Igct inverter protection device and method

Abstract

The embodiment of the present disclosure discloses an IGCT converter protection device and method. The IGCT converter protection device comprises a sampling module, a multi-stage comparison module and a control module; the sampling module is used for collecting a first current of each first alternating current end; the multi-stage comparison module is used for generating a first middle-grade overcurrent state signal and a first high-grade overcurrent state signal according to each first current; the control module is used for adjusting the control strategy of the IGCT converter to a shutdown control strategy or a shunt current reduction control strategy according to each first middle-grade overcurrent state signal and each first high-grade overcurrent state signal, and driving the IGCT converter according to the shutdown control strategy or the shunt current reduction control strategy, so as to protect the IGCT converter; wherein the multi-stage comparison module is realized by at least one of a hardware circuit and a software method. The present disclosure can avoid damage of the IGCT converter due to fast turn-off under large current on the basis of realizing protection of the IGCT converter.

Description

Technical Field

[0001] This disclosure relates to the field of converter technology, and in particular to an IGCT converter protection device and method. Background Technology

[0002] Currently, when power conversion is carried out using power electronic conversion devices such as IGCT converters, a large amount of heat will be generated if a large current overcurrent fault occurs, which can easily cause safety risks. Therefore, overcurrent protection is required.

[0003] However, in related technologies, overcurrent protection for IGCT converters involves rapidly shutting down the IGCT power conversion module to control the converter's shutdown. However, if the current flowing through the IGCT power conversion module becomes too large, rapidly shutting it down can damage the module. Summary of the Invention

[0004] This disclosure provides an IGCT converter protection device and method to protect the IGCT converter and prevent damage to the IGCT converter due to rapid shutdown under high current conditions.

[0005] In a first aspect, embodiments of this disclosure provide an IGCT converter protection device, which includes a sampling module, a multi-level comparison module, and a control module;

[0006] The IGCT converter includes at least one first AC terminal; a sampling module is connected to each first AC terminal, and the sampling module is used to collect the first current of each first AC terminal;

[0007] The sampling module is connected to the multi-level comparison module, which is used to generate a first medium-range overcurrent state signal and a first high-range overcurrent state signal according to each first current.

[0008] Both the multi-level comparison module and the IGCT converter are connected to the control module. The control module is used to adjust the control strategy of the IGCT converter to a shutdown control strategy or a current shunting and reduction control strategy according to each first medium-range overcurrent state signal and each first high-range overcurrent state signal, and drive the IGCT converter according to the shutdown control strategy or the current shunting and reduction control strategy to protect the IGCT converter.

[0009] The multi-level comparison module is implemented using at least one of hardware circuits and / or software methods.

[0010] Secondly, this disclosure also provides an IGCT converter protection method, which includes:

[0011] Collect the first current at each first AC terminal;

[0012] A first medium-range overcurrent state signal and a first high-range overcurrent state signal are generated based on each first current.

[0013] The control strategy for the IGCT converter is adjusted to either a shutdown control strategy or a current reduction control strategy based on each first medium-range overcurrent state signal and each first high-range overcurrent state signal, and the IGCT converter is driven according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter.

[0014] In this embodiment, a sampling module acquires the first current at each first AC terminal. A multi-level comparison module outputs a first mid-range overcurrent state signal and a first high-range overcurrent state signal, indicating the specific range of each first current. Thus, the control module can determine the specific condition of each first current by reading the first mid-range and first high-range overcurrent state signals corresponding to each current. Therefore, if the first current exceeds the current that the IGCT converter can withstand, and the number of carriers injected into the power conversion devices of the IGCT converter can be extracted within the time required to quickly turn off the IGCT converter, a shutdown control strategy can be adopted to control the drive module to drive the IGCT converter. If the first current exceeds the current that the IGCT converter can withstand, and the number of carriers injected into the power conversion devices of the IGCT converter cannot be extracted within the time required to quickly turn off the IGCT converter, the control module can adopt a current reduction control strategy to drive the IGCT converter to conduct multiple power conversion devices. Therefore, this disclosure allows for flexible driving of the IGCT converter, thereby improving the flexibility of IGCT converter protection, preventing damage to the IGCT converter due to rapid shutdown under high current, reducing the workload of IGCT converter maintenance, and improving the robustness of the power generation system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of an IGCT converter protection device provided in an embodiment of the present disclosure;

[0017] Figure 2 This is a schematic diagram of the structure of an IGCT converter provided in an embodiment of the present invention;

[0018] Figure 3This is a schematic diagram of another IGCT converter protection device provided in an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure;

[0020] Figure 5 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure;

[0021] Figure 6 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure;

[0022] Figure 7 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure;

[0023] Figure 8 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure;

[0024] Figure 9 A schematic flowchart of an IGCT converter protection method provided in this embodiment of the present disclosure;

[0025] Figure 10 This is a flowchart illustrating the steps of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy based on each first low-level overcurrent state signal, each first medium-level overcurrent state signal, and each first high-level overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy in accordance with the embodiments of this disclosure.

[0026] Figure 11 A flowchart illustrating another step provided in this disclosure for adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a shunt current reduction control strategy based on each first low-level overcurrent state signal, each first medium-level overcurrent state signal, and each first high-level overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or shunt current reduction control strategy.

[0027] Figure 12 A schematic flowchart of another IGCT converter protection method provided in this embodiment of the present disclosure;

[0028] Figure 13This is a flowchart illustrating the steps of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy based on each first low-level overcurrent state signal, each first medium-level overcurrent state signal, each first high-level overcurrent state signal, each second low-level overcurrent state signal, each second medium-level overcurrent state signal, and each second high-level overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or current shunting and reducing control strategy.

[0029] Figure 14 This is a flowchart illustrating another step in an embodiment of the present disclosure to adjust the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy based on each first low-level overcurrent state signal, each first medium-level overcurrent state signal, each first high-level overcurrent state signal, each second low-level overcurrent state signal, each second medium-level overcurrent state signal, and each second high-level overcurrent state signal, and to drive the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present disclosure, the technical solutions of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present disclosure.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] Figure 1 This is a schematic diagram of the structure of an IGCT converter protection device provided in an embodiment of this disclosure, as shown below. Figure 1 As shown, the IGCT converter protection device includes a sampling module 110, a multi-stage comparison module 120, and a control module 140.

[0033] The IGCT converter 200 includes at least one first AC terminal; a sampling module 110 is connected to each first AC terminal and is used to collect the first current of each first AC terminal.

[0034] The sampling module 110 is connected to the multi-level comparison module 120, which is used to generate a first medium-range overcurrent state signal and a first high-range overcurrent state signal according to each first current.

[0035] The multi-level comparison module 120 and the IGCT converter 200 are both connected to the control module 140. The control module 140 is used to adjust the control strategy of the IGCT converter 200 to a shutdown control strategy or a current reduction control strategy according to each first medium-range overcurrent state signal and each first high-range overcurrent state signal, and drive the IGCT converter 200 according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter 200.

[0036] The multi-level comparison module 120 is implemented using at least one of hardware circuits and / or software methods.

[0037] Figure 2 This is a schematic diagram of the structure of an IGCT converter provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the IGCT converter 200 includes six power conversion branches and a first AC terminal. The first AC terminal is connected to the three power conversion branches on the left. The shutdown control strategy is a strategy to stop the IGCT converter 200 from operation, that is, to turn off all power conversion devices in the power conversion branches of the IGCT converter 200. The current shunting and current reduction control strategy is a strategy to increase the number of power conversion branches that are turned on in the IGCT converter 200, thereby reducing the output current of each power conversion branch. That is, to increase the number of power conversion branches that are turned on in the IGCT converter from one to multiple, so that the current of the IGCT converter DC bus flows out from multiple power conversion branches.

[0038] Specifically, Figure 1The IGCT converter 200 shown is a multi-grid converter, meaning it has multiple grid-side AC terminals (first AC terminals). Each first AC terminal of the IGCT converter 200 refers to the terminal where the IGCT converter 200 is connected to the power grid. The sampling module 110 can collect the current flowing into or out of the IGCT converter 200 through each first AC terminal. For example, the first current flowing into the IGCT converter 200 from the power grid through each first AC terminal or the first current flowing into the power grid from each first AC terminal of the IGCT converter 200, so that the specific situation of the current flowing into or out of the IGCT converter 200 can be known in real time through the first current collected from each first AC terminal. The multi-level comparison module 120 can process the current flowing into or out of the IGCT converter 200 from each first AC terminal to output a first medium-range overcurrent state signal and a first high-range overcurrent state signal that indicate the specific range of the current flowing into or out of the IGCT converter 200 in real time at each first AC terminal.

[0039] The control module 140 can read the first medium-range overcurrent state signal and the first high-range overcurrent state signal generated by the multi-level comparison module 120 for each first current. By reading the first medium-range overcurrent state signal and the first high-range overcurrent state signal for each first current, the control module 140 can determine whether each first current exceeds the current range that the IGCT converter 200 can withstand, and the degree to which each first current exceeds the current range that the IGCT converter 200 can withstand. Based on whether each first current exceeds the current range that the IGCT converter 200 can withstand and the degree to which each first current exceeds the current range that the IGCT converter 200 can withstand, the control module 140 adopts different control strategies to control the drive module 130 to drive the IGCT converter 200. For example, if a first current exceeds the current-bearing range of the IGCT converter 200, and the number of carriers injected into the power conversion devices (IGCT transistors) of the IGCT converter 200 can be fully extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 can adopt a shutdown control strategy to drive the IGCT converter 200 to stop, in order to prevent further damage to the IGCT converter 200 or the occurrence of a safety accident. If a first current exceeds the current-bearing range of the IGCT converter 200, causing the number of carriers injected into the power conversion devices of the IGCT converter 200 to be insufficient to be extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 adopts a current-splitting and current-reducing control strategy that can drive the IGCT converter 200 to conduct multiple power conversion branches, in order to reduce the current flowing into each power conversion device of the IGCT converter 200, thereby preventing further damage to the IGCT converter 200 or the occurrence of a safety accident. Therefore, in response to the overcurrent anomaly of the IGCT converter 200, the IGCT converter 200 can be driven flexibly, thereby improving the flexibility of the protection of the IGCT converter 200, avoiding damage to the IGCT converter 200 due to rapid shutdown under high current, reducing the workload of IGCT converter 200 maintenance, and improving the robustness of the power generation system.

