrode of the gate-commutated thyristor, a second end of the pressure-bearing adjustable switching element is electrically connected to a first end of the voltage source, and a control end of the pressure-bearing adjustable switching element is electrically connected to the control sub-circuit, a second end of the voltage source is electrically connected to a first draw-out electrode of the gate-commutated thyristor, the control sub-circuit is configured to control the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage, based on the control signal.

21. The turn-off circuit according to claim 20, wherein, the control sub-circuit comprises: a first sub-circuit configured to control the pressure-bearing adjustable switching element to be turned on or turned off; and a second sub-circuit configured to control the pressure-bearing adjustable switching element to be clamped at a predetermined voltage.

22. The shutdown circuit of claim 21, wherein, the first sub-circuit comprises: a first switching device, a first end of the first switching device is electrically connected to a first voltage terminal, a second end of the first switching device is electrically connected to a control end of the pressure-bearing adjustable switching element, and a control end of the first switching device is electrically connected to the control device; a first resistor, a first end of the first resistor is electrically connected to the first voltage terminal, and a second end of the first resistor is electrically connected to the control end of the pressure-bearing adjustable switching element; and a second switching device, a first end of the second switching device is electrically connected to a second voltage terminal, a second end of the second switching device is electrically connected to the control end of the pressure-bearing adjustable switching element, and a control end of the second switching device is electrically connected to the control device; wherein a voltage level of the first voltage terminal is less than a voltage level of the second voltage terminal.

23. The turn-off circuit according to claim 22, wherein, the first sub-circuit further comprises: a second resistor arranged between the second end of the first switching device and the control end of the pressure-bearing adjustable switching element; and / or a third resistor arranged between the second end of the second switching device and the control end of the pressure-bearing adjustable switching element.

24. The turn-off circuit according to claim 22 or 23, wherein: The second sub-circuit comprises one or more clamping sub-circuits, wherein, each clamping sub-circuit comprises: a third switching device, a first end of the third switching device is electrically connected to the control end of the pressure-bearing adjustable switching element, and a control end of the third switching device is electrically connected to the control device; a first diode, a negative end of the first diode is electrically connected to a second end of the third switching device; and a voltage stabilizing diode, a positive end of the voltage stabilizing diode is electrically connected to a positive end of the first diode, and a negative end of the voltage stabilizing diode is electrically connected to the first end of the pressure-bearing adjustable switching element.

25. The turn-off circuit according to claim 24, wherein: the voltage stabilizing diode is an avalanche breakdown diode; and / or the pressure-bearing adjustable switching element comprises a metal-oxide-semiconductor field-effect transistor.

26. The shutdown circuit of claim 24 or 25, wherein, The one or more clamping sub-circuits comprise a plurality of clamping sub-circuits, and breakdown voltage thresholds of the zener diodes in the plurality of clamping sub-circuits are not equal.

27. The turn-off circuit of any one of claims 24 to 26, wherein The control device is configured to control the first switching device to be turned on, the second switching device to be turned off, and all the third switching devices in the one or more clamping sub-circuits to be turned off when the gate-commutated thyristor enters the conducting phase; control the first switching device to be turned off, the second switching device to be turned on, and all the third switching devices in the one or more clamping sub-circuits to be turned off when the gate-commutated thyristor enters the turn-off phase; and control the first switching device to be turned off, the second switching device to be turned off, and one of the third switching devices in the one or more clamping sub-circuits to be turned on when the gate-commutated thyristor enters the blocking phase.

28. The turn-off circuit of any one of claims 24 to 27, wherein The first control signal comprises a first sub-control signal, a second sub-control signal, and a third sub-control signal; and the control device is configured to output the first sub-control signal to the first switching device to control the first switching device to be turned off, output the second sub-control signal to the second switching device to control the second switching device to be turned on, and output the third sub-control signal to all the third switching devices in the one or more clamping sub-circuits to control all the third switching devices to be turned off; and / or The second control signal comprises a fourth sub-control signal, a fifth sub-control signal, and a sixth sub-control signal; and the control device is configured to output the fourth sub-control signal to the first switching device to control the first switching device to be turned off, output the fifth sub-control signal to the second switching device to control the second switching device to be turned off, and output the sixth sub-control signal to one of the third switching devices in the one or more clamping sub-circuits to control the one of the third switching devices to be turned on.

29. The shutdown circuit of any one of claims 20 to 28, wherein, The voltage of the voltage source is greater than the breakdown voltage threshold of the PN junction.

30. A shutdown circuit, comprising: The turn-off circuit is used for a gate-commutated thyristor, the gate-commutated thyristor comprising a first drawout pole, a second drawout pole, and a control pole, and the turn-off circuit comprises a control device and a voltage regulation circuit; The control device is configured to output a control signal to the voltage regulation circuit; The voltage regulation circuit comprises a control sub-circuit, a pressure-bearing adjustable switching element, and a voltage source, The first end of the pressure-bearing adjustable switching element is electrically connected to the control pole of the gate-commutated thyristor, the second end of the pressure-bearing adjustable switching element is electrically connected to the first end of the voltage source, and the control end of the pressure-bearing adjustable switching element is electrically connected to the control sub-circuit. The second end of the voltage source is electrically connected to the first drawout pole of the gate-commutated thyristor. The control sub-circuit is configured to control the pressure-bearing adjustable switching element to be turned on or turned off, or to be clamped at a predetermined voltage, based on the control signal.

31. The turn-off circuit according to claim 30, wherein The control sub-circuit comprises: a first sub-circuit configured to control the pressure-bearing adjustable switching element to be turned on or turned off; and a second sub-circuit configured to control the pressure-bearing adjustable switching element to be clamped at a predetermined voltage.

