Gate commutated thyristor driving circuit and turn-off unit thereof

Abstract

The utility model provides a gate commutated thyristor driving circuit and a turn-off unit thereof. The turn-off unit of the gate commutated thyristor driving circuit comprises a voltage source, a voltage conversion module and a driving voltage adjusting switch. The voltage conversion module is electrically connected with the voltage source, the driving voltage adjusting switch and the gate commutation thyristor, the voltage conversion module is used for converting the voltage of the voltage source into one of the multi-stage driving voltages according to the on-off state of the driving voltage adjusting switch, and the driving voltages are used for driving the gate commutation thyristor. According to the gate commutation thyristor driving circuit, the problem that the turn-off unit of the gate commutation thyristor driving circuit in the prior art cannot give consideration to both rapid commutation and reliable turn-off of the PN junction is solved.

Description

Technical Field

[0001] The present application relates to the technical field of power semiconductor devices, and more particularly, to a turn-off unit of a gate-commutated thyristor drive circuit and a gate-commutated thyristor drive circuit. Background Art

[0002] The basic structure of a gate-commutated thyristor is as Figure 1 shown, including four doped regions and three electrodes (anode, gate, and cathode). The first doped region 104 has a first conductivity type (exemplarily, the first conductivity type is P-type) and is connected to the anode A of the gate-commutated thyristor; the second doped region 105 has a second conductivity type (exemplarily, the second conductivity type is N-type); the third doped region 106 has the first conductivity type and is connected to the gate G of the gate-commutated thyristor; the fourth doped region 107 has the second conductivity type and is connected to the cathode K of the commutated thyristor, and the first conductivity type is opposite to the second conductivity type.

[0003] The turn-off unit of the gate-commutated thyristor drive circuit is connected in parallel between the gate G and the cathode K of the gate-commutated thyristor. In the prior art, as shown in Figure 1 and Figure 2 , the turn-off unit is usually composed of a switch group 200 and a voltage source 20 connected in series. When the switch group 200 is closed, a reverse bias voltage is applied between the gate G and the cathode K of the gate-commutated thyristor 1, causing the PN junction formed by the third doped region 106 and the fourth doped region 107 to gradually turn off and remain reverse-biased, and the cathode current I K becomes 0, so that all the anode current I A of the gate-commutated thyristor 1 flows out from the gate G (I G ). Since no current is injected into the third doped region 106, the gate-commutated thyristor 1 turns off in the form of a PNP transistor with an open base.

[0004] The process of turning off the PN junction formed by the third doped region 106 and the fourth doped region 107 and converting the gate-commutated thyristor into the form of a PNP transistor can be detailedly divided into a commutation stage and a PN junction reverse bias stage: transferring the cathode current I K to the gate, the cathode current I K gradually decreases to 0, causing all the anode current I A to flow out from the gate. The current change rate is directly determined by the reverse drive voltage, and a higher drive voltage can achieve a faster commutation speed. In this stage, the PN junction does not bear voltage; the cathode current I KIn the process of reverse increase and the subsequent establishment of the reverse voltage across the PN junction, the reverse voltage source in the turn-off unit maintains the reverse bias of the PN junction. To improve the turn-off ability of the gate-commutated thyristor, a faster commutation speed is required, that is, a higher reverse drive voltage is needed; to maintain the reliable turn-off of the PN junction without causing reverse breakdown, the reverse bias voltage of the PN junction cannot be too high.

[0005] In the existing turn-off unit design, a single drive voltage is adopted, that is, the highest voltage that ensures the reliable turn-off of the PN junction between the third doping region 106 and the fourth doping region 107 without causing reverse breakdown is used as the reverse drive voltage during the commutation stage. Therefore, the improvement of the commutation speed is limited, and it is impossible to balance fast commutation and the reliable turn-off of the PN junction. Summary of the Invention

[0006] The main purpose of this application is to provide a turn-off unit of a gate-commutated thyristor drive circuit and a gate-commutated thyristor drive circuit, so as to solve the problem that the turn-off unit of the gate-commutated thyristor drive circuit in the prior art cannot balance fast commutation and the reliable turn-off of the PN junction.

[0007] To achieve the above object, according to one aspect of this application, a turn-off unit of a gate-commutated thyristor drive circuit is provided, including a voltage source, a voltage conversion module, and a drive voltage adjustment switch; the voltage conversion module is electrically connected to the voltage source, the drive voltage adjustment switch, and the gate-commutated thyristor respectively. The voltage conversion module is used to convert the voltage of the voltage source into one of the multi-level drive voltages according to the switch state of the drive voltage adjustment switch, and the drive voltage is used to drive the gate-commutated thyristor.

[0008] Optionally, the turn-off unit further includes: a current detection module, the current detection module is electrically connected to the cathode of the gate-commutated thyristor, and the current detection module is used to detect the current signal of the cathode of the gate-commutated thyristor; a control module, the control module is electrically connected to the drive voltage adjustment switch and the current detection module respectively, and the control module is used to control the switch state of the voltage adjustment switch to be in the closed state or the normally open state according to the current signal.