[0040] For example, Figure 3 This is a schematic diagram of another IGCT converter protection device provided in an embodiment of the present invention. Figure 3The IGCT converter 200 shown has one grid-side AC terminal, i.e., one first AC terminal. In this case, the sampling module 110 can collect the first current input from the grid to the first AC terminal or the first current output from the first AC terminal to the grid. The multi-level comparison module 120 can generate a first mid-range overcurrent state signal and a first high-range overcurrent state signal based on the first current; the control module 140 adjusts the control strategy for the IGCT converter 200 to a shutdown control strategy based on the first mid-range overcurrent state signal, and drives the IGCT converter 200 according to the shutdown control strategy; or, the control module adjusts the control strategy for the IGCT converter 200 to a current shunting and current reduction control strategy based on the first high-range overcurrent state signal, and drives the IGCT converter 200 according to the current shunting and current reduction control strategy to protect the IGCT converter 200. As can be seen from the above description, in this embodiment, the sampling module 110 collects the first current of each first AC terminal; the multi-level comparison module 120 can output a first mid-range overcurrent state signal and a first high-range overcurrent state signal that indicate the specific range of each first current. Therefore, the control module 140 can obtain the specific situation of each first current by reading the first medium-range overcurrent state signal and the first high-range overcurrent state signal corresponding to each current. Thus, when the first current exceeds the current that the IGCT converter 200 can withstand, and the number of carriers injected by the power conversion device of the IGCT converter 200 can be extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 can adopt a shutdown control strategy to drive the IGCT converter 200. When the first current exceeds the current that the IGCT converter 200 can withstand, and the number of carriers injected by the power conversion device of the IGCT converter 200 cannot be extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 can adopt a current reduction control strategy to drive the IGCT converter 200 to conduct multiple power conversion branches. Therefore, this disclosure allows for flexible driving of the IGCT converter 200, thereby improving the flexibility of IGCT converter 200 protection, preventing damage to the IGCT converter 200 due to rapid turn-off under high current, reducing the maintenance workload of the IGCT converter 200, and improving the robustness of the power generation system. Optionally, based on the above embodiments, the multi-stage comparison module 120 is further configured to generate a first low-level overcurrent state signal corresponding to each first current.

[0041] The control module 140 is used to adjust the control strategy of the IGCT converter 200 according to each first low-level overcurrent state signal, each first medium-level overcurrent state signal and each first high-level overcurrent state signal, to a temporary blocking wave control strategy, a shutdown control strategy or a current shunting and current reduction control strategy, and to drive the IGCT converter 200 according to the temporary blocking wave control strategy, shutdown control strategy or current shunting and current reduction control strategy to protect the IGCT converter 200.

[0042] The temporary shutdown control strategy refers to a control strategy that temporarily shuts off the power conversion branch that the IGCT converter 200 needs to conduct, and can re-turn on the power conversion branch that the IGCT converter 200 needs to conduct at any time.

[0043] The first low-range overcurrent state signal, the first medium-range overcurrent state signal, and the first high-range overcurrent state signal corresponding to each first current are signals that represent the specific range of the first current, that is, signals that can reflect the specific range of the current flowing out or into the first AC terminal of the IGCT converter 200.

[0044] The control module 140 reads the first low-range overcurrent status signal, the first medium-range overcurrent status signal, and the first high-range overcurrent status signal corresponding to each first current to determine whether each first current exceeds the current carrying capacity of the IGCT converter 200 and the degree to which each first current exceeds the current carrying capacity of the IGCT converter 200. Based on this, different control strategies are adopted to drive the IGCT converter 200. Cases where the first current exceeds the limit by a small degree are mostly temporary overcurrents caused by external factors such as grid faults or grid voltage fluctuations. Cases where the first current exceeds the limit by a large degree are mostly long-term overcurrents caused by factors such as internal damage to the IGCT converter 200. Therefore, if only the first current exceeds the current carrying capacity of the IGCT converter 200 by a small degree, the control module 140 can adopt a temporary shutdown control strategy that temporarily drives some relevant power conversion devices of the IGCT converter 200 to shut down, and then allows the power conversion devices to drive normally again when the current returns to normal. If the first current significantly exceeds the current capacity of the IGCT converter 200, and the number of carriers injected into the power conversion devices of the IGCT converter 200 can be fully extracted within the time required for the rapid shutdown of the IGCT converter 200, the control module 140 can adopt a shutdown control strategy to drive the IGCT converter 200 to stop, thereby preventing further damage to the IGCT converter 200 or causing a safety accident. If the first current significantly exceeds the current capacity of the IGCT converter 200, and the number of carriers injected into the power conversion devices of the IGCT converter 200 cannot be fully extracted within the time required for the rapid shutdown of the IGCT converter 200, the control module 140 can adopt a current reduction control strategy that can drive the IGCT converter 200 to conduct multiple power conversion devices, thereby reducing the current flowing into each power conversion device of the IGCT converter 200, and thus preventing further damage to the IGCT converter 200 or causing a safety accident.

[0045] Therefore, the multi-level comparison module 120 and control module 140 of this disclosure realize flexible driving of IGCT converter 200 by judging the degree of overcurrent abnormality of IGCT converter 200 current, thereby improving the flexibility of IGCT converter 200 protection. Through the temporary blocking wave control strategy, the number of IGCT converter 200 shutdowns can be reduced, the maintenance workload of IGCT converter 200 can be reduced, the waste of power generation and power generation resources can be reduced, and the robustness of the power generation system can be improved.

[0046] Based on the above embodiments, optionally, Figure 4 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure. Figure 4 As shown, the IGCT converter protection device also includes a drive module 130; the sampling module 110 includes at least one first sampling unit 111; the multi-level comparison module 120 includes at least one first comparison unit group 121, each first comparison unit group 121 including a first comparator 1211, a second comparator 1212 and a third comparator 1213; the drive module 130 includes at least one first drive unit 131.

[0047] Each first sampling unit 111 is connected to a first AC terminal. Each first comparator 1211, each second comparator 1212, and each third comparator 1213 are all connected to a first sampling unit 111. The first comparator 1211, the second comparator 1212, and the third comparator 1213 of each first comparison unit group 121 are connected to the same first sampling unit 111. Each first comparator 1211, each second comparator 1212, each third comparator 1213, and each first drive unit 131 are all connected to the control module 140. Each first drive unit 131 is all connected to the IGCT converter 200.

[0048] Each first sampling unit 111 is used to collect the first current of its corresponding connected first AC terminal; each first comparison unit group 121 is used to determine the range of the first current collected by the corresponding connected first sampling unit 111, and outputs a first low-range overcurrent state signal, a first medium-range overcurrent state signal, and a first high-range overcurrent state signal that can indicate the specific range of the first current flowing into or out of the IGCT converter 200. Specifically, each first comparator 1211 is used to generate a first low-range overcurrent state signal based on the input first current, each second comparator 1212 is used to generate a first medium-range overcurrent state signal based on the input first current, and each third comparator 1213 is used to generate a first high-range overcurrent state signal based on the input first current.

[0049] For example, the current threshold defined by the second comparator 1212 is greater than the current threshold defined by the first comparator 1211, and the current threshold defined by the third comparator 1213 is greater than the current threshold defined by the second comparator 1212. If the first current does not exceed the current threshold defined by the first comparator 1211, it indicates that the first current does not exceed the acceptable range of the IGCT converter 200; if the first current only exceeds the current threshold defined by the first comparator 1211 and does not exceed the current threshold defined by the second comparator 1212, it indicates that the first current exceeds the acceptable range of the IGCT converter 200 by a small margin; if the first current exceeds the current threshold defined by the second comparator 1212 but does not exceed the current threshold defined by the third comparator 1213, it indicates that the first current exceeds the acceptable range. The IGCT converter 200 has a large tolerance range, which means that the number of carriers injected into the power conversion device of the IGCT converter 200 can be extracted within the time of rapid turn-off of the IGCT converter 200. If the first current exceeds the current threshold defined by the third comparator 1213, it indicates that the first current exceeds the tolerance range of the IGCT converter 200 by a large margin, and that the number of carriers injected into the power conversion device of the IGCT converter 200 cannot be extracted within the time of rapid turn-off of the IGCT converter 200. Each first drive unit 131 is used to adjust the first current of a first AC terminal of the device under test.

[0050] The control module 140 is used to determine the overcurrent level of the first current output by each first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal and the first high-level overcurrent state signal corresponding to the first current output by each first AC terminal, and to adopt different control strategies based on the overcurrent level of each first current to control the drive module 130 to drive the IGCT converter 200.

[0051] Specifically, the control module 140 can determine whether each first current exceeds the current that the IGCT converter 200 can withstand by reading the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current output from each first AC terminal, and confirm the degree to which each first current exceeds the current that the IGCT converter 200 can withstand, that is, confirm the overcurrent level of each first current. Therefore, the control module 140 can adopt different control strategies based on the overcurrent level of each first current to control the drive module 130 to drive the IGCT converter 200.

[0052] The overcurrent level of the first current includes level zero, low level, medium level, and high level. If the first current does not exceed the current threshold defined by the first comparator 1211, the overcurrent level of the first current is level zero. If the first current only exceeds the current threshold defined by the first comparator 1211 and does not exceed the current threshold defined by the second comparator 1212, the overcurrent level of the first current is low level. If the first current exceeds the current threshold defined by the second comparator 1212 but does not exceed the current threshold defined by the third comparator 1213, the overcurrent level of the first current is medium level. If the first current exceeds the current threshold defined by the third comparator 1213, the overcurrent level of the first current is high level.

[0053] The control module 140 adopts different control strategies based on the overcurrent level of each first current to control the drive module 130 to drive the device under test 200. The specific process is as follows: When the overcurrent level of the first current at all first AC terminals is not medium or high and there is a first current at the first AC terminal with a low overcurrent level, the control module 140 controls the first drive unit 131 corresponding to the first AC terminal with a low first current to drive the IGCT converter 200 according to the temporary blocking wave control strategy; when the overcurrent level of the first current at all first AC terminals is not high and there is a first current at the first AC terminal with a medium overcurrent level, the control module 140 controls each first drive unit 131 to drive the IGCT converter 200 according to the shutdown control strategy; when there is a first current at the first AC terminal with a high overcurrent level, the control module 140 controls the first drive unit 131 corresponding to the first AC terminal with a high first current to drive the IGCT converter 200 according to the current reduction control strategy.

[0054] Based on the above embodiments, alternatively, refer to the following: Figure 2 The IGCT converter 200 also includes at least one first set of power conversion devices 210; wherein each first set of power conversion devices 210 is connected to a first AC terminal; and each first drive unit 131 is connected to a first set of power conversion devices 210.

[0055] Each of the first group of power conversion devices 210 includes three power conversion branches connected to the same first AC terminal. Each first drive unit 131 drives one of the first group of power conversion devices 210 of the IGCT converter 200.

