Current-limited dc circuit breaker and control method for current-limited dc circuit breaker

Abstract

The application provides a current-limited DC circuit breaker and a control method thereof. The current-limited DC circuit breaker comprises an inductor, a first end of which is configured to be electrically connected to a DC power grid; a mechanical switch, a first end of which is electrically connected to a second end of the inductor, and a second end of which is configured to be electrically connected to a load; a thyristor, a first end of which is electrically connected to the first end of the inductor, and a control end of which is configured to receive a first-level signal; a pre-charge capacitor, a first end of which is electrically connected to a second end of the thyristor, and a second end of which is electrically connected to the second end of the inductor, and the second end of the pre-charge capacitor stores a positive charge; and a power electronic switch structure, a first end of which is electrically connected to the first end of the inductor, and a second end of which is electrically connected to the second end of the mechanical switch, and a control end of which is configured to receive a second-level signal. The application solves the problem that it is difficult to limit short-circuit current when a short-circuit fault occurs in the DC power grid in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current power grid, in particular to a current-limiting DC circuit breaker, a control method of the current-limiting DC circuit breaker, a current-limiting DC circuit breaker device and a current-limiting DC circuit breaker system. BACKGROUND

[0002] To promote the energy revolution and ensure the energy supply safety for economic and social development, the central government proposes to build a new power system with new energy as the main body, source-grid-load-storage interaction and multi-energy complementary support. With the large-scale access of high-proportion new energy and energy storage, the increase of direct current load and the development of power electronic technology, direct current power distribution technology has attracted widespread attention. Compared with alternating current power distribution network, direct current power distribution network reduces the conversion link of distributed energy and direct current load access to the power grid, and has significant advantages in saving investment and operation cost and reducing operation loss. The 2030 carbon peak action plan issued by the State Council clearly proposes to use direct current power supply to strengthen energy saving and carbon reduction of infrastructure, and direct current power distribution network technology has become a research hotspot.

[0003] Under the background of new power system construction, a large number of wind power, photovoltaic and other new energy, multi-type energy storage devices and flexible load are connected to the direct current power distribution network through power electronic converters. The alternating current power grid has large generators and transformers, both of which can provide high inductance and limit short-circuit current when short-circuit fault occurs. The direct current power grid does not have such high inductance, and the penetration of short-circuit fault in the direct current power grid is faster and deeper, and the short-circuit current increases faster and higher. In order to minimize the disturbance to the operation of the direct current bus and voltage source converter, it is necessary to clear the fault as soon as possible. Therefore, a fast and reliable direct current circuit breaker is needed to isolate the fault part, so as to avoid the collapse of the direct current power grid. SUMMARY

[0004] The main purpose of the present application is to provide a current-limiting DC circuit breaker, a control method of the current-limiting DC circuit breaker, a current-limiting DC circuit breaker device and a current-limiting DC circuit breaker system, to at least solve the problem that it is difficult to limit short-circuit current when short-circuit fault occurs in the direct current power grid in the prior art.

[0005] To achieve the above object, according to one aspect of the present application, a current-limited DC circuit breaker is provided, comprising: an inductor, a first end of the inductor being configured to be electrically connected with a DC power grid; a mechanical switch, a first end of the mechanical switch being electrically connected with a second end of the inductor, and a second end of the mechanical switch being configured to be electrically connected with a load; a thyristor, a first end of the thyristor being electrically connected with the first end of the inductor, and a control end of the thyristor being configured to receive a first level signal, the first level signal being configured to turn on the thyristor in the case that the DC power grid outputs a short-circuit current; a pre-charge capacitor, a first end of the pre-charge capacitor being electrically connected with a second end of the thyristor, a second end of the pre-charge capacitor being electrically connected with the second end of the inductor, and the second end of the pre-charge capacitor storing a positive charge; and a power electronic switch structure, a first end of the power electronic switch structure being electrically connected with the first end of the inductor, a second end of the power electronic switch structure being electrically connected with the second end of the mechanical switch, and a control end of the power electronic switch structure being configured to receive a second level signal, the second level signal being configured to turn on the power electronic switch structure in the case that the first end of the pre-charge capacitor stores the positive charge.

[0006] Optionally, the current-limited DC circuit breaker further comprises: a non-linear resistor, a first end of the non-linear resistor being electrically connected with the first end of the inductor, and a second end of the non-linear resistor being electrically connected with the second end of the mechanical switch, the second level signal being further configured to turn off the power electronic switch structure in the case that the power electronic switch structure is turned on for a predetermined time length, so that the power electronic switch structure generates a pulse voltage at the moment of turning off, the pulse voltage being greater than or equal to a turn-on voltage of the non-linear resistor.

[0007] Optionally, the non-linear resistor comprises a metal oxide varistor.

[0008] Optionally, the power electronic switch structure comprises: a first sub-switch structure, a first end of the first sub-switch structure being the first end of the power electronic switch structure, and a control end of the first sub-switch structure being configured to receive the second level signal; and a second sub-switch structure, a first end of the second sub-switch structure being electrically connected with a second end of the first sub-switch structure, a second end of the second sub-switch structure being the second end of the power electronic switch structure, and a control end of the second sub-switch structure being configured to receive the second level signal.

