Overcurrent protection device, method and power electronic conversion device

Abstract

The embodiment of the present disclosure discloses a kind of overcurrent protection device, method and power electronic conversion device.The device includes sampling module, comparison module and control module;Sampling module is used to collect the first current of each first alternating current end;Comparison module is used to generate first overcurrent state signal and second overcurrent state signal according to each first current;Control module is used to adjust the control strategy of target equipment to temporary sealing wave control strategy or shutdown control strategy according to each first overcurrent state signal and each second overcurrent state signal, and drives target equipment according to temporary sealing wave control strategy or shutdown control strategy, to protect target equipment.The present disclosure can improve the flexibility of converter power electronic conversion device protection, reduce the number of substation power electronic conversion device flow machine shutdown, reduce the workload of substation power electronic conversion device maintenance, reduce the waste of power generation and power generation resources, improve the robustness of power generation system.

Description

Technical Field

[0001] This disclosure relates to the field of power electronic conversion device protection technology, and in particular to an overcurrent protection device, method and power electronic conversion device. Background Technology

[0002] Currently, power conversion is carried out using power electronic conversion devices such as inverters and converters. When a large current overcurrent fault occurs in an inverter or converter, a large amount of heat will be generated, which can easily cause safety risks. Therefore, overcurrent protection is required.

[0003] However, in the relevant technologies, overcurrent protection can easily cause unnecessary shutdowns of power electronic conversion devices, reducing the robustness of the system in which they are located (such as power generation systems, electrical equipment, etc.), and manual restart is required after shutdown, increasing manual maintenance costs. Summary of the Invention

[0004] This disclosure provides an overcurrent protection device, method, and power electronic conversion device to improve the flexibility of power electronic conversion device protection, reduce the number of power electronic conversion device shutdowns, reduce the workload of power electronic conversion device maintenance, and improve the robustness of the power generation system.

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

[0006] The target device 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 comparison module. The comparison module is used to generate a first overcurrent state signal and a second overcurrent state signal according to each first current.

[0008] The comparison module is connected to the control module, and the control module is connected to the target device. The control module is used to adjust the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy according to each first overcurrent state signal and each second overcurrent state signal, and drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

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

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

[0011] Collect the first current at each first AC terminal of the target device; generate a first overcurrent state signal and a second overcurrent state signal based on each first current.

[0012] The control strategy for the target device is adjusted to either a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and the target device is driven according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

[0013] Thirdly, embodiments of this disclosure also provide a power electronic conversion device, which includes the overcurrent protection device provided in any embodiment of this disclosure.

[0014] This embodiment of the present disclosure acquires the first current at each of the first AC terminals through a sampling module; the comparison module can output a first overcurrent state signal and a second overcurrent state signal that indicate the specific range of each first current based on each first current. The control module can obtain the specific situation of each first current by reading the first and second overcurrent state signals corresponding to each current, and then adopt an appropriate temporary blocking wave control strategy or shutdown control strategy to control the drive module to drive the target device based on the specific situation of each first current. Thus, this disclosure flexibly drives the target device by judging the degree of overcurrent abnormality of the target device current, thereby improving the flexibility of target device protection, reducing the number of target device shutdowns, reducing the workload of target device maintenance, reducing the waste of power generation and power generation resources, 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 an overcurrent protection device provided in an embodiment of the present disclosure;

[0017] Figure 2 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of a target device provided in an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0022] Figure 7 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention;

[0023] Figure 8 A flowchart illustrating an overcurrent protection method provided in an embodiment of the present invention;

[0024] Figure 9 This is a flowchart illustrating the steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, as provided in an embodiment of the present invention.

[0025] Figure 10 A flowchart illustrating another step provided in this embodiment of the invention: adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy.

[0026] Figure 11 A schematic flowchart of another overcurrent protection method provided in an embodiment of the present invention;

[0027] Figure 12 This is a flowchart illustrating the steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, as provided in an embodiment of this disclosure.

[0028] Figure 13 This is a flowchart illustrating another step in the present disclosure to adjust the control strategy of the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and to drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] Currently, overcurrent protection for power electronic converters primarily relies on setting an overcurrent protection threshold to assess the current flowing through the converter. If the current exceeds this threshold, the converter shuts down, protecting the power conversion module from prolonged overcurrent and preventing malfunctions or safety incidents. However, this protection method is susceptible to frequent shutdowns due to short-term or transient overcurrents caused by various external factors, resulting in low robustness of the entire power generation system. Furthermore, manual restarting is required after each shutdown, leading to a significant maintenance workload.

[0032] To address the above problems, embodiments of the present invention provide an overcurrent protection device. Figure 1 This is a schematic diagram of an overcurrent protection device provided in an embodiment of this disclosure. Figure 1 As shown, the overcurrent protection device includes a sampling module 110, a comparison module 120, and a control module 140;

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

[0034] The sampling module 110 is connected to the comparison module 120. The comparison module 120 is used to generate a first overcurrent state signal and a second overcurrent state signal according to each first current.

[0035] The comparison module 120 is connected to the control module 140, and the control module 140 is connected to the target device 200. The control module 140 is used to adjust the control strategy of the target device 200 to a temporary blocking wave control strategy or a shutdown control strategy according to each first overcurrent state signal and each second overcurrent state signal, and drive the target device 200 according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device 200.

[0036] The comparison module 120 is implemented using at least one of hardware circuits and / or software methods. Specifically, the target device 200 includes an inverter or converter, and each first AC terminal of the target device 200 refers to the AC terminal where the target device 200 is connected to the power grid. The shutdown control strategy is a control strategy that controls the target device 200 to stop operating, that is, controls all power conversion devices of the target device 200 to be completely turned off. The temporary shutdown control strategy refers to a control strategy that temporarily turns off the power conversion devices of the target device 200 that need to be turned on, and can turn them back on at any time.

[0037] The sampling module 110 can collect the current flowing into or out of the target device 200 through each first AC terminal, such as the first current flowing into the target device 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 target device 200, so that the specific situation of the current flowing into or out of the target device 200 can be known in real time through the first current collected through each first AC terminal. The comparison module 120 can process the current flowing into or out of the target device 200 through each first AC terminal to output a first overcurrent state signal and a second overcurrent state signal that can indicate the specific range of the current flowing into or out of the target device 200 through each first AC terminal in real time.