[0056] Specifically, the control module 140 determines the overcurrent level of the first current of each first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of each first AC terminal.

[0057] The control module 140 is used to control the first drive unit corresponding to the first AC terminal with the low first current to drive the IGCT converter 200 according to the temporary blocking wave control strategy when the overcurrent level of the first current at all first AC terminals is not medium or high and there is a first AC terminal with the overcurrent level of the first current is low.

[0058] Specifically, when the overcurrent level of the first current at all first AC terminals is not medium or high and there is a first AC terminal with an overcurrent level of low, the control module 140 controls the first drive unit 131 corresponding to each first AC terminal with an output first current level of low to temporarily block the waveform to control the first group of power conversion devices 210 connected to it to stop operating. When the overcurrent level of the first current drops to level zero, the control module 140 controls the blocked first drive unit 131 to release the waveform to control the first group of power conversion devices 210 connected to it to resume operation.

[0059] The control module 140 is used to control each first drive unit to drive the IGCT converter 200 according to the shutdown control strategy when the overcurrent level of the first current at all first AC terminals is not high and there is an overcurrent level of the first current at the first AC terminals that is medium.

[0060] Specifically, when the overcurrent level of the first current at all first AC terminals is not high and there is an overcurrent level of the first current at the first AC terminals that is medium, the control module 140 controls each first drive unit 131 to permanently block the waveform, so that the first group of power conversion devices 210 connected to each first drive unit 131 stops operating.

[0061] The control module 140 is used to control the first drive unit corresponding to the first AC terminal with the first current of the first AC terminal to drive the IGCT converter 200 according to the current reduction control strategy when the overcurrent level of the first current at the first AC terminal is high.

[0062] Specifically, when the overcurrent level of the first current at the first AC terminal is high, the control module 140 controls the first drive unit 131 corresponding to each first AC terminal with a high output first current level to drive the multi-path power conversion branch of the first group of power conversion devices 210 connected to it to conduct.

[0063] Based on the above embodiments, optionally, Figure 5 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure. Figure 5 As shown, the control module 140 includes at least one first control unit 141;

[0064] Each first comparator 1211, each second comparator 1212, and each third comparator 1213 are connected to a first control unit 141. The first comparator 1211, the second comparator 1212, and the third comparator 1213 of each first comparison unit group 121 are connected to the same first control unit 141. Each first control unit 141 is connected to a first drive unit 131. The first AC terminal connected to the first sampling unit 111, which is connected to the first comparator 1211, the second comparator 1212, and the third comparator 1213 connected to the first drive unit 131 and the first AC terminal corresponding to the first drive unit 131 controlling the IGCT converter 200, is the same. The first control units 141 are interconnected.

[0065] The first control units 141 are interconnected, and the communication connection can be wired or wireless; this disclosure does not impose any specific restrictions on this.

[0066] Specifically, each first control unit 141 determines the overcurrent level of the first current of the first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal and the first high-level overcurrent state signal corresponding to the first current of the first AC terminal.

[0067] When the overcurrent level of the first current at the first AC terminal is medium, each first control unit 141 generates a shutdown control signal and sends the shutdown control signal to the other first control units 141 after a preset time. After receiving or sending the shutdown control signal, it controls the connected first drive unit 131 to drive the IGCT converter 200 according to the shutdown control strategy. When the overcurrent level of the first current at the first AC terminal is low and no shutdown control signal is received after a preset time, each first control unit 141 controls the connected first drive unit 131 to drive the IGCT converter 200 according to the temporary blocking wave control strategy.

[0068] When the overcurrent level of the first current at the first AC terminal is high, each first control unit 141 controls the connected first drive unit 131 to drive the IGCT converter 200 according to the current reduction control strategy.

[0069] The preset time is set according to the time for each first control unit 141 to control the first drive unit 131 connected to drive the IGCT converter 200 according to the current reduction control strategy. The preset time is longer than the time for each first control unit 141 to control the first drive unit 131 connected to drive the IGCT converter 200 according to the current reduction control strategy. Therefore, when there are simultaneously cases where the overcurrent level of the first current at one first AC terminal is medium and the overcurrent level of the first current at another first AC terminal is high, the first control unit 141 corresponding to the high overcurrent level of the first current prioritizes controlling the first drive unit 131 connected to drive the IGCT converter 200 according to the current reduction control strategy. The first control unit 141 corresponding to the medium overcurrent level of the first current broadcasts a shutdown control signal after the preset time, causing each first control unit 141 to control the first drive unit 131 connected to drive the IGCT converter 200 according to the shutdown control strategy. Optionally, based on the above embodiment, Figure 6 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure. Figure 6 As shown, the IGCT converter 200 also includes at least one second AC terminal; the sampling module 110 is connected to each second AC terminal, and the sampling module 110 is used to collect the second current of each second AC terminal;

[0070] The multi-level comparison module 120 is used to generate a second medium-range overcurrent state signal and a second high-range overcurrent state signal according to each second current; the control module 140 is used to adjust the control strategy of the IGCT converter 200 to a shutdown control strategy or a current reduction control strategy according to each first medium-range overcurrent state signal, each first high-range overcurrent state signal, each second medium-range overcurrent state signal and each second high-range overcurrent state signal, and drive the IGCT converter 200 according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter 200.

[0071] in, Figure 6The IGCT converter 200 shown is a multi-grid, multi-machine converter, meaning it has multiple grid-side AC terminals (first AC terminals) and multiple machine-side AC terminals (second AC terminals). Each second AC terminal of the IGCT converter 200 refers to the end where the IGCT converter 200 is connected to the power generation equipment (e.g., a wind turbine). The sampling module 110 can collect the current flowing into or out of the IGCT converter 200 through each second AC terminal. For example, the second current flowing into the IGCT converter 200 from the power generation equipment through each second AC terminal, or the second current flowing into the power generation equipment from each second AC terminal of the IGCT converter 200, so that the specific situation of the current flowing into or out of the IGCT converter 200 can be known in real time through the second current collected through each second AC terminal. The multi-level comparison module 120 can process the current flowing into or out of the IGCT converter 200 through each second AC terminal to output a second medium-range overcurrent state signal and a second high-range overcurrent state signal that can indicate the specific range of the current flowing into or out of the IGCT converter 200 in real time at each second AC terminal.

[0072] The control module 140 can read the second medium-range overcurrent state signal and the second high-range overcurrent state signal generated by the multi-level comparison module 120 according to each second current to determine whether each second current exceeds the current range that the IGCT converter 200 can withstand, and to what extent each second current exceeds the current range that the IGCT converter 200 can withstand. Based on whether each first current and each second current exceed the current range that the IGCT converter 200 can withstand, and to what extent each first current and each second current exceed the current range that the IGCT converter 200 can withstand, different control strategies are adopted to drive the IGCT converter 200.

[0073] If the first current and / or the second current exceed the current-bearing range of the IGCT converter 200, and the number of carriers injected into the power conversion devices (IGCT transistors) of the IGCT converter 200 can be fully extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 can adopt a shutdown control strategy to drive the IGCT converter 200 to stop, in order to prevent further damage to the IGCT converter 200 or cause a safety accident. If the first current and / or the second current exceed the current-bearing range of the IGCT converter 200, causing the number of carriers injected into the power conversion devices of the IGCT converter 200 to be unable to be fully extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 adopts a current-splitting and current-reducing control strategy that can drive the IGCT converter 200 to conduct multiple power conversion branches, in order to reduce the current flowing into each power conversion device of the IGCT converter 200, thereby preventing further damage to the IGCT converter 200 or causing a safety accident. Therefore, in response to the overcurrent anomaly of the IGCT converter 200, the IGCT converter 200 can be driven flexibly, thereby improving the flexibility of the protection of the IGCT converter 200, avoiding damage to the IGCT converter 200 due to rapid shutdown under high current, reducing the workload of IGCT converter 200 maintenance, and improving the robustness of the power generation system.

[0074] Furthermore, when the IGCT converter 200 includes one first AC terminal and one second AC terminal, the IGCT converter 200 can be an ACDC+DCAC type single-network-one-machine converter; when the IGCT converter 200 includes multiple first AC terminals and one second AC terminal, the IGCT converter 200 can be multiple ACDC+DCAC type multi-network-one-machine converters; when the IGCT converter 200 includes one first AC terminal and multiple second AC terminals, the IGCT converter 200 can be an ACDC+multiple DCAC type single-network-multiple-machine converter; when the IGCT converter 200 includes multiple first AC terminals and multiple second AC terminals, the IGCT converter 200 can be multiple ACDC+multiple DCAC type multi-network-multiple-machine converters. The structural diagrams of the aforementioned single-network-one-machine converter, multi-network-one-machine converter, single-network-multiple-machine converter, and multi-network-multiple-machine converter can be obtained from... Figure 6 The number of first and second AC terminals is increased or decreased to obtain the current, which will not be provided in this disclosure. The working principle of the single-network-one-machine converter, multi-network-one-machine converter, single-network-multi-machine converter, and multi-network-multi-machine converter is similar to that of the multi-network-multi-machine converter described above, the only difference being the different numbers of the first and second currents obtained, which will not be elaborated in this disclosure. Based on the above embodiments, optionally, the multi-level comparison module 120 is further used to generate a second low-level overcurrent state signal according to each second current;

[0075] The control module 140 is used to adjust the control strategy of the IGCT converter 200 to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy according to each first low-level overcurrent state signal, each first medium-level overcurrent state signal, each first high-level overcurrent state signal, each second low-level overcurrent state signal, each second medium-level overcurrent state signal, and each second high-level overcurrent state signal. The control module 140 also drives the IGCT converter 200 according to the temporary blocking wave control strategy, the temporary blocking wave control strategy, or the current shunting and current reduction control strategy to protect the IGCT converter 200.

[0076] Among them, the second low-range overcurrent state signal, the second medium-range overcurrent state signal, and the second high-range overcurrent state signal corresponding to each second current are signals that represent the specific range of the second current, that is, signals that can reflect the specific range of the current flowing out or into the second AC terminal of the IGCT converter 200.

[0077] The control module 140 reads the first low-range overcurrent state signal, the first medium-range overcurrent state signal, and the first high-range overcurrent state signal corresponding to each first current, and the second low-range overcurrent state signal, the second medium-range overcurrent state signal, and the second high-range overcurrent state signal corresponding to each second current. It then determines whether each first current and each second current exceeds the current range that the IGCT converter 200 can withstand, and to what extent each first current and each second current exceeds the current that the IGCT converter 200 can withstand. Based on this, it adopts different control strategies to drive the IGCT converter 200.