[0009] Optionally, the first sub-switch structure comprises a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a first resistor and a first transistor, a positive electrode of the first diode is a first end of the first sub-switch structure, a negative electrode of the first diode is electrically connected with a first end of the first transistor, the negative electrode of the first diode is also electrically connected with a negative electrode of the fifth diode, a positive electrode of the fifth diode is electrically connected with a second end of the first transistor, the negative electrode of the first diode is also electrically connected with a positive electrode of the second diode, a negative electrode of the second diode is electrically connected with a negative electrode of the third diode, a positive electrode of the third diode is electrically connected with a first end of the first capacitor through the first resistor, a second end of the first capacitor is electrically connected with the positive electrode of the second diode, the positive electrode of the third diode is also electrically connected with the second end of the first transistor, the positive electrode of the third diode is also electrically connected with a negative electrode of the fourth diode, a positive electrode of the fourth diode is also electrically connected with the positive electrode of the first diode, and the negative electrode of the second diode is a second end of the first sub-switch structure.

[0010] Optionally, the second sub-switch structure comprises a sixth diode, a seventh diode, an eighth diode, a ninth diode, a twelfth diode, a second capacitor, a second resistor and a second transistor, a positive electrode of the sixth diode is a first end of the second sub-switch structure, a negative electrode of the sixth diode is electrically connected with a first end of the second transistor, the negative electrode of the sixth diode is also electrically connected with a negative electrode of the twelfth diode, a positive electrode of the twelfth diode is electrically connected with a second end of the second transistor, the negative electrode of the sixth diode is also electrically connected with a positive electrode of the seventh diode, a negative electrode of the seventh diode is electrically connected with a negative electrode of the eighth diode, a positive electrode of the eighth diode is electrically connected with a first end of the second capacitor through the second resistor, a second end of the second capacitor is electrically connected with the positive electrode of the seventh diode, the positive electrode of the eighth diode is also electrically connected with the second end of the second transistor, the positive electrode of the eighth diode is also electrically connected with a negative electrode of the ninth diode, a positive electrode of the ninth diode is also electrically connected with the positive electrode of the sixth diode, and the negative electrode of the seventh diode is a second end of the second sub-switch structure.

[0011] According to another aspect of the present application, a control method of any of the current-limiting DC circuit breakers is provided, the method comprising: in the case that a short-circuit current is received at the first end of the inductor, controlling the mechanical switch to be closed and sending a first level signal to the control end of the thyristor so that the thyristor is turned on; in the case that a positive charge is stored at the first end of the pre-charge capacitor, controlling the mechanical switch to be opened and sending a second level signal to the control end of the power electronic switch structure so that the power electronic switch structure is turned on.

[0012] Optionally, after sending the second level signal to the control end of the power electronic switch structure, the method further comprises: in the case that the power electronic switch structure is turned on for a predetermined duration, sending the second level signal to the control end of the power electronic switch structure, so that the power electronic switch structure is turned off, so that the power electronic switch structure generates a pulse voltage at the moment of turning off, and the pulse voltage is greater than or equal to the turn-on voltage of the nonlinear resistor.

[0013] According to still another aspect of the present application, there is provided a current-limited DC circuit breaker, comprising: a current-limited DC circuit breaker; and a controller comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise a control method for the current-limited DC circuit breaker.

[0014] According to still another aspect of the present application, there is provided a current-limited DC circuit breaker system, comprising: a DC power grid; a current-limited DC circuit breaker according to any one of the current-limited DC circuit breakers; and a load electrically connected to a second end of the current-limited DC circuit breaker.

[0015] The technical scheme is applied to the current-limiting DC circuit breaker including an inductor, a mechanical switch, a thyristor, a pre-charge capacitor and a power electronic switch structure. The first end of the inductor is electrically connected with a DC power grid. The first end of the mechanical switch is electrically connected with the second end of the inductor. The second end of the mechanical switch is electrically connected with a load. The first end of the thyristor is electrically connected with the first end of the inductor. The control end of the thyristor is used for receiving a first-level signal. The first-level signal is used for turning on the thyristor in the case of a short-circuit current output by the DC power grid. The first end of the pre-charge capacitor is electrically connected with the second end of the thyristor. The second end of the pre-charge capacitor is electrically connected with the second end of the inductor. The second end of the pre-charge capacitor stores a positive charge. The first end of the power electronic switch structure is electrically connected with the first end of the inductor. The second end of the power electronic switch structure is electrically connected with the second end of the mechanical switch. The control end of the power electronic switch structure is used for receiving a second-level signal. The second-level signal is used for turning on the power electronic switch structure in the case that the first end of the pre-charge capacitor stores the positive charge. Compared with the prior art, in the case of normal current flow of the DC power grid, the current normally flows through the inductor and the mechanical switch to the load. In the case of a short-circuit fault of the DC power grid, the thyristor is turned on. Since the second end of the pre-charge capacitor stores the positive charge, the pre-charge capacitor discharges and magnetizes the inductor in the opposite direction, so that the original inductor current decreases and reverses. At this time, the short-circuit current flows through the thyristor, the pre-charge capacitor and the mechanical switch to the load, so that part of the energy of the short-circuit current is consumed. The capacitor voltage opposite to the pre-charge voltage is established on the pre-charge capacitor (i.e. the positive charge is stored at the first end of the pre-charge capacitor). At this time, the mechanical switch is turned off, and the power electronic switch structure is turned on, so that the short-circuit current flows from the power electronic switch structure to the load, so that the energy of the short-circuit current is further consumed, thereby quickly and effectively limiting the short-circuit current, and ensuring that the probability of collapse of the DC power grid is small. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application and are incorporated herein for a purpose of explanations and are not intended as improper limitations to the present application. In the drawings:

[0017] Figure 1 A circuit structure schematic diagram of a current-limiting DC circuit breaker provided in an embodiment of the present application is shown;

[0018] Figure 2 A circuit structure schematic diagram of a specific current-limiting DC circuit breaker provided in an embodiment of the present application is shown;

[0019] Figure 3A circuit structure schematic diagram of a more specific current-limited DC circuit breaker provided in an embodiment of the present application is shown.