[0009] Optionally, the voltage conversion module is a multi-winding transformer.

[0010] Optionally, the multi-winding transformer includes a primary winding and a secondary winding connected in a coupled manner. The drive voltage adjustment switch includes a first switch and a second switch, and the number of turns of the primary winding and the secondary winding is different; the first switch and the primary winding are respectively electrically connected to the voltage source, and the gate-commutated thyristor and the second switch are respectively electrically connected to the secondary winding; the first switch is used to connect or disconnect the voltage source and the primary winding; the second switch is used to connect or disconnect the gate-commutated thyristor and the secondary winding.

[0011] Optionally, the turn-off unit further includes: a turn-off switch connected between the voltage source and the gate-commutated thyristor, and the turn-off switch is connected in parallel with the first switch and the multi-winding transformer.

[0012] Optionally, the secondary winding includes a first induction winding and a second induction winding, the second switch includes a first sub-switch and a second sub-switch, and the number of turns of the first induction winding and the second induction winding is different; the gate-commutated thyristor and the first sub-switch are respectively electrically connected to the first induction winding, and the first sub-switch is used to connect or disconnect the gate-commutated thyristor and the first induction winding; the gate-commutated thyristor and the second sub-switch are respectively electrically connected to the second induction winding, and the second sub-switch is used to connect or disconnect the gate-commutated thyristor and the second induction winding.

[0013] Optionally, the secondary winding includes a third induction winding and a fourth induction winding, the second switch includes a third sub-switch and a fourth sub-switch; the gate-commutated thyristor is electrically connected to the third sub-switch through the fourth induction winding and the third induction winding in sequence; the third sub-switch is used to connect or disconnect the third induction winding and the gate-commutated thyristor; the fourth sub-switch is used to connect or disconnect the fourth induction winding and the gate-commutated thyristor.

[0014] Optionally, the primary winding has a primary like-named end and a primary unlike-named end, the positive pole of the voltage source is electrically connected to the primary like-named end through the first switch, and the negative pole of the voltage source is electrically connected to the primary unlike-named end; the secondary winding has a secondary like-named end and a secondary unlike-named end, the gate of the gate-commutated thyristor is electrically connected to the secondary unlike-named end through the second switch, and the cathode of the gate-commutated thyristor is electrically connected to the secondary like-named end.

[0015] Optionally, the drive voltage regulating switch is an enhancement-mode MOSFET.

[0016] Optionally, the voltage source includes a plurality of capacitors, and any two capacitors are connected in parallel.

[0017] Optionally, the control module is a controller or a control chip.

[0018] Optionally, the current detection module is a current meter.

[0019] To achieve the above object, according to one aspect of the present application, there is provided a gate-commutated thyristor drive circuit, including a gate-commutated thyristor, an on-unit, a holding unit, and a turn-off unit as described in any one of the above, and the turn-off unit, the holding unit, and the on-unit are respectively connected between the gate and the cathode of the gate-commutated thyristor.

[0020] Applying the technical solution of the present application, a turn-off unit of a gate-commutated thyristor drive circuit includes a voltage source, a voltage conversion module, and a drive voltage adjustment switch. The voltage conversion module is electrically connected to the voltage source, the drive voltage adjustment switch, and the gate-commutated thyristor respectively, and the voltage conversion module is used to convert the voltage of the voltage source into one of multiple levels of drive voltages, and the drive voltage is used to drive the gate-commutated thyristor. Through this solution, the voltage conversion module can convert the voltage of the voltage source into different levels of drive voltages under the action of the drive voltage adjustment switch. Based on this, during the process of turning off the gate-commutated thyristor, the turn-off unit can provide different levels of drive voltages for the gate-commutated thyristor during the commutation stage and the PN reverse bias stage, so as to decouple the drive voltages in the commutation stage and the PN reverse bias stage, and relieve the limitation of the drive voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor, thereby solving the problem that the turn-off unit of the gate-commutated thyristor drive circuit in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings forming a part of this application are used to provide a further understanding of the application. The schematic embodiments and descriptions thereof of the application are used to explain the application and do not constitute an improper limitation of the application. In the drawings:

[0022] Figure 1 shows a schematic diagram of the basic structure of a gate-commutated thyristor in the prior art;

[0023] Figure 2 shows a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit in the prior art;

[0024] Figure 3 shows a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit according to a first embodiment of the present application;

[0025] Figure 4 shows a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit according to a third embodiment of the present application;

[0026] Figure 5 shows a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit according to a fourth embodiment of the present application;

[0027] Figure 6 shows a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit according to a fifth embodiment of the present application;

[0028] Figure 7The circuit connection diagram of the turn-off unit of a gate-commutated thyristor drive circuit provided according to the sixth embodiment of the present application is shown;

[0029] Figure 8 The circuit connection diagram of a gate-commutated thyristor drive circuit provided according to the seventh embodiment of the present application is shown.