[0078] Among these, minor overcurrent exceedances are mostly temporary overcurrents caused by external factors such as grid faults or grid voltage fluctuations. Significant overcurrent exceedances are mostly long-term overcurrents caused by factors such as internal damage to the IGCT converter 200. In cases where only the first and / or second currents slightly exceed the IGCT converter 200's current-carrying capacity, the control module 140 can employ a temporary shutdown control strategy that temporarily drives some relevant power conversion devices of the IGCT converter 200 to shut down, allowing the power conversion devices to resume normal operation once the current returns to normal. If the first and / or second currents significantly exceed the IGCT converter 200's current-carrying capacity, and the number of carriers injected into the IGCT converter 200's power conversion devices can be extracted within the time required for rapid shutdown of the IGCT converter 200, the control module 140 can employ a shutdown control strategy that drives the IGCT converter 200 to stop, preventing further damage to the IGCT converter 200 or the occurrence of a safety accident. If the first current and / or the second current exceeds the current that the IGCT converter 200 can withstand by a large margin, and the number of carriers injected into the power conversion devices of the IGCT converter 200 cannot be fully extracted within the time of rapid shutdown of the IGCT converter 200, the control module 140 adopts a current reduction control strategy that can drive the IGCT converter 200 to turn on multiple power conversion devices, so as to reduce the current flowing into each power conversion device of the IGCT converter 200, thereby preventing further damage to the IGCT converter 200 or causing a safety accident. Therefore, the multi-level comparison module 120 and control module 140 of this disclosure realize flexible driving of IGCT converter 200 by judging the degree of overcurrent abnormality of IGCT converter 200 current, thereby improving the flexibility of IGCT converter 200 protection. Through the temporary blocking wave control strategy, the number of IGCT converter 200 shutdowns can be reduced, the maintenance workload of IGCT converter 200 can be reduced, the waste of power generation and power generation resources can be reduced, and the robustness of the power generation system can be improved.

[0079] Based on the above embodiments, optionally, Figure 7 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure. Figure 7 As shown, the IGCT converter protection device also includes a drive module 130; the sampling module 110 further includes at least one second sampling unit 112; the multi-level comparison module 120 includes at least one second comparison unit group 122, each second comparison unit group 122 including a fourth comparator 1221, a fifth comparator 1222 and a sixth comparator 1223; the drive module 130 includes at least one second drive unit 132.

[0080] Each second sampling unit 112 is connected to a second AC terminal. Each fourth comparator 1221, each fifth comparator 1222, and each sixth comparator 1223 are all connected to a second sampling unit 112. The fourth comparator 1221, the fifth comparator 1222, and the sixth comparator 1223 of each second comparison unit group 122 are connected to the same second sampling unit 112. Each fourth comparator 1221, each fifth comparator 1222, each sixth comparator 1223, and each second drive unit 132 are all connected to the control module 140. Each second drive unit 132 is all connected to the IGCT converter 200.

[0081] Each second sampling unit 112 is used to collect the second current of its corresponding connected second AC terminal; each second comparison unit group 122 is used to determine the range of the second current collected by the corresponding connected second sampling unit 112, and outputs a second low-range overcurrent state signal, a second medium-range overcurrent state signal, and a second high-range overcurrent state signal that can indicate the specific range of the second current flowing into or out of the IGCT converter 200. Specifically, each fourth comparator 1221 is used to generate a second low-range overcurrent state signal based on the input second current, each fifth comparator 1222 is used to generate a second medium-range overcurrent state signal based on the input second current, and each sixth comparator 1223 is used to generate a second high-range overcurrent state signal based on the input second current.

[0082] For example, the current threshold defined by the fifth comparator 1222 is greater than the current threshold defined by the fourth comparator 1221, and the current threshold defined by the sixth comparator 1223 is greater than the current threshold defined by the fifth comparator 1222. If the second current does not exceed the current threshold defined by the fourth comparator 1221, it means that the second current does not exceed the acceptable range of the IGCT converter 200; if the second current only exceeds the current threshold defined by the fourth comparator 1221 and does not exceed the current threshold defined by the fifth comparator 1222, it means that the second current exceeds the acceptable range of the IGCT converter 200 by a small margin; if the second current exceeds the current threshold defined by the fifth comparator 1222 but does not exceed the current threshold defined by the sixth comparator 1223, it means that the second current exceeds the acceptable range. The IGCT converter 200 has a large tolerance range, allowing the number of charge carriers injected into the power conversion device of the IGCT converter 200 to be fully extracted within the time of rapid turn-off of the IGCT converter 200. If the second current exceeds the current threshold defined by the sixth comparator 1223, it indicates that the second current exceeds the tolerance range of the IGCT converter 200 by a large margin, resulting in the number of charge carriers injected into the power conversion device of the IGCT converter 200 not being fully extracted within the time of rapid turn-off of the IGCT converter 200. Each second drive unit 132 is used to adjust the second current of a second AC terminal of the device under test.

[0083] The control module 140 is used to determine the overcurrent level of the second current output by each second AC terminal based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal and the second high-level overcurrent state signal corresponding to the second current output by each second AC terminal, and to adopt different control strategies based on the overcurrent level of each second current to control the drive module 130 to drive the IGCT converter 200.

[0084] Specifically, the control module 140 can determine whether each second current exceeds the current capacity of the IGCT converter 200 by reading the second low-level overcurrent status signal, the second medium-level overcurrent status signal, and the second high-level overcurrent status signal corresponding to the second current output from each second AC terminal, and confirm the degree to which each second current exceeds the current capacity of the IGCT converter 200, i.e., confirm the overcurrent level of each second current. Therefore, the control module 140 can adopt different control strategies to control the drive module 130 to drive the IGCT converter 200 based on the overcurrent level of each first current and the overcurrent level of each second current.

[0085] The overcurrent levels of the second current include level zero, low level, medium level, and high level. If the second current does not exceed the current threshold defined by the fourth comparator 1221, the overcurrent level of the second current is level zero. If the second current exceeds the current threshold defined by the fourth comparator 1221 but does not exceed the current threshold defined by the fifth comparator 1222, the overcurrent level of the second current is low level. If the second current exceeds the current threshold defined by the fifth comparator 1222 but does not exceed the current threshold defined by the sixth comparator 1223, the overcurrent level of the second current is medium level. If the second current exceeds the current threshold defined by the sixth comparator 1223, the overcurrent level of the second current is high level.

[0086] The control module 140 adopts different control strategies to control the drive module 130 to drive the device under test 200 based on the overcurrent level of each first current and each second current. The specific process is as follows: The control module 140 determines the overcurrent level of the first current of each first AC terminal according to the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of each first AC terminal; and determines the second current of each second AC terminal according to the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current of each second AC terminal. The overcurrent level; when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high, and the overcurrent level of the first current at the first AC terminal is low, the first drive unit 131 corresponding to the first AC terminal with the low first current is controlled to drive the IGCT converter 200 according to the temporary blocking wave control strategy; when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high, and the overcurrent level of the second current at the second AC terminal is low, the output is controlled according to the temporary blocking wave control strategy. The second drive unit 132 corresponding to the second AC terminal with a low-level second current drives the IGCT converter 200; when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high-level and there is an overcurrent level of the first current at the first AC terminal being medium-level, each first drive unit 131 and each second drive unit 132 drives the IGCT converter 200 according to the shutdown control strategy; when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high-level and there is an overcurrent level of the second current at the second AC terminal being medium-level, each first drive unit 131 and each second drive unit 132 drives the IGCT converter 200 according to the shutdown control strategy; When the overcurrent level is medium, each first drive unit 131 and each second drive unit 132 drive the IGCT converter 200 according to the shutdown control strategy; when the overcurrent level of the first current at the first AC terminal is high, the first drive unit 131 corresponding to the first AC terminal with the high output first current drives the IGCT converter 200 according to the current reduction control strategy; when the overcurrent level of the second current at the second AC terminal is high, the second drive unit 132 corresponding to the second AC terminal with the high output second current drives the IGCT converter 200 according to the current reduction control strategy.

[0087] Based on the above embodiments, alternatively, refer to the following: Figure 2 The IGCT converter 200 also includes at least one second set of power conversion devices 220; wherein each second set of power conversion devices 220 is connected to a second AC terminal; and each second drive unit 132 is connected to a second set of power conversion devices 220.

[0088] Each of the second group of power conversion devices 220 includes three power conversion branches connected to the same second AC terminal. Each second drive unit 132 drives one of the second group of power conversion devices 220 of the IGCT converter 200.

[0089] The control module 140 is configured to temporarily block the first drive unit 131 corresponding to each first AC terminal with a low output first current level when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high and there is a case where the overcurrent level of the first current at the first AC terminal is low. This is to control the first group of power converter devices 210 connected to it to stop operating. When the overcurrent level of the first current drops to level zero, the control module 140 controls the blocked first drive unit 131 to release the wave to control the first group of power converter devices 210 connected to it to resume operation.

[0090] The control module 140 is used to temporarily block the second drive unit 132 corresponding to each second AC terminal with a low output second current level when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high and there is a second AC terminal with a low overcurrent level. This is to control the second group of power conversion devices 220 connected to it to stop operating. When the overcurrent level of the second current drops to level zero, the control module 140 controls the blocked second drive unit 132 to release the wave to control the second group of power conversion devices 220 connected to it to resume operation.

[0091] The control module 140 is used to permanently block the waveform of each first drive unit 131 and each second drive unit 132 when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and the overcurrent level of the first current at the first AC terminals is medium. This causes the first group of power conversion devices 210 controlled by each first drive unit 131 to stop operating and the second group of power conversion devices 220 controlled by each second drive unit 132 to stop operating.

[0092] The control module 140 is used to permanently block the waveform of each first drive unit 131 and each second drive unit 132 when the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and the overcurrent level of the second current at the second AC terminals is medium. This causes the first group of power conversion devices 210 controlled by each first drive unit 131 to stop operating and the second group of power conversion devices 220 controlled by each second drive unit 132 to stop operating.

[0093] The control module 140 is used to control the first drive unit 131 corresponding to the first AC terminal with a high overcurrent level to drive the multi-path power conversion branch of the first group of power conversion devices 210 connected thereto to conduct when the overcurrent level of the first current at the first AC terminal is high.

[0094] The control module 140 is used to control the second drive unit 132 corresponding to each second AC terminal with a high overcurrent level to drive the multi-path power conversion branch of the second group of power conversion devices 220 connected thereto to conduct when the overcurrent level of the second current at the second AC terminal is high.