[0020] Figure 4 A hardware structure block diagram of a mobile terminal for executing a control method of a current-limited DC circuit breaker provided in an embodiment of the present application is shown.

[0021] Figure 5 A flowchart of a control method of a current-limited DC circuit breaker provided in an embodiment of the present application is shown.

[0022] Among the above drawings, the following reference signs are included:

[0023] 102, processor; 104, memory; 106, transmission device; 108, input / output device; 10, inductor; 11, mechanical switch; 12, thyristor; 13, pre-charge capacitor; 14, power electronic switch structure; 15, nonlinear resistor; 16, first sub-switch structure; 17, second sub-switch structure; 18, first diode; 19, second diode; 20, third diode; 21, fourth diode; 22, fifth diode; 23, first capacitor; 24, first resistor; 25, first transistor; 26, sixth diode; 27, seventh diode; 28, eighth diode; 29, ninth diode; 30, twelfth diode; 31, second capacitor; 32, second resistor; 33, second transistor. DETAILED DESCRIPTION

[0024] It should be noted that the embodiments and features in the present application can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] As introduced in the background, it is difficult to limit the short-circuit current when the short-circuit fault occurs in the existing DC power grid, in order to solve the above problem, the embodiments of the present application provide a current limiting type DC circuit breaker, a control method of the current limiting type DC circuit breaker, a current limiting type DC circuit device and a current limiting type DC circuit system.

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application.

[0029] The embodiments of the present application provide a current limiting type DC circuit breaker, as shown in the figure, comprising: Figure 1

[0030] An inductor 10, a first end of the inductor 10 is used for electrical connection with a DC power grid (not shown);

[0031] A mechanical switch 11, a first end of the mechanical switch 11 is electrically connected with a second end of the inductor 10, and a second end of the mechanical switch 11 is used for electrical connection with a load (not shown);

[0032] A thyristor 12, a first end of the thyristor 12 is electrically connected with the first end of the inductor 10, and a control end of the thyristor 12 is used for receiving a first level signal, and the first level signal is used to turn on the thyristor 12 in the case of outputting a short-circuit current by the DC power grid;

[0033] A pre-charge capacitor 13, a first end of the pre-charge capacitor 13 is electrically connected with a second end of the thyristor 12, and a second end of the pre-charge capacitor 13 is electrically connected with the second end of the inductor 10, and the second end of the pre-charge capacitor 13 stores a positive charge;

[0034] ​The power electronic switch structure 14 is electrically connected with the first end of the inductor 10 and the second end of the mechanical switch 11, and the control end of the power electronic switch structure 14 is used for receiving a second level signal, and the second level signal is used for turning on the power electronic switch structure 14 when the first end of the pre-charge capacitor 13 stores a positive charge.

[0035] According to the above embodiment, the current-limited DC circuit breaker includes an inductor, a mechanical switch, a thyristor, a pre-charge capacitor and a power electronic switch structure. The first end of the inductor is electrically connected with a DC power grid. The first end of the mechanical switch is electrically connected with the second end of the inductor. The second end of the mechanical switch is electrically connected with a load. The first end of the thyristor is electrically connected with the first end of the inductor. The control end of the thyristor is used for receiving a first level signal. The first level signal is used for turning on the thyristor when the DC power grid outputs a short-circuit current. The first end of the pre-charge capacitor is electrically connected with the second end of the thyristor. The second end of the pre-charge capacitor is electrically connected with the second end of the inductor. The second end of the pre-charge capacitor stores a positive charge. The first end of the power electronic switch structure is electrically connected with the first end of the inductor. The second end of the power electronic switch structure is electrically connected with the second end of the mechanical switch. The control end of the power electronic switch structure is used for receiving a second level signal. The second level signal is used for turning on the power electronic switch structure when the first end of the pre-charge capacitor stores the positive charge. Compared with the prior art, when the DC power grid normally flows, the current normally flows through the inductor and the mechanical switch to the load. When the DC power grid has a short-circuit fault, the thyristor is turned on. Because the second end of the pre-charge capacitor stores the positive charge, the pre-charge capacitor discharges and magnetizes the inductor in the opposite direction, so that the original inductor current decreases and reverses. At this time, the short-circuit current flows through the thyristor, the pre-charge capacitor and the mechanical switch to the load, so that part of the energy of the short-circuit current is consumed, and the capacitor voltage opposite to the pre-charge voltage (i.e., the positive charge is stored at the first end of the pre-charge capacitor) is established on the pre-charge capacitor. At this time, the mechanical switch is turned off, and the power electronic switch structure is turned on, so that the short-circuit current flows from the power electronic switch structure to the load, so that the energy of the short-circuit current is further consumed, thereby quickly and effectively limiting the short-circuit current, and ensuring that the probability of collapse of the DC power grid is small.

[0036] Specifically, the energy of the positive charge stored at the second end of the pre-charge capacitor is greater than the energy of the inductor.

[0037] Specifically, the aforementioned power electronic switch structure includes a series of power chips such as IGBTs (Insulated Gate Bipolar Transistors) and diodes, and combinations thereof. This power electronic switch structure can be a unidirectional solid-state switch branch, a bidirectional solid-state switch branch, or other power electronic switch structures. In practical applications, those skilled in the art can flexibly select a suitable power electronic switch structure according to actual needs; this application does not impose specific limitations in this regard.

[0038] Specifically, the aforementioned mechanical switch consists of an electromagnetic repulsion mechanism, a holding mechanism, and a drive circuit.