[0038] The control module 140 can read the first overcurrent state signal and the second overcurrent state signal generated by the comparison module 120 for each first current. By reading the first overcurrent state signal and the second overcurrent state signal for each first current, the control module 140 can determine whether each first current exceeds the current tolerance range of the target device 200, and the degree to which each first current exceeds the current tolerance range of the target device 200. Based on whether each first current exceeds the current tolerance range of the target device 200 and the degree to which each first current exceeds the current tolerance range of the target device 200, different control strategies are adopted to drive the target device 200. Among them, the case where the first current exceeds the current tolerance range of the target device 200 by a small degree is mostly caused by external factors such as power grid faults or power grid voltage fluctuations, resulting in temporary overcurrent in some transistors inside the target device 200; the case where the first current exceeds the current tolerance range of the target device 200 by a large degree is mostly caused by factors such as damage to internal components of the target device 200, resulting in long-term overcurrent in some transistors inside the target device 200. Therefore, if there is a small current exceeding the current withstand capability of the target device 200 and no significant first current exceeding the current withstand capability of the target device 200, the control module 140 will drive the target device 200 according to the temporary blocking wave control strategy. The temporary blocking wave control strategy is a control strategy that can temporarily drive the relevant transistors of the target device 200 to shut down due to overcurrent, and drive the transistors to operate normally when the first current flowing through the relevant transistors of the target device 200 is less than the current withstand capability of the target device 200. If there is a significant first current exceeding the current withstand capability of the target device 200, the control module 140 will drive the target device 200 according to the shutdown control strategy. The shutdown control strategy is a control strategy that can drive the target device 200 to shut down. Therefore, in response to the overcurrent anomaly of the target device 200, the target device 200 can be driven flexibly, thereby improving the flexibility of the protection of the target device 200, reducing the number of times the target device 200 is shut down, reducing the maintenance workload of the target device 200, reducing the waste of power generation and power generation resources in the power generation system, and improving the robustness of the power generation system.

[0039] In addition, when the target device 200 includes a first AC terminal, the target device 200 can be an inverter including a DCAC structure or a converter including an ACAC structure; when the IGCT converter 200 includes multiple first AC terminals, the target device 200 can be an inverter including multiple DCAC structures or a converter including multiple ACAC structures.

[0040] As described above, in this embodiment, the sampling module 110 collects the first current at each first AC terminal; the comparison module 120 outputs a first overcurrent state signal and a second overcurrent state signal that indicate the specific range of each first current. The control module 140 can obtain the specific situation of each first current by reading the first and second overcurrent state signals corresponding to each current, and thus adopt an appropriate temporary blocking wave control strategy or shutdown control strategy to drive the target device 200 according to the specific situation of each first current. Therefore, this disclosure flexibly drives the target device 200 by judging the degree of overcurrent abnormality of the target device 200, thereby improving the flexibility of protection of the target device 200, reducing the number of times the target device 200 is shut down, reducing the workload of maintenance of the target device 200, reducing the waste of power generation and power generation resources, and improving the robustness of the power generation system.

[0041] Based on the above embodiments, optionally, Figure 2 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the sampling module 110 includes at least one first sampling unit 111; the comparison module 120 includes at least one first comparison unit group 121, each first comparison unit group 121 including a first comparator 1211 and a second comparator 1212; the driving module 130 includes at least one first driving unit 131.

[0042] Each first sampling unit 111 is connected to a first AC terminal, each first comparator 1211 and each second comparator 1212 are connected to a first sampling unit 111, and the first comparator 1211 and the second comparator 1212 of each first comparison unit group are connected to the same first sampling unit 111; each first comparator 1211, each second comparator 1212 and each first drive unit 131 are connected to the control module 140, and each first drive unit 131 is connected to the target device 200.

[0043] Each first sampling unit 111 is used to collect the first current of its corresponding connected first AC terminal; each first comparison unit group is used to determine the range of the first current collected by the corresponding connected first sampling unit 111, and outputs a first overcurrent state signal and a second overcurrent state signal that can indicate the specific range of the first current flowing into or out of the target device 200. Specifically, each first comparator 1211 is used to generate a first overcurrent state signal according to the input first current, and each second comparator 1212 is used to generate a second overcurrent state signal according to the input first current. For example, the current threshold defined by the second comparator 1212 is greater than the current threshold defined by the first comparator 1211. 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 tolerable range of the target device 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 tolerable range of the target device 200 by a small amount; if the first current exceeds the current threshold defined by the second comparator 1212, it indicates that the first current exceeds the tolerable range of the target device 200 by a large amount. Each first drive unit 131 is used to adjust the first current of a first AC terminal of the target device 200 accordingly.

[0044] 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 overcurrent state signal and the second overcurrent state signal corresponding to the first current output by each first AC terminal, and to adopt different control strategies to drive the target device 200 based on the overcurrent level of each first current.

[0045] The control module 140 can determine whether each first current exceeds the current that the target device 200 can withstand by reading the first overcurrent state signal and the second 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 target device 200 can withstand, that is, confirm the overcurrent level of each first current. Therefore, the control module 140 can adopt different control strategies to drive the target device 200 based on the overcurrent level of each first current.

[0046] The overcurrent level of the first current includes level zero, level one, and level two. 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 level one. If the first current exceeds the current threshold defined by the second comparator 1212, the overcurrent level of the first current is level two.

[0047] The specific process of the control module 140 driving the target device 200 by adopting different control strategies based on the overcurrent level of each first current is as follows: when the overcurrent level of the first current output by all first AC terminals is not the second level and there is a first level of the overcurrent level of the first current output by the first AC terminal, the control module 140 controls the first drive unit 131 corresponding to the first AC terminal with the first level of the first current to drive the target device 200 according to the temporary blocking wave control strategy; when there is a second level of the overcurrent level of the first current output by the first AC terminal, the control module 140 controls each first drive unit 131 to drive the target device 200 according to the shutdown control strategy.

[0048] Optionally, based on the above embodiments, the target device 200 further includes at least one first group of power conversion devices 210; wherein each first group of power conversion devices 210 is connected to a first AC terminal; and each first drive unit 131 is connected to a first group of power conversion devices 210.

[0049] For example, Figure 3 This is a schematic diagram of the structure of a target device provided in an embodiment of the present invention. Figure 3 The target device 200 shown includes a first group of power conversion devices 210, which includes three power conversion branches on the left side, i.e., the first AC terminal is connected to the three power conversion branches on the left side.

[0050] The control module 140 is used to determine the overcurrent level of the first current of each first AC terminal based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of each first AC terminal.