[0095] Based on the above embodiments, optionally, Figure 8 A schematic diagram of another IGCT converter protection device provided in this embodiment of the present disclosure. Figure 8 As shown, the control module 140 also includes at least one second control unit 142;

[0096] Each fourth comparator 1221, each fifth comparator 1222, and each sixth comparator 1223 is connected to a second control unit 142. The fourth comparator 1221, the fifth comparator 1222, and the sixth comparator 1223 of each second comparison unit group 122 are all connected to the same second control unit 142. Each second control unit 142 is connected to a second drive unit 132. The second AC terminal connected to the second sampling unit 112, which is connected to the second drive unit 132 and the second AC terminal corresponding to the second drive unit 132 controlling the IGCT converter 200, is the same. The second control units 142 are interconnected.

[0097] Each second control unit 142 and each first control unit 141 are interconnected. The communication connections between the first control unit 141 and the second control unit 142, as well as between the second control units 142, can be wired or wireless, and this disclosure does not impose any specific limitations on this.

[0098] Specifically, each first control unit 141 determines the overcurrent level of the first current of the first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal and the first high-level overcurrent state signal corresponding to the first current of the first AC terminal.

[0099] Each second control unit 142 determines the overcurrent level of the second current of a second AC terminal based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current of a second AC terminal.

[0100] When the overcurrent level of the first current at the first AC terminal is medium, each first control unit 141 generates a shutdown control signal and sends the shutdown control signal to the other first control units 141 and second control units 142 after a preset time. After receiving or sending the shutdown control signal, the first control units 141 and second control units 142 control the connected first drive unit 131 or second drive unit 132 to drive the IGCT converter 200 according to the shutdown control strategy. That is, each first drive unit 131 and each second drive unit 132 are permanently blocked, so that each first drive unit 131 controls the corresponding connected first group of power conversion devices 210 to stop running, and each second drive unit 132 controls the corresponding connected second group of power conversion devices 220 to stop running.

[0101] When the overcurrent level of the second current at the second AC terminal is medium, each second control unit 142 generates a shutdown control signal and sends the shutdown control signal to the other first control units 141 and second control units 142 after a preset time. After the first control units 141 and second control units 142 receive or send the shutdown control signal, they control the connected first drive unit 131 or second drive unit 132 to drive the IGCT converter 200 according to the shutdown control strategy. That is, they control each first drive unit 131 and each second drive unit 132 to permanently block the waveform, so that each first drive unit 131 controls the corresponding connected first group of power conversion devices 210 to stop running, and each second drive unit 132 controls the corresponding connected second group of power conversion devices 220 to stop running.

[0102] When the overcurrent level of the first current at the first AC terminal of each first control unit 141 is low and no shutdown control signal is received after a preset time, the first drive unit 131 connected to it is controlled to drive the IGCT converter 200 according to the temporary blocking wave control strategy. That is, the first drive unit 131 corresponding to the first AC terminal with the first output current level of the first level is temporarily blocked to control the first group of power conversion devices 210 connected to it to stop running. When the overcurrent level of the first current drops to the zero level, the first drive unit 131 with the blocked wave is controlled to release the wave to control the first group of power conversion devices 210 connected to it to resume operation.

[0103] When the overcurrent level of the second current at the second AC terminal of each second control unit 142 is low and no shutdown control signal is received after a preset time, the second drive unit 132 connected to it is controlled to drive the IGCT converter 200 according to the temporary blocking wave control strategy. That is, the second drive unit 132 corresponding to each second AC terminal with the output second current level of the first level is temporarily blocked to control the second group of power conversion devices 220 connected to it to stop running. When the overcurrent level of the second current drops to the zero level, the blocked second drive unit 132 is controlled to release the wave to control the second group of power conversion devices 220 connected to it to resume operation.

[0104] When the overcurrent level of the first current at the first AC terminal is high, each first control unit 141 controls the connected first drive unit 131 to drive the IGCT converter 200 according to the current reduction control strategy. That is, it controls the first drive unit 131 corresponding to each first AC terminal with a high output first current level to drive the multi-path power conversion branch of the first group of power conversion devices 210 connected to it to be turned on.

[0105] When the overcurrent level of the second current at the second AC terminal is high, each second control unit 142 controls the connected second drive unit 132 to drive the IGCT converter 200 according to the current reduction control strategy. That is, it controls the second drive unit 132 corresponding to each second AC terminal with a high output second current level to drive the multi-path power conversion branch of the connected second group of power conversion devices 220 to be turned on.

[0106] The preset time is defined as the time during which each first control unit 141 controls the first drive unit 131 connected to drive the IGCT converter 200 according to the current reduction control strategy, and the time during which each second control unit 142 controls the second drive unit 132 connected to drive the IGCT converter 200 according to the current reduction control strategy. The preset time is greater than the time during which each first control unit 141 controls the first drive unit 131 connected to drive the IGCT converter 200 according to the current reduction control strategy, and also greater than the time during which each second control unit 142 controls the second drive unit 132 connected to drive the IGCT converter 200 according to the current reduction control strategy. Therefore, the first control unit 141 or second control unit 142 corresponding to a high overcurrent level preferentially drives the IGCT converter 200 according to the current reduction control strategy, while the first control unit 141 or second control unit 142 corresponding to a medium overcurrent level broadcasts a shutdown control signal after the preset time, causing each first control unit 141 and each second control unit 142 to drive the IGCT converter 200 according to the shutdown control strategy.

[0107] Figure 9This is a flowchart illustrating an IGCT converter protection method provided in an embodiment of this disclosure. The IGCT converter protection method is executed using an IGCT converter protection device provided in any embodiment of this disclosure.

[0108] The IGCT converter protection method includes:

[0109] S110, Collect the first current of each first AC terminal.

[0110] The above steps can be performed by the sampling module.

[0111] S120. Generate a first medium-range overcurrent state signal and a first high-range overcurrent state signal based on each first current.

[0112] The above steps can be performed using a multi-level comparison module.

[0113] S130. Adjust the control strategy of the IGCT converter to a shutdown control strategy or a current reduction control strategy according to each first medium-range overcurrent state signal and each first high-range overcurrent state signal, and drive the IGCT converter according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter.

[0114] The above steps can be executed through the control module.

[0115] This embodiment of the disclosure acquires the first current at each first AC terminal; based on each first current, a first mid-range overcurrent state signal and a first high-range overcurrent state signal can be output to indicate the specific range of each first current. Therefore, by reading the first mid-range overcurrent state signal and the first high-range overcurrent state signal corresponding to each current, the specific situation of each first current can be known. Thus, when the first current exceeds the current that the IGCT converter can withstand, and the number of carriers injected by the power conversion device of the IGCT converter can be extracted within the time of rapid IGCT converter shutdown, a shutdown control strategy can be adopted to drive the IGCT converter; when the first current exceeds the current that the IGCT converter can withstand, and the number of carriers injected by the power conversion device of the IGCT converter cannot be extracted within the time of rapid IGCT converter shutdown, the control module can adopt a current reduction control strategy to drive the IGCT converter to conduct multiple power conversion branches. Therefore, this disclosure allows for flexible driving of the IGCT converter, thereby improving the flexibility of IGCT converter protection, preventing damage to the IGCT converter due to rapid shutdown under high current, reducing the workload of IGCT converter maintenance, and improving the robustness of the power generation system.

[0116] Based on the above embodiments, optionally, the IGCT converter protection method is characterized by further comprising:

[0117] A first low-level overcurrent status signal is generated based on each first current.

[0118] The above steps can be performed using a multi-level comparison module.

[0119] The control strategy for the IGCT converter is adjusted according to each first low-range overcurrent state signal, each first medium-range overcurrent state signal, and each first high-range overcurrent state signal. The control strategy is either a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy. The IGCT converter is then driven according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy to protect the IGCT converter.

[0120] The above steps can be executed through the control module.

[0121] Based on the above embodiments, optionally, the steps of generating a first low-level overcurrent state signal, a first medium-level overcurrent state signal, and a first high-level overcurrent state signal according to each first current are described as follows:

[0122] Each first comparator generates a first low-range overcurrent state signal based on the input first current, each second comparator generates a first medium-range overcurrent state signal based on the input first current, and each third comparator generates a first high-range overcurrent state signal based on the input first current.

[0123] Specifically, the first comparator compares the first current with a first overcurrent threshold and generates a first low-range overcurrent status signal based on the comparison result; the first low-range overcurrent status signal includes a first low-range over-limit signal and a first low-range not-over-limit signal. The second comparator compares the first current with a second overcurrent threshold and generates a first medium-range overcurrent status signal based on the comparison result; the first medium-range overcurrent status signal includes a first medium-range over-limit signal and a first medium-range not-over-limit signal. The third comparator compares the first current with a third overcurrent threshold and generates a first high-range overcurrent status signal based on the comparison result; the first high-range overcurrent status signal includes a first high-range not-over-limit signal and a first high-range not-over-limit signal.

[0124] The comparison process of the first comparator is as follows: if the first current is greater than the first overcurrent threshold, the first low-range overcurrent status signal is the first low-range over-limit signal; if the first current is less than or equal to the first overcurrent threshold, the first low-range overcurrent status signal is the first low-range not over-limit signal.

[0125] The comparison process of the second comparator is as follows: if the first current is greater than the second overcurrent threshold, the first medium-range overcurrent status signal is the first medium-range over-limit signal; if the first current is less than or equal to the second overcurrent threshold, the first medium-range overcurrent status signal is the first medium-range not over-limit signal.

[0126] The comparison process of the third comparator is as follows: if the first current is greater than the third overcurrent threshold, the first high-range overcurrent status signal is the first high-range over-limit signal; if the first current is less than or equal to the third overcurrent threshold, the first high-range overcurrent status signal is the first high-range not over-limit signal.

[0127] It should be noted that the second overcurrent threshold is greater than the first overcurrent threshold, and the third overcurrent threshold is greater than the second overcurrent threshold.

[0128] Based on the above embodiments, optionally, Figure 10 This embodiment of the present disclosure provides a step-by-step flowchart illustrating the steps of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, and each first high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or current shunting and current reduction control strategy. Figure 8 The steps for adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, and each first high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or current shunting and current reduction control strategy are described below:

[0129] S210. Determine the overcurrent level of the first current of each first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of each first AC terminal.

[0130] Specifically, the first low-range overcurrent status signal includes a first low-range over-limit signal and a first low-range not-over-limit signal. The first medium-range overcurrent status signal includes a first medium-range over-limit signal and a first medium-range not-over-limit signal. The first high-range overcurrent status signal includes a first high-range not-over-limit signal and a first high-range over-limit signal.