[0039] In one alternative embodiment, the aforementioned current-limiting DC circuit breaker further includes: Figure 2 As shown, a nonlinear resistor 15 is connected at its first end to the first end of the inductor 10, and at its second end to the second end of the mechanical switch 11. The second-level signal is also used to turn off the power electronic switch structure 14 after it has been turned on for a predetermined duration, so that the power electronic switch structure 14 generates a pulse voltage at the moment of turn-off. This pulse voltage is greater than or equal to the on-state voltage of the nonlinear resistor 15. In this embodiment, a pulse voltage greater than or equal to the on-state voltage of the nonlinear resistor is generated at the moment the power electronic switch structure turns off, causing the nonlinear resistor to conduct. This allows the short-circuit current to flow through the nonlinear resistor to the load, further consuming the residual energy of the short-circuit current, further limiting the short-circuit current, and further ensuring a lower probability of DC grid failure.

[0040] Specifically, those skilled in the art can flexibly select appropriate nonlinear resistors according to actual needs, and this application does not impose specific restrictions in this regard.

[0041] In other embodiments, such as Figure 2 and Figure 3 As shown, the aforementioned nonlinear resistor 15 includes a metal oxide varistor. In this embodiment, the metal oxide varistor has a very fast response speed, which can quickly capture transient voltage changes in the circuit. This ensures that the pulse voltage generated at the moment the power electronic switch structure is turned off can be quickly captured by the metal oxide varistor, thereby turning on the metal oxide varistor and allowing the short-circuit current to flow through it. This further ensures that the residual energy of the short-circuit current is consumed, while also ensuring a short turn-off time for the short-circuit current.

[0042] According to some exemplary embodiments of this application, such as Figure 3As shown in the figure, the power electronic switch structure 14 includes a first sub-switch structure 16, a first end of the first sub-switch structure 16 is a first end of the power electronic switch structure 14, a control end of the first sub-switch structure 16 is configured to receive the second level signal; a second sub-switch structure 17, a first end of the second sub-switch structure 17 is electrically connected to a second end of the first sub-switch structure 16, a second end of the second sub-switch structure 17 is a second end of the power electronic switch structure 14, a control end of the second sub-switch structure 17 is configured to receive the second level signal. In the embodiment, the power electronic switch structure includes the first sub-switch structure and the second sub-switch structure in series, which ensures that the energy of the short-circuit current can be consumed by the first sub-switch structure and the second sub-switch structure as much as possible when the short-circuit current flows through the power electronic switch structure.

[0043] According to some other exemplary embodiments of the present application, as Figure 3 As shown in the figure, the first sub-switch structure 16 includes a first diode 18, a second diode 19, a third diode 20, a fourth diode 21, a fifth diode 22, a first capacitor 23, a first resistor 24, and a first transistor 25, a positive electrode of the first diode 18 is a first end of the first sub-switch structure 16, a negative electrode of the first diode 18 is electrically connected to a first end of the first transistor 25, the negative electrode of the first diode 18 is also electrically connected to a negative electrode of the fifth diode 22, a positive electrode of the fifth diode 22 is electrically connected to a second end of the first transistor 25, the negative electrode of the first diode 18 is also electrically connected to a positive electrode of the second diode 19, a negative electrode of the second diode 19 is electrically connected to a negative electrode of the third diode 20, a positive electrode of the third diode 20 is electrically connected to a first end of the first capacitor 23 through the first resistor 24, a second end of the first capacitor 23 is electrically connected to a positive electrode of the second diode 19, the positive electrode of the third diode 20 is also electrically connected to the second end of the first transistor 25, the positive electrode of the third diode 20 is also electrically connected to a negative electrode of the fourth diode 21, the positive electrode of the fourth diode 21 is also electrically connected to the positive electrode of the first diode 18, the negative electrode of the second diode 19 is a second end of the first sub-switch structure 16. In the embodiment, the first sub-switch structure includes the first diode, the second diode, the third diode, the fourth diode, the fifth diode, the first capacitor, the first resistor, and the first transistor, which further ensures that the energy of the short-circuit current can be consumed by the first sub-switch structure as much as possible when the short-circuit current flows through the first sub-switch structure.

[0044] In some other optional schemes of the present application, as Figure 3As shown, the second sub-switch structure 17 includes a sixth diode 26, a seventh diode 27, an eighth diode 28, a ninth diode 29, a tenth diode 30, a second capacitor 31, a second resistor 32, and a second transistor 33. The anode of the sixth diode 26 is the first terminal of the second sub-switch structure 17. The cathode of the sixth diode 26 is electrically connected to the first terminal of the second transistor 33. The cathode of the sixth diode 26 is also electrically connected to the cathode of the tenth diode 30. The anode of the tenth diode 30 is electrically connected to the second terminal of the second transistor 33. The cathode of the sixth diode 26 is also electrically connected to the first terminal of the seventh diode 27. The positive terminals of the seventh diode 27 and the eighth diode 28 are electrically connected. The positive terminal of the eighth diode 28 is electrically connected to the first terminal of the second capacitor 31 through the second resistor 32. The second terminal of the second capacitor 31 is electrically connected to the positive terminal of the seventh diode 27. The positive terminal of the eighth diode 28 is also electrically connected to the second terminal of the second transistor 33. The positive terminal of the eighth diode 28 is also electrically connected to the negative terminal of the ninth diode 29. The positive terminal of the ninth diode 29 is also electrically connected to the positive terminal of the sixth diode 26. The negative terminal of the seventh diode 27 is the second terminal of the second sub-switch structure 17. In this embodiment, the second sub-switch structure includes a sixth diode, a seventh diode, an eighth diode, a ninth diode, a tenth diode, a second capacitor, a second resistor, and a second transistor, further ensuring that the energy of the short-circuit current flowing through the second sub-switch structure can be consumed by the second sub-switch structure as much as possible.