[0051] The control module 140 is used to control the first drive unit 131 corresponding to each first AC terminal with the first current output level of the first AC terminal to temporarily block the wave according to the temporary blocking wave control strategy when the overcurrent level of the first current output at all first AC terminals is not the second level and there is a first AC terminal with the first current output level of the first AC terminal is the first level, so as 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 the zero level, the control module 140 controls the blocked first drive unit 131 to release the wave so as to control the first group of power conversion devices 210 connected to it to resume operation.

[0052] The control module 140 is used to control each first drive unit 131 to permanently block the waveform according to the shutdown control strategy when the overcurrent level of the first current output at the first AC terminal is the second level, so that the first group of power conversion devices 210 controlled by each first drive unit 131 stops operating.

[0053] Based on the above embodiments, optionally, Figure 4 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the control module 140 includes at least one first control unit 141;

[0054] Each first comparator 1211 and each second comparator 1212 are connected to a first control unit 141. The first comparator 1211 and the second comparator 1212 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 and the second comparator 1212 connected to the first drive unit 131 and the same first control unit 141, is the same as a first AC terminal of the first drive unit 131 corresponding to the control target device 200. The first control units 141 are interconnected. Figure 3 (Not shown in the image).

[0055] 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.

[0056] Specifically, each first control unit 141 can determine the overcurrent level of the first current at the first AC terminal based on the first overcurrent state signal corresponding to the input first current and each second overcurrent state signal.

[0057] When the overcurrent level of the first current at the first AC terminal is the second level, each first control unit 141 generates a shutdown control signal and sends the shutdown control signal to the other first control units 141 within a preset time. After receiving or sending the shutdown control signal, it controls the connected first drive unit 131 according to the shutdown control strategy, that is, controls the first drive unit 131 to permanently block the wave, so that the first drive unit 131 controls the first group of power conversion devices 210 to stop running.

[0058] When the overcurrent level of the first current at the first AC terminal is level one and no shutdown control signal is received within a preset time, each first control unit 141 controls the connected first drive unit 131 according to the temporary blocking wave control strategy, that is, controls the first drive unit 131 to temporarily block the wave, so that the first drive unit 131 controls the first group of power conversion devices 210 to stop running. When the overcurrent level of the first current drops to level zero, the first drive unit 131 controls the first drive unit 131 to release the wave, so that the first drive unit 131 controls the first group of power conversion devices 210 to resume operation.

[0059] Based on the above embodiments, optionally, Figure 5 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention, as shown below. Figure 5As shown, the target device 200 also includes at least one second AC terminal, and the target device 200 includes a converter; 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;

[0060] Comparison module 120 is used to generate a third overcurrent state signal and a fourth overcurrent state signal according to each second current;

[0061] The control module 140 is used to adjust the control strategy of the target device 200 to a temporary blocking wave control strategy or a shutdown control strategy according to each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal and each fourth overcurrent state signal, and drive the target device 200 according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device 200.

[0062] Each second AC terminal of the target device 200 refers to the end of the target device 200 that is connected to the power generation equipment (e.g., a wind turbine). When the target device 200 includes only one AC side, the AC side can be either the side that includes only the first AC terminal or the side that includes only the second AC terminal; when the target device 200 includes two AC sides, one AC side of the target device 200 is the side that includes only the first AC terminal, and the other AC side of the target device 200 is the side that includes only the second AC terminal. Figure 5 The target device 200 shown includes at least one first AC terminal and at least one second AC terminal, thus indicating that the target device 200 is a multi-network multi-machine converter.

[0063] The sampling module 110 can collect the current flowing into or out of the target device 200 through each second AC terminal. For example, the second current flowing into the target device 200 from the generator through each second AC terminal or the second current flowing into the generator from each second AC terminal of the target device 200, so that the specific situation of the current flowing into or out of the target device 200 can be known in real time through the second current collected through each second AC terminal. The comparison module 120 can process the current flowing into or out of the target device 200 through each second AC terminal to output a third overcurrent state signal and a fourth overcurrent state signal that can indicate the specific range of the current flowing into or out of the target device 200 through each second AC terminal in real time.

[0064] The control module 140 can read the third overcurrent state signal and the fourth overcurrent state signal generated by the comparison module 120 according to each second current to know whether each second current exceeds the current range that the target device 200 can withstand, and to what extent each second current exceeds the current range that the target device 200 can withstand. Based on whether each first current and each second current exceed the current range that the target device 200 can withstand, and to what extent each first current and each second current exceed the current range that the target device 200 can withstand, different control strategies are adopted to drive the target device 200.

[0065] In cases where the second current slightly exceeds the current withstand capability of the target device 200, it is mostly caused by external factors such as generator failure or generator voltage fluctuations, resulting in temporary overcurrent in some transistors within the target device 200. In cases where the second current significantly exceeds the current withstand capability of the target device 200, it is mostly caused by factors such as damage to internal components within the target device 200, resulting in long-term overcurrent in some transistors within the target device 200. Therefore, if there is a slightly excessive current exceeding the current withstand capability of the target device 200 and no significantly excessive first or second current, the control module 140 will drive the target device 200 according to a temporary blocking wave control strategy. The temporary blocking wave control strategy is a control strategy that can temporarily shut down the relevant transistors in the target device 200 that are experiencing overcurrent, and will normally drive the transistors to operate when the first or second current flowing through the relevant transistors is less than the current withstand capability of the target device 200. If there is a significantly excessive first or second current exceeding the current withstand capability of the target device 200, the control module 140 will drive the target device 200 according to a shutdown control strategy. The shutdown control strategy is a control strategy that can drive the target device 200 to shut down. Therefore, in response to overcurrent anomalies in the target device 200, the target device 200 can be flexibly driven, thereby improving the flexibility of protection for the target device 200, reducing the number of times the target device 200 is shut down, reducing the workload of maintenance, reducing the waste of power generation and resources, and improving the robustness of the power generation system.

[0066] Furthermore, when the target device 200 includes one first AC terminal and one second AC terminal, the target device 200 can be an AC-DC+DCAC type single-network-one-machine converter; when the target device 200 includes multiple first AC terminals and one second AC terminal, the target device 200 can be multiple AC-DCAC type multi-network-one-machine converters; when the target device 200 includes one first AC terminal and multiple second AC terminals, the target device 200 can be an AC-DC+multiple DCAC type single-network-multiple-machine converter; when the target device 200 includes multiple first AC terminals and multiple second AC terminals, the target device 200 can be multiple AC-DC+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 5 The method of increasing or decreasing the number of the first and second AC terminals is not provided in this disclosure. The working principle of the single-network-one-machine converter, the multi-network-one-machine converter, the single-network-multiple-machine converter, and the multi-network-multiple-machine converter is similar to that of the multi-network-multiple-machine converter mentioned above, the only difference being the different amounts of the first and second currents obtained, which will not be elaborated upon in this disclosure.