32. The shutdown circuit of claim 31, wherein, The first sub-circuit comprises: a first switch device, a first end of the first switch device being electrically connected to a first voltage terminal, a second end of the first switch device being electrically connected to a control terminal of the pressure-bearing adjustable switching element, and a control terminal of the first switch device being electrically connected to the control device; a first resistor, a first end of the first resistor being electrically connected to the first voltage terminal, and a second end of the first resistor being electrically connected to the control terminal of the pressure-bearing adjustable switching element; and a second switch device, a first end of the second switch device being electrically connected to a second voltage terminal, a second end of the second switch device being electrically connected to the control terminal of the pressure-bearing adjustable switching element, and a control terminal of the second switch device being electrically connected to the control device; wherein a voltage level of the first voltage terminal is less than a voltage level of the second voltage terminal.

33. The shutdown circuit of claim 32, wherein, The first sub-circuit further comprises: a second resistor arranged between the second end of the first switch device and the control terminal of the pressure-bearing adjustable switching element; and / or a third resistor arranged between the second end of the second switch device and the control terminal of the pressure-bearing adjustable switching element.

34. The turn-off circuit according to claim 32 or 33, wherein: The second sub-circuit comprises one or more clamping sub-circuits, wherein, each clamping sub-circuit comprises: a third switch device, a first end of the third switch device being electrically connected to the control terminal of the pressure-bearing adjustable switching element, and a control terminal of the third switch device being electrically connected to the control device; a first diode, a negative terminal of the first diode being electrically connected to a second end of the third switch device; and a voltage stabilizing diode, a positive terminal of the voltage stabilizing diode being electrically connected to a positive terminal of the first diode, and a negative terminal of the voltage stabilizing diode being electrically connected to a first end of the pressure-bearing adjustable switching element.

35. The turn-off circuit according to claim 34, wherein: the voltage stabilizing diode is an avalanche breakdown diode; and / or the pressure-bearing adjustable switching element comprises a metal-oxide-semiconductor field-effect transistor.

36. The shutdown circuit of claim 34 or 35, wherein, the one or more clamping sub-circuits comprise a plurality of clamping sub-circuits, and the breakdown voltage threshold values of the voltage stabilizing diodes in the plurality of clamping sub-circuits are not equal.

37. The turn-off circuit according to any one of claims 34 to 36, wherein the control device is configured to control the first switch device to be turned on, control the second switch device to be turned off, and control all the third switch devices in the one or more clamping sub-circuits to be turned off when the gate-commutated thyristor enters an on phase, control the first switch device to be turned off, control the second switch device to be turned on, and control all the third switch devices in the one or more clamping sub-circuits to be turned off when the gate-commutated thyristor enters an off phase, and control the first switch device to be turned off, control the second switch device to be turned off, and control one of the third switch devices in the one or more clamping sub-circuits to be turned on when the gate-commutated thyristor enters a blocking phase.

38. A drive circuit for a gate-commutated thyristor, comprising: The turn-off circuit according to any one of claims 1 to 37.

39. An integrated gate-commutated thyristor comprising: The turn-off circuit according to any one of claims 1 to 37.

40. An electrical device comprising: The integrated gate-commutated thyristor according to claim 39.

41. A turn-off method for a gate-commutated thyristor, wherein, The gate-commutated thyristor comprises a first extrinsic electrode, a second extrinsic electrode and a control electrode, wherein a conductivity type of a first doped region connected to the first extrinsic electrode is opposite to a conductivity type of a second doped region connected to the control electrode, and the turn-off method comprises: applying, in a first phase, a first reverse bias voltage to a PN junction formed by the second doped region and the first doped region through the control electrode and the first extrinsic electrode, wherein the first phase comprises at least a part of a voltage build-up phase in a turn-off phase of the gate-commutated thyristor, the at least part of the voltage build-up phase is subsequent to and adjacent to a commutation phase in the turn-off phase, and a voltage value of the first reverse bias voltage is greater than or equal to a breakdown voltage threshold of the PN junction; and applying, in a second phase subsequent to the first phase, a second reverse bias voltage to the PN junction, wherein a voltage value of the second reverse bias voltage is less than the breakdown voltage threshold of the PN junction.

42. The turn-off method of claim 41, wherein, The first phase further comprises the commutation phase.

43. The turn-off method according to claim 41 or 42, wherein applying, in the first phase, the first reverse bias voltage to the PN junction comprises: in response to a current value of a current flowing through the second extrinsic electrode being greater than a current threshold, applying the first reverse bias voltage to the PN junction; and applying, in the second phase subsequent to the first phase, the second reverse bias voltage to the PN junction comprises: in response to the current value of the current flowing through the second extrinsic electrode being less than or equal to the current threshold, applying the second reverse bias voltage to the PN junction.

44. The turn-off method of claim 43, wherein, The current threshold is a current value that is a predetermined percentage of a maximum current value of the current flowing through the second extrinsic electrode.

45. The method of claim 41 or 42, wherein, The first phase corresponds to a predetermined time duration.

46. A turn-off method based on the turn-off circuit according to claim 34, comprising: when the gate-commutated thyristor enters a conducting phase, controlling the first switching device to be turned on, controlling the second switching device to be turned off, and controlling all third switching devices in the one or more clamping sub-circuits to be turned off; when the gate-commutated thyristor enters a turn-off phase, controlling the first switching device to be turned off, controlling the second switching device to be turned on, and controlling all third switching devices in the one or more clamping sub-circuits to be turned off; when the gate-commutated thyristor enters a blocking phase, controlling the first switching device to be turned off, controlling the second switching device to be turned off, and controlling one third switching device in the one or more clamping sub-circuits to be turned on.

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