[0045] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 4 This is a hardware structure block diagram of a mobile terminal for a control method of a current-limiting DC circuit breaker according to an embodiment of the present invention. Figure 4 As shown, a mobile terminal may include one or more ( Figure 4 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 4 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 4 The more or fewer components shown, or having the same Figure 4 The different configurations shown.

[0046] The memory 104 can be used to store computer programs, such as software programs of application software and modules, for example, a computer program corresponding to the control method of the current-limiting DC circuit breaker in the embodiments of the present application. The processor 102 can execute various functional applications and data processing, i.e., implement the above method, by running the computer program stored in the memory 104. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include memories remotely arranged with respect to the processor 102, which can be connected to the mobile terminal through a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific examples of the above network can include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0047] In the embodiments, a control method of a current-limiting DC circuit breaker running on a mobile terminal, a computer terminal or a similar computing device is also provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0048] Figure 5 is a flowchart of the control method of the current-limiting DC circuit breaker according to the embodiments of the present application. As shown in Figure 5 , the method includes the following steps:

[0049] In step S201, in the case that a short-circuit current is received at the first end of the inductor, the mechanical switch is controlled to be closed, and a first level signal is sent to the control end of the thyristor, so that the thyristor is turned on.

[0050] In step S202, in the case that a positive charge is stored at the first end of the pre-charge capacitor, the mechanical switch is controlled to be opened, and a second level signal is sent to the control end of the power electronic switch structure, so that the power electronic switch structure is turned on.

[0051] Through the above embodiment, firstly, in the case that the short-circuit current is received at the first end of the inductor, the mechanical switch is controlled to be closed, and the first level signal is sent to the control end of the thyristor to make the thyristor conductive, and then in the case that the positive charge is stored at the first end of the pre-charging capacitor, the mechanical switch is controlled to be opened, and the second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure conductive. Compared with the problem that the direct current power grid is prone to collapse due to the difficulty in limiting the short-circuit current when the short-circuit fault occurs in the direct current power grid in the prior art, in the case that the short-circuit fault occurs in the direct current power grid, the mechanical switch is controlled to be closed, and the first level signal is sent to the control end of the thyristor to make the thyristor conductive, and since the positive charge is stored at the second end of the pre-charging capacitor, the pre-charging capacitor will discharge to magnetize the inductor in the opposite direction, so that the original inductor current is reduced and reversed, at this time, the short-circuit current flows to the load through the thyristor, the pre-charging capacitor and the mechanical switch, so that part of the energy of the short-circuit current is consumed, and the capacitor voltage opposite to the pre-charging voltage is established on the pre-charging capacitor (i.e. the positive charge is stored at the first end of the pre-charging capacitor), at this time, the mechanical switch is controlled to be opened, and the second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure conductive, so that the short-circuit current flows to the load from the power electronic switch structure, so that the energy of the short-circuit current is further consumed, thereby the short-circuit current is quickly and effectively limited, and the probability of collapse of the direct current power grid is ensured to be small.

[0052] Specifically, in the case that the direct current power grid is normally flowing (i.e. no short-circuit fault occurs), the mechanical switch is controlled to be closed, at this time, the thyristor and the power electronic switch structure are not conductive, and the current flows to the load through the inductor and the mechanical switch.

[0053] In an optional solution, after the second level signal is sent to the control end of the power electronic switch structure, the method further comprises: in the case that the power electronic switch structure is conductive for a predetermined time length, the second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure be turned off, so that a pulse voltage is generated at the moment when the power electronic switch structure is turned off, and the pulse voltage is greater than or equal to the turn-on voltage of the nonlinear resistor. In the embodiment, in the case that the power electronic switch structure is conductive for a predetermined time length, the second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure be turned off, a pulse voltage greater than or equal to the turn-on voltage of the nonlinear resistor is generated at the moment when the power electronic switch structure is turned off, so that the nonlinear resistor is turned on, thereby the short-circuit current flows to the load through the nonlinear resistor, so that the residual energy of the short-circuit current is further consumed, the short-circuit current is further limited, and the probability of collapse of the direct current power grid is further ensured to be small.

[0054] Specifically, in the case that the power electronic switch structure is turned on for the predetermined time length, at this time, the mechanical switch has been opened to the rated opening distance so that the mechanical switch is turned off.

[0055] In actual application, the predetermined time length can be set according to experience value by the person skilled in the art, or can be obtained through multiple experiments, and the present application does not make specific limitation.

[0056] In order to enable the person skilled in the art to understand the technical solutions of the present application more clearly, the implementation process of the control method of the current limiting DC circuit breaker will be described in detail below in combination with specific embodiments.

[0057] The present embodiment relates to a specific control method of a current limiting DC circuit breaker, comprising the following steps:

[0058] Step S1: in the case that the first end of the inductor does not receive the short-circuit current, the mechanical switch is controlled to be closed;

[0059] Step S2: in the case that the first end of the inductor receives the short-circuit current, a first level signal is sent to the control end of the thyristor, so that the thyristor is turned on;

[0060] Step S3: in the case that the first end of the pre-charge capacitor stores a positive charge, the mechanical switch is controlled to be turned off, and a second level signal is sent to the control end of the power electronic switch structure, so that the power electronic switch structure is turned on;

[0061] Step S4: in the case that the power electronic switch structure is turned on for a predetermined time length, the second level signal is sent to the control end of the power electronic switch structure, so that the power electronic switch structure is turned off, so that the power electronic switch structure generates a pulse voltage at the moment of turning off, and the pulse voltage is greater than or equal to the turn-on voltage of the nonlinear resistance.