[0067] Based on the above embodiments, optionally, Figure 6 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the sampling module 110 further includes at least one second sampling unit 112; the comparison module 120 includes at least one second comparison unit group 122, each second comparison unit group 122 including a third comparator 1221 and a fourth comparator 1222; the driving module 130 includes at least one second driving unit 132.

[0068] Each second sampling unit 112 is connected to a second AC terminal. Each third comparator 1221 and each fourth comparator 1222 are connected to a second sampling unit 112. The third comparator 1221 and the fourth comparator 1222 of each second comparison unit group are connected to the same second sampling unit 112. Each third comparator 1221, each fourth comparator 1222 and each second drive unit 132 are connected to the control module 140. Each second drive unit 132 is connected to the target device 200.

[0069] Each second sampling unit 112 is used to collect the second current of its corresponding connected second AC terminal; each second comparison unit group is used to determine the range of the second current collected by the corresponding connected second sampling unit 112, and outputs a third overcurrent state signal and a fourth overcurrent state signal that can indicate the specific range of the second current flowing into or out of the target device 200. Specifically, each third comparator 1221 is used to generate a third overcurrent state signal according to the input second current, and each fourth comparator 1222 is used to generate a fourth overcurrent state signal according to the input second current. For example, the current threshold defined by the fourth comparator 1222 is greater than the current threshold defined by the third comparator 1221. If the second current does not exceed the current threshold defined by the third comparator 1221, it indicates that the first current does not exceed the acceptable range of the target device 200; if the second current only exceeds the current threshold defined by the third comparator 1221 and does not exceed the current threshold defined by the fourth comparator 1222, it indicates that the second current exceeds the acceptable range of the target device 200 by a small amount; if the second current exceeds the current threshold defined by the fourth comparator 1222, it indicates that the second current exceeds the acceptable range of the target device 200 by a large amount. Each second drive unit 132 is used to adjust the second current of a second AC terminal of the target device 200 accordingly.

[0070] The control module 140 is used to determine the overcurrent level of the second current output by each second input / output terminal based on the third overcurrent state signal and the fourth overcurrent state signal corresponding to the second current output by each second AC terminal, and to drive the target device 200 by adopting different control strategies based on the overcurrent level of each first current and each second current.

[0071] The control module 140 can determine whether each second current exceeds the current that the target device 200 can withstand by reading the third and fourth overcurrent status signals corresponding to the second current output from each second AC terminal, and confirm the degree to which each second current exceeds the current that the target device 200 can withstand, that is, confirm the overcurrent level of each second current. Therefore, the control module 140 can adopt different control strategies to drive the target device 200 based on the overcurrent levels of each first current and each second current.

[0072] The overcurrent levels of the second current include level zero, level one, and level two. If the second current does not exceed the current threshold defined by the third comparator 1221, the overcurrent level of the second current is level zero. If the second current exceeds the current threshold defined by the third comparator 1221 but does not exceed the current threshold defined by the fourth comparator 1222, the overcurrent level of the second current is level one. If the second current exceeds the current threshold defined by the fourth comparator 1222, the overcurrent level of the second current is level two.

[0073] The specific process by which control module 140 drives target device 200 by adopting different control strategies based on the overcurrent levels of each first current and each second current is as follows: Control module 140 determines the overcurrent level of the first current of each first AC terminal according to the first overcurrent state signal and each second overcurrent state signal corresponding to the first current of each first AC terminal; Control module 140 determines the overcurrent level of the second current of each second AC terminal according to the third overcurrent state signal and each fourth overcurrent state signal corresponding to the second current of each second AC terminal; When the overcurrent levels of the first currents of all first AC terminals are not at level two, the overcurrent levels of the first currents of all second AC terminals are not at level two, and there is an overcurrent level of the first current of a first AC terminal that is at level one, control module 140 according to the temporary blocking wave. The strategy controls the first drive unit 131 corresponding to the first AC terminal with the first current of the first level to drive the target device 200; when the overcurrent level of the first current of all first AC terminals is not the second level, the overcurrent level of the second current of all second AC terminals is not the second level, and there is a second current of the second AC terminal with the overcurrent level of the first level, the control module 140 controls the second drive unit 132 corresponding to the second AC terminal with the second current of the first level to drive the target device 200 according to the temporary blocking wave control strategy; when there is a first current of the first AC terminal with the overcurrent level of the second level or there is a second current of the second AC terminal with the overcurrent level of the second level, the control module 140 controls each first drive unit 131 and each second drive unit 132 to drive the target device 200 according to the shutdown control strategy.

[0074] Optionally, based on the above embodiments, the target device 200 further includes at least one second group of power conversion devices 220; wherein each second group of power conversion devices 220 is connected to a second AC terminal; and each second drive unit 132 is connected to a second group of power conversion devices 220.

[0075] Among them, continue to refer to Figure 3 , Figure 3 The target device 200 shown includes a second set of power conversion devices 220, which includes three power conversion branches on the right side, i.e., the second AC terminal is connected to the three power conversion branches on the right side.

[0076] The control module 140 is configured to temporarily block the first drive unit 131 corresponding to each first AC terminal with a first current output level of level 1 when the overcurrent level of the first current output at all first AC terminals is not level 2, the overcurrent level of the second current output at all second AC terminals is not level 2, and there is a first AC terminal with an overcurrent level of level 1 with a first current output level of level 1. This is 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 0, the control module 140 controls the blocked first drive unit 131 to release the wave to control the first group of power conversion devices 210 connected to it to resume operation.

[0077] The control module 140 is used to temporarily block the second drive unit 132 corresponding to each second AC terminal with a first current output level of level 1 when the overcurrent level of the first current output at all first AC terminals is not level 2, the overcurrent level of the second current output at all second AC terminals is not level 2, and there is a second AC terminal with an overcurrent level of level 1 for the second current output at level 1. 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 0, 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.

[0078] The control module 140 is used to permanently block the waveform of each first drive unit 131 and each second drive unit 132 when there is a first current output from the first AC terminal with an overcurrent level of the second level or when there is a second current output from the second AC terminal with an overcurrent level of the second level. This causes each first drive unit 131 to control the corresponding connected first group of power conversion devices 210 to stop operating, and each second drive unit 132 to control the corresponding connected second group of rectifier transistors to stop operating.