[0030] Among them, the above-mentioned drawings include the following reference numerals:

[0031] 1. Gate-commutated thyristor; 2. Turn-off unit; 3. Maintenance unit; 4. Turn-on unit; 20. Voltage source; 21. Voltage conversion module; 22. Drive voltage adjustment switch; 104. First doped region; 105. Second doped region; 106. Third doped region; 107. Fourth doped region; 200. Switch group; 23. Control module; 24. Current detection module; 221. First switch; 211. Primary winding; 212. First induction winding; 213. Second induction winding; 214. Third induction winding; 215. Fourth induction winding; 222. First sub-switch; 223. Second sub-switch; 224. Third sub-switch; 225. Fourth sub-switch. Detailed implementation manners

[0032] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of the present invention herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these process, method, product, or device.

[0035] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element can be directly on the other element, or there can also be intermediate elements. Moreover, in the specification and claims, when an element is described as being "connected" to another element, the element can be "directly connected" to the other element, or "connected" to the other element through a third element.

[0036] As introduced in the background art, in the design of the turn-off unit in the prior art, a single driving voltage is adopted, that is, the highest voltage that ensures the reliable turn-off of the PN junction between the third doping region and the fourth doping region without causing reverse breakdown is used as the reverse driving voltage in the commutation stage. Therefore, the improvement of the commutation speed is limited, and it is impossible to take into account both fast commutation and reliable turn-off of the PN junction. To solve the problem that the turn-off unit of the gate-commutated thyristor driving circuit in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction, the embodiments of the present application provide a turn-off unit of a gate-commutated thyristor driving circuit and a gate-commutated thyristor driving circuit.

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

[0038] Figure 3 It is a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor driving circuit provided according to the first embodiment of the present application. As Figure 3 shown, the turn-off unit includes a voltage source 20, a voltage conversion module 21, and a driving voltage adjustment switch 22; the voltage conversion module 21 is electrically connected to the voltage source 20, the driving voltage adjustment switch 22, and the gate-commutated thyristor 1 respectively. The voltage conversion module 21 is used to convert the voltage of the voltage source 20 into one of the multi-level driving voltages according to the switch state of the driving voltage adjustment switch 22, and the driving voltage is used to drive the gate-commutated thyristor 1. Among them, the gate-commutated thyristor 1 includes three electrodes, namely an anode A, a gate G, and a cathode K.

[0039] Specifically, the above driving voltage can be a reverse driving voltage.

[0040] Specifically, the basic structure of the gate-commutated thyristor 1 is as Figure 1 shown, and will not be elaborated here.

[0041] Specifically, the multi-level driving voltage is multiple driving voltages of different levels. One of the multi-level driving voltages represents one level of the driving voltage.

[0042] Moreover, in the case of different switch states of the driving voltage adjustment switch 22, the voltage conversion module 21 can convert the voltage of the voltage source 20 into driving voltages of different levels.

[0043] Applying the technical solution of the present application, a turn-off unit of a gate-commutated thyristor 1 drive circuit includes a voltage source 20, a voltage conversion module 21, and a drive voltage adjustment switch 22. The voltage conversion module 21 is electrically connected to the voltage source 20, the drive voltage adjustment switch 22, and the gate-commutated thyristor 1 respectively (in other words, the voltage source 20 is electrically connected to the gate-commutated thyristor 1 through the voltage conversion module 21 and the drive voltage adjustment switch 22), and the voltage conversion module 21 is used to convert the voltage of the voltage source 20 into one of multiple levels of drive voltages according to the switch state of the drive voltage adjustment switch 22, and the drive voltage is used to drive the gate-commutated thyristor 1. Through this solution, the voltage conversion module 21 can convert the voltage of the voltage source 20 into drive voltages of different levels under the action of the drive voltage adjustment switch 22. Based on this, during the process of turning off the gate-commutated thyristor 1, the turn-off unit can provide drive voltages of different levels for the gate-commutated thyristor 1 during the commutation stage and the PN reverse bias stage, so as to decouple the drive voltages in the commutation stage and the PN reverse bias stage, and relieve the limitation of the drive voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor 1, thereby solving the problem that the turn-off unit of the gate-commutated thyristor 1 drive circuit in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction.

[0044] The gate-commutated thyristor 1 includes 3 electrodes, namely an anode A, a gate G, and a cathode K. Specifically, as Figure 3 shown, during the commutation stage: transfer the cathode current I K to the gate G, and the cathode current I K gradually drops to 0, so that the anode current I A all flows out from the gate G; during the PN junction reverse bias stage: the cathode current I K increases in the reverse direction, and during the process of establishing a reverse voltage across the PN junction later, the reverse voltage source in the turn-off unit maintains the reverse bias of the PN junction.

[0045] Furthermore, as Figure 3 shown, the above-mentioned turn-off unit further includes: a current detection module 24, the current detection module 24 is electrically connected to the cathode of the gate-commutated thyristor 1, and the current detection module 24 is used to detect the current signal of the cathode of the gate-commutated thyristor 1; a control module 23, the control module 23 is electrically connected to the drive voltage adjustment switch 22 and the current detection module 24 respectively, and the control module 23 is used to control the switch state of the drive voltage adjustment switch 22 to be in a closed state or an open state according to the current signal.