[0062] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0063] The embodiment of the present application provides a current limiting DC circuit breaking device, comprising: any one of the above-mentioned current limiting DC circuit breaker; a controller comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise a program for executing the control method of the current limiting DC circuit breaker.

[0064] Specifically, the control method of the current limiting DC circuit breaker comprises:

[0065] Step S201, in the case of receiving a short-circuit current at the first end of the inductor, the mechanical switch is controlled to be closed, and a first level signal is sent to the control end of the thyristor, so that the thyristor is turned on;

[0066] Step S202, in the case of storing a positive charge at the first end of the pre-charge capacitor, the mechanical switch is controlled to be opened, and a second level signal is sent to the control end of the power electronic switch structure, so that the power electronic switch structure is turned on.

[0067] Optionally, after sending the second level signal to the control end of the power electronic switch structure, the method further comprises: in the case of turning on the power electronic switch structure for a predetermined time, sending the second level signal to the control end of the power electronic switch structure, so that the power electronic switch structure is turned off, so that the power electronic switch structure generates a pulse voltage at the moment of turning off, and the pulse voltage is greater than or equal to the turn-on voltage of the nonlinear resistor.

[0068] The embodiment of the present application provides a current-limited DC circuit breaking system, which comprises: a DC power grid; any one of the current-limited DC circuit breakers, wherein the first end of the current-limited DC circuit breaker is electrically connected with the DC power grid; and a load, wherein the load is electrically connected with the second end of the current-limited DC circuit breaker.

[0069] In the above embodiment, the current-limiting DC circuit breaking system includes a DC power grid, a current-limiting DC circuit breaker, and a load. The current-limiting DC circuit breaker includes an inductor, a mechanical switch, a thyristor, a pre-charge capacitor, and a power electronic switch structure. A first end of the inductor is electrically connected to the DC power grid. A first end of the mechanical switch is electrically connected to a second end of the inductor. A second end of the mechanical switch is electrically connected to the load. A first end of the thyristor is electrically connected to the first end of the inductor. A control end of the thyristor is configured to receive a first-level signal. The first-level signal is configured to turn on the thyristor in the case of a short-circuit current output by the DC power grid. A first end of the pre-charge capacitor is electrically connected to a second end of the thyristor. A second end of the pre-charge capacitor is electrically connected to the second end of the inductor. The second end of the pre-charge capacitor stores a positive charge. A first end of the power electronic switch structure is electrically connected to the first end of the inductor. A second end of the power electronic switch structure is electrically connected to the second end of the mechanical switch. A control end of the power electronic switch structure is configured to receive a second-level signal. The second-level signal is configured to turn on the power electronic switch structure in the case that the first end of the pre-charge capacitor stores the positive charge. Compared with the prior art, in the case of normal current flow of the DC power grid, the current normally flows through the inductor and the mechanical switch to the load. In the case of a short-circuit fault of the DC power grid, the thyristor is turned on. Because the second end of the pre-charge capacitor stores the positive charge, the pre-charge capacitor discharges and magnetizes the inductor in the opposite direction, so that the original inductor current decreases and reverses. At this time, the short-circuit current flows through the thyristor, the pre-charge capacitor, and the mechanical switch to the load, so that part of the energy of the short-circuit current is consumed. A capacitor voltage opposite to a pre-charge voltage is established on the pre-charge capacitor (i.e., the first end of the pre-charge capacitor stores the positive charge). At this time, the mechanical switch is turned off, and the power electronic switch structure is turned on, so that the short-circuit current flows from the power electronic switch structure to the load, so that the energy of the short-circuit current is further consumed, thereby quickly and effectively limiting the short-circuit current and ensuring that the probability of collapse of the DC power grid is small.

[0070] Specifically, the load includes household, commercial, and industrial electrical loads, such as lighting, televisions, refrigerators, air conditioners, and the like.

[0071] It should be apparent to those skilled in the art that the modules or steps of the application described above can be implemented with a general purpose computer, and can be centralized in a single computer or distributed among a network of computers, and can be implemented with program code executable by a computer, and thus can be stored in a storage device and executed by a computer, and in some cases, the steps shown or described can be executed in a different order than shown or described, or can be implemented as separate integrated circuit modules or as a single integrated circuit module, and thus the application is not limited to any particular combination of hardware and software.

[0072] Those skilled in the art will appreciate that embodiments of the application can be devised for a method, a system, or a computer program product. Accordingly, the application can be embodied in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can be in the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk memory, CD-ROMs, optical storage media, etc.) embodying computer readable program code.

[0073] The present application is described herein with reference to the flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0074] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams. Figure 1 one or more functions specified in the flowchart illustrations and / or block diagrams.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart illustrations and / or block diagrams.Figure 1 one or more processes and / or functions specified in one or more blocks Figure 1 one or more processes and / or functions specified in one or more blocks

[0076] In one typical arrangement, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0077] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) and / or cache memory, non-volatile memory, such as read-only memory (ROM), EPROM, and / or flash memory, etc. The memory is an example of computer readable media.