[0079] Based on the above embodiments, optionally, Figure 7 This is a schematic diagram of another overcurrent protection device provided in an embodiment of the present invention, as shown below. Figure 7 The control module 140 shown also includes at least one second control unit 142;

[0080] Each third comparator 1221 and each fourth comparator 1222 are connected to a second control unit 142. The third comparator 1221 and the fourth comparator 1222 of each second comparison unit group are 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 of the second sampling unit 112 connected to the third comparator 1221 and the fourth comparator 1222 connected to the second drive unit 132 and the second AC terminal of the second drive unit 132 corresponding to the control target device 200 is the same. The second control units 142 are interconnected. Each second control unit 142 and each first control unit 141 are interconnected.

[0081] The communication connection between the first control unit 141 and the second control unit 142, as well as the communication connection between the second control units 142, can be a wired connection or a wireless connection, and this disclosure does not impose any specific restrictions on this.

[0082] Specifically, each first control unit 141 can determine the overcurrent level of the first current of each first AC terminal based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of each first AC terminal.

[0083] Each second control unit 142 can determine the overcurrent level of the second current of each second AC terminal based on the third overcurrent state signal and the fourth overcurrent state signal corresponding to the second current of each second AC terminal.

[0084] Each first control unit 141 can generate a shutdown control signal when the overcurrent level of the first current at the first AC terminal is at the second level, and send the shutdown control signal to the other first control units 141 and second control units 142 within a preset time. After receiving or sending the shutdown control signal, the first control units 141 and second control units 142 control the corresponding connected first drive unit 131 or second drive unit 132 according to the shutdown control signal, that is, control each first drive unit 131 and each second drive unit 132 to permanently block the wave, 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 rectifier transistors to stop running.

[0085] Each second control unit can generate a shutdown control signal when the overcurrent level of the second current at the second AC terminal is the second level, and send the shutdown control signal to the other first control units 141 and second control units 142 within a preset time. After receiving or sending the shutdown control signal, the first control units 141 and second control units 142 control the corresponding connected first drive unit 131 or second drive unit 132 according to the shutdown control signal, that is, control each first drive unit 131 and each second drive unit 132 to permanently block the wave, 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 rectifier transistors to stop running.

[0086] Each first control unit 141 can control the connected first drive unit 131 according to the temporary blocking wave control strategy when the overcurrent level of the first current at the first AC terminal is the first level and no shutdown control signal is received within a preset time. That is, it controls the first drive unit 131 corresponding to the first AC terminal with the first output current level of the first level to temporarily block the wave 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 the zero level, it 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.

[0087] Each second control unit 142 can control its connected second drive unit 132 according to the temporary blocking wave control strategy when the overcurrent level of the second current at the second AC terminal is at the first level and no shutdown control signal is received within a preset time. That is, it controls the second drive unit 132 corresponding to each second AC terminal with the output second current level at the first level to temporarily block the wave to control the connected second group of power converter devices 220 to stop operating. When the overcurrent level of the second current drops to the zero level, it controls the blocked second drive unit 132 to release the wave to control the connected second group of power converter devices 220 to resume operation.

[0088] Figure 8 This is a flowchart illustrating an overcurrent protection method provided in an embodiment of the present invention. The overcurrent protection method is executed using an overcurrent protection device provided in any embodiment of the present invention, and specifically includes:

[0089] S110, Collect the first current at each first AC terminal of the target device.

[0090] The above steps can be performed by the sampling module.

[0091] S120. Generate a first overcurrent state signal and a second overcurrent state signal according to each first current.

[0092] The above steps can be performed through the comparison module.

[0093] S130. Adjust the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy according to each first overcurrent state signal and each second overcurrent state signal, and drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

[0094] The above steps can be executed through the control module.

[0095] This disclosure embodiment acquires the first current at each first AC terminal of the target device; based on each first current, it outputs a first overcurrent state signal and a second overcurrent state signal indicating the specific range of each first current. By reading the first and second overcurrent state signals corresponding to each current, the specific situation of each first current is known, and an appropriate temporary blocking wave control strategy or shutdown control strategy is adopted to drive the target device according to the specific situation of each first current. Therefore, this disclosure, by judging the degree of overcurrent anomaly in the target device current, flexibly drives the target device, thereby improving the flexibility of target device protection, reducing the number of times the target device is shut down, reducing the workload of target device maintenance, reducing the waste of power generation and power generation resources, and improving the robustness of the power generation system.

[0096] Based on the above embodiments, optionally, the steps of generating a first overcurrent state signal and a second overcurrent state signal according to each first current are described as follows:

[0097] Each first comparator generates a first overcurrent state signal based on the first input current, and each second comparator generates a second overcurrent state signal based on the first input current.

[0098] Specifically, the first comparator compares the first current with a first overcurrent threshold and generates a first overcurrent state signal based on the comparison result; the first overcurrent state signal includes a first over-limit signal and a first not-over-limit signal. The second comparator compares the first current with a second overcurrent threshold and generates a second overcurrent state signal based on the comparison result; the second overcurrent state signal includes a second over-limit signal and a second not-over-limit signal.

[0099] The comparison process of the first comparator is as follows: if the first current is greater than the first overcurrent threshold, the first overcurrent state signal is the first over-limit signal; if the first current is less than or equal to the first overcurrent threshold, the first overcurrent state signal is the first not-over-limit signal.

[0100] The comparison process of the second comparator is as follows: if the first current is greater than the second overcurrent threshold, the second overcurrent state signal is the second over-limit signal; if the first current is less than or equal to the second overcurrent threshold, the second overcurrent state signal is the second not-over-limit signal.

[0101] It should be noted that the second overcurrent threshold is greater than the first overcurrent threshold.

[0102] Based on the above embodiments, optionally, Figure 9 This is a flowchart illustrating the steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, as provided in this embodiment of the disclosure. Figure 9 The steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, are described below:

[0103] S210. Determine the overcurrent level of the first current of each first AC terminal based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of each first AC terminal.

[0104] Specifically, the first overcurrent state signal includes a first over-limit signal and a first not-over-limit signal, and the second overcurrent state signal includes a second over-limit signal and a second not-over-limit signal;

[0105] If the first overcurrent state signal corresponding to the first current is the first non-overlimit signal and the second overcurrent state signal is the second non-overlimit signal, then the overcurrent level of the first current is level zero.

[0106] If the first overcurrent state signal corresponding to the first current is the first over-limit signal and the second overcurrent state signal is the second not over-limit signal, then the overcurrent level of the first current is the first level.