[0046] Specifically, as Figure 3 shown, one end of the current detection module 24 is electrically connected to the cathode of the gate-commutated thyristor 1, and the other end of the current detection module 24 is electrically connected to the control module 23.

[0047] It should be noted that the process of turning off the gate-commutated thyristor 1 is divided into a commutation stage and a PN junction reverse bias stage, and the current detection module 24 can detect different current signals in the commutation stage and the PN junction reverse bias stage.

[0048] In the above embodiment, after the current detection module 24 detects the current signal of the cathode of the gate-commutated thyristor 1, the control module 23 can receive the current signal and know whether the gate-commutated thyristor 1 is in the commutation stage or the PN junction reverse bias stage, and then can control the switch state of the drive voltage regulating switch 22 to be in the closed state or the normally open state according to the current signal. Further, since different switch states of the drive voltage regulating switch will convert the voltage of the voltage source 20 into drive voltages of different levels, when the control module 23 knows that the gate-commutated thyristor 1 is in the commutation stage or the PN junction reverse bias stage, the voltage source 20 can provide the corresponding drive voltage for the gate-commutated thyristor 1 in the commutation stage or the PN junction reverse bias stage to decouple the drive voltages in the commutation stage and the PN reverse bias stage, and relieve the limitation of the drive voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor 1, thus solving the problem that the turn-off unit of the drive circuit of the gate-commutated thyristor 1 in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction.

[0049] In some embodiments, in order to enable the voltage conversion module to provide multi-level drive voltages, the voltage conversion module can be a multi-winding transformer. In addition, since the current is transferred in the multi-winding transformer through the magnetic field rather than direct electrical connection, using the multi-winding transformer as the voltage conversion module in this solution can also achieve electrical isolation in circuits with multiple voltage levels and improve the safety of the circuit.

[0050] Specifically, the multi-winding transformer includes a primary winding and a secondary winding connected in a coupled manner. In order to achieve voltage transformation, the number of turns of the primary winding and the secondary winding can be different.

[0051] Specifically, the drive voltage regulating switch includes a first switch and a second switch; the first switch and the primary winding are respectively electrically connected to the voltage source, and the gate-commutated thyristor and the second switch are respectively electrically connected to the secondary winding; the first switch is used to connect or disconnect the voltage source and the primary winding; the second switch is used to connect or disconnect the gate-commutated thyristor and the secondary winding.

[0052] It can be seen that when the switch state of the first switch is closed, the voltage source and the primary winding of the multi-winding transformer form an RC discharge circuit, and the oscillating current in the primary side can couple out a negative voltage on the secondary side of the multi-winding transformer. Further, if the switch state of the second switch is closed, the secondary side can be connected to the drive circuit to obtain the drive voltage corresponding to the commutation stage or the reverse bias stage.

[0053] Specifically, the primary side winding has a primary side same-name terminal and a primary side different-name terminal. To protect the gate-commutated thyristor from reverse voltage shock and prevent it from being damaged, the positive pole of the voltage source is electrically connected to the primary side same-name terminal through the first switch, and the negative pole of the voltage source is electrically connected to the primary side different-name terminal; the secondary side winding has a secondary side same-name terminal and a secondary side different-name terminal. The gate of the gate-commutated thyristor is electrically connected to the secondary side different-name terminal through the second switch, and the cathode of the gate-commutated thyristor is electrically connected to the secondary side same-name terminal.

[0054] In some embodiments, according to the turn-off unit of a gate-commutated thyristor drive circuit provided in the second embodiment of the present application, the turn-off unit further includes: a turn-off switch, which is connected between the voltage source and the gate-commutated thyristor, and the turn-off switch is connected in parallel with the first switch and the multi-winding transformer.

[0055] Specifically, in this embodiment, the primary side same-name terminal of the multi-winding transformer is electrically connected to the positive pole of the voltage source through the first switch, the primary side different-name terminal of the multi-winding transformer is electrically connected to the negative pole of the voltage source, the secondary side same-name terminal of the multi-winding transformer is electrically connected to the cathode of the gate-commutated thyristor, and the secondary side different-name terminal of the multi-winding transformer is electrically connected to the gate of the gate-commutated thyristor through the second switch; the turn-off switch may include a first turn-off switch and a second turn-off switch. The positive pole of the voltage source is electrically connected to the cathode of the gate-commutated thyristor through the first turn-off switch, and the negative pole of the voltage source is electrically connected to the gate of the gate-commutated thyristor through the second turn-off switch.

[0056] Furthermore, when the turn-off unit further includes the above control module and current detection module, the turn-off switch (the first turn-off switch and the second turn-off switch) is electrically connected to the above control module. And the electrical connection relationship between the drive voltage adjustment switch and the control module may include: the first switch and the second switch are respectively electrically connected to the above control module. Among them, the control module is used to control the switch states of the turn-off switch (the first turn-off switch and the second turn-off switch), the first switch or the second switch to be in a closed state or a normally open state. Specifically, the turn-off switch may be an enhancement-mode MOSFET, which remains off (i.e., in the normally open state) when the gate input is at a low level and closes (i.e., in the closed state) when the gate input is at a high level.