[0131] If the first low-level overcurrent status signal corresponding to the first current is the first low-level non-over-limit signal, then the overcurrent level of the first current is level zero.

[0132] If the first low-level overcurrent status signal corresponding to the first current is the first low-level over-limit signal and the first medium-level overcurrent status signal is the first medium-level not over-limit signal, then the overcurrent level of the first current is low-level.

[0133] If the first medium-range overcurrent status signal corresponding to the first current is the first medium-range over-limit signal and the first high-range overcurrent status signal is the first high-range not over-limit signal, then the overcurrent level of the first current is medium.

[0134] If the first high-level overcurrent status signal corresponding to the first current is the first high-level over-limit signal, then the overcurrent level of the first current is high-level.

[0135] S220. When the overcurrent level of the first current at all first AC terminals is not medium or high and there is a first current at the first AC terminal with a low overcurrent level, the first drive unit corresponding to the first AC terminal with the low first current is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0136] S230, when the overcurrent level of the first current at all first AC terminals is not high and there is an overcurrent level of the first current at the first AC terminal that is medium, control each first drive unit to drive the IGCT converter according to the shutdown control strategy.

[0137] S240. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit corresponding to the first AC terminal with the high output first current is controlled to drive the IGCT converter according to the current reduction control strategy.

[0138] Based on the above embodiments, optionally, the specific process of controlling the first drive unit corresponding to the first AC terminal of the low-level phase to drive the IGCT converter according to the temporary blocking wave control strategy is as follows:

[0139] The first drive unit corresponding to the first AC terminal with the first current level of each output is temporarily blocked to control the first group of power conversion devices connected to it to stop operating. When the overcurrent level of the first current drops to the zero level, the first drive unit with the blocked wave is released to control the first group of power conversion devices connected to it to resume operation.

[0140] The specific process of controlling each first drive unit to drive the IGCT converter according to the shutdown control strategy is as follows:

[0141] Each first drive unit is permanently blocked, so that the first group of power conversion devices connected to each first drive unit stops operating;

[0142] The specific process of controlling the output first current of the IGCT converter by the first drive unit corresponding to the first AC terminal of the high-level shunt current reduction control strategy is as follows:

[0143] The first drive unit corresponding to the first AC terminal with a high first current level controls the multi-path power conversion branch of the first group of power conversion devices connected to it to be turned on.

[0144] Based on the above embodiments, optionally, Figure 11This is a flowchart illustrating another step in the process of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a shunt current reduction control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, and each first high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or shunt current reduction control strategy, as provided in this embodiment of the disclosure. Figure 11 The steps for adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and current reduction control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, and each first high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or current shunting and current reduction control strategy are described below:

[0145] S310. Determine the overcurrent level of the first current of the first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of the first AC terminal.

[0146] S320: When the overcurrent level of the first current at the first AC terminal is medium, a shutdown control signal is generated and sent to the other first control units after a preset time; after receiving or sending the shutdown control signal, the first drive unit connected to the shutdown control strategy drives the IGCT converter.

[0147] S330 When the overcurrent level of the first current at the first AC terminal is low and no shutdown control signal is received after a preset time, the first drive unit connected to the circuit is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0148] S340 When the overcurrent level of the first current at the first AC terminal is high, the first drive unit connected to the IGCT converter is controlled to drive the converter according to the current reduction control strategy.

[0149] It should be noted that the above steps are executed by each first control unit. The preset time is longer than the time required for the first drive unit connected to the IGCT converter to drive the converter according to the current reduction control strategy.

[0150] Based on the above embodiments, optionally, the IGCT converter further includes at least one second AC terminal; the sampling module is connected to each second AC terminal.

[0151] Figure 12 A flowchart illustrating another IGCT converter protection method provided in this disclosure embodiment is shown below. Figure 12 As shown, the IGCT converter protection method includes:

[0152] S410: Collect the first current of each first AC terminal and the second current of each second AC terminal.

[0153] The above steps can be performed by the sampling module.

[0154] S420: Generate a first medium-range overcurrent state signal and a first high-range overcurrent state signal based on each first current; generate a second medium-range overcurrent state signal and a second high-range overcurrent state signal based on each second current.

[0155] The above steps can be performed using a multi-level comparison module.

[0156] S430: Adjust the control strategy of the IGCT converter to a shutdown control strategy or a current reduction control strategy according to each first intermediate-range overcurrent state signal, each first high-range overcurrent state signal, each second intermediate-range overcurrent state signal and each second high-range overcurrent state signal, and drive the IGCT converter according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter.

[0157] The above steps can be executed through the control module.

[0158] Optionally, based on the above embodiments, the IGCT converter protection method further includes...

[0159] A second low-level overcurrent status signal is generated based on each second current.

[0160] The above steps can be performed using a multi-level comparison module.

[0161] Based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, each first high-range overcurrent state signal, each second low-range overcurrent state signal, each second medium-range overcurrent state signal, and each second high-range overcurrent state signal, the control strategy for the IGCT converter is adjusted to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy. The IGCT converter is then controlled and driven according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy to protect the IGCT converter.

[0162] The above steps can be executed through the control module.

[0163] Based on the above embodiments, optionally, the steps of generating a second low-level overcurrent state signal, a second medium-level overcurrent state signal, and a second high-level overcurrent state signal according to each second current are described as follows:

[0164] Each fourth comparator generates a second low-range overcurrent state signal based on the input second current, each fifth comparator generates a second medium-range overcurrent state signal based on the input second current, and each sixth comparator generates a second high-range overcurrent state signal based on the input second current.

[0165] Specifically, the fourth comparator compares the second current with the first overcurrent threshold and generates a second low-range overcurrent status signal based on the comparison result; the second low-range overcurrent status signal includes a second low-range over-limit signal and a second low-range not-over-limit signal. The fifth comparator compares the second current with the second overcurrent threshold and generates a second medium-range overcurrent status signal based on the comparison result; the second medium-range overcurrent status signal includes a second medium-range over-limit signal and a second medium-range not-over-limit signal. The sixth comparator compares the second current with the third overcurrent threshold and generates a second high-range overcurrent status signal based on the comparison result; the second high-range overcurrent status signal includes a second high-range not-over-limit signal and a second high-range not-over-limit signal.

[0166] The comparison process of the first comparator is as follows: if the second current is greater than the first overcurrent threshold, the second low-range overcurrent status signal is the second low-range over-limit signal; if the second current is less than or equal to the first overcurrent threshold, the second low-range overcurrent status signal is the second low-range not over-limit signal.

[0167] The comparison process of the second comparator is as follows: if the second current is greater than the second overcurrent threshold, the second medium-range overcurrent status signal is the second medium-range over-limit signal; if the second current is less than or equal to the second overcurrent threshold, the second medium-range overcurrent status signal is the second medium-range not over-limit signal.

[0168] The comparison process of the third comparator is as follows: if the second current is greater than the third overcurrent threshold, the second high-range overcurrent status signal is the second high-range over-limit signal; if the second current is less than or equal to the third overcurrent threshold, the second high-range overcurrent status signal is the second high-range not over-limit signal.

[0169] It should be noted that the second overcurrent threshold is greater than the first overcurrent threshold, and the third overcurrent threshold is greater than the second overcurrent threshold.

[0170] Based on the above embodiments, optionally, Figure 13 This is a flowchart illustrating the steps of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a shunt current reduction control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, each first high-range overcurrent state signal, each second low-range overcurrent state signal, each second medium-range overcurrent state signal, and each second high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or shunt current reduction control strategy. Figure 13As shown, the steps for adjusting the control strategy of the IGCT converter according to the first low-range overcurrent state signal, the first medium-range overcurrent state signal, the first high-range overcurrent state signal, the second low-range overcurrent state signal, the second medium-range overcurrent state signal, and the second high-range overcurrent state signal—whether it be a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy—and driving the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy are explained:

[0171] S510. Determine the overcurrent level of the first current of each first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of each first AC terminal.

[0172] S520. Determine the overcurrent level of the second current of each second AC terminal based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current of each second AC terminal.

[0173] Specifically, the second low-range overcurrent status signal includes a second low-range over-limit signal and a second low-range not-over-limit signal. The second medium-range overcurrent status signal includes a second medium-range over-limit signal and a second medium-range not-over-limit signal. The second high-range overcurrent status signal includes a second high-range not-over-limit signal and a second high-range over-limit signal.

[0174] If the overcurrent status signal of the second low gear corresponding to the second current is the second low gear not exceeding limit signal, then the overcurrent level of the second current is level zero.

[0175] If the overcurrent status signal of the second low level corresponding to the second current is the overcurrent signal of the second low level and the overcurrent status signal of the second medium level is the overcurrent signal of the second medium level, then the overcurrent level of the second current is low level.

[0176] If the second medium-range overcurrent status signal corresponding to the second current is the second medium-range over-limit signal and the second high-range overcurrent status signal is the second high-range not over-limit signal, then the overcurrent level of the second current is medium.

[0177] If the second high-level overcurrent status signal corresponding to the second current is the second high-level over-limit signal, then the overcurrent level of the second current is high-level.

[0178] S530 When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are neither medium nor high, and the overcurrent level of the first current at the first AC terminal is low, the first drive unit corresponding to the first AC terminal with the low-level output first current is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0179] S540 When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are neither medium nor high, and the overcurrent level of the second current at the second AC terminal is low, the second drive unit corresponding to the second AC terminal with the low-level output second current is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0180] S550 When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and there is an overcurrent level of the first current at the first AC terminals that is medium, control each first drive unit and each second drive unit to drive the IGCT converter according to the shutdown control strategy.

[0181] S560 When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and there is an overcurrent level of the second current at the second AC terminals that is medium, control each first drive unit and each second drive unit to drive the IGCT converter according to the shutdown control strategy.

[0182] S570. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit corresponding to the first AC terminal with the high output first current is controlled to drive the IGCT converter according to the current reduction control strategy.

[0183] S580: When the overcurrent level of the second current at the second AC terminal is high, the second drive unit corresponding to the second AC terminal with the high output second current is controlled to drive the IGCT converter according to the current reduction control strategy.

[0184] Based on the above embodiments, optionally, the IGCT converter further includes at least one second set of power conversion devices; wherein each second set of power conversion devices is connected to a second AC terminal; and each second drive unit is connected to a second set of power conversion devices.

[0185] The specific process of controlling the first drive unit corresponding to the first AC terminal of the low-level stage to drive the IGCT converter according to the temporary blocking wave control strategy is as follows:

[0186] The first drive unit corresponding to the first AC terminal with the first current level of each output is temporarily blocked to control the first group of power conversion devices connected to it to stop operating. When the overcurrent level of the first current drops to the zero level, the first drive unit with the blocked wave is released to control the first group of power conversion devices connected to it to resume operation.