[0107] If the first overcurrent state signal corresponding to the first current is the first over-limit signal and the second overcurrent state signal is the second over-limit signal, then the overcurrent level of the first current is the second level.

[0108] S220. When the overcurrent level of the first current at all first AC terminals is not the second level and there is a first current level of the first AC terminal, the first drive unit corresponding to the first AC terminal with the first current level of the first level is controlled to drive the target device according to the temporary blocking wave control strategy.

[0109] S230. When the overcurrent level of the first current at the first AC terminal is the second level, control each first drive unit to drive the target device according to the shutdown control strategy.

[0110] Based on the above embodiments, optionally, the specific process of driving the target device by the first driving unit corresponding to the first AC terminal with the first current output as the first level according to the temporary blocking wave control strategy is as follows:

[0111] The first drive unit corresponding to the first AC terminal of each output first current level 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 of the blocked wave is released to control the first group of power conversion devices connected to it to resume operation.

[0112] The specific process of controlling each first drive unit to drive the target device according to the shutdown control strategy is as follows:

[0113] Each first drive unit is permanently blocked, causing the first group of power conversion devices connected to each first drive unit to stop operating.

[0114] Based on the above embodiments, optionally,

[0115] Figure 10 A flowchart illustrating another step provided by an embodiment of the present invention, wherein the control strategy for the target device is adjusted to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and the target device is driven according to the temporary blocking wave control strategy or the shutdown control strategy, is shown below. Figure 10 The steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal and each second overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, are described below:

[0116] S310. Determine the overcurrent level of the first current of the first AC terminal based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of the first AC terminal.

[0117] S320: When the overcurrent level of the first current at the first AC terminal is the second level, a shutdown control signal is generated and sent to the other first control units within a preset time. After receiving or sending the shutdown control signal, the connected first drive unit drives the target device according to the shutdown control strategy.

[0118] S330 When the overcurrent level of the first current at the first AC terminal is level one and no shutdown control signal is received within a preset time, the first drive unit connected to the device is controlled to drive the target device according to the temporary blocking wave control strategy.

[0119] It should be noted that the above steps are performed by each first control unit.

[0120] Based on the above embodiments, optionally, 11 is a flowchart illustrating another overcurrent protection method provided by an embodiment of the present invention, as shown below. Figure 11 As shown, the specific steps of this overcurrent protection method include:

[0121] S410: Collect the first current of each first AC terminal and the second current of each second AC terminal of the target device.

[0122] The above steps can be performed by the sampling module.

[0123] S420. Generate a first overcurrent state signal and a second overcurrent state signal according to each first current, and generate a third overcurrent state signal and a fourth overcurrent state signal according to each second current.

[0124] The above steps can be performed through the comparison module.

[0125] S430. Adjust the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy according to each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal and each fourth overcurrent state signal, and drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

[0126] The above steps can be executed through the control module.

[0127] Based on the above embodiments, optionally, the steps for collecting the first current of each first AC terminal and the second current of each second AC terminal are described as follows:

[0128] Specifically, the first sampling unit collects the first current at the first AC terminal, and the second sampling unit collects the second current at the second AC terminal.

[0129] The steps for generating the third and fourth overcurrent state signals based on each second current are explained below:

[0130] Each third comparator generates a third overcurrent state signal based on the input second current, and each fourth comparator generates a fourth overcurrent state signal based on the input second current.

[0131] Specifically, the third comparator compares the second current with the first overcurrent threshold and generates a third overcurrent state signal based on the comparison result; the third overcurrent state signal includes a third over-limit signal and a third not-over-limit signal; the fourth comparator compares the second current with the second overcurrent threshold and generates a fourth overcurrent state signal based on the comparison result; the fourth overcurrent state signal includes a fourth over-limit signal and a fourth not-over-limit signal.

[0132] The comparison process of the third comparator is as follows: if the second current is greater than the first overcurrent threshold, the third overcurrent state signal is the third over-limit signal; if the second current is less than or equal to the first overcurrent threshold, the third overcurrent state signal is the third not over-limit signal.

[0133] The comparison process of the fourth comparator is as follows: if the second current is greater than the second overcurrent threshold, the fourth overcurrent state signal is the fourth over-limit signal; if the second current is less than or equal to the second overcurrent threshold, the fourth overcurrent state signal is the fourth not-over-limit signal.

[0134] It should be noted that the second overcurrent threshold is greater than the first overcurrent threshold.

[0135] Based on the above embodiments, optionally, Figure 12 This is a flowchart illustrating the steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, as provided in this embodiment of the disclosure. Figure 12 As shown, the steps of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy are explained:

[0136] S510. Determine the overcurrent level of the first current of each first AC terminal based on the first overcurrent state signal corresponding to the first current of each first AC terminal and each second overcurrent state signal.

[0137] S520. Determine the overcurrent level of the second current of each second AC terminal based on the third overcurrent state signal corresponding to the second current of each second AC terminal and each fourth overcurrent state signal.

[0138] Specifically, the third overcurrent status signal includes a third over-limit signal and a third not-over-limit signal, and the fourth overcurrent status signal includes a fourth over-limit signal and a fourth not-over-limit signal;

[0139] If the third overcurrent status signal is the third non-overcurrent signal and the fourth overcurrent status signal is the fourth non-overcurrent signal, then the overcurrent level of the second current is level zero.

[0140] If the third overcurrent status signal is the third over-limit signal and the fourth overcurrent status signal is the fourth not over-limit signal, then the overcurrent level of the second current is the first level.

[0141] If the third overcurrent status signal is the third over-limit signal and the fourth overcurrent status signal is the fourth over-limit signal, then the overcurrent level of the second current is the second level.

[0142] S530, when the overcurrent level of the first current at all first AC terminals is not the second level, the overcurrent level of the first current at all second AC terminals is not the second level, and there is an overcurrent level of the first current at the first AC terminal that is the first level, the first drive unit corresponding to the first AC terminal with the first current of the first level is controlled to drive the target device according to the temporary blocking wave control strategy.

[0143] S540 When the overcurrent level of the first current at all first AC terminals is not the second level, and the overcurrent level of the second current at all second AC terminals is not the second level, but there is a second current at a second AC terminal with the overcurrent level of the first level, the second drive unit corresponding to the second AC terminal with the second current of the first level is controlled to drive the target device according to the temporary blocking wave control strategy.