[0057] In the above embodiments, when the turn-off switch is connected in parallel with the first switch and the multi-winding transformer, by selecting to close the first switch and the second switch and keep the closing switch open, an RC discharge circuit is formed between the voltage source and the primary winding of the multi-winding transformer, and the secondary winding of the multi-winding transformer is connected to the drive circuit to drive the gate-commutated thyristor; alternatively, by selecting to keep the first switch and / or the second switch open and closing the turn-off switch, the voltage source is connected to the drive circuit to directly drive the gate-commutated thyristor. It can be seen that through this embodiment, the turn-off unit can provide different levels of drive voltage for the gate-commutated thyristor during the commutation stage and the PN reverse bias stage through the above selection (selecting to close the first switch and the second switch and keep the closing switch open; or selecting to keep the first switch and / or the second switch open and closing the turn-off switch), so as to decouple the drive voltages during the commutation stage and the PN reverse bias stage, and relieve the limitation of the drive voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor, thus solving the problem that the turn-off unit of the gate-commutated thyristor drive circuit in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction.

[0058] In some alternative embodiments, Figure 4 is a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit according to the third embodiment of the present application. As Figure 4 shown, when the multi-winding transformer includes the above-mentioned coupled primary winding 211 and secondary winding, and the drive voltage regulating switch includes the first switch 221 and the second switch, the secondary winding includes the first induction winding 212 and the second induction winding 213, the second switch includes the first sub-switch 222 and the second sub-switch 223, and the number of turns of the first induction winding 212 and the second induction winding 213 is different; the gate-commutated thyristor 1 and the first sub-switch 222 are respectively electrically connected to the first induction winding 212, and the first sub-switch 222 is used to connect or disconnect the gate-commutated thyristor 1 and the first induction winding 212; the gate-commutated thyristor 1 and the second sub-switch 223 are respectively electrically connected to the second induction winding 213, and the second sub-switch 223 is used to connect or disconnect the gate-commutated thyristor 1 and the second induction winding 213.

[0059] Specifically, in this embodiment, the positive electrode of the voltage source 20 can be connected to the original side homonymous end of the primary winding 211 of the multi-winding transformer through the first switch 221, and the negative electrode of the voltage source 20 can be connected to the original side heteronymous end of the primary winding 211 of the multi-winding transformer. The first induction winding 212 is set as a winding with a large number of turns and a high output voltage. The heteronymous end of the secondary side of the first induction winding 212 is connected to the gate G of the gate-commutated thyristor 1 through the first sub-switch 222, and the homonymous end of the secondary side of the first induction winding 212 is connected to the cathode K of the gate-commutated thyristor 1. The second induction winding 213 is set as a winding with a small number of turns and a low output voltage. The heteronymous end of the secondary side of the second induction winding 213 is connected to the gate G of the gate-commutated thyristor 1 through the second sub-switch 223, and the homonymous end of the secondary side of the second induction winding 213 is connected to the cathode K of the gate-commutated thyristor 1. When the first switch 221 is closed, the voltage source 20 and the primary winding 211 of the multi-winding transformer form an RC discharge circuit, and the oscillating current on the primary side couples out a negative voltage on the secondary side; when the gate-commutated thyristor 1 is in the commutation stage, the first sub-switch 222 is closed and the second sub-switch 223 is opened, and the first induction winding 212 is connected to the drive circuit to obtain a high reverse drive voltage to achieve fast commutation; when the gate-commutated thyristor 1 is in the stage where the PN junction composed of the third doping region and the fourth doping region is reverse-biased, the second sub-switch 223 is closed and the first sub-switch 222 is opened, and the second induction winding 213 is connected to the drive circuit to obtain a low reverse drive voltage to maintain the reliable reverse bias of the PN junction.

[0060] Specifically, as Figure 4 shown, the gate-commutated thyristor 1 includes three electrodes, namely the anode A, the gate G, and the cathode K. Commutation stage: Transfer the cathode current I K to the gate G, and the cathode current I K gradually drops to 0, so that the anode current I A all flows out from the gate G; PN junction reverse bias stage: The cathode current I K increases in the reverse direction, and in the process of establishing a reverse voltage across the PN junction later, the reverse voltage source in the turn-off unit maintains the reverse bias of the PN junction.

[0061] Furthermore, Figure 5 is a schematic circuit connection diagram of the turn-off unit of a gate-commutated thyristor drive circuit according to the fourth embodiment of the present application. As Figure 5 shown, in Figure 4Based on the above-described turn-off unit, when the turn-off unit further includes the above control module 23 and current detection module 24, the current detection module 24 is electrically connected to the cathode K of the gate-commutated thyristor 1 for detecting the current signal of the cathode K of the gate-commutated thyristor 1 and sending the current signal to the control module 23. The control module 23 is electrically connected to the first switch 221, the first sub-switch 222, and the second sub-switch 223 respectively. When the current signal input to the control module 23 indicates that the cathode current (current signal) is flowing out of the gate-commutated thyristor 1, the control module 23 controls the switching states of the first switch 221, the first sub-switch 222, and the second sub-switch 223 to make the first switch 221, the first sub-switch 222, and the second sub-switch 223 operate in the states corresponding to the commutation stage. When the current signal input to the control module 23 indicates that the cathode current (current signal) is 0 or flowing into the gate-commutated thyristor 1, the control module 23 controls the switching states of the first switch 221, the first sub-switch 222, and the second sub-switch 223 to make the first switch 221, the first sub-switch 222, and the second sub-switch 223 operate in the states corresponding to the stage where the PN junction formed by the third doped region and the fourth doped region is reverse-biased.