[0078] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disc read-only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0079] It should also be noted that the terms "comprising", "containing", or any other variant thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0080] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0081] 1) In the current-limiting DC circuit breaker of the application, the current-limiting DC circuit breaker comprises an inductor, a mechanical switch, a thyristor, a pre-charge capacitor and a power electronic switch structure, wherein the first end of the inductor is used for electrical connection with a DC power grid, the first end of the mechanical switch is electrically connected with the second end of the inductor, the second end of the mechanical switch is used for electrical connection with a load, the first end of the thyristor is electrically connected with the first end of the inductor, the control end of the thyristor is used for receiving a first-level signal, the first-level signal is used for turning on the thyristor in the case of short-circuit current output by the DC power grid, the first end of the pre-charge capacitor is electrically connected with the second end of the thyristor, the second end of the pre-charge capacitor is electrically connected with the second end of the inductor, the second end of the pre-charge capacitor stores a positive charge, the first end of the power electronic switch structure is electrically connected with the first end of the inductor, the second end of the power electronic switch structure is electrically connected with the second end of the mechanical switch, and the control end of the power electronic switch structure is used for receiving a second-level signal, the second-level signal is used for turning on the power electronic switch structure in the case that the first end of the pre-charge capacitor stores a positive charge. Compared with the problem that it is difficult to limit the short-circuit current when the DC power grid has a short-circuit fault in the prior art, in the case of normal current flow of the DC power grid, the current normally flows through the inductor and the mechanical switch to the load, and the thyristor is turned on in the case of short-circuit fault of the DC power grid. Since the second end of the pre-charge capacitor stores a positive charge, the pre-charge capacitor will discharge and magnetize the inductor in the opposite direction, so that the original inductor current decreases and reverses. At this time, the short-circuit current flows through the thyristor, the pre-charge capacitor and the mechanical switch to the load, so that part of the energy of the short-circuit current is consumed, and a capacitor voltage opposite to the pre-charge voltage (i.e. the first end of the pre-charge capacitor stores a positive charge) is established on the pre-charge capacitor. At this time, the mechanical switch is turned off, and the power electronic switch structure is turned on, so that the short-circuit current flows from the power electronic switch structure to the load, so that the energy of the short-circuit current is further consumed, thereby quickly and effectively limiting the short-circuit current, and ensuring that the probability of collapse of the DC power grid is small.

[0082] 2) In the control method of the current-limiting DC circuit breaker, firstly, in the case that the short-circuit current is received at the first end of the inductor, the mechanical switch is controlled to be closed, and a first level signal is sent to the control end of the thyristor to make the thyristor conductive, then in the case that the positive charge is stored at the first end of the pre-charging capacitor, the mechanical switch is controlled to be opened, and a second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure conductive. Compared with the problem that the short-circuit current is difficult to limit when the short-circuit fault occurs in the DC power grid in the prior art, which leads to the collapse of the DC power grid, in the application, when the short-circuit fault occurs in the DC power grid, the mechanical switch is controlled to be closed, and a first level signal is sent to the control end of the thyristor to make the thyristor conductive, because the positive charge is stored at the second end of the pre-charging capacitor, the pre-charging capacitor will discharge and magnetize the inductor in the opposite direction, so that the original inductor current decreases and reverses, at this time, the short-circuit current flows to the load through the thyristor, the pre-charging capacitor and the mechanical switch, so that part of the energy of the short-circuit current is consumed, and the capacitor voltage opposite to the pre-charging voltage is established on the pre-charging capacitor (i.e. the positive charge is stored at the first end of the pre-charging capacitor), at this time, the mechanical switch is controlled to be opened, and a second level signal is sent to the control end of the power electronic switch structure to make the power electronic switch structure conductive, so that the short-circuit current flows to the load from the power electronic switch structure, so that the energy of the short-circuit current is further consumed, thereby the short-circuit current is quickly and effectively limited, and the probability of the collapse of the DC power grid is small.

[0083] 3) In the current-limiting DC circuit breaking system of the application, the current-limiting DC circuit breaking system comprises a DC power grid, a current-limiting DC circuit breaker, and a load, wherein the current-limiting DC circuit breaker comprises an inductor, a mechanical switch, a thyristor, a pre-charge capacitor, and a power electronic switch structure, wherein a first end of the inductor is configured to be electrically connected with the DC power grid, a first end of the mechanical switch is electrically connected with a second end of the inductor, a second end of the mechanical switch is configured to be electrically connected with the load, a first end of the thyristor is electrically connected with the first end of the inductor, a control end of the thyristor is configured to receive a first level signal, the first level signal is configured to turn on the thyristor in the case of a short-circuit current output by the DC power grid, a first end of the pre-charge capacitor is electrically connected with a second end of the thyristor, a second end of the pre-charge capacitor is electrically connected with the second end of the inductor, the second end of the pre-charge capacitor stores a positive charge, a first end of the power electronic switch structure is electrically connected with the first end of the inductor, a second end of the power electronic switch structure is electrically connected with the second end of the mechanical switch, and a control end of the power electronic switch structure is configured to receive a second level signal, the second level signal is configured to turn on the power electronic switch structure in the case that the first end of the pre-charge capacitor stores the positive charge. Compared with the problem that the DC power grid is prone to collapse due to the difficulty in limiting the short-circuit current when a short-circuit fault occurs in the DC power grid in the prior art, in the case of normal current flow of the DC power grid, the current normally flows through the inductor and the mechanical switch to the load, and the thyristor is turned on in the case of a short-circuit fault of the DC power grid. Since the second end of the pre-charge capacitor stores a positive charge, the pre-charge capacitor will discharge and magnetize the inductor in the opposite direction, so that the original inductor current decreases and reverses. At this time, the short-circuit current flows through the thyristor, the pre-charge capacitor, and the mechanical switch to the load, so that part of the energy of the short-circuit current is consumed, and a capacitor voltage opposite to the pre-charge voltage (i.e., the positive charge is stored at the first end of the pre-charge capacitor) is established on the pre-charge capacitor. At this time, the mechanical switch is turned off, and the power electronic switch structure is turned on, so that the short-circuit current flows from the power electronic switch structure to the load, so that the energy of the short-circuit current is further consumed, thereby quickly and effectively limiting the short-circuit current and ensuring that the probability of collapse of the DC power grid is small.