[0144] S550: When the overcurrent level of the first current at the first AC terminal is level two or the overcurrent level of the second current at the second AC terminal is level two, control each first drive unit and each second drive unit to drive the target device according to the shutdown control strategy.

[0145] Based on the above embodiments, optionally, the specific process of controlling the first drive unit corresponding to the first AC terminal of the first stage to drive the target device according to the temporary blocking wave control strategy is as follows:

[0146] The first drive unit corresponding to the first AC terminal of each output first current level 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 of the blocked wave is released to control the first group of power conversion devices connected to it to resume operation.

[0147] The specific process of driving the target device by the second drive unit corresponding to the second AC terminal of the first stage, according to the temporary blocking wave control strategy, is as follows:

[0148] The second drive unit corresponding to the second AC terminal of each output second current level 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.

[0149] The specific process of controlling each first drive unit and each second drive unit to drive the target device according to the shutdown control strategy is as follows:

[0150] Each first drive unit and each second drive unit are permanently blocked, so that each first drive unit controls the corresponding first group of power conversion devices to stop operating, and each second drive unit controls the corresponding second group of power conversion devices to stop operating.

[0151] Based on the above embodiments, optionally, Figure 13 A flowchart illustrating another step provided in this disclosure, showing the adjustment of the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, is shown below. Figure 13 The steps described are as follows: adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each first overcurrent state signal, each second overcurrent state signal, each third overcurrent state signal, and each fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy.

[0152] S610. Determine the overcurrent level of the first current of the first AC terminal based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of the first AC terminal.

[0153] S620. Determine the overcurrent level of the second current of the second AC terminal based on the third overcurrent state signal and the fourth overcurrent state signal corresponding to the second current of the second AC terminal.

[0154] S630. When the overcurrent level of the first current at the first AC terminal is the second level, a shutdown control signal is generated and the shutdown control signal is sent to the other first control unit and second control unit within a preset time. After receiving or sending the shutdown control signal, the corresponding connected first drive unit or second drive unit is controlled to drive the target device according to the shutdown control signal.

[0155] S640: When the overcurrent level of the second current at the second AC terminal is the second level, a shutdown control signal is generated, and the shutdown control signal is sent to the other first control unit and second control unit within a preset time. After receiving or sending the shutdown control signal, the corresponding connected first drive unit or second drive unit is controlled to drive the target device according to the shutdown control signal.

[0156] S650 When the overcurrent level of the first current at the first AC terminal is the first level and no shutdown control signal is received within a preset time, the first drive unit connected to the device is controlled to drive the target device according to the temporary blocking wave control strategy.

[0157] S660 When the overcurrent level of the second current at the second AC terminal is level one and no shutdown control signal is received within a preset time, the second drive unit connected to it is controlled to drive the target device according to the temporary blocking wave control strategy.

[0158] It should be noted that the above steps can be performed by each first control unit and each second control unit.

[0159] This disclosure also provides a power electronic conversion device, which includes the overcurrent protection device provided in any embodiment of this disclosure and thus has the beneficial effects of the overcurrent protection device provided in any embodiment of this disclosure. Further details will not be provided here.

[0160] The overcurrent protection device for the target device provided in any embodiment of this disclosure can be applied to devices such as 2-level NPC, 3-level NPC, 3-level ANPC, cascaded H-bridge, and photovoltaic energy storage. Therefore, it has the beneficial effects of the overcurrent protection device provided in any embodiment of this disclosure, which will not be elaborated further.

[0161] 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.

[0162] 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. An overcurrent protection device, characterized in that, It includes a sampling module, a comparison module, and a control module; The target device 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 a first current of each of the first AC terminals; The sampling module is connected to the comparison module, and the comparison module is used to generate a first overcurrent state signal and a second overcurrent state signal according to each first current. The comparison module is connected to the control module, and the control module is connected to the target device. The control module is used to adjust the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy according to each of the first overcurrent state signals and each of the second overcurrent state signals, and drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device. The comparison module is implemented using at least one of hardware circuits and / or software methods.

2. The overcurrent protection device according to claim 1, characterized in that, It also includes a driving module; the sampling module includes at least one first sampling unit; the comparison module includes at least one first comparison unit group, each of the first comparison unit groups including a first comparator and a second comparator; the driving module includes at least one first driving unit; Each of the first sampling units is connected to a first AC terminal, each of the first comparators and each of the second comparators are connected to a first sampling unit, and the first comparators and the second comparators of each group of first comparison units are connected to the same first sampling unit. Each of the first comparators, each of the second 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 target device.

3. The overcurrent protection device according to claim 2, characterized in that, The target device 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 overcurrent state signal and the second overcurrent state signal corresponding to the first current of each first AC terminal. The control module is configured to, according to the temporary blocking wave control strategy, temporarily block the first drive unit corresponding to each first AC terminal with the first current output at the first level, so as to control the first group of power conversion devices connected to it to stop operating when the overcurrent level of the first current at all first AC terminals is not the second level and there is a first level of the overcurrent level of the first current at the first AC terminal. When the overcurrent level of the first current drops to the zero level, the control module controls the blocked first drive unit to release the wave so as to control the first group of power conversion devices connected to it to resume operation. The control module is used to permanently block the waveform of each first drive unit according to the shutdown control strategy when the overcurrent level of the first current at the first AC terminal is the second level, so that the first group of power conversion devices connected to each first drive unit stops operating.

4. The overcurrent protection device according to claim 3, characterized in that, The control module includes at least one first control unit; Each of the first comparators and each of the second comparators is connected to a first control unit. The first comparators and the second 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 and the second comparator connected to the first drive unit and the first AC terminal corresponding to the first drive unit controlling the target device are the same. The first control units are interconnected.

5. The overcurrent protection device according to any one of claims 4, characterized in that, The target device further includes at least one second AC terminal, and the target device includes a converter; 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 comparison module is used to generate a third overcurrent state signal and a fourth overcurrent state signal according to each of the second currents; The control module is used to adjust the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy according to each of the first overcurrent state signal, each of the second overcurrent state signal, each of the third overcurrent state signal and each of the fourth overcurrent state signal, and drive the target device according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

6. The overcurrent protection device according to claim 5, characterized in that, The sampling module further includes at least one second sampling unit; the comparison module includes at least one second comparison unit group, each second comparison unit group including a third comparator and a fourth comparator; the driving module includes at least one second driving unit. Each of the second sampling units is connected to a second AC terminal, each of the third comparators and each of the fourth comparators is connected to a second sampling unit, and the third comparators and the fourth comparators of each group of second comparison units are connected to the same second sampling unit; Each of the third comparators, each of the fourth 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 target device.