[0062] Optionally, as Figure 5 shown, in order to detect the cathode current of the gate-commutated thyristor 1, the current detection module 24 is a current meter.

[0063] Specifically, first, the first switch 221 is closed to couple a negative voltage from the first induction winding 212 and the second induction winding 213 of the multi-winding transformer. When the current detection module 24 detects that the cathode current (current signal) is flowing out of the gate-commutated thyristor 1, it indicates that the gate-commutated thyristor 1 is in the commutation stage. The control module 23 closes the first sub-switch 222, opens the second sub-switch 223, and connects the first induction winding 212 with more turns to the drive circuit to obtain a high reverse drive voltage and achieve fast commutation. When the current detection module 24 detects that the cathode current (current signal) is 0 or flowing into the gate-commutated thyristor 1, it indicates that the gate-commutated thyristor 1 is in the stage where the PN junction formed by the third doped region and the fourth doped region is reverse-biased. The control module 23 closes the second sub-switch 223, opens the first sub-switch 222, and connects the second induction winding 213 with fewer turns to the drive circuit to obtain a low reverse drive voltage and maintain the reliable reverse bias of the PN junction.

[0064] In some alternative embodiments, Figure 6 is a schematic circuit connection diagram of the turn-off unit of a gate-commutated thyristor drive circuit according to the fifth embodiment of the present application. As Figure 6As shown, in the case where the multi-winding transformer includes the above-mentioned coupled primary winding 211 and secondary winding, and the drive voltage regulating switch 22 includes a first switch 221 and a second switch, the secondary winding includes a third induction winding 214 and a fourth induction winding 215, and the second switch includes a third sub-switch 224 and a fourth sub-switch 225; the gate-commutated thyristor 1 is electrically connected to the third sub-switch 224 through the fourth induction winding 215 and the third induction winding 214 in sequence; the third sub-switch 224 is used to connect or disconnect the third induction winding 214 and the gate-commutated thyristor 1; the fourth sub-switch 225 is used to connect or disconnect the fourth induction winding 215 and the gate-commutated thyristor 1.

[0065] Specifically, the positive pole of the voltage source 20 is connected to the primary same-named end of the primary winding 211 of the multi-winding transformer through the first switch 221, and the negative pole of the voltage source 20 is connected to the primary different-named end of the primary winding 211 of the multi-winding transformer; the secondary different-named end of the third induction winding 214 of the multi-winding transformer is connected to the gate G of the gate-commutated thyristor 1 through the third sub-switch 224, the secondary same-named end of the third induction winding 214 of the multi-winding transformer is connected to the secondary different-named end of the fourth induction winding 215 of the multi-winding transformer, and they are jointly connected to the gate G of the gate-commutated thyristor 1 through the fourth sub-switch 225, and the secondary same-named end of the fourth induction winding 215 of the multi-winding transformer is connected to the cathode K of the gate-commutated thyristor 1. When the first switch 221 is closed, the voltage source 20 and the primary winding 211 of the multi-winding transformer form an RC discharge circuit, and the oscillating current on the primary side couples out a negative voltage on the secondary side (the third induction winding 214 and the fourth induction winding 215). When the gate-commutated thyristor 1 is in the commutation stage, the third sub-switch 224 is closed and the fourth sub-switch 225 is opened, connecting the third induction winding 214 and the fourth induction winding 215 to the drive circuit together to obtain a high reverse drive voltage and achieve fast commutation; when the gate-commutated thyristor 1 is in the stage where the PN junction composed of the third doping region and the fourth doping region is reverse-biased, the fourth sub-switch 225 is closed and the third sub-switch 224 is opened, connecting the fourth induction winding 215 to the drive circuit to obtain a low reverse drive voltage and maintain the reliable reverse bias of the PN junction.

[0066] Specifically, as Figure 6 shown, the gate-commutated thyristor 1 includes 3 electrodes, namely the anode A, the gate G, and the cathode K. Commutation stage: Transfer the cathode current I K to the gate G, and the cathode current I K gradually drops to 0, so that the anode current I A flows out entirely from the gate G; PN junction reverse bias stage: The cathode current I K increases in the reverse direction, and during the process of the PN junction establishing a reverse voltage later, the reverse voltage source in the turn-off unit maintains the reverse bias of the PN junction.