[0187] The specific process of driving the IGCT converter by the second drive unit corresponding to the second AC terminal of the lower stage, according to the temporary blocking wave control strategy, is as follows:

[0188] The second drive unit corresponding to the second AC terminal with the second current level of each output is temporarily blocked to control the second group of power conversion devices connected to it to stop operating. When the overcurrent level of the second current drops to the zero level, the blocked second drive unit releases the wave to control the second group of power conversion devices connected to it to resume operation.

[0189] The specific process of controlling each first drive unit and each second drive unit to drive the IGCT converter according to the shutdown control strategy is as follows:

[0190] Each first drive unit and each second drive unit are permanently blocked, so that the first group of power conversion devices connected to each first drive unit stops operating, and the second group of power conversion devices connected to each second drive unit stops operating.

[0191] The specific process of controlling the output first current of the IGCT converter by the first drive unit corresponding to the first AC terminal of the high-level shunt current reduction control strategy is as follows:

[0192] The first drive unit corresponding to the first AC terminal with a high first current level controls the multi-path power conversion branch of the first group of power conversion devices connected to it to be turned on.

[0193] The specific process of controlling the output second current of the IGCT converter by the second drive unit corresponding to the advanced second AC terminal according to the current reduction control strategy is as follows:

[0194] The second drive unit corresponding to the second AC terminal of each output second current level (high) drives the multi-path power conversion branch of the second group of power conversion devices connected to it to conduct.

[0195] Based on the above embodiments, optionally, Figure 14 This embodiment of the present disclosure provides another step of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a shunt current reduction control strategy based on each first low-grade overcurrent state signal, each first medium-grade overcurrent state signal, each first high-grade overcurrent state signal, each second low-grade overcurrent state signal, each second medium-grade overcurrent state signal, and each second high-grade overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or shunt current reduction control strategy. (See flowchart below.) Figure 14The following describes the steps for adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, a shutdown control strategy, or a current shunting and reducing control strategy based on each first low-range overcurrent state signal, each first medium-range overcurrent state signal, each first high-range overcurrent state signal, each second low-range overcurrent state signal, each second medium-range overcurrent state signal, and each second high-range overcurrent state signal, and driving the IGCT converter according to the temporary blocking wave control strategy, shutdown control strategy, or current shunting and reducing control strategy:

[0196] S610. Determine the overcurrent level of the first current of the first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current of the first AC terminal.

[0197] S620. Determine the overcurrent level of the second current of the second AC terminal based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current of the second AC terminal.

[0198] S630 When the overcurrent level of the first current at the first AC terminal is medium, a shutdown control signal is generated, and after a preset time, the shutdown control signal is sent to the remaining first control unit and second control unit; after receiving or sending the shutdown control signal, the connected first drive unit or second drive unit is controlled to drive the IGCT converter according to the shutdown control strategy.

[0199] S640 When the overcurrent level of the second current at the second AC terminal is medium, a shutdown control signal is generated, and after a preset time, the shutdown control signal is sent to the remaining first control unit and second control unit; after receiving or sending the shutdown control signal, the connected first drive unit or second drive unit is controlled to drive the IGCT converter according to the shutdown control strategy.

[0200] S650 When the overcurrent level of the first current at the first AC terminal is low and no shutdown control signal is received after a preset time, the first drive unit connected to the circuit is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0201] S660 When the overcurrent level of the second current at the second AC terminal is low and no shutdown control signal is received after a preset time, the second drive unit connected to the circuit is controlled to drive the IGCT converter according to the temporary blocking wave control strategy.

[0202] S670 When the overcurrent level of the first current at the first AC terminal is high, the first drive unit connected to the IGCT converter is controlled to drive the converter according to the current reduction control strategy.

[0203] S680 When the overcurrent level of the second current at the second AC terminal is high, the second drive unit connected to the IGCT converter is controlled to drive the converter according to the current reduction control strategy.

[0204] It should be noted that the above steps can be performed by each first control unit and each second control unit.

[0205] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this disclosure can be achieved, and this is not limited herein.

[0206] The specific embodiments described above do not constitute a limitation on the scope of protection of this disclosure. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A protection device for an IGCT converter, characterized in that, It includes a sampling module, a multi-level comparison module, and a control module; The IGCT converter includes at least one first AC terminal; the sampling module is connected to each of the first AC terminals, and the sampling module is used to collect the first current of each of the first AC terminals. The sampling module is connected to the multi-level comparison module, and the multi-level comparison module is used to generate a first medium-range overcurrent state signal and a first high-range overcurrent state signal according to each of the first currents. Both the multi-level comparison module and the IGCT converter are connected to the control module; the control module is used to adjust the control strategy of the IGCT converter to a shutdown control strategy or a current shunting and reduction control strategy according to each of the first medium-range overcurrent state signals and each of the first high-range overcurrent state signals, and drive the IGCT converter according to the shutdown control strategy or the current shunting and reduction control strategy to protect the IGCT converter; The multi-level comparison module is implemented using at least one of hardware circuits and / or software methods.

2. The IGCT converter protection device according to claim 1, characterized in that, The multi-level comparison module is also used to generate a first low-level overcurrent state signal according to each of the first currents. The control module is used to adjust the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy according to each of the first low-range overcurrent state signals, each of the first medium-range overcurrent state signals, and each of the first high-range overcurrent state signals, and to drive the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy to protect the IGCT converter.

3. The IGCT converter protection device according to claim 2, characterized in that, It also includes a driver module; The sampling module includes at least one first sampling unit; the multi-level comparison module includes at least one first comparison unit group, each first comparison unit group including a first comparator, a second comparator, and a third comparator; the driving module includes at least one first driving unit. Each of the first sampling units is connected to a first AC terminal, and each of the first comparators, each of the second comparators, and each of the third comparators is connected to a first sampling unit. The first comparators, the second comparators, and the third comparators of each of the first comparison unit groups are connected to the same first sampling unit. Each of the first comparators, each of the second comparators, each of the third comparators, and each of the first drive units are connected to the control module, and each of the first drive units is connected to the IGCT converter.

4. The IGCT converter protection device according to claim 3, characterized in that, The IGCT converter further includes at least one first group of power conversion devices; wherein each of the first group of power conversion devices is connected to a first AC terminal; Each of the first drive units is connected to one of the first group of power conversion devices; The control module is used to determine the overcurrent level of the first current of each first AC terminal based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal and the first high-level overcurrent state signal corresponding to the first current of each first AC terminal. The control module is used to control the first drive unit corresponding to the first AC terminal with the low first current to drive the IGCT converter according to the temporary blocking wave control strategy when the overcurrent level of the first current at all the first AC terminals is not medium or high and there is a first AC terminal with the low overcurrent level. The control module is used to control each first drive unit to drive the IGCT converter according to the shutdown control strategy when the overcurrent level of the first current at all first AC terminals is not high and there is an overcurrent level of the first current at the first AC terminal that is medium. The control module is used to control the first drive unit corresponding to the first AC terminal with the first current of the first AC terminal being of the high level to drive the IGCT converter according to the current reduction control strategy.

5. The IGCT converter protection device according to claim 4, characterized in that, The control module includes at least one first control unit; Each of the first comparators, each of the second comparators, and each of the third comparators is connected to a first control unit. The first comparators, the second comparators, and the third comparators of each first comparison unit group are connected to the same first control unit. Each first control unit is connected to a first drive unit. The first AC terminal connected to the first sampling unit of the first comparator, the second comparator, and the third comparator connected to the first drive unit and the first AC terminal corresponding to the first drive unit controlling the IGCT converter are the same. The first control units are interconnected.

6. The IGCT converter protection device according to any one of claims 2-5, characterized in that, The IGCT converter further includes at least one second AC terminal; the sampling module is connected to each second AC terminal, and the sampling module is used to collect the second current of each second AC terminal; The multi-level comparison module is used to generate a second medium-range overcurrent state signal and a second high-range overcurrent state signal according to each of the second currents. The control module is used to adjust the control strategy of the IGCT converter to a shutdown control strategy or a current shunting and reduction control strategy according to each of the first medium-range overcurrent state signal, each of the first high-range overcurrent state signal, each of the second medium-range overcurrent state signal and each of the second high-range overcurrent state signal, and drive the IGCT converter according to the shutdown control strategy or the current shunting and reduction control strategy to protect the IGCT converter.

7. The IGCT converter protection device according to claim 6, characterized in that, The multi-level comparison module is also used to generate a second low-level overcurrent state signal according to each of the second currents; The control module is used to adjust the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reduction control strategy according to each of the first low-grade overcurrent state signal, each of the first medium-grade overcurrent state signal, each of the first high-grade overcurrent state signal, each of the second low-grade overcurrent state signal, each of the second medium-grade overcurrent state signal, and each of the second high-grade overcurrent state signal. The module also drives the IGCT converter according to the temporary blocking wave control strategy, the temporary blocking wave control strategy, or the current shunting and reduction control strategy to protect the IGCT converter.

8. The IGCT converter protection device according to claim 7, characterized in that, It also includes a driving module; the sampling module includes at least one second sampling unit; the multi-level comparison module includes at least one second comparison unit group, each second comparison unit group including a fourth comparator, a fifth comparator, and a sixth comparator; the driving module includes at least one second driving unit; Each of the second sampling units is connected to a second AC terminal, and each of the fourth comparators, the fifth comparators, and the sixth comparators are all connected to a second sampling unit. The fourth comparators, the fifth comparators, and the sixth comparators of each group of second comparison units are connected to the same second sampling unit. Each of the fourth comparators, each of the fifth comparators, each of the sixth comparators, and each of the second drive units are connected to the control module, and each of the second drive units is connected to the IGCT converter.

9. The IGCT converter protection device according to claim 8, characterized in that, The IGCT converter further includes at least one second set of power conversion devices; wherein each of the second set of power conversion devices is connected to a second AC terminal; Each of the second drive units is connected to a second set of power conversion devices.

10. The IGCT converter protection device according to claim 9, characterized in that, The control module includes at least one second control unit; Each of the fourth, fifth, and sixth comparators is connected to a second control unit. The fourth, fifth, and sixth comparators of each second comparison unit group are all connected to the same second control unit. Each second control unit is connected to a second drive unit. The second AC terminal connected to the second sampling unit of the fourth, fifth, and sixth comparators connected to the second drive unit and the second AC terminal corresponding to the second drive unit controlling the IGCT converter are the same. The second control units are interconnected.