7. The overcurrent protection device according to claim 6, characterized in that, The target device 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.

8. The overcurrent protection device according to claim 6, characterized in that, The control module further includes at least one second control unit; Each of the third comparators and each of the fourth comparators is connected to a second control unit. The third comparators and fourth comparators in each group of second comparison units are 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 third and fourth comparators connected to the second drive unit in the same second control unit is the same as the second AC terminal of the second drive unit that controls the target device. The second control units are interconnected. Each second control unit and each first control unit are interconnected.

9. An overcurrent protection method, characterized in that, include: Collect the first current at each first AC terminal of the target device; A first overcurrent state signal and a second overcurrent state signal are generated according to each of the first currents. The control strategy for the target device is adjusted to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signals and each of the second overcurrent state signals, and the target device is driven according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

10. The overcurrent protection method according to claim 9, characterized in that, The step of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signals and each of the second overcurrent state signals, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, includes: The overcurrent level of the first current of each first AC terminal is determined based on the first overcurrent state signal and the second overcurrent state signal corresponding to the first current of each first AC terminal. When the overcurrent level of the first current at all the first AC terminals is not the second level and there is a first level of the overcurrent level of the first current at the first AC terminal, the first driving unit corresponding to the first AC terminal with the first current of the first level is controlled to drive the target device according to the temporary blocking wave control strategy. When the overcurrent level of the first current at the first AC terminal is level two, each of the first drive units is controlled to drive the target device according to the shutdown control strategy.

11. The overcurrent protection method according to claim 10, characterized in that, The step of controlling the first drive unit corresponding to the first AC terminal with the first current of the first stage, which is controlled according to the temporary blocking wave control strategy, to drive the target device 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 target device 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.

12. The overcurrent protection method according to claim 11, characterized in that, The step of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signals and each of the second overcurrent state signals, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, includes: The overcurrent level of the first current at the first AC terminal is determined based on the first overcurrent state signal and the second 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 the second level, a shutdown control signal is generated and sent to the other first control units within a preset time. After receiving or sending the shutdown control signal, the first drive unit connected to the control unit drives the target device according to the shutdown control strategy. When the overcurrent level of the first current at the first AC terminal is level one and no shutdown control signal is received within the preset time, the first drive unit connected to the device is controlled to drive the target device according to the temporary blocking wave control strategy.

13. The overcurrent protection method according to claim 12, characterized in that, include: Collect the first current at each of the first AC terminals and the second current at each of the second AC terminals of the target device; A first overcurrent state signal and a second overcurrent state signal are generated according to each of the first currents, and a third overcurrent state signal and a fourth overcurrent state signal are generated according to each of the second currents. The control strategy for the target device is adjusted to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signal, each of the second overcurrent state signal, each of the third overcurrent state signal and each of the fourth overcurrent state signal, and the target device is driven according to the temporary blocking wave control strategy or the shutdown control strategy to protect the target device.

14. The overcurrent protection method according to claim 13, characterized in that, The step of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signal, each of the second overcurrent state signal, each of the third overcurrent state signal, and each of the fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, includes: The overcurrent level of the first current at each first AC terminal is determined based on the first overcurrent state signal corresponding to the first current at each first AC terminal and each second overcurrent state signal. The overcurrent level of the second current at each second AC terminal is determined based on the third overcurrent state signal corresponding to the second current at each second AC terminal and each of the fourth overcurrent state signals. When the overcurrent level of the first current at all first AC terminals is not the second level, the overcurrent level of the first current at all second AC terminals is not the second level, and there is an overcurrent level of the first current at the first AC terminal that is the first level, the first drive unit corresponding to the first AC terminal with the first current outputting the first level is controlled to drive the target device according to the temporary blocking wave control strategy. When the overcurrent level of the first current at all first AC terminals is not the second level, the overcurrent level of the second current at all second AC terminals is not the second level, and there is a second current at a second AC terminal with the overcurrent level of the first level, the second drive unit corresponding to the second AC terminal with the second current of the first level is controlled to drive the target device according to the temporary blocking wave control strategy. When the overcurrent level of the first current at the first AC terminal is level two, or the overcurrent level of the second current at the second AC terminal is level two, each of the first drive units and each of the second drive units is controlled to drive the target device according to the shutdown control strategy.

15. The overcurrent protection method according to claim 14, characterized in that, According to the temporary blocking wave control strategy, the first drive unit corresponding to the first AC terminal with the first current output as the first level drives the target device, including: 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 of the first stage, which outputs the second current according to the temporary blocking wave control strategy, to drive the target device includes: The second drive unit corresponding to the second AC terminal of each output second current level 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 target device according to the shutdown control strategy includes: Each of the first drive unit and each of the second drive units is permanently blocked, so that each of the first drive units controls the corresponding connected first group of power conversion devices to stop operating, and each of the second drive units controls the corresponding connected second group of power conversion devices to stop operating.

16. The overcurrent protection method according to claim 15, characterized in that, The step of adjusting the control strategy for the target device to a temporary blocking wave control strategy or a shutdown control strategy based on each of the first overcurrent state signal, each of the second overcurrent state signal, each of the third overcurrent state signal, and each of the fourth overcurrent state signal, and driving the target device according to the temporary blocking wave control strategy or the shutdown control strategy, includes: The overcurrent level of the first current at the first AC terminal is determined based on the first overcurrent state signal and the second 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 third overcurrent state signal and the fourth 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 the second level, a shutdown control signal is generated, and the shutdown control signal is sent to the remaining first control unit and second control unit within a preset time. After receiving or sending the shutdown control signal, the corresponding connected first drive unit or second drive unit is controlled to drive the target device according to the shutdown control signal. When the overcurrent level of the second current at the second AC terminal is the second level, a shutdown control signal is generated, and the shutdown control signal is sent to the remaining first control unit and second control unit within a preset time. After receiving or sending the shutdown control signal, the corresponding connected first drive unit or second drive unit is controlled to drive the target device according to the shutdown control signal. When the overcurrent level of the first current at the first AC terminal is level one and no shutdown control signal is received within the preset time, the first drive unit connected to the device is controlled to drive the target device according to the temporary blocking wave control strategy. When the overcurrent level of the second current at the second AC terminal is level one and no shutdown control signal is received within the preset time, the second drive unit connected to it is controlled to drive the target device according to the temporary blocking wave control strategy.

17. A power electronic conversion device, characterized in that, Includes the overcurrent protection device as described in any one of claims 1-8.

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