[0067] Further, Figure 7 is a schematic circuit connection diagram of a turn-off unit of a gate-commutated thyristor drive circuit provided according to the sixth embodiment of the present application. As Figure 7 shown, on the basis of the turn-off unit shown in Figure 6 when the turn-off unit further includes the above control module 23 and current detection module 24, the current detection module 24 is electrically connected to the cathode K of the gate-commutated thyristor 1, and is used to detect the current signal of the cathode of the gate-commutated thyristor 1 and send the current signal to the control module 23. When the current signal input to the control module 23 indicates that the cathode current (current signal) is flowing out of the gate-commutated thyristor 1, the control module 23 controls the switching states of the first switch 221, the third sub-switch 224, and the fourth sub-switch 225, so that the first switch 221, the third sub-switch 224, and the fourth sub-switch 225 operate in the states corresponding to the commutation stage. When the current signal input to the control module 23 indicates that the cathode current (current signal) is 0 or flowing into the gate-commutated thyristor 1, the control module 23 controls the switching states of the first switch 221, the third sub-switch 224, and the fourth sub-switch 225, so that the first switch 221, the third sub-switch 224, and the fourth sub-switch 225 operate in the states corresponding to the stage where the PN junction formed by the third doping region and the fourth doping region is reverse-biased.

[0068] Specifically, first, the first switch 221 is closed to couple a negative voltage from the third induction winding 214 and the fourth induction winding 215 of the multi-winding transformer. When the current detection module 24 detects that the cathode current (current signal) is flowing out of the gate-commutated thyristor 1, it indicates that the gate-commutated thyristor 1 is in the commutation stage. The control module 23 closes the third sub-switch 224, opens the fourth sub-switch 225, and connects the third induction winding 214 and the fourth induction winding 215 to the drive circuit together to obtain a high reverse drive voltage and achieve fast commutation. When the current detection module 24 detects that the cathode current (current signal) is 0 or flowing into the gate-commutated thyristor 1, it indicates that the gate-commutated thyristor 1 is in the stage where the PN junction formed by the third doping region and the fourth doping region is reverse-biased. The control module 23 closes the fourth sub-switch 225, opens the third sub-switch 224, and connects the fourth induction winding 215 to the drive circuit to obtain a low reverse drive voltage and maintain the reliable reverse bias of the PN junction.

[0069] In some optional embodiments, the drive voltage regulating switch is an enhancement-mode MOSFET. Among them, it remains open (i.e., normally open state) when the gate input is at a low level and closes (i.e., closed state) when the gate input is at a high level.

[0070] In some embodiments, in order to provide a stable voltage source, the voltage source may include a plurality of capacitors, and any two capacitors are connected in parallel.

[0071] In order to intelligently adjust the switching states of the first switch, the second switch, or the turn-off switch according to the feedback information of the current detection module and achieve dynamic control of the driving voltage, in some alternative embodiments, the control module is a controller or a control chip.

[0072] In some alternative embodiments, Figure 8 FIG. 5 shows a schematic circuit connection diagram of a gate-commutated thyristor driving circuit according to a seventh embodiment of the present application. As Figure 8 shown, a gate-commutated thyristor driving circuit includes a gate-commutated thyristor 1, a turn-on unit 4, a holding unit 3, and a turn-off unit 2 as described in any of the above. The turn-off unit 2, the holding unit 3, and the turn-on unit 4 are respectively connected between the gate G and the cathode K of the gate-commutated thyristor 1.

[0073] Specifically, the turn-off unit 2, the holding unit 3, and the turn-on unit 4 are connected in parallel in pairs. The holding unit 3 and the turn-on unit 4 may be composed of a switch group (not shown in the figure) and a current source (not shown in the figure) connected in series. When the switch group is closed, the turn-on unit 4 injects a steep-wave strong trigger current pulse into the gate G of the gate-commutated thyristor 1. When the current exceeds the threshold, the gate-commutated thyristor 1 will be triggered into conduction. During the current-carrying period, to maintain the conduction state of the gate-commutated thyristor 1, the holding unit 3 injects a holding current with a constant amplitude into the gate G to ensure reliable and uniform conduction of the gate-commutated thyristor 1.

[0074] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0075] 1. Applying the technical solution of the present application, a turn-off unit of a gate-commutated thyristor driving circuit includes a voltage source, a voltage conversion module, and a driving voltage adjustment switch. The voltage conversion module is electrically connected to the voltage source, the driving voltage adjustment switch, and the gate-commutated thyristor respectively, and the voltage conversion module is used to convert the voltage of the voltage source into one of multiple levels of driving voltage, and the driving voltage is used to drive the gate-commutated thyristor. Through this solution, the voltage conversion module can, under the action of the driving voltage adjustment switch, convert the voltage of the voltage source into different levels of driving voltage. Based on this, during the process of turning off the gate-commutated thyristor, the turn-off unit can provide different levels of driving voltage for the gate-commutated thyristor during the commutation stage and the PN reverse bias stage, so as to decouple the driving voltages in the commutation stage and the PN reverse bias stage, and relieve the limitation of the driving voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor, thereby solving the problem that the turn-off unit of the gate-commutated thyristor driving circuit in the prior art cannot take into account both fast commutation and reliable turn-off of the PN junction.