[0084] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A current-limiting DC circuit breaker, characterized in that, include: An inductor, wherein the first end of the inductor is used for electrical connection to a DC power grid; A mechanical switch, wherein a first end of the mechanical switch is electrically connected to a second end of the inductor, and the second end of the mechanical switch is used for electrical connection to a load; A thyristor, wherein the first end of the thyristor is electrically connected to the first end of the inductor, and the control end of the thyristor is used to receive a first level signal, which is used to turn on the thyristor when the DC power grid outputs a short-circuit current; A pre-charged capacitor, wherein a first terminal of the pre-charged capacitor is electrically connected to a second terminal of the thyristor, and a second terminal of the pre-charged capacitor is electrically connected to a second terminal of the inductor, and the second terminal of the pre-charged capacitor stores a positive charge; A power electronic switch structure, wherein a first end of the power electronic switch structure is electrically connected to a first end of an inductor, a second end of the power electronic switch structure is electrically connected to a second end of a mechanical switch, and a control end of the power electronic switch structure is used to receive a second level signal, the second level signal being used to turn on the power electronic switch structure when a positive charge is stored at the first end of the pre-charge capacitor; A nonlinear resistor is included, with its first terminal electrically connected to the first terminal of the inductor and its second terminal electrically connected to the second terminal of the mechanical switch. The second level signal is further used to turn off the power electronic switch structure after it has been turned on for a predetermined duration, so that the power electronic switch structure generates a pulse voltage at the moment of turn-off. This pulse voltage is greater than or equal to the on-state voltage of the nonlinear resistor. The power electronic switch structure includes: The first sub-switch structure has a first end that is the first end of the power electronic switch structure, and the control end of the first sub-switch structure is used to receive the second level signal. The second sub-switch structure has a first terminal electrically connected to the second terminal of the first sub-switch structure, and the second terminal of the second sub-switch structure is the second terminal of the power electronic switch structure. The control terminal of the second sub-switch structure is used to receive the second level signal. The first sub-switch structure includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a first capacitor, a first resistor, and a first transistor. The anode of the first diode is the first terminal of the first sub-switch structure. The cathode of the first diode is electrically connected to the first terminal of the first transistor. The cathode of the first diode is also electrically connected to the cathode of the fifth diode. The anode of the fifth diode is electrically connected to the second terminal of the first transistor. The cathode of the first diode is also electrically connected to the anode of the second diode. The cathode of the second diode is electrically connected to the cathode of the third diode. The anode of the third diode is electrically connected to the first terminal of the first capacitor through the first resistor. The second terminal of the first capacitor is electrically connected to the anode of the second diode. The anode of the third diode is also electrically connected to the second terminal of the first transistor. The anode of the third diode is also electrically connected to the cathode of the fourth diode. The anode of the fourth diode is also electrically connected to the anode of the first diode. The cathode of the second diode is the second terminal of the first sub-switch structure.

2. The current-limiting DC circuit breaker according to claim 1, characterized in that, The nonlinear resistor includes a metal oxide varistor.

3. The current-limiting DC circuit breaker according to claim 1, characterized in that, The second sub-switch structure includes a sixth diode, a seventh diode, an eighth diode, a ninth diode, a tenth diode, a second capacitor, a second resistor, and a second transistor. The anode of the sixth diode is the first terminal of the second sub-switch structure. The cathode of the sixth diode is electrically connected to the first terminal of the second transistor. The cathode of the sixth diode is also electrically connected to the cathode of the tenth diode. The anode of the tenth diode is electrically connected to the second terminal of the second transistor. The cathode of the sixth diode is also electrically connected to the anode of the seventh diode. The cathode of the seventh diode is electrically connected to the cathode of the eighth diode. The anode of the eighth diode is electrically connected to the first terminal of the second capacitor through the second resistor. The second terminal of the second capacitor is electrically connected to the anode of the seventh diode. The anode of the eighth diode is also electrically connected to the second terminal of the second transistor. The anode of the eighth diode is also electrically connected to the cathode of the ninth diode. The anode of the ninth diode is also electrically connected to the anode of the sixth diode. The cathode of the seventh diode is the second terminal of the second sub-switch structure.

4. A control method for a current-limiting DC circuit breaker according to any one of claims 1 to 3, characterized in that, The method includes: When a short-circuit current is received at the first end of the inductor, the mechanical switch is closed and a first level signal is sent to the control terminal of the thyristor, so that the thyristor is turned on. When a positive charge is stored at the first end of the pre-charge capacitor, the mechanical switch is controlled to open, and a second level signal is sent to the control terminal of the power electronic switch structure, so that the power electronic switch structure is turned on.

5. The control method for a current-limiting DC circuit breaker according to claim 4, characterized in that, After sending a second-level signal to the control terminal of the power electronic switch structure, the method further includes: When the power electronic switch structure is turned on for a predetermined duration, the second level signal is sent to the control terminal of the power electronic switch structure to turn off the power electronic switch structure, so that the power electronic switch structure generates a pulse voltage at the moment of turn-off, and the pulse voltage is greater than or equal to the on-state voltage of the nonlinear resistor.

6. A current-limiting DC circuit breaker, characterized in that, include: The current-limiting DC circuit breaker according to any one of claims 1 to 3; The controller includes: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include a control method for performing the current-limiting DC circuit breaker as described in claim 4 or 5.

7. A current-limiting DC circuit breaker system, characterized in that, include: DC power grid; The current-limiting DC circuit breaker according to any one of claims 1 to 3, wherein the first terminal of the current-limiting DC circuit breaker is electrically connected to the DC power grid; The load is electrically connected to the second terminal of the current-limiting DC circuit breaker.

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