11. A protection method for an IGCT converter, characterized in that, include: Collect the first current at each first AC terminal; A first medium-range overcurrent state signal and a first high-range overcurrent state signal are generated based on each of the first currents; The control strategy for the IGCT converter is adjusted to either a shutdown control strategy or a current shunting and reduction control strategy based on each of the first intermediate-range overcurrent state signals and each of the first high-range overcurrent state signals, and the IGCT converter is driven according to the shutdown control strategy or the current shunting and reduction control strategy to protect the IGCT converter.

12. The IGCT converter protection method according to claim 11, characterized in that, Also includes: A first low-level overcurrent state signal is generated based on each of the first currents; The control strategy for the IGCT converter is adjusted to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reduction control strategy based on each of the first low-range overcurrent state signals, each of the first medium-range overcurrent state signals, and each of the first high-range overcurrent state signals. The IGCT converter is then driven according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reduction control strategy to protect the IGCT converter.

13. The IGCT converter protection method according to claim 12, characterized in that, The step of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy based on each of the first low-grade overcurrent state signals, each of the first medium-grade overcurrent state signals, and each of the first high-grade overcurrent state signals, and driving the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy, includes: The overcurrent level of the first current at each first AC terminal is determined based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current at each first AC terminal. When the overcurrent level of the first current at all the first AC terminals is not medium or high and there is a first current at the first AC terminal with a low overcurrent level, the first drive unit corresponding to the first AC terminal with the low first current is controlled to drive the IGCT converter according to the temporary blocking wave control strategy. When the overcurrent level of the first current at all first AC terminals is not high and there is an overcurrent level of the first current at the first AC terminal that is medium, each first drive unit is controlled to drive the IGCT converter according to the shutdown control strategy. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit corresponding to the first AC terminal with the high-level first current output is controlled to drive the IGCT converter according to the current reduction control strategy.

14. The IGCT converter protection method according to claim 13, characterized in that, The step of controlling the first drive unit corresponding to the first AC terminal with the first current output as low-level according to the temporary blocking wave control strategy to drive the IGCT converter includes: The first drive unit corresponding to the first AC terminal with the first current level of the first output is temporarily blocked to control the first group of power conversion devices connected to it to stop operating. When the overcurrent level of the first current drops to the zero level, the blocked first drive unit is controlled to release the wave to control the first group of power conversion devices connected to it to resume operation. The step of controlling each of the first drive units to drive the IGCT converter according to the shutdown control strategy includes: Each of the first drive units is permanently blocked, causing the first group of power conversion devices connected to each of the first drive units to stop operating. The step of controlling the first drive unit corresponding to the first AC terminal with the first high current output according to the current reduction control strategy to drive the IGCT converter includes: The first drive unit corresponding to the first AC terminal with the first current level of high output is controlled to drive the multi-path power conversion branch of the first group of power conversion devices connected thereto to conduct.

15. The IGCT converter protection method according to claim 14, characterized in that, The step of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy based on each of the first low-grade overcurrent state signals, each of the first medium-grade overcurrent state signals, and each of the first high-grade overcurrent state signals, and driving the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and current reduction control strategy, includes: The overcurrent level of the first current at the first AC terminal is determined based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current at the first AC terminal. When the overcurrent level of the first current at the first AC terminal is medium, a shutdown control signal is generated, and the shutdown control signal is sent to the other first control units after a preset time; after receiving or sending the shutdown control signal, the first drive unit connected to the control unit drives the IGCT converter according to the shutdown control strategy. When the overcurrent level of the first current at the first AC terminal is low and no shutdown control signal is received after the preset time, the first drive unit connected to the control according to the temporary blocking wave control strategy drives the IGCT converter. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit connected to the control according to the current reduction control strategy drives the IGCT converter.

16. The IGCT converter protection method according to claim 15, characterized in that, The IGCT converter protection method includes: Collect the first current at each of the first AC terminals and the second current at each of the second AC terminals; A first medium-range overcurrent state signal and a first high-range overcurrent state signal are generated based on each of the first currents, and a second medium-range overcurrent state signal and a second high-range overcurrent state signal are generated based on each of the second currents. The control strategy for the IGCT converter is adjusted to either a shutdown control strategy or a current reduction control strategy based on each of the first intermediate-range overcurrent state signals, each of the first high-range overcurrent state signals, each of the second intermediate-range overcurrent state signals, and each of the second high-range overcurrent state signals. The IGCT converter is then driven according to the shutdown control strategy or the current reduction control strategy to protect the IGCT converter.

17. The IGCT converter protection method according to claim 16, characterized in that, Also includes A second low-level overcurrent status signal is generated based on each of the second currents; Based on each of the first low-range overcurrent state signal, each of the first medium-range overcurrent state signal, each of the first high-range overcurrent state signal, each of the second low-range overcurrent state signal, each of the second medium-range overcurrent state signal, and each of the second high-range overcurrent state signal, the control strategy for the IGCT converter is adjusted to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy, and the IGCT converter is driven according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy to protect the IGCT converter.

18. The IGCT converter protection method according to claim 17, characterized in that, The step of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy based on each of the first low-grade overcurrent state signals, each of the first medium-grade overcurrent state signals, each of the first high-grade overcurrent state signals, each of the second low-grade overcurrent state signals, each of the second medium-grade overcurrent state signals, and each of the second high-grade overcurrent state signals, and driving the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy, includes: The overcurrent level of the first current at each first AC terminal is determined based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current at each first AC terminal. The overcurrent level of the second current at each second AC terminal is determined based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current at each second AC terminal. When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high, and there is a case where the overcurrent level of the first current at the first AC terminal is low, the first drive unit corresponding to the first AC terminal with the low first current output is controlled to drive the IGCT converter according to the temporary blocking wave control strategy. When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not medium or high, and there is a second current at the second AC terminal with a low overcurrent level, the second drive unit corresponding to the second AC terminal with the low-level output second current is controlled to drive the IGCT converter according to the temporary blocking wave control strategy. When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and there is an overcurrent level of the first current at the first AC terminals that is medium, the IGCT converter is driven by each first drive unit and each second drive unit according to the shutdown control strategy. When the overcurrent level of the first current at all first AC terminals and the overcurrent level of the second current at all second AC terminals are not high and there is a second current at the second AC terminal with a medium overcurrent level, the IGCT converter is driven by each first drive unit and each second drive unit according to the shutdown control strategy. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit corresponding to the first AC terminal with the high-level output first current is controlled to drive the IGCT converter according to the current reduction control strategy. When the overcurrent level of the second current at the second AC terminal is high, the second drive unit corresponding to the second AC terminal with the high-level output second current is controlled to drive the IGCT converter according to the current reduction control strategy.

19. The IGCT converter protection method according to claim 18, characterized in that, The step of controlling the first drive unit corresponding to the first AC terminal with the first current output as low-level according to the temporary blocking wave control strategy to drive the IGCT converter includes: The first drive unit corresponding to the first AC terminal with the first current level of the first output is temporarily blocked to control the first group of power conversion devices connected to it to stop operating. When the overcurrent level of the first current drops to the zero level, the blocked first drive unit is controlled to release the wave to control the first group of power conversion devices connected to it to resume operation. The step of controlling the second drive unit corresponding to the second AC terminal, which outputs the second current at a low level according to the temporary blocking wave control strategy, to drive the IGCT converter includes: The second drive unit corresponding to the second AC terminal with the second current level of the second output is temporarily blocked to control the second group of power conversion devices connected to it to stop operating. When the overcurrent level of the second current drops to the zero level, the blocked second drive unit is released to control the second group of power conversion devices connected to it to resume operation. The step of controlling each of the first drive unit and each of the second drive units to drive the IGCT converter according to the shutdown control strategy includes: Each of the first drive units and each of the second drive units is permanently blocked, so that the first group of power conversion devices connected to each of the first drive units stops operating, and the second group of power conversion devices connected to each of the second drive units stops operating. The step of controlling the first drive unit corresponding to the first AC terminal with the first high current output according to the current reduction control strategy to drive the IGCT converter includes: Control the first drive unit corresponding to the first AC terminal with the first current level of high output to drive the multi-path power conversion branch of the first group of power conversion devices connected to it to conduct. The step of controlling the second drive unit corresponding to the second AC terminal with the high-level output current according to the current reduction control strategy to drive the IGCT converter includes: The second drive unit corresponding to the second AC terminal with the second current level of high is controlled to drive the multi-path power conversion branch of the second group of power conversion devices connected to it to conduct.

20. The IGCT converter protection method according to claim 19, characterized in that, The step of adjusting the control strategy of the IGCT converter to a temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy based on each of the first low-grade overcurrent state signals, each of the first medium-grade overcurrent state signals, each of the first high-grade overcurrent state signals, each of the second low-grade overcurrent state signals, each of the second medium-grade overcurrent state signals, and each of the second high-grade overcurrent state signals, and driving the IGCT converter according to the temporary blocking wave control strategy, the shutdown control strategy, or the current shunting and reducing control strategy, includes: The overcurrent level of the first current at the first AC terminal is determined based on the first low-level overcurrent state signal, the first medium-level overcurrent state signal, and the first high-level overcurrent state signal corresponding to the first current at the first AC terminal. The overcurrent level of the second current at the second AC terminal is determined based on the second low-level overcurrent state signal, the second medium-level overcurrent state signal, and the second high-level overcurrent state signal corresponding to the second current at the second AC terminal. When the overcurrent level of the first current at the first AC terminal is medium, a shutdown control signal is generated, and after a preset time, the shutdown control signal is sent to the remaining first control unit and second control unit; after receiving or sending the shutdown control signal, the connected first drive unit or second drive unit is controlled to drive the IGCT converter according to the shutdown control strategy. When the overcurrent level of the second current at the second AC terminal is medium, a shutdown control signal is generated, and after a preset time, the shutdown control signal is sent to the remaining first control unit and second control unit; after receiving or sending the shutdown control signal, the connected first drive unit or second drive unit is controlled to drive the IGCT converter according to the shutdown control strategy; When the overcurrent level of the first current at the first AC terminal is low and no shutdown control signal is received after the preset time, the first drive unit connected to the control according to the temporary blocking wave control strategy drives the IGCT converter. When the overcurrent level of the second current at the second AC terminal is low and no shutdown control signal is received after the preset time, the second drive unit connected to the control according to the temporary blocking wave control strategy drives the IGCT converter. When the overcurrent level of the first current at the first AC terminal is high, the first drive unit connected to the IGCT converter is controlled to drive the IGCT converter according to the current reduction control strategy. When the overcurrent level of the second current at the second AC terminal is high, the second drive unit connected to the control system drives the IGCT converter according to the current reduction control strategy.

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