[0076] 2. After the current detection module detects the current signal of the cathode of the gate-commutated thyristor, the control unit can receive the current signal and know whether the gate-commutated thyristor is in the commutation stage or the PN junction reverse bias stage. Furthermore, the control unit can control the switch state of the voltage regulation switch to be in the closed state or the normally open state according to the current signal. Further, since different switch states of the voltage regulation switch will convert the voltage of the voltage source into different levels of driving voltage, when the control unit knows that the gate-commutated thyristor is in the commutation stage or the PN junction reverse bias stage, the voltage source can provide the corresponding driving voltage for the gate-commutated thyristor in the commutation stage or the PN junction reverse bias stage to decouple the driving voltages in the commutation stage and the PN reverse bias stage, removing the limitation of the driving voltage for ensuring reliable turn-off of the PN junction on the commutation speed of the gate-commutated thyristor, thus solving the problem that the turn-off unit of the gate-commutated thyristor driving circuit in the prior art cannot balance fast commutation and reliable turn-off of the PN junction.

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

Claims

1. A turn-off unit of a gate-commutated thyristor drive circuit, characterized in that: It includes a voltage source, a voltage conversion module and a driving voltage regulating switch; The voltage conversion module is electrically connected to the voltage source, the driving voltage regulating switch and the gate-commutated thyristor respectively, and the voltage conversion module is used to convert the voltage of the voltage source into one of a plurality of driving voltages according to the switching state of the driving voltage regulating switch, and the driving voltage is used to drive the gate-commutated thyristor.

2. The shutoff unit according to claim 1, characterized in that: The shut-down unit further includes: A current detection module, the current detection module is electrically connected to the cathode of the gate-commutated thyristor, and the current detection module is used to detect the current signal of the cathode of the gate-commutated thyristor; A control module, wherein the control module is electrically connected to the driving voltage regulating switch and the current detection module respectively, and the control module is used to control the switch state of the voltage regulating switch to be in a closed state or a normally open state according to the current signal.

3. The shutoff unit according to claim 1, characterized in that: The voltage conversion module is a multi-winding transformer.

4. The shutoff unit according to claim 3, characterized in that: The multi-winding transformer comprises a primary winding and a secondary winding which are coupled to each other, the driving voltage regulating switch comprises a first switch and a second switch, and the primary winding and the secondary winding have different numbers of turns; The first switch and the primary winding are electrically connected to the voltage source respectively, and the gate-commutated thyristor and the second switch are electrically connected to the secondary winding respectively; The first switch is used to connect or disconnect the voltage source and the primary winding; The second switch is used to connect or disconnect the gate-commutated thyristor and the secondary winding.

5. The shutoff unit according to claim 4, characterized in that: The shut-down unit further includes: A turn-off switch is connected between the voltage source and the gate-commutated thyristor, and the turn-off switch is connected in parallel with the first switch and the multi-winding transformer.

6. The shutoff unit according to claim 4, characterized in that: The secondary winding includes a first induction winding and a second induction winding, the second switch includes a first sub-switch and a second sub-switch, and the first induction winding and the second induction winding have different numbers of turns; The gate-commutated thyristor and the first sub-switch are electrically connected to the first induction winding respectively, and the first sub-switch is used to connect or disconnect the gate-commutated thyristor and the first induction winding; The gate-commutated thyristor and the second sub-switch are electrically connected to the second inductive winding respectively, and the second sub-switch is used to connect or disconnect the gate-commutated thyristor and the second inductive winding.

7. The shutoff unit according to claim 4, characterized in that: The secondary winding includes a third inductive winding and a fourth inductive winding, and the second switch includes a third sub-switch and a fourth sub-switch; The gate-commutated thyristor is electrically connected to the third sub-switch via the fourth induction winding and the third induction winding in sequence; The third sub-switch is used to connect or disconnect the third induction winding and the gate-commutated thyristor; The fourth sub-switch is used to connect or disconnect the fourth induction winding and the gate-commutated thyristor.

8. The shutoff unit according to claim 4, characterized in that: The primary winding has a primary same-name terminal and a primary opposite-name terminal, the positive electrode of the voltage source is electrically connected to the primary same-name terminal through the first switch, and the negative electrode of the voltage source is electrically connected to the primary opposite-name terminal; The secondary winding has a secondary like-name end and a secondary unlike-name end, the gate of the gate-commutated thyristor is electrically connected to the secondary unlike-name end through the second switch, and the cathode of the gate-commutated thyristor is electrically connected to the secondary like-name end.

9. The shutoff unit according to any one of claims 1 to 8, characterized in that: The driving voltage regulating switch is an enhancement type MOSFET.

10. The shutoff unit according to any one of claims 1 to 8, characterized in that: The voltage source includes a plurality of capacitors, and any two of the capacitors are connected in parallel.

11. The shutoff unit according to claim 2, characterized in that: The control module is a controller or a control chip.

12. The shutoff unit according to claim 2, characterized in that: The current detection module is an ammeter.

13. A gate-commutated thyristor drive circuit, characterized in that: The invention comprises a gate-commutated thyristor, an opening unit, a maintaining unit and a shutoff unit according to any one of claims 1 to 12, wherein the shutoff unit, the maintaining unit and the opening unit are respectively connected between the gate and the cathode of the gate-commutated thyristor.

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